No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Genome-Wide CpG Island Profiling of Intraductal Papillary Mucinous Neoplasms of the Pancreas
Abstract
Intraductal papillary mucinous neoplasms (IPMN) are precursors to infiltrating pancreatic ductal adenocarcinomas. Widespread epigenetic alterations are characteristic of many cancers, yet few studies have systematically analyzed epigenetic alterations of neoplastic precursors. Our goal was to conduct genome-wide CpG island methylation profiling to identify aberrantly methylated loci in IPMNs.
We compared the CpG island methylation profiles of six IPMNs to normal primary pancreatic duct samples using methylation CpG island amplification (MCA) and Agilent CpG island microarray (MCAM) analysis. When selected 13 genes identified as differentially methylated by MCAM for methylation-specific PCR (MSP) analysis in an independent set of IPMNs and normal pancreas samples and conducted expression analysis of selected genes.
We identified 2,259 loci as differentially methylated in at least one of six IPMNs including 245 genes hypermethylated in IPMNs with high-grade dysplasia compared with normal pancreatic duct samples. Eleven of 13 genes evaluated by MSP were more commonly methylated in 61 IPMNs than in 43 normal pancreas samples. Several genes (BNIP3, PTCHD2, SOX17, NXPH1, EBF3) were significantly more likely to be methylated in IPMNs with high-grade than with low-grade dysplasia. One gene, SOX17, showed loss of protein expression by immunohistochemistry in 22% (19 of 88) of IPMNs. The most specific marker, BNIP3, was not methylated in any IPMNs with low-grade dysplasia or in normal pancreas samples.
IPMNs undergo extensive aberrant CpG island hypermethylation. The detection of genes selectively methylated in high-grade IPMNs such as BNIP3 may have use in the clinical evaluation of IPMNs.
... At a tissue level, i.e., resected specimens, cyst fluid, and pancreatic juice, methylation-based markers have previously been investigated for IPMN stratification [17][18][19][20][21][22][23][24]. Some of the studies utilized methylation status of tumor suppressor genes (WWOX, SMAD4, and CDO1 genes) [17,23] or markers related to mucinous lineage (such as GNAS, MUC family) [19,24]. ...
... Some of the studies utilized methylation status of tumor suppressor genes (WWOX, SMAD4, and CDO1 genes) [17,23] or markers related to mucinous lineage (such as GNAS, MUC family) [19,24]. Similar to our study, the investigators used a multigene approach to enhance diagnostic accuracy [20,22]. However, advanced neoplasia was often compared to heterogeneous controls, including cysts with low/ no malignant potential (pseudocysts, serous cystadenomas) or normal pancreatic tissue admixed with IPMN-LGD. ...
... However, advanced neoplasia was often compared to heterogeneous controls, including cysts with low/ no malignant potential (pseudocysts, serous cystadenomas) or normal pancreatic tissue admixed with IPMN-LGD. The inclusion of normal tissue and nonprecancerous lesions in control might have decreased the threshold of diagnostic performance and spurious elevation of AUCs [20,22]. Utilization of only IPMN-LGD as controls caters to a more specific question of malignant stratification of IPMNs. ...
Background
Intraductal papillary mucinous neoplasms (IPMNs), a type of cystic pancreatic cancer (PC) precursors, are increasingly identified on cross-sectional imaging and present a significant diagnostic challenge. While surgical resection of IPMN-related advanced neoplasia, i.e., IPMN-related high-grade dysplasia or PC, is an essential early PC detection strategy, resection is not recommended for IPMN-low-grade dysplasia (LGD) due to minimal risk of carcinogenesis, and significant procedural risks. Based on their promising results in prior validation studies targeting early detection of classical PC, DNA hypermethylation-based markers may serve as a biomarker for malignant risk stratification of IPMNs. This study investigates our DNA methylation-based PC biomarker panel (ADAMTS1, BNC1, and CACNA1G genes) in differentiating IPMN-advanced neoplasia from IPMN-LGDs.
Methods
Our previously described genome-wide pharmaco-epigenetic method identified multiple genes as potential targets for PC detection. The combination was further optimized and validated for early detection of classical PC in previous case–control studies. These promising genes were evaluated among micro-dissected IPMN tissue (IPMN-LGD: 35, IPMN-advanced neoplasia: 35) through Methylation-Specific PCR. The discriminant capacity of individual and combination of genes were delineated through Receiver Operating Characteristics curve analysis.
Results
As compared to IPMN-LGDs, IPMN-advanced neoplasia had higher hypermethylation frequency of candidate genes: ADAMTS1 (60% vs. 14%), BNC1 (66% vs. 3%), and CACGNA1G (25% vs. 0%). We observed Area Under Curve (AUC) values of 0.73 for ADAMTS1, 0.81 for BNC1, and 0.63 for CACNA1G genes. The combination of the BNC1/ CACNA1G genes resulted in an AUC of 0.84, sensitivity of 71%, and specificity of 97%. Combining the methylation status of the BNC1/CACNA1G genes, blood-based CA19-9, and IPMN lesion size enhanced the AUC to 0.92.
Conclusion
DNA-methylation based biomarkers have shown a high diagnostic specificity and moderate sensitivity for differentiating IPMN-advanced neoplasia from LGDs. Addition of specific methylation targets can improve the accuracy of the methylation biomarker panel and enable the development of noninvasive IPMN stratification biomarkers.
... One class of molecular alteration that becomes increasingly prevalent as precancerous lesions progress toward invasive cancer is aberrant DNA methylation (34). Aberrant methylation of numerous genes occurs during pancreatic tumorigenesis (35)(36)(37)(38)(39)(40)(41) including during the development and progression of IPMN (35,(42)(43)(44)(45). In this study, we evaluated the diagnostic utility of pancreatic cyst fluid methylated gene markers for their ability to predict the presence of high-grade dysplasia/invasive carcinoma in pancreatic cystic neoplasms. ...
... One class of molecular alteration that becomes increasingly prevalent as precancerous lesions progress toward invasive cancer is aberrant DNA methylation (34). Aberrant methylation of numerous genes occurs during pancreatic tumorigenesis (35)(36)(37)(38)(39)(40)(41) including during the development and progression of IPMN (35,(42)(43)(44)(45). In this study, we evaluated the diagnostic utility of pancreatic cyst fluid methylated gene markers for their ability to predict the presence of high-grade dysplasia/invasive carcinoma in pancreatic cystic neoplasms. ...
... We previously reported the results of a study aimed at identifying differentially methylated genes in IPMN versus normal pancreas (35). This previous study utilized methylated CpG island amplification and Agilent 244K Human promoter chip-on-chip microarrays and identified 245 commonly hypermethylated genes in IPMN with HGD including SOX17, BNIP3, PTCHD2, SLIT2, EYA4, and SFRP1 (35). ...
Purpose:
Pancreatic cysts are common and pose diagnostic and management challenges. Pancreatic cyst fluid markers have the potential to aid in the management of cysts with concerning imaging findings. Our aim was to evaluate cyst fluid methylated DNA markers for their accuracy for predicting the histologic grade of neoplastic pancreatic cysts.
Experimental design:
Pancreatic cyst fluid samples from 183 patients (29 discovery, 154 validation) aspirated after surgical resection were analyzed for methylated DNA at selected genes (SOX17, BNIP3, FOXE1, PTCHD2, SLIT2, EYA4 and SFRP1) using methylation-specific droplet-digital PCR (dd-QMSP). Methylated DNA levels were evaluated for their accuracy at predicting the grade of dysplasia of the pancreatic cyst.
Results:
All six markers evaluated in the validation set could accurately distinguish high-risk cystic neoplasms (with high-grade dysplasia and/or associated invasive cancer) from low-risk cysts (lower grades of dysplasia) with accuracies from 79.8 to 83.6%. Methylated SOX17 had the highest overall accuracy as a single marker (sensitivity, 78.4%; specificity, 85.6%; accuracy 83.6%, cut-off; 25 methylated DNA molecules/μL cyst fluid). The best four-gene combination had 84.3% sensitivity, 89.4% specificity and 88.0% accuracy at distinguishing cysts with high-grade dysplasia and/or invasive cancer from those without. All six markers were independent predictors of having invasive cancer/high-grade dysplasia after adjusting for clinical/imaging factors known to be associated with grade of dysplasia. The combination of methylated SOX17 with cytology better predicted neoplastic grade than cytology alone.
Conclusion:
A panel of methylated gene markers quantified by dd-QMSP can be used to predict the grade of dysplasia of pancreatic cysts.
... The authors used sensitive methylation-specific PCR (MSP) to detect the altered CpG island methylation and suggested that this may translate well into a future early diagnosis test. Subsequent work using combinations of MSP with microarrays and laser capture microdissection has defined specific hypermethylation and hypomethylation changes not only in pancreatic cancers, but also in PanINs and IPMNs [35][36][37][38][39]. An interesting and consistent observation across multiple studies has also been that the magnitude of changes in methylation correlates with the level of dysplasia in the lesions. ...
... Along with more comprehensive identification of assay targets, the sample collection methods and inclusion of appropriate control populations has also evolved. The initial proof of dysregulated methylation was performed using directly biopsied or resected tumor specimens and cell lines [34,35,[37][38][39]. Early clinical development and validation was done through collection of hormone-stimulated secretion of pancreatic juice [36,41,47]. ...
Pancreatic cancer is a molecularly heterogeneous disease. Epigenetic changes and epigenetic regulatory mechanisms underlie at least some of this heterogeneity and contribute to the evolution of aggressive tumor biology in patients and the tumor’s intrinsic resistance to therapy. Here we review our current understanding of epigenetic dysregulation in pancreatic cancer and how it is contributing to our efforts in early diagnosis, predictive and prognostic biomarker development and new therapeutic approaches in this deadly cancer.
... The patterns of DNA methylation in IPMNs have also been described [76][77][78][79]. Targeted and whole genome analyses have revealed distinct patterns of methylation in IPMNs compared to normal ducts, and some genes, including BNIP3, CDO1, EBF3, NXPH1, PTCHD2, and SOX17, have been reported to be more commonly methylated in high-grade IPMNs than in low-grade IPMNs [79,80]. ...
... The patterns of DNA methylation in IPMNs have also been described [76][77][78][79]. Targeted and whole genome analyses have revealed distinct patterns of methylation in IPMNs compared to normal ducts, and some genes, including BNIP3, CDO1, EBF3, NXPH1, PTCHD2, and SOX17, have been reported to be more commonly methylated in high-grade IPMNs than in low-grade IPMNs [79,80]. Future studies may exploit whole genome methylation profiles to refine IPMN subtyping and classification, as is currently the practice for brain tumor classification and as is emerging for pancreatic neuroendocrine tumors [81]. ...
Background
Intraductal papillary mucinous neoplasms (IPMNs) represent a unique opportunity to treat and prevent a curable neoplasm before it has the chance to progress to incurable cancer. This prospect, however, has to be balanced with the real risk of over treating patients with lesions that would, in fact, never progress during the life of the patient.PurposeInformed clinical decisions in the treatment of IPMNs are first and foremost based on a deep understanding of the pathology of these lesions.Conclusions
Here we review the pathology of IPMNs, with an emphasis on the clinical relevance of the important features that characterize these lesions.
... ppENK and p16 hypermethylation were more common in high-grade IPMN than in low-grade IPMN, and the average number of methylated loci was higher in high-grade than low-grade IPMN [113]. In another study, high-grade IPMNs had a higher number of hypermethylated genes than low-grade IPMNs [114]. The genes BNIP3, PTCHD2, SOX17, NXPH1, and EBF3 were more likely to be hypermethylated in IPMN with high-grade dysplasia than with lowgrade dysplasia or normal tissue [114]. ...
... In another study, high-grade IPMNs had a higher number of hypermethylated genes than low-grade IPMNs [114]. The genes BNIP3, PTCHD2, SOX17, NXPH1, and EBF3 were more likely to be hypermethylated in IPMN with high-grade dysplasia than with lowgrade dysplasia or normal tissue [114]. Studies testing serum-based cell-free DNA promoter hypermethylation as a marker of pancreatic cancer have been limited by small power, and no studies have been performed using this in IPMN [115]. ...
This book incorporates a multi-disciplinary approach to present how research results can be translated into clinical trials. The first part begins with a chapter on variants of pancreatic cancer, precursor lesions and groups of people at risk to developing the disease. There is a particular focus on intraductal papillary mucinous neoplasia as a large-scale clinical challenge in pancreatology. The next two parts focus on diagnosis, biomarkers and stratification that emphasize how various approaches to biomarker development are important as both prognostic and predictive tools. The final part consists of personalized treatment approaches that include preclinical models of pancreatic cancer and stromal, epigenetic and metabolism targeting as promising approaches to be translated into early phase clinical trials. Chapters within this part also deal with approaches that are close to being implemented in clinical practice or are already being tested in (early) clinical trials, such as those that targeting the immune systems and strategies to overcome immunotherapy resistance; phase 1 clinical trials and translational approaches in surgical treatment.
Written by experts in their fields, Translational Pancreatic Cancer Research provides an outlook towards future directions by integrating information both from basic and clinical research and though demonstrating pathways to better understanding pancreatic cancer and current approaches to translating these into clinical practice.
... In IPMN, hypermethylation is evident in more than 80% of cases (49) and more frequently in genes with wellcharacterized functions in tumor suppression -p16, APC, E-cadherin, MLH1, and MGMT (50). The number of methylated genes is higher in high-grade lesions (51) and more genes have been reported with a significant difference between lower and higher grade lesions such as TFPI-2, BNIP3, and PTCHD2, among others (28,51,52). Henceforth the evaluation of methylated DNA in pancreatic juice could be useful for pre-surgical evaluation of non-invasive and invasive lesions (49). ...
... In IPMN, hypermethylation is evident in more than 80% of cases (49) and more frequently in genes with wellcharacterized functions in tumor suppression -p16, APC, E-cadherin, MLH1, and MGMT (50). The number of methylated genes is higher in high-grade lesions (51) and more genes have been reported with a significant difference between lower and higher grade lesions such as TFPI-2, BNIP3, and PTCHD2, among others (28,51,52). Henceforth the evaluation of methylated DNA in pancreatic juice could be useful for pre-surgical evaluation of non-invasive and invasive lesions (49). ...
Intraductal papillary mucinous neoplasm (IPMN) of the pancreas are pre neoplastic lesions defined by the World Health Organization as a grossly visible intraductal epithelial neoplasm that arises in the pancreatic ductal system, composed of mucin producing cells. The predisposing factor for their development as well as genetics are still largely unknown. Pathologists have a pivotal role in IPMN management since features like IPMN subtype, degree of atypia, margins status and presence or absence of an invasive component imply different patient management. In this article, we perform a review of the pathological features and molecular markers of IPMNs.
... DNA methylation can alter the DNA chromatin structure and can lead to the silencing of tumor suppressor genes or activation of oncogenes [7,8]. Many of these changes occur early in tumorigenesis, making epigenetic modifications a promising target as biomarkers for the early detection of cancer [9][10][11][12]. DNA methylation changes occur early in cancer formation for many cancer types including colorectal [13], breast [14], and pancreas [10][11][12]15] and that methylation changes can be potent biomarkers for early detection [16][17][18]. ...
... Many of these changes occur early in tumorigenesis, making epigenetic modifications a promising target as biomarkers for the early detection of cancer [9][10][11][12]. DNA methylation changes occur early in cancer formation for many cancer types including colorectal [13], breast [14], and pancreas [10][11][12]15] and that methylation changes can be potent biomarkers for early detection [16][17][18]. The recent FDA approval of methylation biomarkers for colorectal cancer (Colo-guard®, Epi proColon®) as well as bladder cancer (Exact Sciences Inc.) serves as a blueprint for taking these biomarkers to patient care. ...
Background:
Despite improvements in cancer management, most pancreatic cancers are still diagnosed at an advanced stage. We have recently identified promoter DNA methylation of the genes ADAMTS1 and BNC1 as potential blood biomarkers of pancreas cancer. In this study, we validate this biomarker panel in peripheral cell-free tumor DNA of patients with pancreatic cancer.
Results:
Sensitivity and specificity for each gene are as follows: ADAMTS1 87.2% and 95.8% (AUC = 0.91; 95% CI 0.71-0.86) and BNC1 64.1% and 93.7% (AUC = 0.79; 95% CI 0.63-0.78). When using methylation of either gene as a combination panel, sensitivity increases to 97.3% and specificity to 91.6% (AUC = 0.95; 95% CI 0.77-0.90). Adding pre-operative CA 19-9 values to the combined two-gene methylation panel did not improve sensitivity. Methylation of ADAMTS1 was found to be positive in 87.5% (7/8) of stage I, 77.8% (7/9) of stage IIA, and 90% (18/20) of stage IIB disease. Similarly, BNC1 was positive in 62.5% (5/8) of stage I patients, 55.6% (5/9) of stage IIA, and 65% (13/20) of patients with stage IIB disease. The two-gene panel (ADAMTS1 and/or BNC1) was positive in 100% (8/8) of stage I, 88.9% (8/9) of stage IIA, and 100% (20/20) of stage IIB disease. The sensitivity and specificity of the two-gene panel for localized pancreatic cancer (stages I and II), where the cancer is eligible for surgical resection with curative potential, was 94.8% and 91.6% respectively. Additionally, the two-gene panel exhibited an AUC of 0.95 (95% CI 0.90-0.98) compared to 57.1% for CA 19-9 alone.
