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Coding Molecular Determinants of Thyroid Cancer Development and Progression
Abstract
Thyroid cancer is the most common endocrine malignancy. Its incidence and mortality rates have increased for patients with advanced-stage papillary thyroid cancer. The characterization of the molecular pathways essential in thyroid cancer initiation and progression has made huge progress, underlining the role of intracellular signaling to promote clonal evolution, dedifferentiation, metastasis, and drug resistance. The discovery of genetic alterations that include mutations (BRAF, hTERT), translocations, deletions (eg, 9p), and copy-number gain (eg, 1q) has provided new biological insights with clinical applications. Understanding how molecular pathways interplay is one of the key strategies to develop new therapeutic treatments and improve prognosis.
... Among them, the upward trend of women is the most significant, rising from 7.84/100,000 in 2006 to 13.58/100,000 in 2012 [4]. Thyroid cancer is divided into thyroid follicular carcinoma, papillary thyroid carcinoma, medullary thyroid carcinoma, and undifferentiated thyroid carcinoma according to histological morphology [5], among which, the incidence of papillary thyroid cancer is the highest, accounting for 80%-85% of thyroid cancer [6]. Papillary carcinoma is a common pathological type and has a tendency to develop multicentricity [6]. ...
... Thyroid cancer is divided into thyroid follicular carcinoma, papillary thyroid carcinoma, medullary thyroid carcinoma, and undifferentiated thyroid carcinoma according to histological morphology [5], among which, the incidence of papillary thyroid cancer is the highest, accounting for 80%-85% of thyroid cancer [6]. Papillary carcinoma is a common pathological type and has a tendency to develop multicentricity [6]. In the results of this study, the incidence of multifocal thyroid cancer accounted for 38.18%, and the incidence of polyglandular lobes accounted for 23.64%, which also supports this disease. ...
... This is also one of the important reasons for the increase in the proportion of thyroid micropapillary carcinoma. It can be seen that the diagnosis of this disease is closely related to people's attention and the development of examination and diagnostic techniques [6,7]. In this study, papillary microcarcinoma accounted for 54.55%, and the 2014 WHO Global Cancer Report showed that more than 50% of new cases of thyroid cancer were papillary microcarcinoma of the thyroid, which confirms that the proportion of papillary microcarcinoma of the thyroid is increasing year by year [8]. ...
... Patients with the same histologic subtypes of FCDTC can differ substantially in terms of disease progression, severity, and prognosis, depending on their molecular classification (8,9,31,32). The molecular understanding of FCDTCs opens up possibilities for targeted therapies with selective kinase inhibitors for those patients who have actionable mutations and do not respond to conventional treatment due to the tumor's increased aggressiveness and progression (33). ...
... Despite the limitation of the small number of cases with RAS variants in our study, we still believe that the inclusion of RAS in multigene analysis panels is important, as it may yield prognostic information, especially when associated with other mutations. (13,33), in which a low prevalence of these mutations has been reported in PTC and follicular thyroid cancer. ...
Objectives
To assess the molecular profile of follicular cell-derived thyroid carcinomas (FCDTCs) and correlate the identified mutations with the clinical and pathological features of the affected patients.
Materials and methods
Cross-sectional study of tumor samples from 100 adult patients diagnosed with FCDTC between 2010 and 2019. The patients’ clinical and pathological data were collected. Genomic DNA was extracted from formalin-fixed, paraffin-embedded (FFPE) tumors using the ReliaPrep FFPE gDNA Miniprep System. Genotyping of target genomic regions (KRAS, NRAS, BRAF, EGFR, and PIK3CA) was performed using the AmpliSeq panel, while sequencing was performed on the iSeq 100 platform.
Results
The patients’ mean age was 39 years. In all, 82% of the tumors were classic papillary thyroid carcinomas. Overall, 54 (54%) tumor samples yielded satisfactory results on next-generation sequencing (NGS), of which 31 harbored mutations. BRAF gene mutations were the most frequent, with the BRAFV600E mutation present in 10 tumors. Seven tumors had BRAFNON-V600E mutations not previously described in FCDTCs (G464E, G464R, G466E, S467L, G469E, G596D, and the T599Ifs*10 deletion) but described in other types of cancer (i.e., skin/melanoma, lung, colorectal, and others). One tumor had a previously reported BRAFA598V mutation. EGFR gene mutations were found in 16 (29%) and KRAS or NRAS alterations in 8 (14%) of the 54 tumors analyzed.
Conclusion
We described herein seven non-hotspot/novel variants in the BRAF gene, highlighting their potential role in expanding our understanding of FCDTC genetics.
Keywords
Thyroid cancer; papillary thyroid carcinoma; BRAF V600E ; next-generation sequencing; mutation
... Out of the 107 patients included, 90 were women (84.11%) and 17 35. A comparison of the 4 groups was performed using 2 variables, MPV and PLR through the 4 × 1 one-way ANOVA test way used as parametric statistical analysis. ...
... However, as it occurs with almost everything in medicine, this strategy is not perfect, and over time, some patients may still require conventional treatment. Up until now, the reason why some low-risk patients eventually experience disease persistence or recurrence is not yet clearly understood, not even after identifying the genetic factors associated with aggressiveness 35,36 . Therefore, we should have accessible diagnostic tools to help us make the proper therapeutic decisions 37,38 . ...
... Since the 1970s, ultrasound-guided fine needle aspirations (US-FNA) have been performed for the initial diagnosis of thyroid nodules and for management triage. [7][8][9] Many PTC subtypes exist, including PTCC, FVPTC, solid/trabecular, tall cell, columnar cell, diffuse sclerosing, hobnail, and cribiriform-morular. [10] Most PTC cases are PTCC or FVPTC histologic sub-types, 55%-65% and 23%-41% respectively. Histologic features of PTCC include nuclear grooves, intranuclear inclusions, and papillary architecture. ...
... [15,25,26] In 2013, TERT gene promoter mutations were detected in thyroid carcinoma. [8] TERT is an enzyme involved in telomere elongation. TERT overexpression is caused by a mutation in its promoter region which promotes tumor cell sur-vival. ...
Papillary thyroid carcinoma (PTC) has two major types, classic (PTCC) and follicular variant (FVPTC), which correlate with molecular findings and have varying clinical implications. We assessed the cytologic findings and subsequent surgical pathology findings with the molecular mutations in these two groups, including microcarcinomas. Fourty-four patients with PTC resections over a one-year period were retrospectively examined in conjunction with previous cytologic diagnoses. BRAF, NRAS and TERT promoter mutations for the resected specimens were analyzed. Correlation with previous cytology in regard to molecular mutations and tumor size (microcarcinoma) were made. Significantly more BRAF V600E mutations were seen with PTCC, whereas significantly more NRAS mutations were seen with FVPTC. TERT mutations were only seen with PTCC. Molecular studies for thyroid carcninomas are becoming increasingly more common and influence treatment and patient prognosis. BRAF and or TERT mutations are associated with a worse prognosis. NRAS mutations associated with FVPTC and may lead to milder cytologic changes compared to the BRAF- and TERT-driven PTCC.
... This missense mutation leads to a change in B-raf protein residue 600, replacing glutamic acid with valine (V600E) and the persistent serine/threonine kinase function that damages the suppression loop. As a result, BRAF V600E could initiate itself and also the MAPK signaling cascade [30,32]. ...
Thyroid cancer (TC) remains the most common cancer in endocrinology. Differentiated thyroid cancer (DTC), the most common type of TC, generally has a favorable outlook with conventional treatment, which typically includes surgery along with radioiodine (RAI) therapy and thyroid-stimulating hormone (TSH) suppression through thyroid hormone therapy. However, a small subset of patients (less than 5%) develop resistance to RAI. This resistance occurs due to the loss of Na/I symporter (NIS) activity, which is crucial for iodine absorption in thyroid cells. The decline in NIS activity appears to be due to gene modifications, reconfigurations with irregular stimulation of signaling pathways such as MAPK and PI3K/Akt pathways. These molecular changes lead to a diminished ability of DTC cells to concentrate iodine, which makes RAI therapy ineffective. As a consequence, patients with radioiodine-refractory DTC require alternative treatments. Therapy with tyrosine kinase inhibitors (TKIs) has emerged as the primary treatment option to inhibit proliferation and growth of RAIR-DTC, targeting the pathways responsible for tumor progression. In this article, we analyze molecular processes responsible for RAI resistance and explore both conventional and emerging therapeutic strategies for managing RAIR-DTC, aiming to improve patient outcomes.
... Como todo en medicina, esta vigilancia activa tampoco es perfecta y a lo largo del tiempo algunos pacientes deberán ser tratados de manera convencional. Hasta ahora, la respuesta a por qué unos pacientes con clasificación de bajo riesgo finalmente evolucionan con persistencia o recurrencia de la enfermedad no está claramente dilucidada, ni siquiera con los factores genéticos identificados de agresividad 35,36 . Por ello, mientras se dilucida e identifica con claridad la causa de este comportamiento agresivo, es deseable disponer de herramientas diagnósticas que sean de fácil accesibilidad para una correcta toma de decisión terapéutica 37,38 . ...
Background:
Papillary thyroid cancer is the most common endocrine neoplasia. There are prognostic factors that establish risk of recurrence and mortality; however, patients considered low risk may have a less favorable evolution and hence the importance of finding new markers.
Objective:
To assess whether the mean platelet volume (MPV) and the platelet-lymphocyte index (PLI) show a relationship with the clinical staging in papillary thyroid cancer.
Method:
Retrospective, observational and analytical study. Preoperative MPV and PLI were recorded, its relationship with TNM and MACIS systems was sought, as well as locally advanced invasion and tumor focality.
Results:
107 cases treated from November 2017 to February 2020. No statistically significant difference was observed in these two preoperative parameters with advanced and initial stages, risk groups or tumor focality. The statistical analysis used was one-way ANOVA with SPSS 25, a 95% confidence interval and p < 0.05.
Conclusions:
Despite the logical reasoning of tumor pathophysiology, our study did not find a relationship between papillary thyroid carcinoma with MPV and PLI, and should be complemented with more extensive studies.
... Tumor-related pathways, such as PI3K-Akt, TNF, and NF-κB signaling pathways, may be involved in quercetin treating PTC through KEGG enrichment analysis. Gene alterations caused by partners in the PI3K-AKT signaling pathway are closely associated with thyroid cancer progression [50]. NF-κB is a key regulator of thyroid cancer angiogenesis [51]. ...
Quercetin, a flavonoid with anti-inflammatory and anticancer properties, is expected to be an innovative anticancer therapeutic agent for papillary thyroid carcinoma (PTC). However, the downstream signaling pathways that mediate quercetin-dependent anticancer properties remain to be deciphered. Herein, potential targets of quercetin were screened with several bioinformatic avenues including PharmMapper, Gene Expression Omnibus (GEO) database, protein–protein interaction (PPI) network, and molecular docking. Besides, western blot, CCK-8 transwell analysis of migration and invasion, flow cytometric analysis, and colony formation assays were performed to investigate the underlying mechanism. We found four core nodes (MMP9, JUN, SPP1, and HMOX1) by constructing a PPI network with 23 common targets. Through functional enrichment analysis, we confirmed that the above four target genes are enriched in the TNF, PI3K-AKT, and NF-κB signaling pathways, which are involved in the inflammatory microenvironment and inhibit the development and progression of tumors. Furthermore, molecular docking results demonstrated that quercetin shows strong binding efficiency with the proteins encoded by these 4 key proteins. Finally, quercetin displayed strong antitumor efficacy in PTC cell lines. In this research, we demonstrated the application of network pharmacology in evaluating the mechanisms of action and molecular targets of quercetin, which regulates a variety of proteins and signaling pathways in PTC. These data might explain the mechanism underlying the anticancer effects of quercetin in PTC.
... Thyroid cancer (TC) is one of the most common malignant tumors in the head and neck and endocrine system. Thyroid cancer can be divided into thyroid follicular carcinoma, papillary thyroid carcinoma, medullary thyroid carcinoma, and undifferentiated thyroid carcinoma [9]. Among them, PTC accounts for about 80% of all thyroid cancers. ...
... The continuous emergence of new cases has attracted great attention from the global medical community, despite the fact that there are improved diagnosis and treatment methods and the overall mortality rate has not increased significantly. Thyroid cancer can be divided into thyroid follicular carcinoma, papillary thyroid carcinoma, medullary thyroid carcinoma, anaplastic thyroid carcinoma according to histological morphology [1]. Papillary thyroid carcinoma (PTC) is one of the most common thyroid tumors in clinical practice, accounting for about 80%-85% of all thyroid cancers [2]. ...