Conclusion:
The methylation status of ADAMTS1 and BNC1 in cfDNA shows promise for detecting pancreatic cancer during the early stages when curative resection of the tumor is still possible. This minimally invasive blood-based biomarker panel could be used as a promising tool for diagnosis and screening in a select subset of high-risk populations.
... It is at these sites where methylation functions to either prohibit the proper binding of transcription factors or to facilitate the binding of repressor proteins [62,63]. Previous work using methylation specific polymerase chain reaction (PCR) has identified hundreds of CpG island sites housed within the genome of IPMNs that are differentially methylated with respect to normal pancreatic ductal tissue, as well as methylation sites that are specific to high-grade lesions [64,65]. Such findings suggest that aberrant DNA methylation plays an essential role in the malignant progression of IPMNs. ...
Purpose of review:
As abdominal imaging becomes more sensitive and regularly used, pancreatic cystic lesions (PCLs) are being diagnosed more frequently. A small but clinically significant minority of these lesions have a predisposition to either harbor malignancy or undergo malignant transformation. This review highlights the current state and performance of cystic fluid biomarkers and how they may be incorporated into management.
Recent findings:
Among the major domains of molecular testing for PCLs, DNA based analyses have demonstrated the highest accuracy in identifying cyst type and have the most data to support their clinical use. However, epigenetic and protein biomarker based molecular assessments have emerged with the potential to complement DNA based approaches. In addition, recent studies have increasingly demonstrated the value associated with combinations of mutations and other biomarkers in identifying higher grade mucinous cystic lesions. We present the performance of individual biomarkers in cyst fluid analysis with an emphasis on an algorithmic approach to improve the accurate identification of both cyst type and risk of malignant transformation.
... Furthermore, the average number of methylated loci was found to be significantly increased in high-grade IPMNs vs. low grade IPMNs. CpG island methylation profiles between IPMNs and normal primary pancreatic duct samples revealed that IPMN undergoes extensive CpG hypermethylation [26]. Moreover, many of the aberrantly methylated genes are also aberrantly methylated in pancreatic cancer. ...
Simple Summary
Intraductal papillary mucinous neoplasms (IPMN) are benign pancreatic cysts found in the ducts of the pancreas that have the potential to become malignant. Identifying IPMNs that have high potential to become pancreatic cancer may help prevent unnecessary surgery which is the definitive treatment of IPMNs. Currently, the management of IPMNs are dependent on variable factors including characteristics of the cyst, size of the pancreatic duct, and the presence or absence of obstructive jaundice. Identifying potential biomarkers may help more accurately distinguish high risk IPMNs from low risk IPMNs that do not need surgical intervention. This review summarized the various changes within IPMNs that promotes their progression to pancreatic adenocarcinoma. In addition, this review highlighted potential biomarkers that can distinguish IPMNs that have a high risk of becoming cancerous.
Abstract
Intraductal papillary mucinous neoplasms (IPMN) have the potential to progress to pancreatic ductal adenocarcinoma (PDAC). As with any progression to malignancy, there are a variety of genetic and metabolic changes, as well as other disruptions to the cellular microenvironment including immune alterations and inflammation, that can contribute to tumorigenesis. Previous studies further characterized these alterations, revealing changes in lipid and glucose metabolism, and signaling pathways that mediate the progression of IPMN to PDAC. With the increased diagnosis of IPMNs and pancreatic cysts on imaging, the opportunity to attenuate risk with the removal of high-risk lesions is possible with the understanding of what factors accelerate malignant progression and how they can be clinically utilized to determine the level of dysplasia and stratify the risk of progression. Here, we reviewed the genetic, metabolic, inflammatory, and immunologic pathways regulating the progression of IPMN to PDAC.
... Additional aberrant CpG island methylation patterns have been found more frequently in branch duct IPMNs with high-grade dysplasia than low-grade dysplasia, including in BNIP3, PTCHD2, SOX17, NXPH1, and EBF3 by both genome-wide screens and individual methylation sequencing. Interestingly BNIP3 methylation was not identified in any branch duct IPMNs with low-grade dysplasia [43]. ...
Pancreatic cancer is one of the most lethal human cancers. Early detection and diagnosis of precursor lesions for pancreatic malignancy is essential to improve the morbidity and mortality associated with this diagnosis. Of the cystic precursor lesions, branch duct intraductal papillary mucinous neoplasm (IPMN) is the most frequently identified lesion and has a wide range of malignant potential. Currently, Carcinogenic embryonic antigen (CEA) levels in the cyst fluid and cytology are the two most often utilized tools to diagnose these lesions; however, their diagnostic and risk stratification capabilities are somewhat limited. Within the last decade, the use of endoscopic ultrasound-guided fine-needle aspiration has opened the door for molecular analysis of cystic fluid as an option to enhance both the diagnosis and risk stratification of these lesions. The first step is to differentiate branch duct IPMNs from other lesions. KRAS and GNAS alterations have been shown to be accurate markers for this purpose. Following cyst type identification, mutational analysis, telomere fusion, microRNAs, long non-coding RNA, and DNA methylation have been identified as potential targets for stratifying malignant potential using the cystic fluid. In this review, we will examine the various targets of cyst fluid molecular analysis and their utility in the diagnosis and risk stratification of branch duct IPMNs.
... However, little is known about the molecular basis of the link between such environmental risk factors and PDAC. Also, although previous studies have characterized genome-wide methylation patterns in precancerous pancreatic lesions, identifying genes with distinct methylation patterns [34,35], the change in hydroxymethylation levels in these neoplasms has not been fully investigated. In this study, we hypothesized that aberrant expression of TET1 and subsequent global downregulation or upregulation of 5hmC occur early in human pancreatic tumorigenesis. ...
Epigenetic alterations are increasingly recognized as important contributors to the development and progression of pancreatic ductal adenocarcinoma (PDAC). 5‐hydroxymethylcytosine (5hmC) is an epigenetic DNA mark generated through the ten‐eleven translocation (TET) enzyme‐mediated pathway and is closely linked to gene activation. However, the timing of alterations in epigenetic regulation in the progression of pancreatic neoplasia is not well understood. In this study, we hypothesized that aberrant expression of ten‐eleven translocation methylcytosine dioxygenase 1 (TET1) and subsequent global 5hmC alteration are linked to early tumorigenesis in the pancreas. Therefore, we evaluated alterations of 5hmC and TET1 levels using immunohistochemistry in pancreatic neoplasms (n = 380) and normal ducts (n = 118). The study cohort included representation of the full spectrum of precancerous lesions from low‐ and high‐grade pancreatic intraepithelial neoplasia (PanINs, n = 95), intraductal papillary mucinous neoplasms (IPMNs, all subtypes, n = 129), intraductal oncocytic papillary neoplasms (IOPNs, n = 12), and mucinous cystic neoplasms (MCNs, n = 144). 5hmC and TET1 were significantly downregulated in all types of precancerous lesions and associated invasive PDACs compared with normal ductal epithelium (all P < 0.001), and expression of 5hmC positively correlated with expression of TET1. Importantly, downregulation of both 5hmC and TET1 was observed in most low‐grade precancerous lesions. There were no clear associations between 5hmC levels and clinicopathological factors, thereby suggesting a common epigenetic abnormality across precancerous lesions. We conclude that downregulation of 5hmC and TET1 is an early event in pancreatic tumorigenesis.
This article is protected by copyright. All rights reserved.
... Changes in DNA methylation often occur at early stages of tumorigenesis [15]. This has been confirmed for bladder [16], breast [17], colorectal [18], and lung cancers [19,20], as well as for pre-neoplastic lesions of the pancreas [21][22][23][24]. ...
Pancreatic ductal adenocarcinoma (PDAC) is among the most lethal cancer types world-wide. Its high mortality is related to the difficulty in the diagnosis, which often occurs when the disease is already advanced. As of today, no early diagnostic tests are available, while only a limited number of prognostic tests have reached clinical practice. The main reason is the lack of reliable biomarkers that are able to capture the early development or the progression of the disease. Hence, the discovery of biomarkers for early diagnosis or prognosis of PDAC remains, de facto, an unmet need. An increasing number of studies has shown that cell-free DNA (cfDNA) methylation analysis represents a promising non-invasive approach for the discovery of biomarkers with diagnostic or prognostic potential. In particular, cfDNA methylation could be utilized for the identification of disease-specific signatures in pre-neoplastic lesions or chronic pancreatitis (CP), representing a sensitive and non-invasive method of early diagnosis of PDAC. In this review, we will discuss the advantages and pitfalls of cfDNA methylation studies. Further, we will present the current advances in the discovery of pancreatic cancer biomarkers with early diagnostic or prognostic potential, focusing on pancreas-specific (e.g., CUX2 or REG1A) or abnormal (e.g., ADAMTS1 or BNC1) cfDNA methylation signatures in high risk pre-neoplastic conditions and PDAC.
... En outre, d'autres études ont mis en évidence des hyperméthylations des gènes CDKN2A (protéine p16) et SOX17. Ces hyperméthylations sont associés à une augmentation de la dysplasie (Hong et al., 2012). ...
Le facteur de transcription homéotique CDX2 est spécifiquement exprimé dans l’épithélium intestinal où il maintient l’identité, contrôle l’homéostasie et exerce une fonction suppresseur de tumeurs. Chez l’homme, une expression ectopique (hors de l’intestin) de CDX2 peut survenir, dans les métaplasies intestinales d’organes digestifs, considérées comme pré-cancéreuses. Ce travail de thèse visait à étudier les conséquences physiopathologiques de l’expression ectopique de CDX2. Nous avons développé et validé un modèle murin d’induction conditionnelle de CDX2 dans plusieurs organes digestifs. Nos résultats montrent que cette expression est dépendante du contexte cellulaire, et induit des métaplasies intestinales seulement dans l’estomac et le pancréas. Ces métaplasies n’évoluent pas spontanément en cancer. Cependant, CDX2 sensibilise ces lésions métaplasiques à l’apparition de tumeurs intestinales dans l’estomac placé dans un contexte où le gène Apc est muté. Globalement, ces résultats montrent que CDX2 est essentiel au développement de métaplasies intestinales mais n’exercerait pas de fonction oncogénique en situation ectopique.
... In regard to DNA methylation, Hong et al. performed CpG island amplification followed by microarray analysis to compare the methylation status of IPMN with normal pancreatic ductal epithelium in resected tissue specimens [63]. They found differential methylation in 2259 genetic regions and identified a series of genes including BNIP3, PTCHD2, SOX17, NXPH1, and EBF3 that were characteristically hypermethylated in IPMN with high-grade compared to low-grade dysplasia. ...
Purpose:
Predicting the biologic behavior of intraductal papillary mucinous neoplasm (IPMN) remains challenging. Current guidelines utilize patient symptoms and imaging characteristics to determine appropriate surgical candidates. However, the majority of resected cysts remain low-risk lesions, many of which may be feasible to have under surveillance. We herein characterize the most promising and up-to-date molecular diagnostics in order to identify optimal components of a molecular signature to distinguish levels of IPMN dysplasia.
Methods:
A comprehensive systematic review of pertinent literature, including our own experience, was conducted based on the PRISMA guidelines.
Results:
Molecular diagnostics in IPMN patient tissue, duodenal secretions, cyst fluid, saliva, and serum were evaluated and organized into the following categories: oncogenes, tumor suppressor genes, glycoproteins, markers of the immune response, proteomics, DNA/RNA mutations, and next-generation sequencing/microRNA. Specific targets in each of these categories, and in aggregate, were identified by their ability to both characterize a cyst as an IPMN and determine the level of cyst dysplasia.
Conclusions:
Combining molecular signatures with clinical and imaging features in this era of next-generation sequencing and advanced computational analysis will enable enhanced sensitivity and specificity of current models to predict the biologic behavior of IPMN.
... Significantly, the mismatch repair genes MutL homolog 1 (hMLH1) and O 6 -alkylguanine DNA alkyltransferase (MGMT) are found more frequently methylated in the higher grade IPMNs than in lower grade IPMNs (64). We should mention that, in the adenocarcinomas associated with IPMN, hypermethylation involving three or more promoter regions is found in 55% of the samples, while, in non-invasive IPMNs, 20% of the samples are found methylated in at three or more gene promoters (65). It is assumable that the pancreatic juice can be analyzed concerning the methylated DNA in order to differentiate the invasive from non-invasive IPMNs before surgery. ...
Intraductal papillary mucinous neoplasms (IPMNs) are presumed to evolve from low-grade dysplasia to high-grade dysplasia to invasive carcinoma. Resection of lesions before the development of pancreatic cancer may prevent the development of an incurable process as, once IPMNs progress to invasive cancer, the prognosis may be as poor as resected conventional pancreatic ductal adenocarcinoma. Resection of IPMNs, particularly in the setting of high-grade dysplasia, is presumed to provide a survival benefit. IPMNs also present many challenges as the identification of high-grade dysplasia and early invasive carcinoma and the timing and frequency of malignant progression are not yet established. The limited predictive accuracy presents a challenge as pancreatic resection is associated with a risk of substantial morbidity and mortality; 20-30% and 2-4%, respectively. Diagnostic armamentarium contains pancreas-protocol computed tomography (CT) scan, gadolinium-enhanced magnetic resonance imaging (MRI) with or without magnetic resonance cholangiopancreatography (MRCP) and endoscopic ultrasound (EUS). The most promising method is endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) as this technique allows analysis of cyst fluid using biomarkers. Until now, in clinical practice, we utilize two biomarkers, carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9); however, DNA analysis of pancreatic cystic fluid and genomic analysis could offer new tools to the diagnosis and administration of IPMNs. Novel genomic and serum biomarkers could play an important future role to identify those individuals who will benefit from an early operation and those who will benefit from watchful waiting approach. More prospective studies are needed.
... It has been suggested that tests designed to detect aberrant methylation could be useful approaches to the early detection of pancreatic neoplasia because many methylation events appear to occur early in the development of pancreatic neoplasia. 22,23 The expression of a number of microRNAs is also altered in PC and its precursors, and again, it has been suggested that these alterations could form the basis for the early detection of pancreatic neoplasia. [24][25][26] All of these changes in gene expression ultimately are associated with changes in protein expression, and these alterations in protein expression can form a foundation for a rational basis for chemoprevention and early detection. ...
Pancreatic cancer is the fourth leading cause of cancer related deaths in the United States with a 5-year survival rate of less than 10%. The Division of Cancer Prevention of the National Cancer Institute sponsored the Pancreatic Cancer Chemoprevention Translational Workshop on September 10 to 11, 2015. The goal of the workshop was to obtain information regarding the current state of the science and future scientific areas that should be prioritized for pancreatic cancer prevention research, including early detection and intervention for high-risk precancerous lesions. The workshop addressed the molecular/genetic landscape of pancreatic cancer and precursor lesions, high-risk populations and criteria to identify a high-risk population for potential chemoprevention trials, identification of chemopreventative/immunopreventative agents, and use of potential biomarkers and imaging for assessing short-term efficacy of a preventative agent. The field of chemoprevention for pancreatic cancer is emerging, and this workshop was organized to begin to address these important issues and promote multi-institutional efforts in this area. The meeting participants recommended the development of an National Cancer Institute working group to coordinate efforts, provide a framework, and identify opportunities for chemoprevention of pancreatic cancer.
... This altered gene function arises from both gene silencing associated with aberrant hypermethylation of promoter CpG islands and induction of gene expression associated with gene hypomethylation. DNA methylation abnormalities are thought to contribute to pancreatic cancer development and progression [4][5][6][7][8][9][10][11][12][13]. Several strategies have been used to identify differentially methylated genes in pancreatic cancers including analysis of expression changes after DNA methylation inhibition, array-based methods, and methylome sequencing [5,6,10,11,14,15]. ...
The methylation status of a promoter influences gene expression and aberrant methylation during tumor development has important functional consequences for pancreatic and other cancers. Using methylated CpG island amplification and promoter microarrays, we identified ANK1 as hypomethylated in pancreatic cancers. Expression analysis determined ANK1 as commonly overexpressed in pancreatic cancers relative to normal pancreas. ANK1 was co-expressed with miR-486 in pancreatic cancer cells. Stable knockdown of ANK1 in the pancreatic cancer cell line AsPC1 led to changes in cell morphology, and decreases in colony formation. Stable knockdown of ANK1 also marked reduced the growth of tumors in athymic nude mice. Among patients undergoing pancreaticoduodenectomy, those with pancreatic cancers expressing ANK1 had a poorer prognosis than those without ANK1 expression. These findings indicate a role for ANK1 overexpression in mediating pancreatic cancer tumorigenicity.
... This is in line with the observation that second, independent cancers occur at higher rates in patients who have survived a primary cancer than in a cancer-naive population (18,19). Previous reports suggested some common genetic or epigenetic risk factors in patients with IPMN and EPMs, such as field carcinogenesis, KRAS, TP53, and MUC2 mutations (1,8,(20)(21)(22), but the cause of frequent development of EPMs in patients with IPMN (or vice-versa) is unknown. ...
Intraductal papillary mucinous neoplasm (IPMN) has been associated with a high incidence of extrapancreatic
malignancies (EPMs). However, it is controversial whether IPMN is prognostic for EPM. We aimed to help clarify the issue studying this association in patients with histologically proven IPMN. We reviewed 51surgically resected IPMNs in Saitama Medical Center, Jichi Medical University between January 1991 and June 2012. Mean follow-up was 63.7±47.8 months. The observed EPM incidence was compared with the expected incidence of cancer in Japan. Of the 51 IPMNs, 14 were malignant and the rest benign. Seventeen EPM developed in 15 patients (29.4%), nine of which occurred prior to IPMN diagnosis. For all IPMNs, the standardized incidence ratio (SIR) was significantly increased for the six types of reported EPMs (SIR=2.18, CI=1.31-3.42, P=0.004). Benign IPMNs showed no association with EPMs (SIR=0.92, CI=0.43-1,76, P=0.87). In contrast, malignant IPMNs showed a higher association (SIR=3.83, CI=1.87-7.03, P=0.0009). However, the association was mostly due to the prior EPMs, as removal of metachronous EPMs had no significant effect (SIR=3.63, CI=1.59-7.17, P=0.005). Thus, only malignant IPMNs drive the significant association with prior EPMs, showing a near 4-fold increased incidence compared to the general Japanese population. Histological characterization of IPMNs may offer clinical value for EPM patient management. We hypothesize that these observations may be explained if some patients with EPMs present a higher risk to develop IPMNs (and vice versa), possibly resulting from an uncharacterized multiple cancer predisposition condition.
... In another study by Wu et al [49] , cyst fluid GNAS mutations were detected exclusively in IPMNs and not in any other mucinous, non-mucinous or malignant pancreatic cysts. Hong and associates identified hypermethylation of several genes including BNIP3, PTCHD2, SOX17, NXPH1 and EBF3 in cyst fluid from IPMNs with high-grade dysplasia [50] . In a study comparing the miRNome of low-grade and highgrade pancreatic cystic neoplasms, thirteen miRNAs (miR-138, miR-195, miR-204, miR-216a, miR-217, miR-218, miR-802, miR-155, miR-214, miR-26a, miR-30b, miR-31, and miR-125) were differentially enriched in cyst fluid samples from patients with PDAC [42] . ...
Pancreatic cancer is usually diagnosed at an advanced stage and curative resection is feasible in only a small minority of patients at the time of diagnosis. Diagnosis at an early stage is unequivocally associated with better long-term survival. Several candidate molecular markers for early detection are currently under investigation in different phases of discovery and validation. Recent advances in the technology for whole genome, methylome, ribonucleome, and proteome interrogation has enabled rapid advancements in the field of biomarker discovery. In this review we discuss the current status of molecular markers for detection of pancreatic cancer in blood, pancreatic cyst fluid, pancreatic juice and stool and briefly highlight some promising preliminary results of new approaches that have the potential of advancing this field in the near future.
... Loss of expression of tumor suppressor genes, including p16/ CDKN2, CDKN1C and ppENK, due to hypermethylation, is seen at a greater rate in IPMN compared with PDAC, with increasing number of hypermethylated loci with higher grades of IPMN dysplasia. 99,100 Evolving data suggests a role for microRNA (miRNA), small noncoding RNA molecules that function in the post-transcription regulation of gene expression in the pathogenesis of IPMN. Certain miRNAs, including miR-155, -21, and -122, have been reported to be upregulated in most noninvasive IPMN, with increased overexpression in high-grade IPMNs. ...
Cystic neoplasms of the pancreas are found with increasing prevalence, especially in elderly asymptomatic individuals. Although the overall risk of malignancy is very low, the presence of these pancreatic cysts is associated with a large degree of anxiety and further medical investigation due to concerns about malignancy. This review discusses the different cystic neoplasms of the pancreas and reports diagnostic strategies based on clinical features and imaging data. Surgical and nonsurgical management of the most common cystic neoplasms, based on the recently revised Sendai guidelines, is also discussed, with special reference to intraductal papillary mucinous neoplasm (IPMN; particularly the branch duct variant), which is the lesion most frequently identified incidentally. IPMN pathology, its risk for development into pancreatic ductal adenocarcinoma, the pros and cons of current guidelines for management, and the potential role of endoscopic ultrasound in determining cancer risk are discussed. Finally, surgical treatment, strategies for surveillance of pancreatic cysts, and possible future directions are discussed.
... Significantly more genes are methylated in IPMNs with high-grade dysplasia than in IPMNs with lowgrade dysplasia. Moreover, some genes may be selectively methylated in high-grade lesions, which may be useful in the clinical management of IPMNs (32,76,77). MicroRNAs are also aberrantly expressed in IPMNs (78). ...
Pancreatic cancer is a devastating disease. At time of diagnosis the disease is usually advanced and only a minority of patients are eligible for surgical resection. The overall 5-year survival is 6%. However, survival of patients with early stage pancreatic cancer is significantly better. To improve the prognosis of patients with pancreatic cancer, it is essential to diagnose and treat pancreatic cancer in the earliest stage. Prevention of pancreatic cancer by treating noninvasive precursor lesions just before they invade tissues can potentially lead to even better outcomes. Pancreatic carcinogenesis results from a stepwise progression in which accumulating genetic alterations drive neoplastic progression in well-defined precursor lesions, ultimately giving rise to an invasive adenocarcinoma. A thorough understanding of the genetic changes that drive pancreatic carcinogenesis can lead to identification of biomarkers for early detection and targets for therapy. Recent next-generation sequencing (NGS) studies have shed new light on our understanding of the natural history of pancreatic cancer and the precursor lesions that give rise to these cancers. Importantly, there is a significant window of opportunity for early detection and treatment between the first genetic alteration in a cell in the pancreas and development of full-blown pancreatic cancer. The current views on the pathology and genetics of pancreatic carcinogenesis that evolved from studies of pancreatic cancer and its precursor lesions are discussed in this review.
... 16,76,80,82 Although both GNAS 16,76,82 and performed CpG island amplification followed by microarray analysis to compare the methylation status in IPMNs with normal pancreatic ductal epithelium. 86 They found differential methylation in 2,259 genetic regions, and identified a series of genes including BNIP3, PTCHD2, SOX17, NXPH1, and EBF3, which were characteristically hypermethylated in IPMNs with high-grade compared with low-grade dysplasia. ...
... Five-year survival of pediatric AML varies from 15% -70%, relapse rate varies from 33% -78%, and its incidence is expected to increase. Hypermethylation of EBF3 has been reported in patients with rheumatoid arthritis [33], gastric carcinoma [26], head and neck squamous cell carcinoma [34], and neoplasms of the pancreas [35]. In this study, we found that the EBF3 promoter was hypermethylated in pediatric AML. ...
Background
Pediatric acute myeloid leukemia (AML) comprises up to 20% of all childhood leukemia. Recent research shows that aberrant DNA methylation patterning may play a role in leukemogenesis. The epigenetic silencing of the EBF3 locus is very frequent in glioblastoma. However, the expression profiles and molecular function of EBF3 in pediatric AML is still unclear.Methods
Twelve human acute leukemia cell lines, 105 pediatric AML samples and 30 normal bone marrow/idiopathic thrombocytopenic purpura (NBM/ITP) control samples were analyzed. Transcriptional level of EBF3 was evaluated by semi-quantitative and real-time PCR. EBF3 methylation status was determined by methylation specific PCR (MSP) and bisulfite genomic sequencing (BGS). The molecular mechanism of EBF3 was investigated by apoptosis assays and PCR array analysis.Results EBF3 promoter was hypermethylated in 10/12 leukemia cell lines. Aberrant EBF3 methylation was observed in 42.9% (45/105) of the pediatric AML samples using MSP analysis, and the BGS results confirmed promoter methylation. EBF3 expression was decreased in the AML samples compared with control. Methylated samples revealed similar survival outcomes by Kaplan-Meier survival analysis. EBF3 overexpression significantly inhibited cell proliferation and increased apoptosis. Real-time PCR array analysis revealed 93 dysregulated genes possibly implicated in the apoptosis of EBF3-induced AML cells.Conclusion
In this study, we firstly identified epigenetic inactivation of EBF3 in both AML cell lines and pediatric AML samples for the first time. Our findings also showed for the first time that transcriptional overexpression of EBF3 could inhibit proliferation and induce apoptosis in AML cells. We identified 93 dysregulated apoptosis-related genes in EBF3-overexpressing, including DCC, AIFM2 and DAPK1. Most of these genes have never been related with EBF3 over expression. These results may provide new insights into the molecular mechanism of EBF3-induced apoptosis; however, further research will be required to determine the underlying details.Our findings suggest that EBF3 may act as a putative tumor suppressor gene in pediatric AML.
... Hong and coauthors 86 performed CpG island amplification followed by microarray analysis to compare the methylation status in IPMNs with normal pancreatic ductal epithelium. 86 They found differential methylation in 2,259 genetic regions, and identified a series of genes including BNIP3, PTCHD2, SOX17, NXPH1, and EBF3, which were characteristically hypermethylated in IPMNs with high-grade compared with low-grade dysplasia. ...
The recognition of pancreatic cysts and intraductal papillary mucinous neoplasms of the pancreas (IPMN) has increased largely secondary to greater utilization of high-quality cross-sectional abdominal imaging.1, 2 Although the general characteristics of IPMNs, radiographic diagnosis, cyst fluid composition, and their delineation from other pancreatic tumors have been well established, several issues regarding their growth and progression into malignancy remain poorly described. The degree of neoplastic transformation within IPMN is highly variable, from those with an entirely innocuous cell population typically resembling gastric epithelium and lacking any cytologic atypia, to those that have progressively increasing degrees of cytoarchitectural atypia. Though some patients with highly dysplastic and invasive IPMN may present with clinical symptoms or characteristic radiographic findings, including jaundice, an associated pancreatic mass, or main pancreatic duct dilation; increasingly IPMN are incidentally discovered. Once IPMN are radiographically diagnosed, there is currently no reliable way to determine the level of epithelial dysplasia or to predict the time frame of progression to high-grade dysplasia or cancer.3–6 A biologic marker of IPMNs is urgently needed – one that can be easily obtained and tested without significant morbidity for the patient.
An evidence-based expert meeting on pancreatic branch-duct IPMNs (BD-IMPN) was held in Verona, Italy and the authors reviewed the current role of existing technologies and molecular markers for predicting the biological behavior of IPMNs. The status of endoscopic ultrasound (EUS) and EUS-guided fine needle aspiration (FNA) cytology, cyst fluid biochemistry, mucins, cytokines, DNA, and microRNA profiles were critically reviewed by the group in order to identify the most promising clinically relevant biomarkers, and to target analyses for further development.
Endoscopic ultrasound
Endoscopic ultrasound (EUS) is a highly sensitive imaging modality for the evaluation of pancreatic cystic lesions that was developed as a diagnostic modality, but rapidly gained a role in IPMN for morphologic assessment and for its interventional capabilities, namely aspiration of cyst fluid and fine-needle aspiration (FNA). Diagnosis of IPMN based solely on EUS findings requires attention to cyst size, characteristics of the cyst wall, internal characteristics of the cyst, communication with the MPD, and the existence of any background lesions. Using EUS morphologic parameters, the sensitivity, specificity and accuracy to differentiate between benign and malignant, or potentially malignant, cystic lesions has been reported to be between 56%–91%, 45%–60% and 51%–72%, respectively7, 8 Although evaluation and the differential diagnosis of cystic lesions based solely on EUS morphology is feasible; inter-observer variability, operator dependency, and moderate diagnostic performance limit its accuracy without the addition of cyst fluid aspiration and FNA cytology, especially for determination of high-risk IPMN without overt malignant features.
Simple Summary
Pancreatic cysts are being identified with increasing frequency, and the prevalence increases with age to 10–25% by the 7th decade of life. They also have the potential for malignant transformation. The effective monitoring of the progression of pancreatic cysts and the early detection of pancreatic cancer is crucial. Here, we review recent advances in the molecular pathology of pancreatic cystic lesions and discuss how the revised tumorigenesis and progression model in an intraductal papillary mucinous neoplasm (IPMN) could provide insights into refining strategies for the risk stratification of pancreatic cysts and the early detection of cancer.
Abstract
The malignant progression of pancreatic cystic lesions (PCLs) remains understudied with a knowledge gap, yet its exploration is pivotal for effectively stratifying patient risk and detecting cancer at its earliest stages. Within this review, we delve into the latest discoveries on the molecular level, revealing insights into the IPMN molecular landscape and revised progression model, associated histologic subtypes, and the role of inflammation in the pathogenesis and malignant progression of IPMN. Low-grade PCLs, particularly IPMNs, can develop into high-grade lesions or invasive carcinoma, underscoring the need for long-term surveillance of these lesions if they are not resected. Although KRAS and GNAS remain the primary oncogenic drivers of neoplastic development in IPMNs, additional genes that are important in tumorigenesis have been recently identified by whole exome sequencing. A more complete understanding of the genes involved in the molecular progression of IPMN is critical for effective monitoring to minimize the risk of malignant progression. Complicating these strategies, IPMNs are also frequently multifocal and multiclonal, as demonstrated by comparative molecular analysis. Algorithms for preoperative cyst sampling and improved radiomic techniques are emerging to model this spatial and temporal genetic heterogeneity better. Here, we review the molecular pathology of PCLs, focusing on changes associated with malignant progression. Developing models of molecular risk stratification in PCLs which can complement radiologic and clinical features, facilitate the early detection of pancreatic cancer, and enable the development of more personalized surveillance and management strategies are summarized.
Brain Type Glycogen Phosphorylase (PYGB) has been revealed to participate in the progression of multiple human cancers. Nevertheless, the clinical significance and biological function of PYGB in pancreatic ductal adenocarcinoma (PAAD) remains unclarified. This study first analyzed the expression pattern, diagnostic value, and prognostic significance of PYGB in PAAD using the TCGA database. Subsequently, western blot assessed the protein expression of genes in PAAD cells. The viability, apoptosis, migration, and invasion of PAAD cells were assessed by CCK-8, TUNEL, and Transwell assays. Finally, in vivo experiment evaluated the effect of PYGB on PAAD tumor growth and metastasis. Through our investigation, it was revealed that PYGB had extremely high expression in PAAD and predicted a worse prognosis in patients with PAAD. Besides, the aggressiveness of PAAD cells could be suppressed or enhanced by depleting or supplementing PYGB. In addition, we demonstrated that METTL3 enhanced the translation of PYGB mRNA in an m6A-YTHDF1-dependent manner. Moreover, PYGB was revealed to regulate the malignant behaviors of PAAD cells by the mediation of the NF-κB signaling. Finally, PYGB depletion suppressed the growth and distant metastasis of PAAD in vivo. To conclude, our results indicated that METTL3-mediated m6A modification of PYGB exerted the tumor-promotive effect on PAAD through NF-κB signaling, suggesting PYGB is a potential therapeutic target in PAAD.
Pancreatic cyst fluid analysis can help diagnose pancreatic cyst type and the risk of high-grade dysplasia and cancer. Recent evidence from molecular analysis of cyst fluid has revolutionized the field with multiple markers showing promise in accurate diagnosis and prognostication of pancreatic cysts. The availability of multi-analyte panels has great potential for more accurate prediction of cancer.
Exome sequence analysis of patient tissues have identified specific mutations in intraductal papillary mucinous neoplasm (IPMN), such as GNAS and KLF4, suggesting that IPMN may have a distinctive progression pathway compared to pancreatic intraepithelial neoplastic lesion, a preneoplastic lesion of conventional pancreatic ductal adenocarcinoma (PDAC). Many topics remain to be resolved in IPMN, including the mechanism by which they imitate various gastrointestinal histologies, such as gastric or intestinal tissues. The biological differences among IPMN derived cancer, conventional PDAC, and IPMN concomitant cancer are an important issue.
Therefore, we have been elucidating the characteristics of IPMN with the hope of finding IPMN lineage specific therapeutic targets. To achieve this, we have established series of patient-derived organoids from IPMN and IPMN cancers, for which human models have been limited so far. This enabled us to thoroughly apply a wide range of cutting-edge genomic and epigenomic sequencing techniques in IPMN together with phenotyping their vulnerabilities. We discovered that IPMN lineages have distinct epigenomic profiles with characteristic addictive biological behaviors supported by MNX1-HNF1B axis, implying the feasibility of therapeutic implementation. We present the unique biology of IPMN with future research perspectives.
Background
Patients with pancreatobiliary tract cancer usually have a poor clinical outcome, with a 5-year overall survival rate below 20%. This is mainly associated with the late diagnosis. In addition, the standard-of-care for patients with malignant biliary stenosis involves a major surgery, the Whipple procedure. An accurate preoperative diagnosis, including differentiation from benign diseases, is critical to avoid unnecessary treatment. Here we developed BileScreen, a sensitive detection modality for the diagnosis of pancreatobiliary tract cancer based on massively parallel sequencing mutation and methylation changes in bile samples.
Methods
A total of 338 patients, from five hospitals in China, with pancreatobiliary system disorders were enrolled in this study between November 2018 and October 2020, and 259 were included for the analysis of BileScreen. We profiled 23 gene mutations and 44 genes with methylation modifications in parallel from bile samples, and set up a model for the detection of malignancy based on multi-level biomarkers.
Findings
We applied the BileScreen assay in a training cohort (n = 104) to set up the model and algorithm. The model was further evaluated in a validation cohort (n = 105), resulting in 92% sensitivity and 98% specificity. The performance of BileScreen was further assessed in a prospective test cohort (n = 50) of patients diagnosed with suspicious or negative pathology by endoscopic retrograde cholangiopancreatography and were confirmed in follow-up. BileScreen yielded 90% sensitivity and 80% specificity, and outcompeted serum carbohydrate antigen 19-9 in detecting pancreatobiliary tract cancer in all three cohorts, especially in terms of specificity.