... Thyroid cancer (TC) is the most common cancer of the endocrine system, and its incidence is rising rapidly [67,101]. Papillary thyroid carcinoma (PTC) is the most common well-differentiated TC and accounts for 80%-85% of thyroid malignancies [102][103][104]. Although the efficacy of clinical treatment of TC has improved, the disease still has a high recurrence rate [105]. ...
The importance of microRNAs (miRNAs or miRs) has attracted more and more attention. MiRNA is an approximately 22-nucleotide, single-stranded, non-coding RNA molecule that affects the expression of downstream target genes. MiRNAs regulate the occurrence and development of human diseases. The objective of this article is to explore the abnormal expression of miR-198 in a variety of human diseases. The relationships between abnormally expressed miR-198 and clinicopathological characteristics are also summarized. Its roles in various diseases and potential molecular mechanisms include involvement in many biological processes, such as cell cycle regulation, proliferation, invasion, migration, apoptosis, and drug resistance. The potential value of miR-198 for disease diagnosis, treatment, and especially, prognosis, are discussed. More in-depth research on miRNA will support the conversion from basic research to clinical applications of this molecule.
... Currently, TC is the fourth most common female malignancy. Papillary TC (PTC) accounts for 80-85% of thyroid cancers (1). Compared with other TC types, PTC is less malignant, but it also has a higher incidence of distant metastasis and higher recurrence rates. ...
Background:
Studies have shown that cervical carcinoma high-expressed long non-coding RNA 1 (lncRNA-CCHE1) may promote tumor development by regulating tumor migration and invasion in a variety of cancers; yet, the role of lncRNA-CCHE1 in papillary thyroid carcinoma (PTC) remains unclear. The purpose of this study was to explore the mechanism of lncRNA-CCHE1 in PTC.
Methods:
The expression of lncRNA-CCHE1 in 51 PTC carcinoma tissues and normal adjacent tissues was measured using real-time quantitative polymerase chain reaction (RT-qPCR). Cell Counting Kit-8 (CCK8), plate cloning assay, transwell assay, and flow cytometry were used to analyze the effect of lncRNA-CCHE1 on PTC cell proliferation, invasion, and apoptosis in vitro.
Results:
A higher expression of lncRNA-CCHE1 was found in PTC tissues than in adjacent tissues. High expression of lncRNA-CCHE1 was positively correlated with the number of tumors, extra-glandular invasion, and tumor stage. In addition, the down-regulation of lncRNA-CCHE1 reduced the proliferation and invasion of PTC cell lines and promoted cell apoptosis, while its up-regulation caused the opposite effect. These effects were regulated via the extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK/MAPK) pathway.
Conclusions:
The lncRNA-CCHE1 is closely related to PTC progression and may be used as a potential biomarker for early diagnosis and treatment of PTC.
... Thyroid cancer (THCA) is the most common malignant endocrine tumor, and the incidence of THCA has been increasing annually worldwide in recent decades. THCA has thus become one of the fastest growing malignancies in China (Valvo and Nucera, 2019). The development of high-throughput molecular and multi-omics techniques has improved our understanding of molecular changes related to the occurrence and progression of THCA (Boufraqech and Nilubol, 2019). ...
Macrophages are key innate immune cells in the tumor microenvironment that regulate primary tumor growth, vascularization, metastatic spread and response to therapies. Macrophages can polarize into two different states (M1 and M2) with distinct phenotypes and functions. To investigate the known tumoricidal effects of M1 macrophages, we obtained RNA expression profiles and clinical data from The Cancer Genome Atlas Thyroid Cancer (TCGA-THCA). The proportions of immune cells in tumor samples were assessed using CIBERSORT, and weighted gene co-expression network analysis (WGCNA) was used to identify M1 macrophage-related modules. Univariate Cox analysis and LASSO-Cox regression analysis were performed, and four genes (SPP1, DHRS3, SLC11A1, and CFB) with significant differential expression were selected through GEPIA. These four genes can be considered hub genes. The four-gene risk-scoring model may be an independent prognostic factor for THCA patients. The validation cohort and the entire cohort confirmed the results. Univariate and multivariate Cox analysis was performed to identify independent prognostic factors for THCA. Finally, a prognostic nomogram was built based on the entire cohort, and the nomogram combining the risk score and clinical prognostic factors was superior to the nomogram with individual clinical prognostic factors in predicting overall survival. Time-dependent ROC curves and DCA confirmed that the combined nomogram is useful. Gene set enrichment analysis (GSEA) was used to elucidate the potential molecular functions of the high-risk group. Our study identified four genes associated with M1 macrophages and established a prognostic nomogram that predicts overall survival for patients with THCA, which may help determine clinical treatment options for different patients.
... Another important issue, showing huge progress in recent years, is the analysis of molecular pathways, bringing new light to the molecular pathogenesis of metastasis [32]. Such analyses were also carried out in thyroid carcinoma [33,34]. It is believed that understanding the interplay and deregulation in molecular pathways may be crucial for the development of new therapeutic strategies and finally lead to the improvement of long-term prognosis. ...
Molecular mechanisms of distant metastases (M1) in papillary thyroid cancer (PTC) are poorly understood. We attempted to analyze the gene expression profile in PTC primary tumors to seek the genes associated with M1 status and characterize their molecular function. One hundred and twenty-three patients, including 36 M1 cases, were subjected to transcriptome oligonucleotide microarray analyses: (set A—U133, set B—HG 1.0 ST) at transcript and gene group level (limma, gene set enrichment analysis (GSEA)). An additional independent set of 63 PTCs, including 9 M1 cases, was used to validate results by qPCR. The analysis on dataset A detected eleven transcripts showing significant differences in expression between metastatic and non-metastatic PTC. These genes were validated on microarray dataset B. The differential expression was positively confirmed for only two genes: IGFBP3, (most significant) and ECM1. However, when analyzed on an independent dataset by qPCR, the IGFBP3 gene showed no differences in expression. Gene group analysis showed differences mainly among immune-related transcripts, indicating the potential influence of tumor immune infiltration or signal within the primary tumor. The differences in gene expression profile between metastatic and non-metastatic PTC, if they exist, are subtle and potentially detectable only in large datasets.
... In the past decade, the discovery of genetic landscape of thyroid carcinogenesis and progression helped to deepen our understanding of the complex and diverse clinical and biological behaviors of differentiated thyroid cancer. [16] The progression to more aggressive behavior may be predicted based on both histological subtypes and molecular signatures. Subtypes of PTC including the tall cell, columnar cell, diffuse sclerosing, and oncocytic variants tend to be more aggressive and have higher risks of recurrence and metastases. ...
Rationale:
The unpredictability of thyroid cancer can be striking, as the disease may rapidly progress to death in some individuals. Herein, we reported a rare case of aggressive papillary thyroid cell carcinoma (PTC) in an elderly patient de-differentiated into squamous cell carcinoma (SCC).
Patient concerns:
We describe a case of a 79-year-old Thai woman presented with hoarseness and neck mass for 2 months and she had been diagnosed with a 3-cm papillary thyroid carcinoma (PTC) in the right side of the thyroid gland. Later on PTC de-differentiated into SCC within 3 years after initial presentation.
Diagnosis:
De-differentiation from papillary thyroid carcinoma to squamous cell carcinoma.
Interventions:
The patient underwent a total thyroidectomy at the initial hospital and received high dose radioactive iodine (RAI) treatment at our hospital 1 month following the surgery and then was lost to follow-up. Two years later she came back with new development of right solid-cystic neck mass which was found to be recurrent PTC. A radical neck dissection was done and another high dose RAI treatment was given. However, she developed recurrent mass with tenderness at the site above previous solid cystic mass 6 months later. Re-exploration of the neck mass revealed an inflamed midline mass 2 cm with enlarged right lateral cervical lymph nodes.
Outcomes:
A histopathological examination of the midline neck mass showed poorly differentiated SCC with lymphatic invasion. The intermingling of two morphologically distinct tumors, a typical PTC and a poorly differentiated SCC, had been identified in 1 out of 14 excised cervical lymph nodes. The patient underwent external beam radiation without chemotherapy. She is still in stable condition at 18 months post-treatment.
Lessons:
This case clearly demonstrated that SCC transformed from a pre-existing PTC. The clinician should consider a possible transformation of papillary thyroid cancer into more aggressive histological types in elderly patients who present with rapidly progressive clinical behavior. However, some patients could have long-term survival if the tumor did not transform into anaplastic thyroid cancer.
... The genetic hallmark of human PTC is the somatic BRAF V600E mutation. Constitutive activation of the BRAF protooncogene (e.g., valine to glutamic acid substitution, V600E) leads to activation of ERK1/2 pathway and other intracellular pathways associated with abnormal cell proliferation and growth (1)(2)(3). ...
The introduction of ultra-precision targeted therapy has become a significant advancement in cancer therapeutics by creating treatments with less off target effects. Specifically with papillary thyroid carcinoma (PTC), the cancer's hallmark genetic mutation BRAFV600E can be targeted with selective inhibitors, such as vemurafenib. Despite initial positive tumor responses of regression and decreased viability, both single agent or combination agent drug treatments provide a selective pressure for drug resistant evolving clones within the overall heterogeneous tumor. Also, there are evidences suggesting that sequential monotherapy is ineffective and selects for resistant and ultimately lethal tumor clones. Reconstructing both clonal and subclonal thyroid tumor heterogeneous cell clusters for somatic mutations and epigenetic profile, copy number variation, cytogenetic alterations, and non-coding RNA expression becomes increasingly critical as different clonal enrichments implicate how the tumor may respond to drug treatment and dictate its invasive, metastatic, and progressive abilities, and predict prognosis. Therefore, development of novel preclinical and clinical empirical models supported by mathematical assessment will be the tools required for estimating the parameters of clonal and subclonal evolution, and unraveling the dormant vs. non-dormant state of thyroid cancer. In sum, novel experimental models performing the reconstruction both pre- and post-drug treatment of the thyroid tumor will enhance our understanding of clonal and sub-clonal reconstruction and tumor evolution exposed to treatments during ultra-precision targeted therapies. This approach will improve drug development strategies in thyroid oncology and identification of disease-specific biomarkers.
Thyroid cancer (TC), due to its heterogeneous nature, remains a clinical challenge. Many factors can initiate the carcinogenesis process of various types of TC, which complicates diagnosis and treatment. The presented review gathers current information on specific types of TC, taking into account the effects of the COVID-19 pandemic. It is likely that COVID-19 has influenced and continues to influence the function of the thyroid gland. A high percentage of patients with COVID-19 showing simultaneous pathological changes in the thyroid suggests that SARS-CoV-2 may disrupt the function of this gland and initiate pro-oxidative mechanisms, inflammatory states, and autoimmune diseases, thereby promoting the formation of neoplastic changes. Furthermore, changes in the expression of the ACE2, TMPRSS2, CLEC4M and DPP4 genes, observed in TC, also occur in COVID-19. Therefore, it is probable that the interaction of SARS-CoV-2 with thyroid cell receptors may initiate carcinogenesis in this gland. Additionally, some drugs used in TC therapy (e.g., levothyroxine) may increase the affinity of SARS-CoV-2 for cells, which could contribute to a more severe course of COVID-19 and the emergence of long-term symptoms (post-COVID-19). Moreover, the consequences of sanitary restrictions (limited access to medical services, reduction in endocrinological and oncological procedures) that took place in many countries during the COVID-19 pandemic may lead in the future to an increased number of missed diagnoses and the emergence of aggressive cancers.
Background:
Molecular testing (MT) is emerging as a potential prognostic factor that can be available before treatment of differentiated thyroid carcinoma begins. Among patients eligible for either lobectomy or total thyroidectomy as their initial therapy, our study aim was to assess (1) if conventionally available preoperative factors are associated with incomplete response to initial therapy, and (2) if molecular testing (MT) results can be a surrogate for the ATA Risk Stratification System (RSS) to estimate risk of recurrence.
Methods:
The data of consecutive thyroid cancer patients without preoperative lateral neck disease or distant metastasis who underwent index thyroidectomy between November 1, 2017 and October 31, 2021 were reviewed. Logistic regression models including preoperative variables such as MT and/or the postoperatively available RSS were constructed to predict disease recurrence, either structural or biochemical. Model discrimination using the c-statistic and goodness-of-fit were compared.