Interpretation
Taken together, BileScreen has the ability to interrogate mutations and methylation changes in bile samples in parallel, thus rendering it a potentially sensitive detection method to help in the diagnosis of pancreatobiliary tract cancer in a safe, convenient and less-invasive manner.
Funding
This study was supported by the Capital's Funds for Health Improvement and Research (2020-2-4025 to S.H.), the National Natural Science Foundation of China (81972311 to H.Z.), CAMS Innovation Fund for Medical Sciences (CIFMS) (2017-12M-4-002 to H.Z.), the CAMS Innovation Fund for Medical Sciences(CIFMS) (2021-I2M-1-066 to CJQ), the Non-profit Central Research Institution Fund of Chinese Academy of Medical Sciences (2019PT310026 to H.Z.) and Sanming Project of Medicine in Shenzhen (SZSM202011010 to H.Z.).
Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest types of cancer worldwide. There are many reasons for this dismal prognosis, including the advanced stage at the time of diagnosis and the lack of effective therapeutic approaches. Intraductal papillary mucinous neoplasms (IPMNs) represent detectable and treatable precursor lesions of PDAC. Our understanding of the pathology of IPMNs has evolved over the past few decades, and new advances in diagnostic tools have emerged. The new World Health Organization (WHO) classification scheme now recognizes the previously considered variants of IPMNs, such as intraductal oncocytic papillary neoplasms (IOPNs) and intraductal tubulopapillary neoplasms (ITPNs), as distinct neoplasms. New imaging and molecular diagnostic tests are being developed to recognize these PDAC precursor lesions better. Here, we review the advances in diagnostic tools for IPMNs, IOPNs, and ITPNs, emphasizing the new (5th edition, 2019) WHO classification for pathological diagnosis, molecular markers, new laboratory tests, and imaging tools.
Background: Neuroblastoma (NB), the most common solid tumor in children, exhibits vastly different genomic abnormalities and clinical behaviors. While significant progress has been made on the research of relations between clinical manifestations and genetic abnormalities, it remains a major challenge to predict the prognosis of patients to facilitate personalized treatments.
Materials and Methods: Six data sets of gene expression and related clinical data were downloaded from the Gene Expression Omnibus (GEO) database, ArrayExpress database, and Therapeutically Applicable Research to Generate Effective Treatments (TARGET) database. According to the presence or absence of MYCN amplification, patients were divided into two groups. Differentially expressed genes (DEGs) were identified between the two groups. Enrichment analyses of these DEGs were performed to dig further into the molecular mechanism of NB. Stepwise Cox regression analyses were used to establish a five-gene prognostic signature whose predictive performance was further evaluated by external validation. Multivariate Cox regression analyses were used to explore independent prognostic factors for NB. The relevance of immunity was evaluated by using algorithms, and a nomogram was constructed.
Results: A five-gene signature comprising CPLX3, GDPD5, SPAG6, NXPH1, and AHI1 was established. The five-gene signature had good performance in predicting survival and was demonstrated to be superior to International Neuroblastoma Staging System (INSS) staging and the MYCN amplification status. Finally, a nomogram based on the five-gene signature was established, and its clinical efficacy was demonstrated.
Conclusion: Collectively, our study developed a novel five-gene signature and successfully built a prognostic nomogram that accurately predicted survival in NB. The findings presented here could help to stratify patients into subgroups and determine the optimal individualized therapy.
Pancreatic ductal adenocarcinoma (PDAC) is the most malignant form of gastrointestinal tumor and is the fourth leading cause of deaths due to cancer in Japan. This cancer shows a poor outcome due to the difficulty of its early diagnosis and its rapid growth. Once this disease becomes clinically evident, it is frequently accompanied by distant metastasis at the time of diagnosis. A recent multicenter study in Japan revealed that patients with the early stage of this disease (stage 0 and I) showed favorable prognosis after surgical resection, indicating the importance of early detection for improvement of PDAC prognosis. PDAC develops through a stepwise progression from the precursor lesion, and over the last few decades molecular analyses have shown the detailed genetic alterations that occur in this process. Since advances in molecular technologies have enabled the detection of genetic changes from a very small quantity of samples, a large number of non-invasive molecular approaches have been utilized in an attempt to find precursor or non-invasive carcinoma lesions. In this review, the current efforts in terms of the molecular approaches applied for the early detection of PDAC—especially using body fluids such as pancreatic juice, blood, and saliva—are summarized.
Purpose: With the increased utilization of cross-sectional imaging, pancreatic cystic lesions (PCL) are common incidental findings, detected in up to 20% of abdominal MRI scans in adults. While PCL, especially mucinous PCL, have the capacity to develop into invasive carcinoma, it is increasingly being recognized that their malignant potential is neither uniform nor certain. Indeed, while data from long-term cohorts of PCL have identified a small but ongoing risk to the development of carcinoma, this must be balanced against the increasing data demonstrating low yield and high potential morbidity of surgical intervention in elderly patients with non-worrisome PCL. Furthermore, ongoing surveillance of PCL of little or no risk represents a large cost and strain on healthcare systems. Current guidelines that rely on clinical and imaging criteria to stratify risk of malignancy while sensitive, are highly non-specific. Given the morbidity and mortality associated with pancreatic resections, there remains an unmet need for molecular tools to stratify high-risk/malignant from low-risk lesions.
Background
The prevalence of incidental pancreatic cystic neoplasms (PCNs) has increased dramatically with advancements in cross-sectional imaging. Diagnostic imaging is limited in differentiating between benign and malignant PCNs. The aim of this review is to provide an overview of biomarkers that can be used to distinguish PCNs.MethodsA review of the literature on molecular diagnosis of cystic neoplasms of the pancreas was performed.ResultsPancreatic cysts can be categorized into inflammatory and non-inflammatory lesions. Inflammatory cysts include pancreatic pseudocysts. Noninflammatory lesions include both mucinous and non-mucinous lesions. Mucinous lesions include intraductal papillary mucinous neoplasm (IPMN) and mucinous cystic neoplasm. Non-mucinous lesions include serous cystadenoma and solid-pseudopapillary tumor of the pancreas. Imaging, cyst aspiration, and histologic findings, as well as carcinoembryonic antigen and amylase are commonly used to distinguish between cyst types. However, molecular techniques to detect differences in genetic mutations, protein expression, glycoproteomics, and metabolomic profiling are important developments in distinguishing between cyst types.DiscussionNomograms incorporating common clinical, laboratory, and imaging findings have been developed in a better effort to predict malignant IPMN. The incorporation of top molecular biomarker candidates to nomograms may improve the predictive ability of current models to more accurately diagnose malignant PCNs.
An increasing number of patients are being referred to pancreatic centres around the world due to often incidentally discovered cystic neoplasms of the pancreas. The evaluation and management of pancreatic cystic neoplasms is a controversial topic and with existing guidelines based on a lack of strong evidence there is discordance between centres and guidelines with regard to when to offer surgery and when to favour surveillance. The frequency, duration and modality of surveillance is also controversial as this is resource-consuming and must be balanced against the perceived benefits and risks involved. While there is consensus that the risk of malignancy should be balanced against the life-expectancy and comorbidities, the indications for surgery and surveillance strategies vary among the guidelines. Thus, the tug of war between surveillance or resection continues. Here we discuss the recommendations from guidelines with further accumulating data and emerging reports on intraductal papillary mucinous neoplasm in the literature.
Pancreatico-biliary pathology includes a broad spectrum of neoplastic diseases, such as pancreatic ductal adenocarcinoma (PDACA) and its precursor lesions, cholangiocarcinoma (ChACA), neuroendocrine and acinar tumors, and solid pseudopapillary neoplasm (SPN). Differentiating these entities from one another may be challenging by morphologic analysis alone, especially when examining the small quantities of material inherent to cytologic specimens. Fortunately, the advent of next-generation sequencing (NGS) and other novel methods of genetic, epigenetic, and proteomic characterization has facilitated the development of a broad range of molecular and other ancillary techniques for diagnostic, prognostic, and predictive evaluation of pancreatico-biliary lesions. Ancillary studies are particularly important in the subset of cases for which cytomorphologic analysis provides a result that is equivocal or insufficient to guide clinical management. In some cases, clinical management requires that pathologists differentiate among several diagnostic entities. In others, pathologists must simply identify the presence of dysplasia or malignancy. Different ancillary tests provide pathologists with different information, and selection of the correct ancillary test may be critical for patient care. Ancillary tests typically have been validated separately for evaluation of specimens collected from solid lesions, cystic lesions, and pancreatic and bile duct strictures. This chapter discusses ancillary methods for the diagnosis of pancreatic ductal adenocarcinoma and cholangiocarcinoma in both fine needle aspiration biopsy and pancreatico-biliary duct fluid, washing, and brushing specimens. Ancillary studies for the diagnosis of other neoplasms are also discussed, as well as precursor lesions of pancreatic ductal adenocarcinoma.
Pancreatic ductal adenocarcinoma (PDAC) is an aggressive tumor and the fourth common cause of cancer death in the Western world. The lack of effective therapeutic strategies is attributed to the late diagnosis of this disease. Methylation markers could improve early detection and help in the surveillance of PDAC after treatment. Analysis of hypermethylation in the tumor tissue and tumor-derived exosomes might help to identify new therapeutic strategies and aid in the understanding of the pathophysiological changes occurring in pancreatic cancer. There are several methods for the detection of methylation events. Whereas methylation-specific PCR (MSP-PCR) is the method of choice, the cost reductions in DNA sequencing enables researchers to add bisulfite sequencing (BSS) to their repertoire if a small number of genes will be tested in a larger set of patients’ samples. During the last years, several techniques to isolate and analyze DNA methylation have been proposed, but DNA modification using sodium bisulfite is still the gold standard.
Cyst fluid biomarkers may be used to identify pancreatic cyst subtypes. Biomarkers are selected based on their ability to accurately distinguish mucinous from nonmucinous cysts and to risk stratify cysts based on malignant potential. Biomarkers of interest include but are not limited to amylase, oncogenes, DNA analysis, and epigenetic markers. The introduction of next-generation sequencing and molecular panels has aided in improved diagnostic accuracy and risk stratification. This review presents the diagnostic performance of currently available biomarkers and proposes an algorithm to incorporate their use in the diagnosis of pancreatic cysts.
This chapter provides an overview of the most common pancreatic cystic neoplasms, including management, especially focusing on branch duct intraductal papillary mucinous neoplasms (IPMNs) which likely represent a significant majority of cystic neoplasms of the pancreas (CNP), and the role of endoscopic ultrasound (EUS) in the diagnosis and management of the patient with an incidentally-discovered pancreatic cyst. Both mucinous cystic neoplasm of the pancreas (MCN) and IPMN typically have elevated cyst concentrations of carcinoembryonic antigen (CEA), which can be used to differentiate these lesions from macrocystic serous cystadenoma (SCA). Many cystic pancreatic endocrine neoplasms (CPEN) are indistinguishable from other pancreatic cystic neoplasms on preoperative computed tomography (CT) or magnetic resonance imaging (MRI). Surgical resection is the treatment of choice for symptomatic patients with cystic neoplasms of the pancreas and for those with incidentally-discovered tumors that are deemed to have a high likelihood of malignancy.
Die muzinös-zystischen Neoplasien und die intraduktalen papillär-muzinösen Neoplasien weisen eine morphologisch gut charakterisierte Adenom-Karzinom-Sequenz auf, welche dreistufig eingeteilt wird. Auf dem Boden der dysplastischen Veränderungen in MCN und IPMN entstehen meistens Karzinome vom duktalen Typ. Eine Ausnahme bildet die IPMN vom intestinalen Typ, die meistens mit einem muzinösen (kolloid) Karzinom assoziiert ist. Die meisten bekannten genetischen Veränderungen in MCN und IPMN sind identisch mit denen im duktalen Adenokarzinom, ausgenommen das GNAS-Gen, welches unter den Pankreastumoren ausschließlich in IPMN mutiert ist. Die vier IPMN-Subtypen unterscheiden sich histogenetisch und klinisch markant. Allerdings fehlt uns derzeit das Verständnis für die molekularen Mechanismen, die diesen phänotypischen Unterschieden zugrunde liegen.
Pancreatic ductal adenocarcinoma (PDAC) is an aggressive disease associated with a poor
prognosis and high morbidity. Early diagnosis and complete tumor removal are still the principal
factors extending life expectancy in PDAC patients. Here, the relationship of neurexophillin 1 (NXPH1) and NXPH2
expressions with clinicopathological parameters of PDAC was evaluated. Immunohistochemical
analysis of NXPH1 and NXPH2 was performed in one tissue microarray of 96 surgical specimens,
including normal pancreatic duct tissue (n = 5), PDACs at various stages of differentiation (n = 77),
and pancreatic neuroendocrine tumors (n = 14). The intensity of both NXPH1 and NXPH2 staining
was weak in only a small proportion of benign pancreatic ductal epithelial cells and was significantly
higher in most PDAC specimens than in non-neoplastic pancreatic tissue specimens. However,
no correlation of the expression of these PDAC biomarkers with tumor grades, T, N, and American Joint
Committee on Cancer (AJCC) pathologic stages was established. Contrary to our expectation, the immunohistochemical results of
NXPH1 and NXPH2 were inversely correlated with N stage in PDAC. NXPH1 and NXPH2 as PDAC
biomarkers may be used to identify patients with this tumor, help delineate appropriate surgical
margins, and identify lymph node metastasis in imaging studies.
Purpose:
Pancreatic cysts frequently pose clinical dilemmas. On one hand, cysts with high-grade dysplasia offer opportunities for cure, on the other hand, those with low-grade dysplasia are easily over treated. Cyst fluid markers have the potential to improve the evaluation of these cysts. Since telomerase activity is commonly activated in malignant cells, we evaluated the diagnostic performance of cyst fluid telomerase activity measurements for predicting histologic grade.
Experimental design:
Telomerase activity was measured using telomerase repeat amplification with digital-droplet PCR in surgically-aspirated cyst fluid samples from 219 patients who underwent pancreatic resection for a cystic lesion (184, discovery, 35 validation) and 36 patients who underwent endoscopic ultrasound fine needle aspiration. Methodological and clinical factors associated with telomerase activity were examined.
Results:
Telomerase activity was reduced in samples that had undergone prior thawing. Among 119 samples not previously thawed, surgical cyst fluids from cystic neoplasms with high-grade dysplasia +/- associated invasive cancer had higher telomerase activity (median [interquartile range], 1158 [295.9-13033] copies/μL of cyst fluid than those without (19.74 [2.58-233.6] copies/μL) (P < 0.001). Elevated cyst fluid telomerase activity had a diagnostic accuracy for invasive cancer/high-grade dysplasia of 88.1% (discovery), 88.6% (validation), and 88.2% (merged). Among cysts classified preoperatively as having "worrisome features", cyst fluid telomerase activity had high diagnostic performance (sensitivity 73.7%, specificity 90.6%, accuracy, 86.1%). In multivariate analysis, telomerase activity independently predicted the presence of invasive cancer/high-grade dysplasia.
Conclusion:
Cyst fluid telomerase activity can be a useful predictor of the neoplastic grade of pancreatic cysts.
Pancreatic cancer remains one of the deadliest malignancies. In addition to genetic alterations a wide variety of epigenetic aberrations have been identified in pancreatic neoplasms, some of them are thought to play an important role in neoplastic development and maintenance. Latest technologies are helping to better characterize cancer epigenomes. Efforts are underway to identify epigenetic alterations that would make optimal diagnostic markers and therapeutic targets. Recent comprehensive pancreatic cancer genome project found that pancreatic adenocarcinomas harbored 63 intragenic mutations or amplifications/homozygous deletions and these alterations clustered in 12 signaling pathways. In this chapter, we have discussed recent development in pancreatic cancer epigenetics and potential targets for future research and treatment.
Pancreatic cancer is the fourth leading cause of cancer-related death in the USA. Each year about 44,000 patients are newly diagnosed with pancreatic cancer in the USA. Most of these patients present with advanced disease and have a very poor prognosis.
Given this dismal prognosis, the challenge is to identify pancreatic cancer in an early stage or, better, patients at risk for pancreatic cancer before an incurable invasive carcinoma has developed. Several distinctive precursor lesions of pancreatic cancer are now known, which theoretically allows for detection of patients at risk of developing pancreatic cancer. These precursor lesions are the microscopic pancreatic intraepithelial neoplasia (PanIN) and the macroscopic cystic precursor lesions intraductal papillary mucinous neoplasia (IPMN), intraductal tubulopapillary neoplasm (ITPN), and mucinous cystic neoplasia/mucinous cystadenoma (MCN).
Insight in the molecular biology of pancreatic adenocarcinoma and these precursor lesions has substantially increased during the past decades. Accurate understanding of the successive molecular genetic alterations in these lesions may eventually lead to biomarkers that can predict biological behavior and guide treatment of patients at risk of invasive pancreatic cancer. This chapter reviews the clinical, diagnostic, and molecular genetic aspects of these pancreatic cancer precursor lesions.
Intraductal papillary mucinous neoplasms (IPMNs) of the pancreas are noninvasive neoplasms which occur in the main pancreatic duct or its major branches. IPMNs have an important meaning in the clinic and in research since they represent around 20% of all resected pancreatic neoplasms. Morphologically, branch duct, main duct and mixed-type IPMNs can be distinguished. Histologically, they can be divided into gastric, intestinal, pancreatobiliary and oncocytic type. There are different mutations in genes such as KRAS, GNAS, RNF43 and p53. The expression of miRNAs is specific to IPMNs; altogether, 14 miRNAs have been identified so far which are differently expressed in all IPMNs in contrast to normal pancreatic tissue. It has also been observed that methylation levels can be altered in IPMNs. This review summarizes the molecular characteristics of IPMNs of the pancreas and presents currently known markers.
This chapter provides an overview of the different molecular technologies being exploited to elucidate the mechanisms underlying pancreatic cancer, which is key to the development of novel diagnostic and prognostic biomarkers as well as the implementation of effective therapies. We also describe approaches developed for integrated profiling analysis, discussing studies implementing a robust comparative analysis method for the study of primary data and specific data integration systems, such as the Pancreatic Expression Database, which have been designed to mine, integrate and visualise genes and pathways reported as being associated with pancreatic cancer. We discuss the International Cancer Genome Consortium project on pancreatic cancer, its data portal and underlying data mining technology. We also highlight some of the major issues that are a barrier to research efforts, in particular the lack of good clinical reporting in studies, the need for detailed controlled vocabularies and the importance of interoperability between research resources to maximise data mining and data sharing.
Pancreatic cancer remains one of the deadliest malignancies. In addition to genetic alterations a wide variety of epigenetic aberrations have been identified in pancreatic neoplasms some of which are thought to play an important role in neoplastic development and maintenance. Newer technologies are helping to better characterize cancer epigenomes. Efforts are underway to identify epigenetic alterations that would make optimal diagnostic markers and therapeutic targets. In this chapter, we discuss recent findings in the field of pancreatic cancer epigenetics and the implications they hold for future research.
Pancreatic ductal adenocarcinoma (PDAC) is an aggressive tumor and the fourth common cause of cancer death in the Western world. The lack of effective therapeutic strategies is due to the late diagnosis of this disease. Methylation markers could improve early detection and help in the surveillance of PDAC after treatment. Analysis of hypermethylation in the tumor tissue might help to identify new therapeutic strategies and aid in the understanding of the pathophysiological changes occurring in pancreatic cancer. There are several methods for the detection of methylated events, but methylation-specific PCR (MSP-PCR) is the method of choice if a small number of genes will be tested in a larger set of patients samples. After isolation of the DNA by standard procedure, the DNA is then modified using sodium bisulfide.
Pancreatic ductal adenocarcinoma (PDAC) is an intractable disease as a result of its rapid dissemination and resistance to conventional chemotherapy and radiotherapy. Surgical resection is the only curative therapy, but most of the tumors are unresectable at the time of diagnosis. The molecular mechanisms underlying the biological aggressiveness of this tumor type remain to be clarified. Epithelial to mesenchymal transition (EMT) is a developmental process that leads the phenotype shift from an epithelial morphology to a motile, fibroblast-like morphology. Recent studies showed that EMT is involved in the invasion and metastasis of many types of carcinomas including PDAC. In addition, PDAC cells with the EMT phenotype also exhibit chemoresistance and the cancer stem cell property. Various factors such as cytokines, growth factors, or transcriptional factors were found to promote the EMT program in PDAC cells. In this review, we summarize the current knowledge about the EMT in PDAC cells, focusing on the involvement of this process and its regulatory molecules including microRNA during the development of PDAC cells.
Pancreatic cancer is one of the worst prognostic cancers because of the late diagnosis and the absence of effective treatment. Within all subtypes of this disease, ductal adenocarcinoma has the shortest survival time. In recent years, global genomics profiling allowed the identification of hundreds of genes that are perturbed in pancreatic cancer. The integration of different omics sources in the study of pancreatic cancer has revealed several molecular mechanisms, indicating the complex history of its development. However, validation of these genes as biomarkers for early diagnosis, prognosis or treatment efficacy is still incomplete but should lead to new approaches for the treatment of the disease in the future.
To understand the role of gene promoter methylation in neoplastic evolution and progression, the methylation changes associated with 15 candidate tumor suppressor genes were studied throughout stages of tumor progression involving intraductal papillary mucinous neoplasms (IPMN) of the pancreas. Genomic DNA from 28 pancreatic IPMN tissue samples, categorized histologically as non-invasive intraductal IPMN (n 3), IPMN with carcinoma in situ (n 7), IPMN with microinvasion 1 mm (n 4), and infiltrative IPMN with associated adenocarcinoma (n 14), was modified by bisulfite treatment and analyzed with methylation-specific PCR (MSP). Promoter methylation of at least one tumor suppressor gene was present in 26/28 (92%) of the IPMNs. The cell cycle control genes, p16 and p73, were methylated frequently (50%) in both non-invasive and invasive tumors. APC methylation was discovered in 10% of the non-invasive IPMNs versus 45% of the IPMNs associated with infiltrative adenocarcin-oma, P 0.040. Mismatch repair genes, hMLH1 and MGMT, were frequently methylated in the invasive IPMNs compared with the non-invasive tumors (38 versus 10% and 45 versus 20%, respectively) as was E-cadherin (38 versus 10%), P 0.11. Multiple gene methylation at greater than three loci was present in 55% of the invasive tumors compared with 20% of the non-invasive tumors, P 0.075. Lymph node status did not predict multi-gene methylation among tumors associated with invasive cancer. Compared with non-invasive IPMNs of the pancreas, IPMNs associated with adenocarcinoma demonstrate higher rates of aberrant tumor suppressor gene methylation. The sequential acquisition of hypermethylation at multiple gene promoter sites may explain tumor progression in IPMNs and other malignancies. Detection of methylation within selected genes may afford an accurate diagnostic molecular marker and predictor of neoplastic behavior.
Only a minority of patients who undergo surgical resection for pancreatic ductal adenocarcinoma are cured. Since patient outcome is not reliably predicted using pathological factors (tumor stage, differentiation, resection margin status) alone, markers of tumor behavior are needed. One candidate predictor of pancreatic cancer outcome is e-cadherin status. CDH1 is a tumor suppressor gene encoding an important cell adhesion molecule (e-cadherin). The aim of this study was to determine if, among patients undergoing pancreaticoduodenectomy for pancreatic adenocarcinoma, loss of e-cadherin expression was an independent predictor of poor outcome.
We examined patterns of loss of e-cadherin by immunohistochemistry in tissue microarrays of 329 surgically resected pancreatic ductal adenocarcinomas. E-cadherin expression was then correlated with outcome. Kaplan-Meier analysis and Cox proportional hazards regression modeling were used to assess the mortality risk.
One hundred forty-one pancreatic adenocarcinomas (43%) had partial or complete loss of e-cadherin expression within the analyzed tissue cores. In most instances (134 cases, 41%) this loss was partial. Patients whose pancreatic adenocarcinomas had either complete loss (n=7; median survival, 5.5 months) or partial loss (n=134; 12.7 months) o f e-cadherin expression had significantly worse median survival than those with uniformly intact e-cadherin expression (n=188; 18.5 months) by univariate (p=0.002) and multivariate (p=0.006) analyses. In subgroup analysis, patients with poorly differentiated cancers had a worse prognosis if their cancers had partial loss of e-cadherin expression (p=0.02).
Among patients undergoing pancreaticoduodenectomy for pancreatic ductal adenocarcinoma, partial loss of tumoral e-cadherin expression is an independent predictor of poor outcome.
Because early detection of pancreatic cancer is the best way to cure this disease, investigators continue to try to identify accurate markers of early pancreatic cancer. Because early-stage pancreatic cancer is generally asymptomatic, the only reliable way to detect it is by targeting individuals at increased risk for pancreatic screening.
Pancreatic intraepithelial neoplasia (PanIN) lesions are the most common non-invasive precursors of pancreatic adenocarcinoma. We postulated that accumulating DNA damage within the PanIN epithelium activates checkpoint mechanisms. Tissue microarrays were constructed from 81 surgically resected primary pancreatic adenocarcinomas and an independent set of 58 PanIN lesions (31 PanIN-1, 14 PanIN-2, and 13 PanIN-3). Immunohistochemical labeling was carried out using anti-gammaH2AX(Ser139), anti-phosphoATM(Ser1981), anti-phosphoChk2(Thr68), and anti-p53. A 'histologic score' combining area and intensity of labeling in the nuclear compartment was determined for each lesion. A progressive increase in gammaH2AX(Ser139) labeling, consistent with escalating DNA damage, was observed in the non-invasive precursor lesions (scores of 4.34, 6.21, and 7.50, respectively, for PanIN-1, -2, and -3), compared with the pancreatic ductal epithelium (score 2.36) (ANOVA, P<0.0001). In conjunction, activation of the ataxia telangiectasia mutated (ATM)-Chk2 checkpoint pathway was observed in all histological grades of PanIN lesions. Specifically, pATM(Ser1981) histologic scores for PanIN-1, PanIN-2, and PanIN-3 were 4.83, 5.14, and 7.17, respectively, versus 2.33 for the ductal epithelium (ANOVA, P<0.0001); the corresponding scores for pChk2(Thr68) were 5.43, 7.64, and 5.44 in PanINs-1, -2, and -3, respectively, versus 2.75 in the ductal epithelium (ANOVA, P<0.0001). In contrast, absent to minimal nuclear p53 was observed in the ductal epithelium, and in PanINs-1 and -2 (a histologic score of 0-1.86), with a significant upregulation (corresponding to mutational inactivation) seen only at the stage of PanIN-3 and invasive neoplasia (histologic scores of 4.00 and 4.22). Nuclear p53 accumulation in cancers was associated with attenuation of the ATM-Chk2 checkpoint and a restitution to 'baseline' levels. To conclude, activation of the ATM-Chk2 checkpoint pathway is commonly observed in PanINs, likely in response to the accumulating DNA damage from events such as oncogene mutations and telomere dysfunction. Loss of p53 function appears to be a critical determinant for bypassing this checkpoint and the subsequent progression to invasive adenocarcinoma.
There are currently few therapeutic options for patients with pancreatic cancer, and new insights into the pathogenesis of
this lethal disease are urgently needed. Toward this end, we performed a comprehensive genetic analysis of 24 pancreatic cancers.
We first determined the sequences of 23,219 transcripts, representing 20,661 protein-coding genes, in these samples. Then,
we searched for homozygous deletions and amplifications in the tumor DNA by using microarrays containing probes for ∼106 single-nucleotide polymorphisms. We found that pancreatic cancers contain an average of 63 genetic alterations, the majority
of which are point mutations. These alterations defined a core set of 12 cellular signaling pathways and processes that were
each genetically altered in 67 to 100% of the tumors. Analysis of these tumors' transcriptomes with next-generation sequencing-by-synthesis
technologies provided independent evidence for the importance of these pathways and processes. Our data indicate that genetically
altered core pathways and regulatory processes only become evident once the coding regions of the genome are analyzed in depth.
Dysregulation of these core pathways and processes through mutation can explain the major features of pancreatic tumorigenesis.
Expression of transcription factors that mediate epithelial-mesenchymal transition (EMT), such as Twist and Slug, is correlated with poor prognosis in many tumor types. Selected EMT markers were studied in a series of pancreatic ductal adenocarcinomas (PDAs) and benign pancreatic tissues to determine whether expression levels correlated with diagnosis, histologic grade, or patient outcome.
Immunohistochemical stains for Twist, Slug, and N-cadherin were performed using a tissue microarray containing 68 PDAs and 38 samples of normal pancreas or chronic pancreatitis tissues.
Twist and Slug were identified in both the nucleus and cytoplasm of benign pancreatic ductal epithelium, chronic pancreatitis, and PDA. Compared with normal ductal epithelium, nuclear levels of Twist are decreased in PDA. None of the other EMT markers showed significant differences in staining indices among the diagnostic groups. There were no correlations between EMT marker expression and histologic grade. Epithelial-mesenchymal transition marker expression was not associated with N-cadherin expression, patient outcome, or duration of survival.
Decreased expression of nuclear Twist is observed in malignant pancreatic epithelium. However, use of Twist as a diagnostic marker is precluded because decreased expression is also seen in chronic pancreatitis. None of the markers studied were predictive of patient outcome.
Current generation MDCT technology facilitates identification of small, nonenhancing lesions in the pancreas. The objective of this study was to determine the prevalence of findings of unsuspected pancreatic cysts on 16-MDCT in a population of adult outpatients imaged for disease unrelated to the pancreas.
Contrast-enhanced MDCT scans of the abdomen were reviewed from 2,832 consecutive examinations to identify pancreatic cysts. Patients with a history of pancreatic lesions or predisposing factors for pancreatic disease or who were referred for pancreatic CT were excluded.
A total of 73 patients had pancreatic cysts, representing a prevalence of 2.6 per 100 patients (95% CI, 2.0-3.2). Cysts ranged in size from 2 to 38 mm (mean, 8.9 mm) and were solitary in 85% of cases. Analysis of demographic information showed a strong correlation between pancreatic cysts and age, with no cysts identified among patients under 40 years and a prevalence of 8.7 per 100 (95% CI, 4.6-12.9) in individuals from 80 to 89 years. After controlling for age, cysts were more common in individuals of the Asian race than all other race categories, with an odds ratio of 3.57 (95% CI, 1.05-12.13). There was no difference by sex in the prevalence of cysts (p = 0.527); however, cysts were on average 3.6 mm larger (p = 0.014) in men than women.
In this outpatient population, the prevalence of unsuspected pancreatic cysts identified on 16-MDCT was 2.6%. Cyst presence strongly correlated with increasing age and the Asian race.
Precise mapping of DNA methylation patterns in CpG islands has become essential for understanding diverse biological processes such as the regulation of imprinted genes, X chromosome inactivation, and tumor suppressor gene silencing in human cancer. We describe a new method, MSP (methylation-specific PCR), which can rapidly assess the methylation status of virtually any group of CpG sites within a CpG island, independent of the use of methylation-sensitive restriction enzymes. This assay entails initial modification of DNA by sodium bisulfite, converting all unmethylated, but not methylated, cytosines to uracil, and subsequent amplification with primers specific for methylated versus unmethylated DNA. MSP requires only small quantities of DNA, is sensitive to 0.1% methylated alleles of a given CpG island locus, and can be performed on DNA extracted from paraffin-embedded samples. MSP eliminates the false positive results inherent to previous PCR-based approaches which relied on differential restriction enzyme cleavage to distinguish methylated from unmethylated DNA. In this study, we demonstrate the use of MSP to identify promoter region hypermethylation changes associated with transcriptional inactivation in four important tumor suppressor genes (p16, p15, E-cadherin, and von Hippel-Lindau) in human cancer.
Aberrant methylation of CpG islands and genomic deletion are two predominant mechanisms of gene inactivation in tumorigenesis, but the extent to which they interact is largely unknown. The lack of an integrated approach to study these mechanisms has limited the understanding of tumor genomes and cancer genes. Restriction landmark genomic scanning (RLGS; ref. 1) is useful for global analysis of aberrant methylation of CpG islands, but has not been amenable to alignment with deletion maps because the identity of most RLGS fragments is unknown. Here, we determined the nucleotide sequence and exact chromosomal position of RLGS fragments throughout the genome using the whole chromosome of origin of the fragments and in silico restriction digestion of the human genome sequence. To study the interaction of these gene-inactivation mechanisms in primary brain tumors, we integrated RLGS-based methylation analysis with high-resolution deletion maps from microarray-based comparative genomic hybridization (array CGH; ref. 3). Certain subsets of gene-associated CpG islands were preferentially affected by convergent methylation and deletion, including genes that exhibit tumor-suppressor activity, such as CISH1 (encoding SOCS1; ref. 4), as well as genes such as COE3 that have been missed by traditional non-integrated approaches. Our results show that most aberrant methylation events are focal and independent of deletions, and the rare convergence of these mechanisms can pinpoint biallelic gene inactivation without the use of positional cloning.
To understand the role of gene promoter methylation in neoplastic evolution and progression, the methylation changes associated with 15 candidate tumor suppressor genes were studied throughout stages of tumor progression involving intraductal papillary mucinous neoplasms (IPMN) of the pancreas. Genomic DNA from 28 pancreatic IPMN tissue samples, categorized histologically as non-invasive intraductal IPMN (n = 3), IPMN with carcinoma in situ (n = 7), IPMN with microinvasion <1 mm (n = 4), and infiltrative IPMN with associated adenocarcinoma (n = 14), was modified by bisulfite treatment and analyzed with methylation-specific PCR (MSP). Promoter methylation of at least one tumor suppressor gene was present in 26/28 (92%) of the IPMNs. The cell cycle control genes, p16 and p73, were methylated frequently (>50%) in both non-invasive and invasive tumors. APC methylation was discovered in <10% of the non-invasive IPMNs versus 45% of the IPMNs associated with infiltrative adenocarcinoma, P = 0.040. Mismatch repair genes, hMLH1 and MGMT, were frequently methylated in the invasive IPMNs compared with the non-invasive tumors (38 versus 10% and 45 versus 20%, respectively) as was E-cadherin (38 versus 10%), P = 0.11. Multiple gene methylation at greater than three loci was present in 55% of the invasive tumors compared with 20% of the non-invasive tumors, P = 0.075. Lymph node status did not predict multi-gene methylation among tumors associated with invasive cancer. Compared with non-invasive IPMNs of the pancreas, IPMNs associated with adenocarcinoma demonstrate higher rates of aberrant tumor suppressor gene methylation. The sequential acquisition of hypermethylation at multiple gene promoter sites may explain tumor progression in IPMNs and other malignancies. Detection of methylation within selected genes may afford an accurate diagnostic molecular marker and predictor of neoplastic behavior.