Results:
Among 945 patients studied, 50 (5.2%) recurred with 18-month median follow up. Recurrences were detected in 17 (2.9%), 20 (6.7%), and 13 (22.8%) patients with RSS-Low, -Intermediate, and -High cancers, respectively (p<0.001). In multivariable analysis, only tumor size was associated with recurrence (OR 1.3, 95% CI 1.1-1.5). In a different model analyzing 440 (46.6%) patients with available MT results, recurrence was associated with both larger tumor size (OR 1.4, 95% CI 1.1-1.8) and MT results (p<0.001). Including MT improved the c-statistic by 27%, which was statistically no different than the model incorporating only the RSS (p=0.15).
Conclusions:
Disease recurrence was observed across all ATA RSS categories in short-term follow-up, and tumor size was the only conventional preoperative factor associated with recurrence. When MT results were incorporated, they not only improved predictive ability beyond tumor size alone, but also yielded similar ability as the gold standard ATA RSS. Thus, MT results might aid the development of novel preoperative risk stratification algorithms.
Background:
Molecular testing improves the diagnostic accuracy of thyroid cancer. Whether specific molecular testing results are associated with tumor phenotype or provide prognostic information needs further delineation.
Methods:
Consecutive thyroid cancer patients after index thyroidectomy with ThyroSeq version 3 (Rye Brook, NY) molecular testing obtained on preoperative fine-needle aspiration or thyroidectomy specimens from patients with thyroid cancer were categorized into 3 molecular risk groups based on detected mutations, fusions, copy number alterations, and/or gene expression alterations and correlated with histopathology and recurrence, defined as biochemical or structural.
Results:
Of 578 patients, 49.9%, 37.5%, and 12.6% had molecular risk group-low, molecular risk group-intermediate, and molecular risk group-high cancers, respectively. With a median 19-month follow-up, 9.1% patients recurred. Compared with molecular risk group-low, molecular risk group-intermediate cancers were diagnosed in younger patients and more often had microscopic extrathyroidal extension, involved margins, and nodal disease. Compared with molecular risk group-intermediate, molecular risk group-high cancers were diagnosed in older patients and more often had gross extrathyroidal extension and vascular invasion. In multivariable analysis, recurrence was more likely in molecular risk group-high cancers than in molecular risk group-intermediate (hazard ratio = 4.0; 95% confidence interval, 1.9-8.6; P < .001) and more likely in molecular risk group-intermediate than in molecular risk group-low (hazard ratio = 5.0; 95% confidence interval, 2.0-12.5; P < .001).
Conclusion:
Using modern comprehensive genotyping, the genetic profile of thyroid cancers can be categorized into 3 novel molecular risk groups that were associated with histopathologic phenotype and recurrence in short-term follow-up.
Background
Numerous circular RNAs (circRNAs) are functionally investigated in human cancers. However, there are still a large number of circRNAs with unclear functions.Objective
The objective of this study was to determine the role of circ_0101622 in thyroid cancer. The expression of circ_0101622, microRNA-1179 (miR-1179), and Ras-associated binding protein 23 (RAB23) was measured using quantitative real-time PCR method. The protein levels of E-cadherin, N-cadherin, and RAB23 were detected by western blot. For functional analyses, cell proliferation, apoptosis, migration, and invasion were assessed using cell counting kit-8 (CCK-8) assay, flow cytometry assay, wound-healing assay, and Transwell assay, respectively. Glycolysis was assessed by glucose consumption and lactate production. The binding between miR-1179 and circ_0101622 or RAB23 was determined by dual-luciferase reporter assay and RIP assay. Animal study was performed to verify the role of circ_0101622. Circ_0101622 showed high expression in thyroid cancer tissues and cells.ResultsCirc_0101622 knockdown inhibited cell proliferation, migration, invasion, and glycolysis metabolism in vitro and blocked tumor growth in vivo. Mechanism analysis found that circ_0101622 functioned as miR-1179 sponge to release RAB23. Circ_0101622 knockdown inhibited cancer development by enriching miR-1179, and miR-1179 restoration inhibited cancer development by sequestering RAB23.Conclusion
Circ_0101622 might act as an oncogenic driver to promote the malignant progression of thyroid cancer by mediating the miR-1179/RAB23 pathway.
Introdução: o carcinoma diferenciado da tireoide corresponde aproximadamente a 90% dos casos de neoplasias da tireoide, sendo que, desses, 80-85% dos casos são de carcinoma papilífero da tireoide. Apesar de a maioria desses carcinomas serem bem diferenciados e com baixa taxa de invasão local, recidiva ou metástases (regionais ou distantes), existe um subgrupo que apresenta uma heterogeneidade genética com variantes mais agressivas, podendo tornar o câncer de tireoide mais invasivo e letal. Objetivos: 1) Relatar o caso de um paciente adulto portador de carcinoma diferenciado da tireoide avançado, com metástase pulmonar, em terapia supressiva com levotiroxina, após tratamento combinado com cirurgia e radioiodoterapia; 2) Discutir sobre as características patológicas e moleculares como fatores relevantes no direcionamento de condutas terapêuticas. Caso clínico: trata-se de um paciente do sexo masculino, com 39 anos de idade, cuja a punção aspirativa com agulha fina (PAAF) foi compatível com carcinoma papilífero da tireoide que, na sequência, foi submetido a tireoidectomia total, com esvaziamento cervical. O exame anatomopatológico revelou carcinoma papilífero da tireoide clássico, com metástase em cinco linfonodos. A análise molecular realizada por sequenciamento de nova geração evidenciou a mutação no gene BRAF (V600E), o qual tem associação significativa com estágios mais avançados do tumor, metástases e radioiodorefratariedade. Conclusão: este relato possibilita discutir a necessidade da avaliação molecular como direcionamento na conduta terapêutica de cada paciente oncológico.
We report a case of the anaplastic spindle cell squamous carcinoma(SC) arising from classical papillary thyroid carcinoma(PTC) with foci of columnar cell component in a 69-year-old Chinese woman. The tumor of the right lobe was composed of spindle cell SC and PTC. Histologically,the spindle cell SC were arranged into bundles with marked cellular atypia, nuclear pleomorphism and more mitotic figures. The tumor of the left lobe was a PTC without any SC elements,which was composed of two components, namely classical and columnar cell variants PTC. The columnar cell elements occupied more than 20% of PTC, which showed striking stratification of nuclei with no characteristic nuclei for the classical type of PTC. The patient has not received any other treatment after radical surgery. She had no tumor recurrence and other complications 13 months after operation. Only classical PTC but not columnar cell PTC and SC had been identified in 7 out of 50 excised cervical lymph nodes. In order to clarify the origin of PTC and spindle cell SC, we performed the BRAFV600E(c.1799 T > A) mutational analysis. The results of molecular analysis showed that BRAFV600E(c.1799 T > A) mutation existed in both components, which further confirmed that spindle cell SC was transformed from PTC.
Our study assesses the effect of bone marrow mesenchymal stem cells (BMSCs) exosomes miR-153 on papillary thyroid carcinoma (PTC). Adipogenesis and osteogenic induction of MSCs was performed and labeled with Cy5 labeled miR inhibitor. Cells were transfected followed by analysis of miR-153 level by real-time PCR, P-gp level by immunoblotting, and cell viability. MSCs are non-hematopoietic bone marrow-derived cells and symmetrical fibroblasts have the same characteristics as MSCs. MSCs have the potential for adipogenesis and osteogenic differentiation; miR-Cy5 can only enter PTC cells through vesicle transfer. TMZ treatment upregulated miR-153 in exosomes; MSC-derived exosomes can be directly transferred to PTC cells. miR-153-inhibitor-Cy5 can effectively inhibit miR-153 transcription and expression of resistance-related proteins. miR-153-inhibitor can promote TMZ’s effect and lead to cell death as demonstrated by increased level of active caspase-3. Inhibiting the endogenous transcription of miR-153 by miR-153 inhibitor can significantly down-regulate cell resistance protein, thereby promoting cell apoptosis under the action of TMZ.
HYOU1 is upregulated in many kinds of cancer cells, and its high expression is associated with tumour invasiveness and poor prognosis. However, the role of HYOU1 in papillary thyroid cancer (PTC) development and progression remains to be elucidated. Here, we reported that HYOU1 was highly expressed in human PTC and associated with poor prognosis. HYOU1 silencing suppressed the proliferation, migration and invasion of PTC cells. Mechanistic analyses showed that HYOU1 silencing promoted oxidative phosphorylation while inhibited aerobic glycolysis via downregulating LDHB at the posttranscriptional level. We further confirmed that the 3'UTR of LDHB mRNA is the indirect target of HYOU1 silencing and HYOU1 silencing increased miR‐375‐3p levels. While LDHB overexpression significantly suppressed the inhibitory effects of HYOU1 silencing on aerobic glycolysis, proliferation, migration and invasion in PTC cells. Taken together, our findings suggest that HYOU1 promotes glycolysis and malignant progression in PTC cells via upregulating LDHB expression, providing a potential target for developing novel anticancer agents.
Purpose of review:
We review the new systemic treatment strategies for differentiated thyroid carcinoma, as well as the acquaintance of its molecular biology.
Recent findings:
Multiple kinase inhibitor drugs have become the standard therapy for thyroid cancer, albeit several adverse effects. In the last few years, new molecules have raised with an overall safety profile. Most of them, are considered targeted therapies directed toward driven-molecules alterations, such as neurotrophic tyrosine kinase receptor (NTRK) inhibitors for NTRK-fusion thyroid cancer and rearranged during transfection (RET) inhibitors for RET-fusion thyroid cancer. Recently, promising outcomes and safety data have been presented. Furthermore, other novel strategies for advanced thyroid carcinoma are currently investigated in clinical trials.The ability to provide precision medicine to patients in routine clinical settings depends on the availability of molecular profiling test at their cancer centers. The impossibility to perform molecular characterization could turn out to be a diagnostic and treatment limitation for some patients.
Summary:
The treatment of advanced differentiated thyroid carcinoma has undergone rapid evolution in the last decade. An emerging treatment era is coming. From now to then, we will need to face the different types of diagnostic tools for molecular characterization, their interpretation and, finally the access to targeted therapies.
Differentiated thyroid cancer often metastasizes to cervical lymph nodes, characteristically with slow growth rate and low-level aggressiveness. Cervical lymph node resection is the treatment of choice, but ethanol ablation offers a therapeutic option for patients with few nodes unresponsive to radioiodine therapy and who are poor surgical candidates. The ethanol ablation procedure is minimally invasive, guided sonographically, easily and safely repeated, and easily implemented with minimal technology and cost. Transient nerve injury is infrequent and virtually the only important complication. Current experience indicates that ethanol ablation has the safest therapeutic profile compared to surgery and thermal ablation, and the effectiveness is comparable to thermal ablation and approaches that of surgery. Well-designed clinical trials are lacking.
The newly introduced pathologic diagnosis of noninvasive follicular thyroid neoplasm with papillary‐like nuclear features (NIFTP) will result in less bilateral thyroid surgery as well as deescalation in T4 suppressive and radioactive iodine treatment. Although, NIFTP is a nonmalignant lesion that has nuclear features of some papillary malignancies, the challenge for the surgeon is to identify a lesion as possibly NIFTP before the pathologic diagnosis. NIFTP, due to its reduction of overall rates of malignancy, will result in the initial surgical pendulum swinging toward lobectomy instead of initial total thyroidectomy. This American Head and Neck Society endocrine section consensus statement is intended to inform preoperative evaluation to attempt to identify those patients whose final pathology report may ultimately harbor NIFTP and can be offered a conservative surgical plan to assist in cost‐effective, optimal management of patients with NIFTP.
The unique oncogene duet of coexisting BRAF V600E and TERT promoter mutations are widely found to be a robust genetic background promoting human cancer aggressiveness, but the mechanism is unclear. Here, we demonstrate that the BRAF V600E/MAP kinase pathway phosphorylates and activates FOS, which in turn acts as a transcription factor to bind and activate the GABPB promoter, increasing GABPB expression and driving formation of GABPA-GABPB complex; the latter selectively binds and activates mutant TERT promoter, upregulating TERT expression. Elevated TERT functions as a strong oncoprotein, robustly promoting aggressive behaviors of cancer cells and tumor development. We thus identify a molecular mechanism for the activation of mutant TERT by the BRAF V600E/MAP kinase pathway, in which FOS as a transcriptional factor of GABPB promoter plays a key role in functionally bridging the two oncogenes in cooperatively promoting oncogenesis, providing important cancer biological and clinical implications.