Deregulated expression of SPARC/osteonectin, a secreted glycoprotein with multiple biological functions, has been associated with the progression of various cancers. Using microarrays, we previously identified SPARC as one of the genes induced by treatment with a DNA methylation inhibitor in pancreatic cancer cells. We therefore analysed the expression pattern and methylation status of the SPARC gene in pancreatic cancer. Gene expression profiling by oligonucleotide microarray and reverse transcription-PCR analyses demonstrated that SPARC mRNA was expressed in non-neoplastic pancreatic ductal epithelial cells, but was not expressed in a majority of pancreatic cancer cell lines. The loss of SPARC expression was associated with aberrant hypermethylation of its CpG island. Immunohistochemical labeling revealed that the SPARC protein was overexpressed in the stromal fibroblasts immediately adjacent to the neoplastic epithelium in primary pancreatic cancers, but rarely expressed in the cancers themselves. Primary fibroblasts derived from pancreatic cancer strongly expressed SPARC mRNA and secreted SPARC protein into the conditioned media, and treatment of pancreatic cancer cells with exogenous SPARC resulted in growth suppression. SPARC expression in fibroblasts from noncancerous pancreatic tissue was augmented by coculture with pancreatic cancer cells. These findings suggest that SPARC is a frequent target for aberrant methylation in pancreatic cancer and that SPARC expression in fibroblasts adjacent to pancreatic cancer cells is regulated through tumor-stromal interactions.
Hypoxic conditions exist within pancreatic adenocarcinoma, yet pancreatic cancer cells survive and replicate within this environment. To understand the mechanisms involved in pancreatic cancer adaptation to hypoxia, we analyzed expression of a regulator of hypoxia-induced cell death, Bcl-2/adenovirus E1B 19 kDa interacting protein 3 (BNIP3). We found that BNIP3 was down-regulated in nine of nine pancreatic adenocarcinomas compared with normal pancreas despite the up-regulation of other hypoxia-inducible genes, including glucose transporter-1 and insulin-like growth factor-binding protein 3. Also, BNIP3 expression was undetectable even after hypoxia treatment in six of seven pancreatic cancer cell lines. The BNIP3 promoter, which was remarkably activated by hypoxia, is located within a CpG island. The methylation status of CpG dinucleotides within the BNIP3 promoter was analyzed after bisulfite treatment by sequencing and methylation-specific PCR. Hypermethylation of the BNIP3 promoter was observed in all BNIP3-negative pancreatic cancer cell lines and eight of 10 pancreatic adenocarcinoma samples. Treatment of BNIP3-negative pancreatic cancer cell lines with a DNA methylation inhibitor, 5-aza-2' deoxycytidine, restored hypoxia-induced BNIP3 expression. BNIP3 expression was also restored by introduction of a construct consisting of a full-length BNIP3 cDNA regulated by a cloned BNIP3 promoter. Restoration of BNIP3 expression rendered the pancreatic cancer cells notably more sensitive to hypoxia-induced cell death. In conclusion, down-regulation of BNIP3 by CpG methylation likely contributes to resistance to hypoxia-induced cell death in pancreatic cancer.
Using microarrays, we have screened for genes reactivated by drugs that modify epigenetic mechanisms in pancreatic cancer cells. One of the genes identified was tissue factor pathway inhibitor 2 (TFPI-2), which encodes for a broad-spectrum serine proteinase inhibitor that negatively regulates the extracellular matrix degradation, an essential step in tumor invasion and metastasis. We therefore investigated the expression and methylation patterns of the TFPI-2 gene in pancreatic adenocarcinoma, and determined its role in tumor growth and invasion. In contrast to its abundant expression in normal pancreas, TFPI-2 mRNA was undetectable in a high fraction of pancreatic cancer cell lines and in primary pancreatic ductal neoplasms (IPMNs). Loss of TFPI-2 expression was associated with aberrant hypermethylation of its promoter CpG island. Treatment with the phorbol ester (PMA), known to stimulate the TFPI-2 promoter activity, augmented the TFPI-2 expression in cell lines with unmethylated or partially methylated TFPI-2, but failed to induce the expression in cell lines that harbored fully methylated TFPI-2. Aberrant methylation of TFPI-2 was also detected in 73% (102/140) of pancreatic cancer xenografts and primary pancreatic adenocarcinomas, was more likely in older patients with pancreatic cancer, and significantly correlated with progression of IPMNs (P=0.0002). Restored expression of the TFPI-2 gene in nonexpressing pancreatic cancer cells resulted in marked suppression in their proliferation, migration, and invasive potential in vitro. We thus conclude that epigenetic inactivation of TFPI-2 is a common mechanism that contributes to the aggressive phenotype of pancreatic ductal adenocarcinoma.
The recently identified tumor-suppressor gene TSLC1 on chromosome 11q23.2 is frequently inactivated in human non-small cell lung adenocarcinoma by DNA methylation-associated silencing. The aim of this study was to determine if TSLC1 is inactivated in adenocarcinoma of the pancreas. We analyzed 17 pancreatic cancer cell lines, 91 primary pancreatic adenocarcinoma, 46 pancreatic intraepithelial (PanIN) precursor lesions and 15 microscopically normal pancreata for methylation of the 5' CpG island of the TSLC1 gene through methylation-specific PCR. We observed 5' CpG methylation of TSLC1 in 4 of 17 cell lines (24%). In each cell line the aberrant methylation was associated with loss of TSLC1 expression by RT-PCR that was reversible after treatment with the DNA methyl-transferase inhibitor 5-aza-2'- deoxycytidine. Furthermore, we observed that TSLC1 was methylated in 25 of 91 primary pancreatic adenocarcinomas (27%), and in 2 of 7 highgrade PanIN-3 lesions (29%), but not in low-grade PanIN (0 of 9 PanlN-2 and 0 of 30 PanIN-1) lesions or in normal pancreata (n=15). We conclude that epigenetic silencing of TSLC1 expression through 5' CpG island associated methylation is common in pancreatic adenocarcinoma and is a late event in pancreatic neoplastic development.
Now that more than two decades have passed since the first reports of intraductal papillary-mucinous neoplasms (IPMNs), it has become clear that IPMN consists of a spectrum of neoplasms with both morphological and immunohistochemical variations. At a meeting of international experts on pancreatic precursor lesions held in 2003, it was agreed that a consensus classification of IPMN subtypes should be established to enable a more detailed analysis of the clinicopathological significance of the variations. Based on our experience and on information from the literature, we selected representative histological examples of IPMNs and defined a consensus nomenclature and criteria for classifying variants as distinctive IPMN subtypes including gastric type, intestinal type, pancreatobiliary type, and oncocytic type. These definitions can be used for further analyses of the clinicopathological significance of the variations of IPMN.
Molecular markers of pancreatic neoplasia could aid in the evaluation of visible pancreatic lesions and indicate neoplasia invisible to imaging. We evaluated methylation-specific PCR (MSP) assays that detect aberrantly methylated DNA for their use as markers of pancreatic neoplasia. Methylation analysis was done on pancreatic juice collected endoscopically or surgically from 155 individuals with suspected pancreatic disease: 56 patients had pancreatic ductal adenocarcinoma, 17 had intraductal papillary mucinous neoplasms, 26 had symptomatic chronic pancreatitis, 12 controls lacked evidence of pancreatic disease, and 44 were asymptomatic individuals at increased risk of developing familial pancreatic cancer undergoing screening for pancreatic neoplasia. Pancreatic juice DNA was analyzed for promoter methylation using conventional MSP assays for 17 genes. For six genes, pancreatic juice methylation was quantified using real-time quantitative MSP (QMSP; Cyclin D2, FOXE1, NPTX2, ppENK, p16, and TFPI2). Quantifying pancreatic juice methylation using QMSP with a cutoff of >1% methylated DNA could better predict pancreatic cancer than detecting methylation using conventional MSP. In the endoscopic group, 9 of 11 patients with pancreatic cancer, but none of 64 individuals without neoplasia had > or =1% methylation for two or more of the best five QMSP assays (82% sensitivity and 100% specificity; P < 0.0001). The prevalence of pancreatic juice methylation in patients with chronic pancreatitis was less than in patients with pancreatic cancer but higher than in controls and similar to high-risk individuals. The detection and quantification of aberrantly methylated DNA in pancreatic juice is a promising approach to the diagnosis of pancreatic cancer.
Recent studies have reported high frequencies of somatic mutations in the phosphoinositide-3-kinase catalytic-alpha (PIK3CA) gene in various human solid tumors. More than 75% of those somatic mutations are clustered in the helical (exon 9) and kinase domains (exon 20). The three hot-spot mutations, E542K, E545K, and H1047R, have been proven to elevate the lipid kinase activity of PIK3CA and activate the Akt signaling pathway. The mutational status of PIK3CA in intraductal papillary mucinous neoplasm/carcinoma (IPMN/IPMC) has not been evaluated previously.
To evaluate a possible role for PIK3CA in the tumorigenesis of IPMN and IPMC, exons 1, 4, 5, 6, 7, 9, 12, 18, and 20 were analyzed in 36 IPMN/IPMC and two mucinous cystadenoma specimens by direct genomic DNA sequencing.
We identified four missense mutations in the nine screened exons of PIK3CA from 36 IPMN/IPMC specimens (11%). One of the four mutations, H1047R, has been previously reported as a hot-spot mutation. The remaining three mutations, T324I, W551G, and S1015F, were novel and somatic.
This is the first report of PIK3CA mutation in pancreatic cancer. Our data provide evidence that the oncogenic properties of PIK3CA contribute to the tumorigenesis of IPMN/IPMC.
In a genome-wide screen for putative tumor suppressor genes, the EBF3 locus on the human chromosome 10q26.3 was found to be deleted or methylated in 73% of the examined cases of brain tumors. EBF3 is expressed in normal brain but is silenced in brain tumors. Therefore, it is suggested that EBF3 is a tumor suppressor. However, it remains unknown whether inactivation of EBF3 locus also occurs in other types of tumors and what functions of EBF3 underlie EBF3-mediated tumor suppression. We show here that expression of EBF3 resulted in cell cycle arrest and apoptosis. The expression of cyclin-dependent kinase inhibitors was profoundly affected with early activation and then repression of p21(cip1/waf1) and persistent activation of both p27(kip1) and p57(kip2), whereas genes involved in cell survival and proliferation were suppressed. EBF3 bound directly to p21(cip1/waf1) promoter and regulated transcription from both p21(cip1/waf1) and p27(kip1) promoters in reporter assays. Apoptosis occurred 48 hours after EBF3 expression with caspase-3 activation. Silencing of the EBF3 locus was observed in brain, colorectal, breast, liver, and bone tumor cell lines and its reactivation was achieved on treatment with 5-aza-2'-deoxycytidine and trichostatin A in a significant portion of these tumor cells. Therefore, EBF3 regulates a transcriptional program underlying a putative tumor suppression pathway.
Prognosis of invasive pancreatic ductal adenocarcinoma is bleak and the vast majority of patients with pancreatic cancer die of their disease. The detection and treatment of the non-invasive precursor lesions of pancreatic cancer offer the opportunity to cure this devastating disease and therefore great efforts are being made to identify the precursors to pancreatic cancer. Several distinct precursor lesions have been identified. Mucinous cystic neoplasms (MCNs), intraductal papillary mucinous neoplasms (IPMNs), and pancreatic intraepithelial neoplasias (PanINs) all harbor varying degrees of dysplasia and stepwise accumulation of genetic alterations, suggesting progression of these lesions from benign toward malignant neoplasms. MCNs have a characteristic ovarian-type stroma. About one-third of MCNs are associated with invasive carcinoma of ductal phenotype. IPMNs are recently established clinical entity with characteristic features of mucin hypersecretion and duct dilatation. Some IPMNs are associated with invasive carcinoma and IPMNs are recognized precursors to pancreatic cancer. PanINs are microscopic proliferative lesions arising from any parts of the pancreatic duct system. Low grade PanINs are commonly found in pancreatic ducts of elder individuals, while high grade PanINs, previously called carcinoma in situ/severe ductal dysplasia, may eventually give rise to invasive pancreatic cancer. Appropriate clinical managements are requisite for patients with MCNs, IPMNs and PanINs. Further investigation of these precursor lesions is expected to reduce the mortality from pancreatic cancer.
Early steps for cardiac specification are problematic for the study of mammalian embryos, which has favored using pluripotent cells that recapitulate cardiac myogenesis. Furthermore, circuits governing cardiac specification have relevance to the application of ES cells and other cells for heart repair. In mouse teratocarcinoma cells, canonical Wnts that inhibit heart formation in avian or amphibian embryos and explants activate cardiogenesis, paradoxically. Here, we show that the Wnt/β-catenin pathway also is essential for cardiac myogenesis to occur in ES cells, acting at a gastrulation-like stage, mediating mesoderm formation and patterning (two prerequisites for cardiac myogenesis itself). Among genes associated temporally with this step was Sox17, encoding an endodermal HMG-box transcription factor. Using lentiviral vectors for RNA interference in differentiating ES cells, an essential role for Sox17 was proven in cardiac muscle cell formation. Sox17 short-hairpin RNA suppresses cardiac myogenesis selectively, acting subsequent to mesoderm formation yet before induction of Mesp1 and Mesp2, a pair of related basic helix–loop–helix transcription factors that together are indispensable for creating heart mesoderm. Sox17 short-hairpin RNA blocks cardiac myogenesis non-cell autonomously and impairs the induction of Hex, a homeodomain transcription factor that is known to be required for the production of endoderm-derived heart-inducing factors.
• cardiac myogenesis
• differentiation
• β-catenin
• heart
• Wnt
Pancreatic cancer is a highly malignant tumor, and is difficult to be diagnosed in its early stage. microRNAs (miRNAs) are small single-stranded RNA molecules of 19-23 nucleotides and have been recognized as a post-transcriptional negative regulator of the expression of target genes, thereby affecting the development, differentiation and apoptosis of tumor cells. Aberrant miRNAs expression patterns have been described in recent studies in tumor tissue, cell line, precancerous tissue and plasma of pancreatic cancer, which suggest that miRNAs might have some value in mechanism research on the genesis and progress, diagnosis, treatment and prognostic assessment of pancreatic cancer. This article reviewed recent progress in related field.
We have demonstrated that crosstalk between the Hedgehog-GLI-GLI and EGFR signaling pathway exists and contribute to pancreatic tumorigenesis. This interaction can be abrogated by targeting both pathways simultaneously and results in a synergistic antitumor effect in vitro and in vivo in pancreatic tumor models. Based on these results we have undertaken a phase I trial of GDC-0449 (an orally administered Hedgehog pathway inhibitor) and erlotinib (EGFR tyrosine kinase inhibitor to: 1) determine the maximally tolerated dose (MTD) of GDC-0449 combined with erlotinib in unresectable solid tumors; 2) describe the adverse events associated with this treatment combination; 3) describe the responses of this treatment combination; and 4) to assess the effect of the erlotinib and GDC-0449 combination on selected biomarkers in circulating tumor cells (CTCs), tumor biopsies, and FDG-PET in a cohort of patients with metastatic pancreatic cancer patients treated at the MTD. During the dose escalation portion of the trial, eligible patients receive GDC-0449 150 mg p.o. daily and erlotinib 50, 75, 100, or 150 mg daily p.o. at dose levels 1, 2, 3, and 4 respectively. Eligibility criteria include: histologic proof of solid tumors that are unresectable, not amenable to any other standard therapies, or patient refused standard therapy,; ANC ≥> 1500/μL; PLT ≥> 100,000/ μL; Total bilirubin ≤< upper limit of normal (ULN); AST ≤< 3 x ULN; Creatinine ≤< 1.5 x ULN; Hemoglobin ≥> 9.0 g/dL; INR within normal limits (Cohort II [MTD Cohort] only); ECOG performance status (PS) 0, 1 or ≤ 2. For the MTD cohort, only patients with metastatic adenocarcinoma of the pancreas without prior systemic therapy for metastatic disease and tumor amenable to biopsies are eligible. Toxicity assessment is performed at each 28-day treatment cycles and response assessment every second treatment 28 day cycle. 12 patients have been entered-pancreas (3), colorectal (3), neuroendocrine (2), scc anus (2), gallbladder (1), thymoma (1). No dose-limiting toxicity (DLT) was reported at dose level 4. At the MTD, up to 20 patients with previously untreated metastatic pancreatic cancer will be entered to assess the biologic effect of GDC-0449+erlotinib. Pre- and post- treatment biopsies of metastases and FDG-PET will be performed. Weekly collection of CTCs will be undertaken and immunofluorescence microscopy of total & phosphoMAPK, EGFR, AKT, PATCHED1, GLI1, BCL-2, and quantitative PCR (Q-PCR) of PATCHED1, GLI1, and its target genes (BCL-2, BFL-1/A1, 4-1BB) will be performed. In addtion, total & phosphoMAPK, EGFR, and AKT, as well as PATCHED1, GLI1, BCL-2 by immunohistochemistry and Q-PCR of PATCHED1, GLI1, BCL-2, BFL-1/A1, 4-1BB will be analyzed in tumor biopsies. Supported by CA69912, CA136526 and CA102701.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1807.