Purpose
Papillary thyroid carcinoma (PTC) is the most frequent endocrine tumor. BRAFV600E represents the PTC hallmark and is targeted with selective inhibitors (e.g. vemurafenib). Although there have been promising results in clinical trials using these inhibitors, most patients develop resistance and progress. Tumor clonal diversity is proposed as one mechanism underlying drug resistance. Here we have investigated mechanisms of primary and secondary resistance to vemurafenib in BRAFWT/V600E–positive PTC patient-derived cells with P16-/- (CDKN2A-/-).
Experimental Design
Following treatment with vemurafenib, we expanded a sub-population of cells with primary resistance and characterized them genetically and cytogenetically. We have used exome sequencing, metaphase chromosome analysis, FISH and oligonucleotide SNP-microarray assays to assess clonal evolution of vemurafenib-resistant cells. Furthermore, we have validated our findings by networks and pathways analyses using PTC clinical samples.
Results
Vemurafenib-resistant cells grow similarly to naïve cells but are refractory to apoptosis upon treatment with vemurafenib, and accumulate in G2-M phase. We find that vemurafenib-resistant cells show amplification of chromosome 5 and de novo mutations in the RBM (RNA-binding motifs) genes family (i.e. RBMX, RBM10). RBMX knockdown in naïve-cells contributes to tetraploidization, including expansion of clones with chromosome 5 aberrations (e.g. isochromosome 5p). RBMX elicits gene regulatory networks with chromosome 5q cancer-associated genes and pathways for G2-M and DNA damage-response checkpoint regulation in BRAFWT/V600E-PTC. Importantly, combined therapy with vemurafenib plus palbociclib (inhibitor of CDK4/6, mimicking P16 functions) synergistically induces stronger apoptosis than single agents in resistant-cells and in anaplastic thyroid tumor cells harboring the heterozygous BRAFWT/V600E mutation.
Conclusions
Critically, our findings suggest for the first time that targeting BRAFWT/V600E and CDK4/6 represents a novel therapeutic strategy to treat vemurafenib-resistant or vemurafenib-naïve radioiodine-refractory BRAFWT/V600E-PTC. This combined therapy could prevent selection and expansion of aggressive PTC cell sub-clones with intrinsic resistance, targeting tumor cells either with primary or secondary resistance to BRAFV600E inhibitor.
Importance
Thyroid cancer incidence has increased substantially in the United States over the last 4 decades, driven largely by increases in papillary thyroid cancer. It is unclear whether the increasing incidence of papillary thyroid cancer has been related to thyroid cancer mortality trends.
Objective
To compare trends in thyroid cancer incidence and mortality by tumor characteristics at diagnosis.
Design, Setting, and Participants
Trends in thyroid cancer incidence and incidence-based mortality rates were evaluated using data from the Surveillance, Epidemiology, and End Results-9 (SEER-9) cancer registry program, and annual percent change in rates was calculated using log-linear regression.
Exposure
Tumor characteristics.
Main Outcomes and Measures
Annual percent changes in age-adjusted thyroid cancer incidence and incidence-based mortality rates by histologic type and SEER stage for cases diagnosed during 1974-2013.
Results
Among 77?276 patients (mean [SD] age at diagnosis, 48 [16] years; 58?213 [75%] women) diagnosed with thyroid cancer from 1974-2013, papillary thyroid cancer was the most common histologic type (64?625 cases), and 2371 deaths from thyroid cancer occurred during 1994-2013. Thyroid cancer incidence increased, on average, 3.6% per year (95% CI, 3.2%-3.9%) during 1974-2013 (from 4.56 per 100?000 person-years in 1974-1977 to 14.42 per 100?000 person-years in 2010-2013), primarily related to increases in papillary thyroid cancer (annual percent change, 4.4% [95% CI, 4.0%-4.7%]). Papillary thyroid cancer incidence increased for all SEER stages at diagnosis (4.6% per year for localized, 4.3% per year for regional, 2.4% per year for distant, 1.8% per year for unknown). During 1994-2013, incidence-based mortality increased 1.1% per year (95% CI, 0.6%-1.6%) (from 0.40 per 100?000 person-years in 1994-1997 to 0.46 per 100?000 person-years in 2010-2013) overall and 2.9% per year (95% CI, 1.1%-4.7%) for SEER distant stage papillary thyroid cancer.
Conclusions and Relevance
Among patients in the United States diagnosed with thyroid cancer from 1974-2013, the overall incidence of thyroid cancer increased 3% annually, with increases in the incidence rate and thyroid cancer mortality rate for advanced-stage papillary thyroid cancer. These findings are consistent with a true increase in the occurrence of thyroid cancer in the United States.
Mutations 1 295 228 C>T and 1 295 250 C>T (termed C228T and C250T respectively), corresponding to −124 C>T and −146 C>T from the translation start site in the promoter of the telomerase reverse transcriptase (TERT) gene, have recently been reported in human cancers, but not in thyroid cancers yet. We explored these mutations in thyroid cancers by genomic sequencing of a large number of primary tumor samples. We found the C228T mutation in 0 of 85 (0.0%) benign thyroid tumors, 30 of 257 (11.7%) papillary thyroid cancers (PTC), 9 of 79 (11.4%) follicular thyroid cancers (FTC), 3 of 8 (37.5%) poorly differentiated thyroid cancers (PDTC), 23 of 54 (42.6%) anaplastic thyroid cancers (ATC), and 8 of 12 (66.7%) thyroid cancer cell lines. The C250T mutation was uncommon, but mutually exclusive with the C228T mutation, and the two mutations were collectively found in 11 of 79 (13.9%) FTC, 25 of 54 (46.3%) ATC, and 11 of 12 (91.7%) thyroid cancer cell lines. Among PTC variants, the C228T mutation was found in 4 of 13 (30.8%) tall-cell PTC (TCPTC), 23 of 187 (12.3%) conventional PTC, and 2 of 56 (3.6%) follicular variant PTC samples. No TERT mutation was found in 16 medullary thyroid cancer samples. The C228T mutation was associated with the BRAF V600E mutation in PTC, being present in 19 of 104 (18.3%) BRAF mutation-positive PTC vs 11 of 153 (7.2%) the BRAF mutation-negative PTC samples (P=0.0094). Conversely, BRAF mutation was found in 19 of 30 (63.3%) C228T mutation-positive PTC vs 85 of 227 (37.4%) C228T mutation-negative PTC samples (P=0.0094). We thus for the first time, to our knowledge, demonstrate TERT promoter mutations in thyroid cancers, that are particularly prevalent in the aggressive thyroid cancers TCPTC, PDTC, ATC and BRAF mutation-positive PTC, revealing a novel genetic background for thyroid cancers.
PAX8-PPARG fusion protein (PPFP) results from a t(2;3)(q13;p25) chromosomal translocation, is found in 30% of follicular thyroid carcinomas, and demonstrates oncogenic capacity in transgenic mice. A PPARG ligand, pioglitazone, is highly therapeutic in mice with PPFP thyroid cancer. However, only limited data exist to characterize the binding sites and oncogenic function of PPFP, or to explain the observed therapeutic effect of pioglitazone. Here we used our previously characterized transgenic mouse model of PPFP follicular thyroid carcinoma to identify PPFP binding sites in vivo using ChIP-seq, and to distinguish genes and pathways regulated directly or indirectly by PPFP with and without pioglitazone treatment via integration with RNA-seq data. PPFP bound to DNA regions containing the PAX8 and/or the PPARG motif, near genes involved in lipid metabolism, the cell cycle, apoptosis, and cell motility; the binding site distribution was highly concordant with our previous study in a rat PCCL3 cell line. Most strikingly, pioglitazone induced an immune cell infiltration including macrophages and T cells only in the presence of PPFP, which may be central to its therapeutic effect.
Importance:
BRAF V600E and TERT promoter mutations can coexist in papillary thyroid cancer (PTC). This genetic duet was indicated to be involved in the aggressiveness of PTC, but its prognostic value in PTC-related mortality remains to be specifically established.
Objective:
To establish the prognostic power of this genetic duet in PTC-specific mortality.
Design, setting, and participants:
This genetic-clinical correlation study examined BRAF V600E and TERT promoter mutations (chr5:1,295,228C>T and chr5:1,295,250C>T) and PTC-specific mortality in 1051 patients (764 women and 287 men) with a median (interquartile range [IQR]) age of 46 (36-57) years, with a median (IQR) follow-up time of 89 (48-142) months (7.4 years).
Main outcomes and measures:
BRAF V600E and TERT promoter mutation patterns and associated patient deaths caused by PTC.
Results:
Papillary thyroid cancer-specific mortality occurred in 4 of 629 patients (0.6%) with neither mutation; 7 of 292 (2.4%) with BRAF V600E alone; 4 of 64 (6.3%) with TERT promoter mutation alone; and 15 of 66 (22.7%) with the genetic duet; and deaths per 1000-person years in patients harboring neither mutation, BRAF V600E alone, TERT mutation alone, or both mutations were 0.80 (95% CI, 0.30-2.13), 3.08 (95% CI, 1.47-6.46), 6.62 (95% CI, 2.48-17.64), and 29.86 (95% CI, 18.00-49.52), respectively. Compared with patients harboring neither mutation, HRs (95% CIs) for PTC-specific mortality were 3.08 (0.87-10.84) for BRAF V600E alone; 8.18 (2.04-32.75) with TERT mutation alone; and 37.77 (12.50-114.09) with both mutations. Papillary thyroid cancer-specific mortality for cases with both mutations remained significant (HR, 9.34; 95% CI, 2.53-34.48) after adjustment for clinicopathological factors, and the genetic duet showed a strong incremental and synergistic impact over either mutation alone. Kaplan-Meier analyses revealed a flat PTC-specific patient survival curve with neither mutation, a modest decline in the curve with either mutation alone, and a sharp decline in the curve with coexisting mutations. Even more robust mortality associations of the genetic duet were seen when only conventional-variant PTC (CPTC) was analyzed (HR, 54.46; 95% CI, 12.26-241.82), which remained strongly significant (HR, 18.56; 95% CI, 2.97-116.18) after adjustment for clinicopathological factors.
Conclusions and relevance:
These results demonstrate a simple 4-genotype classification of PTC, particularly CPTC, with a disease-specific mortality risk order of the genetic duet>BRAF V600E alone = TERT promoter mutation alone > wild-type for both genes, representing a powerful molecular prognostic system that can help pinpoint patients with the highest mortality risk.
Mutations in ß-catenin are traditionally described as late events in thyroid cancer progression. However, the functional implications of ß-catenin dysregulation in the context of tumor initiating events remain unclear. The aim of this work was to investigate whether the two main oncogenic drivers in thyroid cancer, RAS and BRAF, could activate the Wnt/ß-catenin pathway. Expression of HRASV12 but not BRAFV600E in thyroid cells induced ß-catenin nuclear localization, increased ß-catenin-dependent transcriptional activity and inhibited GSK3ß. In a panel of human thyroid cancer cell lines representative of the main genetic events in thyroid cancer, ß-catenin activation was highly dependent on PI3K/AKT activity through its phosphorylation at S552, but not on MAPK. Silencing of ß-catenin expression in cell lines led to a dramatic reduction in proliferation due to an induction of senescence, which was concordant with a reduction in tumor size in nude mice. Moreover, ß-catenin silencing suppressed the expression of EMT-related genes and reduced the invasive capacity of the tumor cells. In conclusion, this work demonstrates that RAS-driven tumors induce PI3K/AKT-dependent ß-catenin activation.
Compelling epidemiologic evidence indicates that obesity is associated with a high risk of human malignancies, including thyroid cancer. We previously demonstrated that a high fat diet (HFD) effectively induces the obese phenotype in a mouse model of aggressive follicular thyroid cancer (ThrbPV/PVPten+/-mice). We showed that HFD promotes cancer progression through aberrant activation of the leptin-JAK2-STAT3 signaling pathway. HFD-promoted thyroid cancer progression allowed us to test other molecular targets for therapeutic opportunity for obesity-induced thyroid cancer. Metformin is a widely used drug to treat patients with type II diabetes. It has been shown to reduce incidences of neoplastic diseases and cancer mortality in type II diabetes patients. The present study aimed to test whether metformin could be a therapeutic for obesity-activated thyroid cancer. ThrbPV/PVPten+/-mice were fed HFD together with metformin or vehicle-only, as controls, for 20 weeks. While HFD-ThrbPV/PVPten+/-mice had shorter survival than LFD-treated mice, metformin had no effects on the survival of HFD-ThrbPV/PVPten+/-mice. Remarkably, metformin markedly decreased occurrence of capsular invasion and completely blocked vascular invasion and anaplasia in HFD-ThrbPV/PVPten+/-mice without affecting thyroid tumor growth. The impeded cancer progression was due to the inhibitory effect of metformin on STAT3-ERK-vimentin and fibronectin-integrin signaling to decrease tumor cell invasion and de-differentiation. The present studies provide additional molecular evidence to support the link between obesity and thyroid cancer risk. Importantly, our findings suggest that metformin could be used as an adjuvant in combination with antiproliferative modalities to improve the outcome of patients with obesity-activated thyroid cancer.
RAS mutations play an important role in thyroid tumorigenesis. Considerable effort has been made in the last decade to apply RAS mutations as molecular markers to the clinical management of thyroid nodules and thyroid cancer. Yet, for the low diagnostic sensitivities and specificities of RAS mutations, when used alone, and for their uncertain role in the clinical outcomes of thyroid cancer, it has been unclear how to appropriately use them to assist the management of thyroid nodules and thyroid cancer. Studies from recent years, now added from the Alexander group, have shed light on this issue, making a blurred clinical picture now emerge clearer—RAS mutations, when combined with other genetic markers, have high diagnostic negative predictive values for thyroid cancer; cytologically benign thyroid nodules, including those positive for RAS mutations, have long-term clinical stability when non-surgically managed; and differentiated thyroid cancers harboring RAS mutations alone have an excellent prognosis. This progress in understanding RAS mutations in thyroid cancer is showing a major impact on molecular-based practice in the management of thyroid cancer.
Please see related research articles: http://dx.doi.org/10.1186/s12916-016-0554-1 and http://dx.doi.org/10.1186/s12916-015-0419-z
BRAFV600E mutation exerts an essential oncogenic function in many tumors, including papillary thyroid carcinoma (PTC). Although BRAFV600E inhibitors are available, lack of response has been frequently observed. To study the mechanism underlying intrinsic resistance to the mutant BRAFV600E selective inhibitor vemurafenib, we established short-term primary cell cultures of human metastatic/recurrent BRAFV600E-PTC, intrathyroidal BRAFV600E-PTC, and normal thyroid (NT). We also generated an early intervention model of human BRAFV600E-PTC orthotopic mouse. We find that metastatic BRAFV600E-PTC cells elicit paracrine-signaling which trigger migration of pericytes, blood endothelial cells and lymphatic endothelial cells as compared to BRAFWT-PTC cells, and show a higher rate of invasion. We further show that vemurafenib therapy significantly suppresses these aberrant functions in non-metastatic BRAFV600E-PTC cells but lesser in metastatic BRAFV600E-PTC cells as compared to vehicle treatment. These results concur with similar folds of down-regulation of tumor microenvironment-associated pro-metastatic molecules, with no effects in BRAFWT-PTC and NT cells. Our early intervention preclinical trial shows that vemurafenib delays tumor growth in the orthotopic BRAFWT/V600E-PTC mice. Importantly, we identify high copy number gain of MCL1 (chromosome 1q) and loss of CDKN2A (P16, chromosome 9p) in metastatic BRAFV600E-PTC cells which are associated with resistance to vemurafenib treatment. Critically, we demonstrate that combined vemurafenib therapy with BCL2/MCL1 inhibitor increases metastatic BRAFV600E-PTC cell death and ameliorates response to vemurafenib treatment as compared to single agent treatment. In conclusion, short-term PTC and NT cultures offer a predictive model for evaluating therapeutic response in patients with PTC. Our PTC pre-clinical model suggests that combined targeted therapy might be an important therapeutic strategy for metastatic and refractory BRAFV600E-positive PTC.
A chromosomal translocation results in production of an oncogenic PAX8-PPARG fusion protein (PPFP) in thyroid carcinomas. PAX8 is a thyroid transcription factor, and PPARG is a transcription factor that plays important roles in adipocytes and macrophages. PPFP retains the DNA binding domains of both proteins; however, the genomic binding sites of PPFP have not been identified, and only limited data exist to characterize gene expression in PPFP thyroid carcinomas. Therefore, the oncogenic function of PPFP is poorly understood. We expressed PPFP in PCCL3 rat thyroid cells and used ChIP-seq to identify PPFP genomic binding sites (PPFP peaks) and RNA-seq to characterize PPFP-dependent gene expression. PPFP peaks (~20,000) include known PAX8 and PPARG binding sites and are enriched with both motifs, indicating that both DNA binding domains are functional. PPFP binds to and regulates many genes involved in cancer-related processes. In PCCL3 thyroid cells, PPFP binds to adipocyte PPARG target genes in preference to macrophage PPARG target genes, consistent with the pro-adipogenic nature of PPFP and its ligand pioglitazone in thyroid cells. PPFP induces oxidative stress in thyroid cells, and pioglitazone increases susceptibility to further oxidative stress. Our data highlight the complexity of PPFP as a transcription factor and the numerous ways that it regulates thyroid oncogenesis.
Ch22q LOH is preferentially associated with RAS mutations in papillary and in poorly differentiated thyroid cancer (PDTC). The 22q tumor suppressor NF2, encoding merlin, is implicated in this interaction because of its frequent loss of function in human thyroid cancer cell lines. Nf2 deletion or Hras mutation are insufficient for transformation, whereas their combined disruption leads to murine PDTC with increased MAPK signaling. Merlin loss induces RAS signaling in part through inactivation of Hippo, which activates a YAP-TEAD transcriptional program. We find that the three RAS genes are themselves YAP-TEAD1 transcriptional targets, providing a novel mechanism of promotion of RAS-induced tumorigenesis. Moreover, pharmacological disruption of YAP-TEAD with verteporfin blocks RAS transcription and signaling, and inhibits cell growth. The increased MAPK output generated by NF2 loss in RAS-mutant cancers may inform therapeutic strategies, as it generates greater dependency on the MAPK pathway for viability.
Significance:
Intensification of mutant Ras signaling through copy-number imbalances is commonly associated with transformation. We show that NF2/merlin inactivation augments mutant RAS signaling by promoting YAP/TEAD-driven transcription of oncogenic and wild-type RAS, resulting in greater MAPK output and increased sensitivity to MEK inhibitors.
NF-κB signaling plays an important role in tumor cell proliferation, cell survival, angiogenesis, invasion, metastasis and drug/radiation resistance. Combination therapy involving NF-κB pathway inhibition is an attractive strategy for the treatment of advanced forms of thyroid cancer. This study was designed to test the efficacy of NF-κB pathway inhibition in combination with cytotoxic chemotherapy, using docetaxel and ionizing radiation in in vitro models of thyroid cancer. We found that while both docetaxel and ionizing radiation activated NF-κB signaling in thyroid cancer cells, there was no synergistic effect on cell proliferation and/or programmed cell death with either genetic (transduction of a dominant negative mutant form of IκBα) or pharmacologic (proteasome inhibitor bortezomib and IKKβ inhibitor GO-Y030) inhibition of the NF-κB pathway in thyroid cancer cell lines BCPAP, 8505C, THJ16T and SW1736. Docetaxel plus bortezomib synergistically decreased in vitro invasion of 8505C cells, but not in the other cell lines. Screening of a panel of clinically relevant targeted therapies for synergy with genetic NF-κB inhibition in a proliferation/cytotoxicity assay identified the histone deacetylase (HDAC) inhibitor suberoylanilide hydroxamic acid (SAHA) as a potential candidate. However, the synergistic effect was confirmed only in the BCPAP cells. These results indicate that NF-κB inhibitors are unlikely to be beneficial as combination therapy with taxane cytotoxic chemotherapy, external radiation therapy or radioiodine therapy. There may be unique circumstances where NF-κB inhibitors may be considered in combination with docetaxel to reduce tumor invasion or in combination with HDAC inhibitors to reduce tumor growth, but this does not appear to be a combination therapy that could be broadly applied to patients with advanced thyroid cancer. Further research may identify which subsets of patients/tumors may respond to this therapeutic approach.
Cachexia is the result of complex metabolic alterations which causes morbidity in patients with advanced cancers including undifferentiated (anaplastic) thyroid carcinoma (ATC). ATC is a lethal disease with limited therapeutic options and unclear etiology for cachexia. We hypothesize that the BRAF(V600E) oncoprotein triggers microvascular endothelial cell tubule formation (in vitro angiogenesis) by means of factors which play a crucial role in angiogenic switch, inflammation/immune response and cachexia. We use human ATC cells and applied multiplex ELISA assay to screen for and measure angiogenic/cachectic and pro-inflammatory factors in the ATC-derived secretome. We find that vemurafenib anti-BRAF(V600E) therapy significantly reduces secreted VEGFA, VEGFC and IL6 protein levels compared to vehicle-treated ATC cells. As a result, the secretome from vemurafenib-treated ATC cells inhibits microvascular endothelial cell-related in vitro angiogenesis. Furthermore, ATC clinical samples express VEGFA, VEGFC and IL6 proteins. Our results suggest that angiogenic/cachectic and pro-inflammatory/immune response factors could play a crucial role in BRAF(V600E)-positive human ATC aggressiveness. Understanding the extent to which microenvironment-associated angiogenic factors participate in cachexia and cancer metabolism in advanced thyroid cancers will reveal new biomarkers and foster novel therapeutic approaches.
Copyright © 2015. Published by Elsevier Ireland Ltd.
The tumor suppressor PTEN is frequently inactivated in human cancers. A major downstream effector of PTEN is Akt, which is hyperactivated via PTEN inactivation. It is not known, however, whether diminished Akt activity is sufficient to inhibit tumorigenesis initiated by Pten deficiency. Here we showed that the deficiency of Akt1 is sufficient to dramatically inhibit tumor development in Pten+/- mice. Akt1 deficiency had a profound effect on endometrium and prostate neoplasia, two types of human cancer, in which PTEN is frequently mutated, and also affected thyroid and adrenal medulla tumors and intestinal polyps. Even haplodeficiency of Akt1 was sufficient to markedly attenuate the development of high-grade prostate intraepithelial neoplasia (PIN) and endometrial carcinoma. These results have significant implications for cancer therapy.
Context:
The aggressive role of TERT promoter mutations has been well established in differentiated thyroid cancer but has not been established in anaplastic thyroid cancer (ATC).
Research design:
We tested the mutation status by sequencing genomic tumor DNA and examined its relationship with clinicopathological characteristics of ATC.
Results:
Among 106 American and Chinese ATC samples, TERT 1,295,228 C>T (termed TERT C228T) mutation was found in 37 (34.9%) cases, TERT promoter mutation 1,295,250 C>T was found in four cases (3.8%), and the two mutations were mutually exclusive and collectively found in 41 cases (38.7%). TERT C228T occurred in 28 of 90 (31.1%) wild-type BRAF cases vs nine of 16 (56.3%) BRAF V600E cases, with an odds ratio of 2.85 (95% confidence interval, 0.96-8.42; P = .05). Patient age was 67.6 ± 13.6 vs 61.6 ± 11.4 years in the TERT C228T vs wild-type TERT patients (P = .02), demonstrating an association between TERT C228T and older patient age. This association was also seen within the American cohort. In this cohort, which had more available clinicopathological data, TERT C228T was associated with distant metastasis of the tumor; specifically, distant metastasis occurred in 15 of 18 (83.3%) TERT C228T patients vs eight of 26 (30.8%) wild-type TERT patients, with an odds ratio of 11.25 (95% confidence interval, 2.53-50.08; P = .001). No association was found with patient sex, tumor size, lymph node metastasis, and extrathyroidal invasion of ATC.
Conclusions:
This is the largest study on the aggressive role of TERT promoter mutations in ATC, demonstrating an association of TERT C228T with BRAF V600E, older patient age, and tumor distant metastasis in ATC.
Papillary thyroid carcinoma (PTC) is the most common type of thyroid cancer. Here, we describe the genomic landscape of 496 PTCs. We observed a low frequency of somatic alterations (relative to other carcinomas) and extended the set of known PTC driver alterations to include EIF1AX, PPM1D, and CHEK2 and diverse gene fusions. These discoveries reduced the fraction of PTC cases with unknown oncogenic driver from 25% to 3.5%. Combined analyses of genomic variants, gene expression, and methylation demonstrated that different driver groups lead to different pathologies with distinct signaling and differentiation characteristics. Similarly, we identified distinct molecular subgroups of BRAF-mutant tumors, and multidimensional analyses highlighted a potential involvement of oncomiRs in less-differentiated subgroups. Our results propose a reclassification of thyroid cancers into molecular subtypes that better reflect their underlying signaling and differentiation properties, which has the potential to improve their pathological classification and better inform the management of the disease.