Each year, the American Cancer Society estimates the numbers of new cancer cases and deaths expected in the United States in the current year and compiles the most recent data on cancer incidence, mortality, and survival based on incidence data from the National Cancer Institute, the Centers for Disease Control and Prevention, and the North American Association of Central Cancer Registries and mortality data from the National Center for Health Statistics. A total of 1,596,670 new cancer cases and 571,950 deaths from cancer are projected to occur in the United States in 2011. Overall cancer incidence rates were stable in men in the most recent time period after decreasing by 1.9% per year from 2001 to 2005; in women, incidence rates have been declining by 0.6% annually since 1998. Overall cancer death rates decreased in all racial/ethnic groups in both men and women from 1998 through 2007, with the exception of American Indian/Alaska Native women, in whom rates were stable. African American and Hispanic men showed the largest annual decreases in cancer death rates during this time period (2.6% and 2.5%, respectively). Lung cancer death rates showed a significant decline in women after continuously increasing since the 1930s. The reduction in the overall cancer death rates since 1990 in men and 1991 in women translates to the avoidance of about 898,000 deaths from cancer. However, this progress has not benefitted all segments of the population equally; cancer death rates for individuals with the least education are more than twice those of the most educated. The elimination of educational and racial disparities could potentially have avoided about 37% (60,370) of the premature cancer deaths among individuals aged 25 to 64 years in 2007 alone. Further progress can be accelerated by applying existing cancer control knowledge across all segments of the population with an emphasis on those groups in the lowest socioeconomic bracket.
Substantial progress has been made in our understanding of the biology of pancreatic cancer, and advances in patients' management have also taken place. Evidence is beginning to show that screening first-degree relatives of individuals with several family members affected by pancreatic cancer can identify non-invasive precursors of this malignant disease. The incidence of and number of deaths caused by pancreatic tumours have been gradually rising, even as incidence and mortality of other common cancers have been declining. Despite developments in detection and management of pancreatic cancer, only about 4% of patients will live 5 years after diagnosis. Survival is better for those with malignant disease localised to the pancreas, because surgical resection at present offers the only chance of cure. Unfortunately, 80-85% of patients present with advanced unresectable disease. Furthermore, pancreatic cancer responds poorly to most chemotherapeutic agents. Hence, we need to understand the biological mechanisms that contribute to development and progression of pancreatic tumours. In this Seminar we will discuss the most common and deadly form of pancreatic cancer, pancreatic ductal adenocarcinoma.
The goal of this study was to comprehensively identify CpG island methylation alterations between pancreatic cancers and normal pancreata and their associated gene expression alterations.
We employed methylated CpG island amplification followed by CpG island microarray, a method previously validated for its accuracy and reproducibility, to analyze the methylation profile of 27,800 CpG islands covering 21 MB of the human genome in nine pairs of pancreatic cancer versus normal pancreatic epithelial tissues and in three matched pairs of pancreatic cancer versus lymphoid tissues from the same individual.
This analysis identified 1,658 known loci that were commonly differentially methylated in pancreatic cancer compared with normal pancreas. By integrating the pancreatic DNA methylation status with the gene expression profiles of the same samples before and after treatment with the DNA methyltransferase inhibitor 5-aza-2'-deoxycytidine, and the histone deacetylase inhibitor, trichostatin A, we identified dozens of aberrantly methylated and differentially expressed genes in pancreatic cancers including a more comprehensive list of hypermethylated and silenced genes that have not been previously described as targets for aberrant methylation in cancer.
We expected that the identification of aberrantly hypermethylated and silenced genes will have diagnostic, prognostic, and therapeutic applications.
Each year, the American Cancer Society estimates the number of new cancer cases and deaths expected in the United States in the current year and compiles the most recent data regarding cancer incidence, mortality, and survival based on incidence data from the National Cancer Institute, the Centers for Disease Control and Prevention, and the North American Association of Central Cancer Registries and mortality data from the National Center for Health Statistics. Incidence and death rates are age-standardized to the 2000 US standard million population. A total of 1,529,560 new cancer cases and 569,490 deaths from cancer are projected to occur in the United States in 2010. Overall cancer incidence rates decreased in the most recent time period in both men (1.3% per year from 2000 to 2006) and women (0.5% per year from 1998 to 2006), largely due to decreases in the 3 major cancer sites in men (lung, prostate, and colon and rectum [colorectum]) and 2 major cancer sites in women (breast and colorectum). This decrease occurred in all racial/ethnic groups in both men and women with the exception of American Indian/Alaska Native women, in whom rates were stable. Among men, death rates for all races combined decreased by 21.0% between 1990 and 2006, with decreases in lung, prostate, and colorectal cancer rates accounting for nearly 80% of the total decrease. Among women, overall cancer death rates between 1991 and 2006 decreased by 12.3%, with decreases in breast and colorectal cancer rates accounting for 60% of the total decrease. The reduction in the overall cancer death rates translates to the avoidance of approximately 767,000 deaths from cancer over the 16-year period. This report also examines cancer incidence, mortality, and survival by site, sex, race/ethnicity, geographic area, and calendar year. Although progress has been made in reducing incidence and mortality rates and improving survival, cancer still accounts for more deaths than heart disease in persons younger than 85 years. Further progress can be accelerated by applying existing cancer control knowledge across all segments of the population and by supporting new discoveries in cancer prevention, early detection, and treatment.
Aberrant DNA methylation and microRNA expression play important roles in the pathogenesis of pancreatic cancer. While interrogating differentially methylated CpG islands in pancreatic cancer, we identified two members of miR-200 family, miR-200a and miR-200b, that were hypomethylated and overexpressed in pancreatic cancer. We also identified prevalent hypermethylation and silencing of one of their downstream targets, SIP1 (ZFHX1B, ZEB2), whose protein product suppresses E-cadherin expression and contributes to epithelial mesenchymal transition. In a panel of 23 pancreatic cell lines, we observed a reciprocal correlation between miR-200, SIP1, and E-cadherin expression, with pancreatic cancer-associated fibroblasts showing the opposite expression pattern to most pancreatic cancers. In Panc-1 cells, which express SIP1, have low E-cadherin expression, and do not express miR-200a or miR-200b, treatment with miR-200a and miR-200b downregulated SIP1 mRNA and increased E-cadherin expression. However, most pancreatic cancers express miR-200a and miR-200b, but this expression does not affect SIP1 expression, as the SIP1 promoter is silenced by hypermethylation and in these cancers E-cadherin is generally expressed. Both miR-200a and miR-200b were significantly elevated in the sera of pancreatic cancer and chronic pancreatitis patients compared with healthy controls (P < 0.0001), yielding receiver operating characteristic curve areas of 0.861 and 0.85, respectively. In conclusion, most pancreatic cancers display hypomethylation and overexpression of miR-200a and miR-200b, silencing of SIP1 by promoter methylation, and retention of E-cadherin expression. The elevated serum levels of miR-200a and miR-200b in most patients with pancreatic cancer could have diagnostic utility.
The activation of Wnt/beta-catenin signaling causes the development of gastric and colon cancers. Sox17 represses Wnt/beta-catenin signaling and is down-regulated in colon cancer. This study was designed to elucidate the role of Sox17 during the course of gastrointestinal tumorigenesis.
Sox17 expression was examined in gastrointestinal tumors of mouse models and humans. The roles of Sox17 in gastric tumorigenesis were examined by cell culture experiments and by construction of Sox17 transgenic mice.
Sox17 was induced in K19-Wnt1/C2mE mouse gastric tumors and K19-Wnt1 preneoplastic lesions, where Wnt/beta-catenin signaling was activated. Consistently, Wnt activation induced Sox17 expression in gastric cancer cells. In contrast, Sox17 was rarely detected by immunohistochemistry in gastric and colon cancers, whereas strong nuclear staining of Sox17 was found in >70% of benign gastric and intestinal tumors. Treatment with a demethylating agent induced Sox17 expression in gastric cancer cells, thus indicating the down-regulation of Sox17 by methylation. Moreover, transfection of Sox17 in gastric cancer cells suppressed both the Wnt activity and colony formation efficiency. Finally, transgenic expression of Sox17 suppressed dysplastic tumor development in K19-Wnt1/C2mE mouse stomach.
Sox17 plays a tumor suppressor role through suppression of Wnt signaling. However, Sox17 is induced by Wnt activation in the early stage of gastrointestinal tumorigenesis, and Sox17 is down-regulated by methylation during malignant progression. It is therefore conceivable that Sox17 protects benign tumors from malignant progression at an early stage of tumorigenesis, and down-regulation of Sox17 contributes to malignant progression through promotion of Wnt activity.
We performed a global methylation profiling assay on 1505 CpG sites across 807 genes to characterize DNA methylation patterns in pancreatic cancer genome. We found 289 CpG sites that were differentially methylated in normal pancreas, pancreatic tumors and cancer cell lines. We identified 23 and 35 candidate genes that are regulated by hypermethylation and hypomethylation in pancreatic cancer, respectively. We also identified candidate methylation markers that alter the expression of genes critical to gemcitabine susceptibility in pancreatic cancer. These results indicate that aberrant DNA methylation is a frequent epigenetic event in pancreatic cancer; and by using global methylation profiling assay, it is possible to identify these markers for diagnostic and therapeutic purposes in this disease.
Ductal adenocarcinoma of the pancreas is the fourth leading cause of cancer death and is usually diagnosed late. Intraductal papillary mucinous neoplasms are an increasingly recognized precursor to invasive ductal adenocarcinoma of the pancreas. Identifying the alterations in DNA methylation that arise during intraductal papillary mucinous neoplasm development may facilitate the development of markers that could be used to differentiate intraductal papillary mucinous neoplasms from non-neoplastic pancreatic cystic lesions. Surgically resected intraductal papillary mucinous neoplasms and adjacent ductal adenocarcinomas were microdissected from 50 patients. Normal pancreas was also obtained from 27 patients with intraductal papillary mucinous neoplasms or pancreatic adenocarcinomas and 10 patients with well-differentiated pancreatic endocrine neoplasms. Methylation-specific PCR was performed on isolated DNA for seven genes (SPARC, SARP2, TSLC1, RELN, TFPI2, CLDN5, UCHL1) known to be commonly aberrantly methylated in pancreatic ductal adenocarcinomas. The mean percentage of genes methylated in invasive ductal adenocarcinomas arising in association with an intraductal papillary mucinous neoplasm (mean+/-s.d., 81+/-17%) was significantly higher than that in noninvasive-intraductal papillary mucinous neoplasms (57+/-26%, P=0.007) or peritumoral normal epithelial cells (22+/-17%, P<0.0001). Carcinomas (intraductal papillary mucinous neoplasms with carcinoma in situ or their associated infiltrating adenocarcinoma) had significantly more methylated genes (71+/-19%) than low-grade (low and moderate dysplasia) intraductal papillary mucinous neoplasms (44+/-26%, P<0.0001). The mean percentage of genes methylated in histologically normal pancreatic ductal cells from patients with ductal neoplasia (22+/-17%) was significantly higher than in normal ductal cells from patients with well-differentiated pancreatic endocrine neoplasms (4+/-7%, P=0.002). Thus, aberrant DNA methylation increases with histologic grades of intraductal papillary mucinous neoplasm. Low-level aberrant methylation in the normal ductal cells is more prevalent in patients with ductal neoplasia than in controls without ductal neoplasms and may contribute to carcinogenesis. The detection of aberrant methylation in pancreatic cystic lesions could facilitate the diagnosis of intraductal papillary mucinous neoplasms.
Intraductal papillary growth of mucin producing hypersecreting, columnar cells characterizes a group of rare pancreatic exocrine neoplasms which we propose to call intraductal papillary-mucinous tumors (IPMT). We analysed the histopathology of 26 IPMT in relation to gastro-enteropancreatic marker expression, genetic changes and biology. Four IPMT showing only mild dysplasia were considered to be adenomas. Nine tumours displayed moderate dysplasia and were regarded as borderline. Severe dysplasia-carcinoma in situ changes were found in 13 IPMT which were therefore classified as intraductal carcinomas. Six of these carcinomas were frankly invasive and two of these had lymph node metastases. The invasive component resembled mucinous non-cystic carcinoma in all but one tumour which showed a ductal invasion pattern. Immunohistochemically, an intestinal marker type was found in most carcinomas, while gastric type differentiation prevailed among adenomas or borderline tumours. K-ras mutations (seven at codon 12 and one at codon 13) were found in 31% of IPMT (2 adenomas, 1 borderline, 5 carcinomas). Nuclear p53 overexpression was detected in 31% of IPMT (6 carcinomas and 2 borderline IPMT) and correlated with p53 mutations (one at exon 8 and the other at exon 5) in two carcinomas. p53 abnormalities were unrelated to K-ras mutation. c-erbB-2 overexpression was observed in 65% of IPMT, with various grades of dysplasia. Twenty-two of 24 patients are alive and well after a mean post-operative follow-up of 41 months. Only two patients, both with invasive cancer at the time of surgery, died of tumour disease. It is concluded that pancreatic IPMT encompass neoplasms which, in general, have a favorable prognosis, but are heterogeneous in regard to grade of dysplasia and marker expression. Adenoma, borderline tumour, intraductal carcinoma and invasive carcinoma can be differentiated. p53 changes but not K-ras mutation or c-erbB-2 overexpression are related to the grade of malignancy. Most IPMT differ in histological structure, marker expression and behaviour from ductal adenocarcinoma.
The National Cancer Database is an electronic registry system sponsored jointly by the American College of Surgeons Commission on Cancer and the American Cancer Society. Patients diagnosed with pancreatic adenocarcinoma from 1985 to 1995 were analyzed for trends in stage of disease, treatment patterns, and outcomes.
Seven annual requests for data were issued by the National Cancer Database from 1989 through 1995. Data on 100,313 patients were voluntarily submitted using a standardized reporting format.
The anatomic site distribution was: head, 78%; body, 11%; and tail, 11%. The ratios of limited to advanced disease (Stage I/Stage IV) were 0.70 for tumors in the head, 0.24 for body tumors, and 0.10 for tail tumors. Of all patients, 83% did not have a surgical procedure and 58% did not have cancer-directed treatment. Resection was done for 9,044 (9%) patients, including 22% of those with Stage I disease. The overall 5-year survival rate was 23.4% for patients who had pancreatectomy, compared with 5.2% for those who had no cancer-directed treatment.
Overall survival rates for pancreatic cancer have not changed in 2 decades. A small minority of patients presented with limited, resectable disease, but the best survival rates per stage were achieved after surgical resection. Five-year survival rates after resection reported herein corroborated the improved survival rates of more recent large, single institution studies.
Despite the growing awareness of intraductal papillary-mucinous neoplasms (IPMNs) of the pancreas among clinicians, the molecular features of IPMNs have not been well characterized. Previous reports suggest that inactivation of the STK11/LKB1, a tumor-suppressor gene responsible for Peutz-Jeghers syndrome (PJS), plays a role in the pathogenesis of gastrointestinal hamartomas as well as several cancers, including pancreatic adenocarcinoma. Using polymerase chain reaction amplification of five microsatellite markers from the 19p13.3 region harboring the STK11/LKB1 gene, we analyzed DNA from 22 IPMNs for loss of heterozygosity (LOH). LOH at 19p13.3 was identified in 2 of 2 (100%) IPMNs from patients with PJS and 5 of 20 (25%) from patients lacking features of PJS (7 of 22, 32% overall). Sequencing analysis of the STK11/LKB1 gene in these IPMNs with LOH revealed a germline mutation in one IPMN that arose in a patient with PJS and a somatic mutation in 1 of the 20 sporadic IPMNs. None of the 22 IPMNs showed hypermethylation of the STK11/LKB1 gene. These results suggest that the STK11/LKB1 gene is involved in the pathogenesis of some IPMNs.
The molecular pathology of precursor lesions leading to invasive pancreatic ductal adenocarcinomas remains relatively unknown. We have applied cDNA microarray analysis to characterize gene expression profiles in a series of intraductal papillary-mucinous tumors (IPMTs) of the pancreas, which represents one of the alternative routes of intraepithelial progression to full malignancy in the pancreatic duct system. Using a cDNA microarray containing 4992 human genes, we screened a total of 13 IPMTs including nine noninvasive and four invasive cases. Expression change in more than half of the tumors was observed for 120 genes, ie, 62 up-regulated and 58 down-regulated genes. Some of the up-regulated genes in this study have been previously described in classical pancreatic carcinomas such as lipocalin 2, galectin 3, claudin 4, and cathepsin E. The most highly up-regulated genes in IPMTs corresponded to three members of the trefoil factor family (TFF1, TFF2, and TFF3). Immunohistochemistry performed on five genes found to be differentially expressed at the RNA level (TFF1, TFF2, TFF3, lipocalin 2, and galectin 3) showed a good concordance between transcript level and protein abundance, except for TFF2. Hierarchical clustering organized the cases according to the dysplastic and invasive phenotype of theIPMTs. This analysis has permitted us to implicate several genes (caveolin 1, glypican 1, growth arrest-specific 6 protein, cysteine-rich angiogenic inducer 61) in tumor progression. The observation that several genes are differentially expressed both in IPMTs and pancreatic carcinomas suggests that they may be involved at an early stage of pancreatic carcinogenesis.
The functional abrogation of several tumor suppressor genes, including p16, DPC4, and p53, is a major mechanism underlying pancreatic ductal carcinogenesis. However, mutational inactivation of these genes is relatively uncommon in intraductal papillary mucinous neoplasms (IPMNs) of the pancreas. We hypothesized that an alternative mechanism for gene inactivation (notably, transcriptional silencing by promoter methylation) could be important in the pathogenesis of IPMNs.
Using methylation-specific polymerase chain reaction, we analyzed the methylation status of 7 CpG islands previously identified as aberrantly methylated in pancreatic adenocarcinoma (including preproenkephalin [ppENK], p16, and thrombospondin 1) in 51 IPMNs of different histologic grades. The relationship between methylation status and expression was evaluated using reverse-transcription polymerase chain reaction for ppENK and immunohistochemistry for p16.
We found that more than 80% of the IPMNs exhibited hypermethylation of at least one of these CpG islands. Hypermethylation of ppENK and p16 was detected at a significant higher frequency in high-grade (in situ carcinoma) IPMNs than in low-grade (adenoma/borderline) IPMNs (ppENK, 82% vs. 28%, P = 0.0002; p16, 21% vs. 0%, P = 0.04). Furthermore, the average number of methylated loci was significantly higher in high-grade IPMNs than in low-grade IPMNs (2.4 vs. 0.9; P = 0.0008). Aberrant methylation of ppENK and p16 was associated with loss of expression.
These results suggest that de novo methylation of multiple CpG islands is one of the critical pathways that contributes to the malignant progression of IPMNs.
Homeobox genes comprise a large and essential family of developmental regulators that are vital for all aspects of growth and differentiation. Although many studies have reported their deregulated expression in cancer, few studies have established direct functional roles for homeobox genes in carcinogenesis. Nonetheless, most cases of deregulated homeobox gene expression in cancer conform to a simple rule: those that are normally expressed in undifferentiated cells are upregulated in cancer, whereas those that are normally expressed in differentiated tissues are downregulated in cancer.
Previous work has identified members of the homeodomain and basic helix-loop-helix families of transcription factors as critical determinants of mammalian pancreatic development. Here, we describe the identification of HMG-box transcription factors of the Sox gene family in the mouse pancreas. We detected transcripts for Sox11, Sox4, Sox13, Sox5, Sox9, Sox8, Sox10, Sox7, Sox17, Sox18, Sox15, and Sox30 in embryonic pancreas and found Sox4, Sox9, and Sox13 in adult pancreatic islets. Expression of seven of these Sox factors was studied in more detail by in situ hybridization from the stage of early pancreatic outgrowth to birth. Expression of Sox11 was found in the mesenchyme surrounding the pancreatic buds, whereas Sox4 and Sox9 were confined to the pancreatic epithelium and later to islets. Sox13 and L-Sox5 showed expression in most of the pancreatic epithelial cells between embryonic days 12.5 and 14.5. Sox8 and Sox10 were detected in a thin layer of cells surrounding the islets. The expression patterns of Sox genes in the embryonic pancreas suggest that they could have important and possibly redundant functions in pancreas development.
Relatives of patients with pancreatic cancer and persons with certain inherited syndromes are at increased risk for developing pancreatic cancer. We prospectively evaluated the feasibility of screening for pancreatic neoplasia in high-risk individuals.
Individuals from familial pancreatic cancer kindreds and a patient with Peutz-Jeghers syndrome underwent screening endoscopic ultrasound (EUS). If the EUS was abnormal, EUS-guided fine-needle aspiration, endoscopic retrograde cholangiopancreatography (ERCP), and spiral computed tomography (CT) were performed. Patients with abnormalities suggesting neoplasia had surgery.
Thirty-eight patients were studied; 31 (mean age, 58 yr; 42% men) from kindreds with > or =3 affected with pancreatic cancer; 6 from kindreds with 2 affected relatives, 1 was a patient with Peutz-Jeghers syndrome. None had symptoms referable to the pancreas or suggestive of malignancy. Six pancreatic masses were found by EUS: 1 invasive ductal adenocarcinoma, 1 benign intraductal papillary mucinous neoplasm, 2 serous cystadenomas, and 2 nonneoplastic masses. Hence, the diagnostic yield for detecting clinically significant pancreatic neoplasms was 5.3% (2 of 38). The 1 patient with pancreatic cancer was treated and still is alive and disease-free >5 years after surgery. EUS changes similar to those associated with chronic pancreatitis were found, which were more common in patients with a history of regular alcohol intake (P = 0.02), but also occurred in patients who did not consume alcohol. Screening also led to a new diagnosis and treatment of symptomatic upper-gastrointestinal conditions in 18.4% of patients.
EUS-based screening of asymptomatic high-risk individuals can detect prevalent resectable pancreatic neoplasia but false-positive diagnoses also occur.
Invasive pancreatic ductal adenocarcinoma is an almost uniformly fatal disease. Several distinct noninvasive precursor lesions can give rise to invasive adenocarcinoma of the pancreas, and the prevention, detection, and treatment of these noninvasive lesions offers the potential to cure early pancreatic cancers. Noninvasive precursors of invasive ductal adenocarcinoma of the pancreas include pancreatic intraepithelial neoplasias (PanINs), intraductal papillary mucinous neoplasms (IPMNs), and mucinous cystic neoplasms. Diagnostic criteria, including a distinct ovarian-type stroma, and a consistent nomenclature are well established for mucinous cystic neoplasms. By contrast, consistent nomenclatures and diagnostic criteria have been more difficult to establish for PanINs and IPMNs. Because both PanINs and IPMNs consist of intraductal neoplastic proliferations of columnar, mucin-containing cells with a variable degree of papilla formation, the distinction between these two classes of precursor lesions remains problematic. Thus, considerable ambiguities still exist in the classification of noninvasive neoplasms in the pancreatic ducts. A meeting of international experts on precursor lesions of pancreatic cancer was held at The Johns Hopkins Hospital from August 18 to 19, 2003. The purpose of this meeting was to define an international acceptable set of diagnostic criteria for PanINs and IPMNs and to address a number of ambiguities that exist in the previously reported classification systems for these neoplasms. We present a consensus classification of the precursor lesions in the pancreatic ducts, PanINs and IPMNs.
The development of pancreatic cancer (PC) several years after curative resection for noninvasive intraductal papillary mucinous neoplasm (IPMN) and the presence of PC distant from IPMN suggest that PC may develop independently of the IPMN. Here, we identified pancreatic intraepithelial neoplasia (PanIN) lesions, the putative precursors of PC, in the ducts of pancreata resected for IPMN and assessed the frequency of molecular aberrations common to PanIN and PC, within these lesions. The protein expression of p53, p21(WAF1/CIP1), cyclin D1, p16(INK4A) and DPC4/Smad4 were examined by immunohistochemistry in 267 PanIN lesions from a cohort of 23 patients with IPMN. Overexpression of p21(WAF1/CIP1) was present in PanIN-1A and -1B lesions and increased in frequency in PanIN-2 and PanIN-3. Overexpression of p53 and cyclin D1, and loss of p16(INK4A) expression were detected in PanIN-2 and PanIN-3 lesions. Loss of DPC4/Smad4 expression occurred only in the PanIN-3 lesions. PanIN lesions that were more dysplastic than the coincident IPMN were identified in 5 of 12 patients, and 2 of these contained a greater number of aberrations in protein expression than the IPMN. PanIN lesions seen in association with IPMN demonstrate molecular and histologic changes identical to PanIN lesions found in association with PC and, in some cases, are more advanced than the associated IPMN. These data suggest that PanIN lesions found in the ducts of a pancreas with IPMN may be relevant to the development of PC either coincident with IPMN or in the remnant pancreas after curative resection of IPMN.
Ever since the classification of pancreatic intraepithelial neoplasia (PanIN) was published, studies on the precursor lesions of pancreatic cancer have been advancing along a new directions, using standardized terminology. There are few studies that have examined the biological differences between PanIN and intraductal papillary mucinous neoplasm (IPMN) in detail.
PanIN and IPMN, which are similar in morphology, were compared using various indicators, with the aim of identifying the similarities and differences between the two.
A total of 46 PanINs and 37 ducts with IPMN were identified in 19 patients with invasive ductal carcinoma and 18 patients with IPMN. These PanINs and IPMNs were examined immunohistologically with respect to the expression patterns of HER2/neu, DPC4/Smad4, Akt/PKB, p53, cyclin A, Ki67, MUC1, and MUC2.
Significant differences in the expression of MUC1 and MUC2 were observed between IPMNadenoma and PanIN-2 and between CIS and PanIN-3 (MUC1: p = 0.001 and p = 0.005, respectively; MUC2: p = 0.002 and p < 0.001, respectively). A significant difference in the p53 expression level was also observed between CIS and PanIN-3 (p = 0.015).
In both IPMN and PanIN, the grade of atypism increased with increasing expression of HER2/neu, DPC4/Smad4, and Akt/PKB, along with progression in the process of multistage carcinogenesis. Although the expression levels of these factors reflected the grade of atypism, they did not reflect any differences in the grade of biological malignancy between IPMN and PanIN. On the other hand, MUC1 and MUC2 may serve as indicators of the direction of differentiation, i.e., either progression to IDAC or IPMN. Positivity for MUC1 was believed to suggest differentiation into IDAC, and positivity for MUC2 appeared to be indicative of differentiation into IPMN. Such indication of the direction of differentiation seemed to appear in PanIN1-2, even before abnormalities of HER2/neu, Akt/PKB, DPC4/Smad4, p53, and cyclin A expression began to be detected.
The goal of this study was to evaluate the consistency of distinction between pancreatic intraepithelial neoplasia (PanIN) and intraductal papillary-mucinous neoplasms (IPMN) and the hypothesis that guidelines for their distinction might be inadequate.
A group of 93 pancreas specimens from surgical resections or autopsies that contained lesions consistent with histopathological diagnoses of PanIN-1A, PanIN-1B, PanIN-2, or IPMN (adenoma or borderline) was collected. The classification of these neoplasms by 6 pathologists, 2 from Europe, 2 from Japan, and 2 from the United States, was compared. The pathologists initially used guidelines current in their practice and then reviewed 47 of the 93 specimens a second time using new consensus definitions and guidelines for PanIN and IPMN that were developed in 2003.
The initial comparison showed frequent disagreement regarding both category and grade of the lesions. Agreement was greater for category than grade. In the second review, agreement among the 6 reviewers improved, remaining higher for category, although disagreements persisted for both category and grade.
We conclude that the new definitions of PanIN and IPMN improve the consistency in classifying these lesions, but additional work is needed to further improve the reproducibility of their classification.
Non-inflammatory cystic lesions of the pancreas are increasingly recognized. Two distinct entities have been defined, i.e., intraductal papillary mucinous neoplasm (IPMN) and mucinous cystic neoplasm (MCN). Ovarian-type stroma has been proposed as a requisite to distinguish MCN from IPMN. Some other distinct features to characterize IPMN and MCN have been identified, but there remain ambiguities between the two diseases. In view of the increasing frequency with which these neoplasms are being diagnosed worldwide, it would be helpful for physicians managing patients with cystic neoplasms of the pancreas to have guidelines for the diagnosis and treatment of IPMN and MCN. The proposed guidelines represent a consensus of the working group of the International Association of Pancreatology.
Recently described genome-wide approaches robustly detect many candidate genes that are regulated by DNA methylation, but many of these genes do not represent important targets for functional inactivation. Here we used a microarray-based strategy to identify biologically relevant genes associated with epigenetic silencing in pancreatic cancer.
We compared information from differential gene expression analysis with the transcriptional responses to epigenetic modifiers.
Using this approach, we identified 7 novel targets for aberrant methylation in pancreatic cancer. One of the genes identified, RELN (Reelin), a key regulator of neuronal migration, is frequently silenced in pancreatic cancers, as are several of its downstream mediators. Importantly, small interfering RNA-mediated knockdown of RELN in pancreatic cancer cells that retain RELN expression resulted in greatly enhanced cell motility, invasiveness, and colony-forming ability. Increased cell motility was also induced by knockdown of downstream components of the RELN pathway, including ApoER2, VLDLR, and DAB1. Treatment of pancreatic cancer cells with histone deacetylase inhibitors, valproic acid and suberoylanilide hydroxamic acid, restored the expression of RELN and DAB1 and markedly inhibited their migration.
The high prevalence of the silencing of RELN pathway components and its reversal by histone deacetylase inhibitors suggest the importance of this pathway as a diagnostic and therapeutic target for pancreatic cancer.
While incidental masses in certain organs have received particular attention, periampullary and pancreatic incidentalomas (PIs) remain poorly characterized.
We reviewed 1944 consecutive pancreaticoduodenectomies (PD) over an 8-year period (April 1997 to October 2005). A total of 118 patients (6% of all PDs) presented with an incidental finding of a periampullary or pancreatic mass. The PI patients were analyzed and compared with the rest of the cohort (NI, nonincidentaloma group, n = 1826).
Thirty-one percent of the PI patients (n = 37) had malignant disease (versus 76% of the NI patients, P < 0.001), 47% (n = 55) had premalignant disease, and the remaining 22% (n = 26) had little or no risk for malignant progression. The 3 most common diagnoses in the PI group were IPMN without invasive cancer (30%), cystadenoma (17%), and pancreatic ductal adenocarcinoma (10%). The PI group had a higher overall complication rate (55% versus 43%, P = 0.02), due in part to a significantly increased rate of pancreatic fistulas (18.4% PI versus 8.5% NI, P < 0.001). Patients in the PI group with malignant disease had a superior long-term survival (median, 30 months, P = 0.01) compared with patients in the NI group with malignant disease (median, 21 months).
Incidentally discovered periampullary and pancreatic masses comprise a substantial proportion of patients undergoing PD. Roughly three fourths of these lesions are malignant or premalignant, and amenable to curative resection. Resected malignant PIs have favorable pathologic features as compared with resected malignant NIs, and resection of these early lesions in asymptomatic individuals is associated with improved survival, compared with patients with symptomatic disease.
Individuals with a strong family history of pancreatic cancer and persons with Peutz-Jeghers syndrome (PJS) have an increased risk for pancreatic cancer. This study screened for early pancreatic neoplasia and compared the pancreatic abnormalities in high-risk individuals and control subjects.
High-risk individuals with PJS or a strong family history of pancreatic cancer were prospectively evaluated with baseline and 12-month computed tomography (CT) scan and endoscopic ultrasonography (EUS). If EUS was abnormal, EUS-fine-needle aspiration and endoscopic retrograde cholangiopancreatography (ERCP) were performed. Surgery was offered to patients with potentially neoplastic lesions. Radiologic findings and pathologic diagnoses were compared. Patients undergoing EUS and/or ERCP for benign non-pancreatic indications were concurrently enrolled as control subjects.
Seventy-eight high-risk patients (72 from familial pancreatic cancer kindreds, 6 PJS) and 149 control patients were studied. To date, 8 patients with pancreatic neoplasia have been confirmed by surgery or fine-needle aspiration (10% yield of screening); 6 patients had 8 benign intraductal papillary mucinous neoplasms (IPMNs), 1 had an IPMN that progressed to invasive ductal adenocarcinoma, and 1 had pancreatic intraepithelial neoplasia. EUS and CT also diagnosed 3 patients with 5 extrapancreatic neoplasms. At EUS and ERCP abnormalities suggestive of chronic pancreatitis were more common in high-risk patients than in control subjects.
Screening EUS and CT diagnosed significant asymptomatic pancreatic and extrapancreatic neoplasms in high-risk individuals. IPMN should be considered a part of the phenotype of familial pancreatic cancer. Abnormalities suggestive of chronic pancreatitis are identified more commonly at EUS and ERCP in high-risk individuals.
To identify potential targets for aberrant methylation in pancreatic cancer, we analyzed global changes in gene expression profiles of four pancreatic cancer cell lines after treatment with the demethylating agent 5-aza-2'-deoxycytidine (5Aza-dC) and/or the histone deacetylase inhibitor trichostatin A. A substantial number of genes were induced 5-fold or greater by 5Aza-dC alone (631 transcripts), trichostatin A alone (1196 transcripts), and by treatment with both agents (857 transcripts). Four hundred and seventy-five genes were markedly (>5-fold) induced after 5Aza-dC treatment in pancreatic cancer cell lines but not in a nonneoplastic pancreatic epithelial cell line. The methylation status of 11 of these 475 genes was examined in a panel of 42 pancreatic cancers, and all 11 of these genes were aberrantly methylated in pancreatic cancer but rarely, if any, methylated in 10 normal pancreatic ductal epithelia. These genes include UCHL1 (methylated in 100% of 42 pancreatic cancers), NPTX2 (98%), SARP2 (95%), CLDN5 (93%), reprimo (86%), LHX1 (76%), WNT7A (71%), FOXE1 (69%), TJP2 (64%), CDH3 (19%), and ST14 (10%). Three of these 11 genes (NPTX2, SARP2, and CLDN5) were selected for further analysis in a larger panel of specimens, and aberrant methylation of at least one of these three genes was detectable in 100% of 43 primary pancreatic cancers and in 18 of 24 (75%) pancreatic juice samples obtained from patients with pancreatic cancer. Thus, a substantial number of genes are induced by 5Aza-dC treatment of pancreatic cancer cells, and many of them may represent novel targets for aberrant methylation in pancreatic carcinoma.