Undifferentiated thyroid carcinoma is one of the most aggressive human cancers with frequent RAS mutations. How mutations of the RAS gene contribute to undifferentiated thyroid cancer remains largely unknown. Mice harboring a potent dominant negative mutant thyroid hormone receptor β, TRβPV (ThrbPV/PV), spontaneously develop well-differentiated follicular thyroid cancer similar to human cancer. We genetically targeted the KrasG12D mutation to thyroid epithelial cells of ThrbPV/PV mice to understand how KrasG12D mutation could induce undifferentiated thyroid cancer in ThrbPV/PVKrasG12D mice. ThrbPV/PVKrasG12D mice exhibited poorer survival due to more aggressive thyroid tumors with capsular invasion, vascular invasion, and distant metastases to the lung occurring at an earlier age and at a higher frequency than ThrbPV/PV mice did. Importantly, ThrbPV/PVKrasG12D mice developed frequent anaplastic foci with complete loss of normal thyroid follicular morphology. Within the anaplastic foci, the thyroid-specific transcription factor paired box gene 8 (PAX8) expression was virtually lost and the loss of PAX8 expression was inversely correlated with elevated MYC expression. Consistently, co-expression of KRASG12D with TRβPV upregulated MYC levels in rat thyroid pccl3 cells, and MYC acted to enhance the TRβPV-mediated repression of the Pax8 promoter activity of a distant upstream enhancer, critical for thyroid-specific Pax8 expression. Our findings indicated that synergistic signaling of KRASG12D and TRβPV led to increased MYC expression. Upregulated MYC contributes to the initiation of undifferentiated thyroid cancer, in part, through enhancing TRβPV-mediated repression of the Pax8 expression. Thus, MYC might serve as a potential target for therapeutic intervention.
Purpose:
To investigate the prognostic value of the BRAF V600E mutation and the recently identified TERT promoter mutation chr5:1,295,228C>T (C228T), individually and in their coexistence, in papillary thyroid cancer (PTC).
Patients and methods:
We performed a retrospective study of the relationship of BRAF and TERT C228T mutations with clinicopathologic outcomes of PTC in 507 patients (365 women and 142 men) age 45.9 ± 14.0 years (mean ± SD) with a median follow-up of 24 months (interquartile range, 8 to 78 months).
Results:
Coexisting BRAF V600E and TERT C228T mutations were more commonly associated with high-risk clinicopathologic characteristics of PTC than they were individually. Tumor recurrence rates were 25.8% (50 of 194;77.60 recurrences per 1,000 person-years; 95% CI, 58.81 to 102.38) versus 9.6% (30 of 313; 22.88 recurrences per 1,000 person-years; 95% CI, 16.00 to 32.72) in BRAF mutation-positive versus -negative patients (hazard ratio [HR], 3.22; 95% CI, 2.05 to 5.07) and 47.5% (29 of 61; 108.55 recurrences per 1,000 person-years; 95% CI, 75.43 to 156.20) versus 11.4% (51 of 446; 30.21 recurrences per 1,000 person-years; 95% CI, 22.96 to 39.74) in TERT mutation-positive versus -negative patients (HR, 3.46; 95% CI, 2.19 to 5.45). Recurrence rates were 68.6% (24 of 35; 211.76 recurrences per 1,000 person-years; 95% CI, 141.94 to 315.94) versus 8.7% (25 of 287; 21.60 recurrences per 1,000 person-years; 95% CI, 14.59 to 31.97) in patients harboring both mutations versus patients harboring neither mutation (HR, 8.51; 95% CI, 4.84 to 14.97), which remained significant after clinicopathologic cofactor adjustments. Disease-free patient survival curves displayed a moderate decline with BRAF V600E or TERT C228T alone but a sharp decline with two coexisting mutations.
Conclusion:
Coexisting BRAF V600E and TERT C228T mutations form a novel genetic background that defines PTC with the worst clinicopathologic outcomes, providing unique prognostic and therapeutic implications.
Context:
Promoter mutations chr5:1,295,228C>T and chr5:1,295,250C>T (termed C228T and C250T, respectively) in the gene for telomerase reverse transcriptase (TERT) have been reported in various cancers and need to be further investigated in thyroid cancer.
Objective:
The aim of the study was to explore TERT promoter mutations in various thyroid tumors and examine their relationship with BRAF V600E mutation, iodine intake, and clinicopathological behaviors of thyroid cancer.
Design:
TERT promoter and BRAF mutations were identified by sequencing genomic DNA of primary thyroid tumors from normal- and high-iodine regions in China, and clinicopathological correlation was analyzed.
Results:
The C228T mutation was found in 9.6% (39 of 408) of papillary thyroid cancer (PTC), C250T was found in 1.7% (7 of 408) of PTC, and they were collectively found in 11.3% (46 of 408) of PTC. C228T was found in 31.8% (7 of 22) and C250T in 4.6% (1 of 22) of follicular thyroid cancer (FTC), and they were collectively found in 36.4% (8 of 22) of FTC. No TERT mutation was found in 44 benign thyroid tumors. The two mutations occurred in 3.8% (6 of 158) of BRAF mutation-negative PTC vs 16.0% (40 of 250) of BRAF mutation-positive PTC (P = 5.87 × 10(-4)), demonstrating their association. Unlike BRAF mutation, TERT promoter mutations were not associated with high iodine intake, but they were associated with older patient age, larger tumor size, extrathyroidal invasion, and advanced stages III/IV of PTC. Coexisting TERT and BRAF mutations were even more commonly and more significantly associated with clinicopathological aggressiveness.
Conclusions:
In this large cohort, we found TERT promoter mutations to be common, particularly in FTC and BRAF mutation-positive PTC, and associated with aggressive clinicopathological characteristics.
Significance
Thyroid cancer is common and has an excellent outcome in many cases, although a proportion of these tumors have a progressive clinical course and high mortality. Using whole-transcriptome (RNA-sequencing) analysis, we discovered previously unknown genetic events, anaplastic lymphoma kinase ( ALK ) gene fusions, in thyroid cancer and demonstrate that they occur more often in aggressive cancers. The most common fusion identified in these tumors involved the striatin ( STRN ) gene, and we show that it is transforming and tumorigenic in vivo. Finally, we demonstrate that the kinase activity of STRN-ALK can be blocked by ALK inhibitors, raising a possibility that ALK fusions may be used as a therapeutic target for patients with the most aggressive and frequently lethal forms of thyroid cancer.
Context:
Telomerase promoter mutations (TERT) were recently described in follicular cell-derived thyroid carcinomas (FCDTC) and seem to be more prevalent in aggressive cancers.
Objectives:
We aimed to evaluate the frequency of TERT promoter mutations in thyroid lesions and to investigate the prognostic significance of such mutations in a large cohort of patients with differentiated thyroid carcinomas (DTCs).
Design:
This was a retrospective observational study.
Setting and patients:
We studied 647 tumors and tumor-like lesions. A total of 469 patients with FCDTC treated and followed in five university hospitals were included. Mean follow-up (±SD) was 7.8 ± 5.8 years.
Main outcome measures:
Predictive value of TERT promoter mutations for distant metastasization, disease persistence at the end of follow-up, and disease-specific mortality.
Results:
TERT promoter mutations were found in 7.5% of papillary carcinomas (PTCs), 17.1% of follicular carcinomas, 29.0% of poorly differentiated carcinomas, and 33.3% of anaplastic thyroid carcinomas. Patients with TERT-mutated tumors were older (P < .001) and had larger tumors (P = .002). In DTCs, TERT promoter mutations were significantly associated with distant metastases (P < .001) and higher stage (P < .001). Patients with DTC harboring TERT promoter mutations were submitted to more radioiodine treatments (P = .009) with higher cumulative dose (P = .004) and to more treatment modalities (P = .001). At the end of follow-up, patients with TERT-mutated DTCs were more prone to have persistent disease (P = .001). TERT promoter mutations were significantly associated with disease-specific mortality [in the whole FCDTC (P < .001)] in DTCs (P < .001), PTCs (P = .001), and follicular carcinomas (P < .001). After adjusting for age at diagnosis and gender, the hazard ratio was 10.35 (95% confidence interval 2.01-53.24; P = .005) in DTC and 23.81 (95% confidence interval 1.36-415.76; P = .03) in PTCs.
Conclusions:
TERT promoter mutations are an indicator of clinically aggressive tumors, being correlated with worse outcome and disease-specific mortality in DTC. TERT promoter mutations have an independent prognostic value in DTC and, notably, in PTC.
Thyroid carcinoma is the most common endocrine malignant tumor and accounts for 1% of all new malignant diseases. Among all types and subtypes of thyroid cancers that have been described so far, papillary thyroid carcinoma is the most frequent. The standard management treatment of these tumors consists of surgery, followed by radioiodine treatment in case of high risk of relapse. The most aggressive forms are commonly treated by chemotherapy, radiotherapy or experimental drug testing. We recently reported the case of a patient presenting an anaplastic thyroid carcinoma with lung metastases. Fluorescence in situ hybridization analysis allowed us to detect a rearrangement of the anaplastic lymphoma kinase (ALK) gene in both tumors. The patient was treated with crizotinib and presented an excellent drug response. We present here the subsequent investigations carried out to further characterize this genetic alteration and to assess the prevalence of ALK rearrangements in thyroid lesions. High resolution array-comparative genomic hybridization data complemented by RT-PCR and sequencing analyses, allowed us to demonstrate the presence of a STRN/ALK fusion. The STRN/ALK transcript consisted of the fusion between exon 3 of STRN and exon 20 of ALK. Subsequent screening of 75 various thyroid tumors by RT-PCR revealed that 2 out of 29 papillary thyroid carcinomas exhibited the same fusion transcript. None was detected in other types of malignant or benign thyroid lesions analyzed. These findings could pave the way for the development of new targeted therapeutic strategies in the treatment of papillary thyroid carcinomas and point to ALK inhibitors as promising agents that merit rapid evaluation.
BACKGROUND: In their previous analysis of papillary thyroid carcinomas (PTCs) from an Ukrainian-American cohort that was exposed to iodine-131 ((131) I) from the Chernobyl accident, the authors identified RET/PTC rearrangements and other driver mutations in 60% of tumors.
METHODS: In this study, the remaining mutation-negative tumors from that cohort were analyzed using RNA sequencing (RNA-Seq) and reverse transcriptase-polymerase chain reaction to identify novel chromosomal rearrangements and to characterize their relation with radiation dose.
RESULTS: The ETS variant gene 6 (ETV6)-neurotrophin receptor 3 (NTRK3) rearrangement (ETV6-NTRK3) was identified by RNA-Seq in a tumor from a patient who received a high (131) I dose. Overall, the rearrangement was detected in 9 of 62 (14.5%) post-Chernobyl PTCs and in 3 of 151 (2%) sporadic PTCs (P = .019). The most common fusion type was between exon 4 of ETV6 and exon 14 of NTRK3. The prevalence of ETV6-NTRK3 rearrangement in post-Chernobyl PTCs was associated with increasing (131) I dose, albeit at borderline significance (P = .126). The group of rearrangement-positive PTCs (ETV6-NTRK3, RET/PTC, PAX8-PPARγ) was associated with significantly higher dose response compared with the group of PTCs with point mutations (BRAF, RAS; P < .001). In vitro exposure of human thyroid cells to 1 gray of (131) I and γ-radiation resulted in the formation of ETV6-NTRK3 rearrangement at a rate of 7.9 × 10(-6) cells and 3.0 × 10(-6) cells, respectively.
CONCLUSIONS: The authors report the occurrence of ETV6-NTRK3 rearrangements in thyroid cancer and demonstrate that this rearrangement is significantly more common in tumors associated with exposure to (131) I and has a borderline significant dose response. Moreover, ETV6-NTRK3 rearrangement can be directly induced in thyroid cells by ionizing radiation in vitro and, thus, may represent a novel mechanism of radiation-induced carcinogenesis.
Context:
The BRAF V600E mutation (BRAF-MUT) confers an aggressive phenotype in papillary thyroid carcinoma, but unidentified additional genomic abnormalities may be required for full phenotypic expression.
Objective:
RNA sequencing (RNA-Seq) was performed to identify genes differentially expressed between BRAF-MUT and BRAF wild-type (BRAF-WT) tumors and to correlate changes to patient clinical status.
Design:
BRAF-MUT and BRAF-WT tumors were identified in patients with T1N0 and T2-3N1 tumors evaluated in a referral medical center. Gene expression levels were determined (RNA-Seq) and fusion transcripts were detected. Multiplexed capture/detection and digital counting of mRNA transcripts (nCounter, NanoString Technologies) validated RNA-Seq data for immune system-related genes.
Patients:
BRAF-MUT patients included nine women, three men; nine were TNM stage I and three were stage III. Three (25%) had tumor infiltrating lymphocytes. BRAF-WT included five women, three men; all were stage I, and five (62.5%) had tumor infiltrating lymphocytes.
Results:
RNA-Seq identified 560 of 13 085 genes differentially expressed between BRAF-MUT and BRAF-WT tumors. Approximately 10% of these genes were related to MetaCore immune function pathways; 51 were underexpressed in BRAF-MUT tumors, whereas 4 (HLAG, CXCL14, TIMP1, IL1RAP) were overexpressed. The four most differentially overexpressed immune genes in BRAF-WT tumors (IL1B; CCL19; CCL21; CXCR4) correlated with lymphocyte infiltration. nCounter confirmed the RNA-Seq expression level data. Eleven different high-confidence fusion transcripts were detected (four interchromosomal; seven intrachromosomal) in 13 of 20 tumors. All in-frame fusions were validated by RT-PCR.
Conclusion:
BRAF-MUT papillary thyroid cancers have reduced expression of immune/inflammatory response genes compared with BRAF-WT tumors and correlate with lymphocyte infiltration. In contrast, HLA-G and CXCL14 are overexpressed in BRAF-MUT tumors. Sixty-five percent of tumors had between one and three fusion transcripts. Functional studies will be required to determine the potential role of these newly identified genomic abnormalities in contributing to the aggressiveness of BRAF-MUT and BRAF-WT tumors.
Purpose:
The BRAFV600E oncogene modulates the papillary thyroid carcinoma (PTC) microenvironment, in which pericytes are critical regulators of tyrosine-kinase (TK)-dependent signaling pathways. Although BRAFV600E and TK inhibitors are available, their efficacy as bimodal therapeutic agents in BRAFV600E-PTC is still unknown.
Experimental design:
We assessed the effects of vemurafenib (BRAFV600E inhibitor) and sorafenib (TKI) as single agents or in combination in BRAFWT/V600E-PTC and BRAFWT/WT cells using cell-autonomous, pericyte co-culture, and an orthotopic mouse model. We also used BRAFWT/V600E-PTC and BRAFWT/WT-PTC clinical samples to identify differentially expressed genes fundamental to tumor microenvironment.
Results:
Combined therapy blocked tumor cell proliferation, increased cell death, and decreased motility via BRAFV600E inhibition in thyroid tumor cells in vitro Vemurafenib produces cytostatic effects in orthotopic tumors, whereas combined therapy (likely reflecting sorafenib activity) generates biological fluctuations with tumor inhibition alternating with tumor growth. We demonstrate that pericytes secrete TSP-1 and TGFβ1, and induce the rebound of pERK1/2, pAKT and pSMAD3 levels to overcome the inhibitory effects of the targeted therapy in PTC cells. This leads to increased BRAFV600E-PTC cell survival and cell death refractoriness. We find that BRAFWT/V600E-PTC clinical samples are enriched in pericytes, and TSP1 and TGFβ1 expression evoke gene-regulatory networks and pathways in the microenvironment essential for BRAFWT/V600E-PTC cell survival. Critically, antagonism of the TSP-1/TGFβ1 axis reduces tumor cell growth and overcomes drug resistance.
Conclusions:
Pericytes shield BRAFV600E-PTC cells from targeted therapy via TSP-1 and TGFβ1, suggesting this axis as a new therapeutic target for overcoming resistance to BRAFV600E and TK inhibitors.
Compelling epidemiological evidence shows a strong positive correlation of obesity with thyroid cancer. In vivo studies have provided molecular evidence that high-fat-diet-induced obesity promotes thyroid cancer progression by aberrantly activating leptin-JAK2-STAT3 signaling in a mouse model of thyroid cancer (ThrbPV/PVPten+/- mice). The ThrbPV/PVPten+/- mouse expresses a dominantly negative thyroid hormone receptor β (denoted as PV) and a deletion of one single allele of the Pten gene. The ThrbPV/PVPten+/- mouse spontaneously develops follicular thyroid cancer, which allows its use as a preclinical mouse model to test potential therapeutics. We recently showed that inhibition of STAT3 activity by a specific inhibitor markedly delays thyroid cancer progression in high-fat-diet-induced obese ThrbPV/PVPten+/- mice (HFD-ThrbPV/PVPten+/- mice). Further, metformin, a widely used antidiabetic drug, blocks invasion and metastasis, but not thyroid tumor growth in HFD-ThrbPV/PVPten+/- mice. To improve efficacy in reducing thyroid tumor growth, we treated HFD-ThrbPV/PVPten+/- with JQ1, a potent inhibitor of the activity of bromodomain and extraterminal domain (BET), and with metformin. We found that the combined treatment synergistically suppressed thyroid tumor growth by attenuating STAT3 and ERK signaling, resulting in decreased anti-apoptotic key regulators such as Mcl-1, Bcl-2, and sruvivin and increased pro-apoptotic regulators such as Bim, BAD and cleave caspase 3. Furthermore, combined treatment of JQ1 and metformin reduced cMyc protein levels to suppress vascular invasion, anaplasia, and lung metastasis. These findings indicate that combined treatment is more effective than metformin alone and suggest a novel treatment modality for obesity-activated thyroid cancer.
The follicular variant (FV) of papillary thyroid carcinoma is characterized by a follicular growth pattern and cytologic features of papillary carcinoma. ret/PTC rearrangements are common in classic papillary thyroid carcinoma (PTC) and PAX8-PPARγ and ras mutations in follicular thyroid carcinoma. Their prevalence in FV has not been established. We studied these genetic alterations and clinical-pathologic features in 30 FV cases and compared those with 46 non-FV papillary carcinomas. FV cases revealed 1 ret/PTC rearrangement (3%) and 13 ras mutations (43%). Non-FV cases harbored 13 ret/PTC (28%) (P = .006) and no ras mutations (P = .0002). No PAX8-PPARγ was found in either group. FV cases demonstrated a significantly higher prevalence of tumor encapsulation, angiovascular invasion, and poorly differentiated areas and a lower rate of lymph node metastases. These data indicate that the FV of papillary carcinoma has a distinct set of molecular alterations and is characterized by a high frequency of ras point mutations.
Objective:
PTC-specific analysis identified novel fusions involving RET, BRAF, NTRK1, NTRK3, AGK and ALK genes in adults and pediatric PTC. Although many novel fusions are PTC-specific event and, therefore, are ideal for diagnosis purposes, validation across additional and larger cohorts is essential for introducing these potential diagnostic or prognostic biomarkers into the clinical practice. As most of the BRAF, NTRK3 and ALK fusions were initially found in pediatric PTC or in more aggressive thyroid carcinomas, and there is a great disparity across population, in this study, we screened a large set of adult sporadic PTC cases for the most prevalent kinases fusion lately described in the TCGA.
Design and methods:
The prevalence of the fusions was determined by RT-PCR in 71 classical PTC, 45 follicular variant of PTC (FVPTC), 19 follicular thyroid adenomas (FTA) and 22 follicular thyroid carcinomas (FTC).
Results:
ETV6-NTRK3 was exclusively found in FVPTC, in both encapsulated and infiltrative variants, but was not found in FTAs and FTCs. STRN-ALK was found in both classical PTC and FVPTC. No AGK-BRAF fusion was identified in this series, endorsing that AGK-BRAF is a genetic event mainly associated with pediatric PTCs.
Conclusions:
The identification of kinases fusions in thyroid carcinomas helps to expand our knowledge about the landscape of oncogenic alterations in PTC. As ETV6-NTRK3 and STRN-ALK are recurrent and not identified in benign lesions, they can certainly help with diagnosis of thyroid nodules. Further analysis is needed to define if they can also be useful for prognosis and guiding therapy.
Metastasis suppressors are key regulators of tumor growth, invasion, and metastases. Loss of metastasis suppressors has been associated with aggressive tumor behaviors and metastatic progression. We previously showed that regulator of calcineurin 1, isoform 4 (RCAN1-4) was upregulated by the KiSS1 metastatic suppression pathway and could inhibit cell motility when overexpressed in cancer cells. To test the effects of endogenous RCAN1-4 loss on thyroid cancer in vivo, we developed RCAN1-4 knockdown stable cells. Subcutaneous xenograft models demonstrated that RCAN1-4 knockdown promotes tumor growth. Intravenous metastasis models demonstrated that RCAN1-4 loss promotes tumor metastases to the lungs and their subsequent growth. Finally, stable induction of RCAN1-4 expression reduced thyroid cancer cell growth and invasion. Microarray analysis predicted that nuclear factor, erythroid 2-like 3 (NFE2L3) was a pivotal downstream effector of RCAN1-4. NFE2L3 overexpression was shown to be necessary for RCAN1-4-mediated enhanced growth and invasiveness and NEF2L3 overexpression independently increased cell invasion. In human samples, NFE2L3 was overexpressed in TCGA thyroid cancer samples versus normal tissues and NFE2L3 overexpression was demonstrated in distant metastasis samples from thyroid cancer patients. In conclusion, we provide the first evidence to our knowledge that RCAN1-4 is a growth and metastasis suppressor in vivo and that it functions in part through NFE2L3.
Aneuploidy, the state of having gained or lost chromosomes, is a hallmark of cancer. Approximately 90% of tumors have gained or lost at least one chromosome. In spite of aneuploidy occurring as frequently as, if not more often than, disruption of the p53 pathway, whether and how aneuploidy influences tumorigenesis is still poorly understood. Here, we take advantage of large-scale tumor sequencing efforts to assess karyotypic alterations across many cancer types and review recent sequencing studies that show how karyotypes change in space and time. We further summarize findings that describe the effects of aneuploidy on untransformed cells, the mechanisms by which aneuploidy could drive tumorigenesis, and the potential to target aneuploidy for cancer therapy. Expected final online publication date for the Annual Review of Cancer Biology Volume 1 is March 04, 2017. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
Purpose:
New therapeutic approaches are needed for patients with thyroid cancer refractory to radioiodine treatment. An inhibitor of bromodomain and extraterminal domain (BET) proteins, JQ1, shows potent anti-tumor effects in hematological cancers and solid tumors. To evaluate whether JQ1 is effective against thyroid cancer, we examined anti-tumor efficacy of JQ1 using the ThrbPV/PVKrasG12D mouse, a model of anaplastic thyroid cancer.
Experimental design:
We treated ThrbPV/PVKrasG12D mice with vehicle or JQ1 at a dose of 50 mg/kg body weight/day starting at the age of 8 weeks for a 10-week period and monitored thyroid tumor progression.
Results:
JQ1 markedly inhibited thyroid tumor growth and prolonged survival of these mice. Global differential gene expression analysis showed that JQ1 suppressed the cMyc (hereafter referred to as Myc) transcription program by inhibiting mRNA expression of Myc, ccnd1, and other related genes. JQ1-suppressed Myc expression was accompanied by chromatin remodeling as evidenced by increased expression of histones and hexamethylene bis-acetamide inducible 1, a suppressor of RNA polymerase II transcription elongation. Analyses showed that JQ1 decreased MYC abundance in thyroid tumors and attenuated the cyclin-CDK4-Rb-E2F3 signaling to decrease tumor growth. Further analysis indicated that JQ1 inhibited the recruitment of BDR4 to the promoter complex of the Myc and Ccnd1 genes in rat thyroid follicular PCCL3 cells, resulting in decreased MYC expression at the mRNA and protein levels to inhibit tumor cell proliferation.
Conclusions:
These preclinical findings suggest that BET inhibitors may be an effective agent to reduce thyroid tumor burden for the treatment of refractory thyroid cancer.
Background:
Poorly differentiated thyroid cancer (PDTC) and anaplastic thyroid cancer (ATC) are rare and frequently lethal tumors that so far have not been subjected to comprehensive genetic characterization.
Methods:
We performed next-generation sequencing of 341 cancer genes from 117 patient-derived PDTCs and ATCs and analyzed the transcriptome of a representative subset of 37 tumors. Results were analyzed in the context of The Cancer Genome Atlas study (TCGA study) of papillary thyroid cancers (PTC).
Results:
Compared to PDTCs, ATCs had a greater mutation burden, including a higher frequency of mutations in TP53, TERT promoter, PI3K/AKT/mTOR pathway effectors, SWI/SNF subunits, and histone methyltransferases. BRAF and RAS were the predominant drivers and dictated distinct tropism for nodal versus distant metastases in PDTC. RAS and BRAF sharply distinguished between PDTCs defined by the Turin (PDTC-Turin) versus MSKCC (PDTC-MSK) criteria, respectively. Mutations of EIF1AX, a component of the translational preinitiation complex, were markedly enriched in PDTCs and ATCs and had a striking pattern of co-occurrence with RAS mutations. While TERT promoter mutations were rare and subclonal in PTCs, they were clonal and highly prevalent in advanced cancers. Application of the TCGA-derived BRAF-RAS score (a measure of MAPK transcriptional output) revealed a preserved relationship with BRAF/RAS mutation in PDTCs, whereas ATCs were BRAF-like irrespective of driver mutation.
Conclusions:
These data support a model of tumorigenesis whereby PDTCs and ATCs arise from well-differentiated tumors through the accumulation of key additional genetic abnormalities, many of which have prognostic and possible therapeutic relevance. The widespread genomic disruptions in ATC compared with PDTC underscore their greater virulence and higher mortality.
Funding:
This work was supported in part by NIH grants CA50706, CA72597, P50-CA72012, P30-CA008748, and 5T32-CA160001; the Lefkovsky Family Foundation; the Society of Memorial Sloan Kettering; the Byrne fund; and Cycle for Survival.
A PAX8-PPARgamma rearrangement has been recently identified in follicular thyroid carcinomas, but not in follicular adenomas or other thyroid tumors. We report here the analyses of PAX8-PPARgamma in a series of 118 thyroid tumors using a newly developed RT-PCR assay to detect this rearrangement in frozen and paraffin-embedded tissues and using immunostaining with a PPARgamma antibody. PAX8-PPARgamma was detected by RT-PCR in eight of 15 (53%) follicular carcinomas and two of 25 (8%) follicular adenomas but not in 35 papillary carcinomas (including 12 follicular variants), 12 Hurthle cell carcinomas, 12 Hurthle cell adenomas, two anaplastic carcinomas, one poorly differentiated carcinoma, or 16 hyperplastic nodules. The prevalence was higher in follicular carcinomas from patients with a history of radiation exposure (three of three). Strong, diffuse nuclear immunostaining with the PPARgamma antibody correlated with the presence of PAX8-PPARgamma detected by RTPCR. Most sporadic follicular carcinomas positive for PAX8-PPARgamma were overtly invasive, whereas tumors lacking the rearrangement were predominantly minimally invasive. The two follicular adenomas positive for PAX8-PPARgamma had trabecular growth pattern and thick capsule, but no invasion, and thus may represent "pre-invasive" follicular carcinomas. The absence of PAX8-PPARgamma rearrangements in Hurthle cell tumors and papillary thyroid carcinomas highlights the differences in the molecular pathogenesis of these thyroid tumors.
Background:
An increase in thyroid cancers, predominantly papillary thyroid carcinoma (PTC), has been recently reported in children.
Methods:
The histopathology of 28 consecutive PTCs from the northeast United States was reviewed. None of the patients (ages 6-18 years; 20 females, 8 males) had significant exposure to radiation. Nucleic acid from tumors was tested for genetic abnormalities (n = 27). Negative results were reevaluated by targeted next-generation sequencing.
Results:
Seven of 27 PTCs (26%) had neurotrophic tyrosine kinase receptor (NTRK) fusion oncogenes (NTRK type 3/ets variant 6 [NTRK3/ETV6], n =5; NTRK3/unknown, n = 1; and NTRK type 1/translocated promoter region, nuclear basket protein [NTRK1/TPR], n = 1), including 5 tumors that measured >2 cm and 3 that diffusely involved the entire thyroid or lobe. All 7 tumors had lymphatic invasion, and 5 had vascular invasion. Six of 27 PTCs (22%) had ret proto-oncogene (RET) fusions (RET/PTC1, n = 5; RET/PTC3, n = 1); 2 tumors measured >2 cm and diffusely involved the thyroid, and 5 had lymphatic invasion, with vascular invasion in 2. Thirteen PTCs had the B-Raf proto-oncogene, serine/threonine kinase (BRAF) valine-to-glutamic acid mutation at position 600 (BRAF(V) (600E) ) (13 of 27 tumors; 48%), 11 measured <2 cm, and 6 had lymphatic invasion (46%), with vascular invasion in 3. Fusion oncogene tumors, compared with BRAF(V) (600E) PTCs, were associated with large size (mean, 2.2 cm vs 1.5 cm, respectively; P = .05), solid and diffuse variants (11 of 13 vs 0 of 13 tumors, respectively; P < .001), and lymphovascular invasion (12 of 13 vs 6 of 13 tumors, respectively; P = .02); BRAF(V) (600E) PTCs were predominantly the classic variant (12 of 13 vs 1 of 13 tumors). Two tumors metastasized to the lung, and both had fusion oncogenes (NTRK1/TPR, n = 1; RET/PTC1, n = 1).
Conclusions:
Fusion oncogene PTC presents with more extensive disease and aggressive pathology than BRAF(V) (600E) PTC in the pediatric population. The high prevalence of the NTRK1/NTRK3 fusion oncogene PTCs in the United States is unusual and needs further investigation. Cancer 2016. © 2016 American Cancer Society.
Compelling epidemiologic studies indicate that obesity is a risk factor for many human cancers, including thyroid cancer. In recent decades, the incidence of thyroid cancer has dramatically increased along with a marked rise in obesity prevalence. We previously demonstrated that a high fat diet (HFD) effectively induced the obese phenotype in a mouse model of thyroid cancer (ThrbPV/PVPten+/- mice). Moreover, HFD activates the STAT3 signal pathway to promote more aggressive tumor phenotypes. The aim of the present study was to evaluate the effect of S3I-201, a specific inhibitor of STAT3 activity, on HFD-induced aggressive cancer progression in the mouse model of thyroid cancer. Wild type and ThrbPV/PVPten+/- mice were treated with HFD together with S3I-201 or vehicle-only as controls. We assessed the effects of S3I-201 on HFD-induced thyroid cancer progression, the leptin-JAK2-STAT3 signaling pathway, and key regulators of epithelial-mesenchymal transition. S3I-201 effectively inhibited HFD-induced aberrant activation of STAT3 and its downstream targets to markedly inhibit thyroid tumor growth and to prolong survival. Decreased protein levels of cyclins D1 and B1, cyclin dependent kinase (CDK) 4, CDK 6, and phosphorylated retinoblastoma protein led to the inhibition of tumor cell proliferation in S3I-201-treated ThrbPV/PVPten+/- mice. Reduced occurrence of vascular invasion and blocking of anaplasia and lung metastasis in thyroid tumors of S3I-201-treated ThrbPV/PVPten+/- mice were mediated via decreased expression of vimentin and matrix metalloproteinases, two key effectors of epithelial-mesenchymal transition. The present findings suggest that inhibition of the STAT3 activity would be a novel treatment strategy for obesity-induced thyroid cancer.
Conclusions:
The BRAF K601E mutation is the second most common BRAF mutation after V600E found in thyroid nodules. Unlike BRAF V600E, this mutation is strongly associated with follicular-patterned cancer, particularly with the encapsulated follicular variant of PTC and may also be found in a follicular thyroid carcinoma. Overall, BRAF K601E mutant tumors show better clinical outcomes than BRAF V600E positive tumors, and preoperative BRAF K601E analysis can provide important prognostic information for use in clinical management.
Increased p21 activated kinase (PAK) signaling and expression has been identified in the invasive fronts of aggressive papillary thyroid cancers (PTCs), including those with RET/PTC, BRAF V600E, and mutant RAS expression. Functionally, thyroid cancer cell motility in vitro is dependent on Group 1 PAKs particularly PAK1. In the present study, we hypothesize that BRAF, a central kinase in PTC tumorigenesis and invasion, regulates thyroid cancer cell motility in part through PAK activation. Using three well-characterized human thyroid cancer cell lines, we demonstrated in all cell lines that BRAF knockdown reduced PAK phosphorylation of direct downstream targets. In contrast, inhibition of MEK activity either pharmacologically or with siRNA did not reduce PAK activity indicating MEK is dispensable for PAK activity. Inhibition of cell migration through BRAF loss is rescued by overexpression of either constitutive active (CA) MEK1 or PAK1, demonstrating that both signaling pathways are involved in BRAF-regulated cell motility. To further characterize BRAF-PAK signaling, immunofluorescence and immunoprecipitation demonstrated that both exogenously overexpressed and endogenous PAK1 and BRAF co-localize and physically interact, and that this interaction was enhanced in mitosis. Finally, we demonstrated that acute induction of BRAFV600E expression in vivo in murine thyroid glands results in increased PAK expression and activity confirming a positive signaling relationship in vivo. In conclusion, we have identified a signaling pathway in thyroid cancer cells which BRAF activates and physically interacts with PAK and regulates cell motility.
Background:
There remain a small number of patients with papillary thyroid cancer (PTC) who suffer recurrence, metastases, or death. While mutation of the BRAF gene, corresponding to the constitutively active BRAF(V600E) protein, has been associated with worse clinical outcomes in thyroid cancer, the reasons underlying this observation are presently unknown. Disruption of endogenous host immune surveillance and promotion of tumor immune escape is one mechanism by which BRAF(V600E) tumors may achieve more aggressive behavior. This study evaluated the relationship between BRAF(V600E) status and known strategies of tumor-mediated immune suppression.
Methods:
Tissue sections of PTC tumors from 33 patients were evaluated by immunohistochemistry for tumor-expressed suppressive ligands and enzymes and effector and suppressor populations of tumor-infiltrating immune cells. Presence of BRAF(V600E) was evaluated by direct DNA sequencing of PTC specimens and the results correlated with tumor-expressed molecules and tumor-infiltrating immune cell populations, as well as patient characteristics and pathologic findings.
Results:
BRAF(V600E) tumors more often express high levels of immunosuppressive ligands programmed death ligand 1 (53% vs. 12.5%) and human leukocyte antigen G (41% vs. 12.5%) compared to BRAF wild-type tumors. There was no association between indoleamine 2,3-dioxygenase 1 expression and BRAF(V600E) status. Furthermore, BRAF(V600E) tumors demonstrate both lower CD8(+) effector to FoxP3(+) regulatory T cell, and CD68(+) pan-macrophage to CD163(+) M2 macrophage ratios, indicating relative increases in suppressive T cell and macrophage components, respectively.
Conclusions:
Overall, BRAF(V600E) PTC tumors display a broadly immunosuppressive profile and evidence of disturbed host tumor immune surveillance that may contribute to the poorer outcomes observed in this subset of patients with thyroid cancer.
Background:
Aberrant activation of the Wnt/β-catenin pathway is a common pathogenesis of various human cancers. We investigated the role of the Wnt inhibitor, Dkk-1, in papillary thyroid cancer (PTC).
Methods:
Immunohistochemical β-catenin staining was performed in tissue microarray containing 148 PTCs and five normal thyroid tissues. In vivo effects of Dkk-1 were explored using ectopic tumors with BHP10-3SC cells.
Results:
In 27 PTC patients, 60% of patients showed β-catenin up-regulation and Dkk-1 down-regulation in tumor vs normal tissues. Tissue microarray analysis showed that 14 of 148 PTC samples exhibited cytoplasmic-dominant β-catenin expression compared to membranous-dominant expression in normal tissues. Aberrant β-catenin expression was significantly correlated with higher rates of the loss of membranous E-cadherin expression and poor disease-free survival than that in the normal membranous expression group over a median follow-up period of 14 years. Implantation of Dkk-1-overexpressing BHP10-3SC cells revealed delayed tumor growth, resulting from the rescue of membranous β-catenin and E-cadherin expressions. Furthermore, tissue microarray analysis demonstrated that BRAF(WT) patients had higher rates of aberrant expressions of β-catenin and E-cadherin than BRAF(V600E) patients. Indeed, the inhibitory effects of Dkk-1 on cell survival were more sensitive in BRAF(WT) (BHP10-3SC and TPC-1) than in BRAF(V600E) (SNU-790 and BCPAP) cells. Overexpression of BRAF(V600E) in normal thyroid epithelial (H tori) cells also reduced the effects of Dkk-1 on cell survival.
Conclusion:
A subset of PTC patients showed aberrant expression of β-catenin/E-cadherin signaling and poor disease-free survival. Dkk-1 might have a therapeutic role, particularly in BRAF(WT) patients.
Background:
PAX8/PPARγ rearrangement is a common genetic alteration in follicular thyroid carcinoma (FTC) and has been reported with variable frequency in papillary thyroid carcinoma (PTC). The diagnostic and phenotypic features of thyroid nodules positive for PAX8/PPARγ on preoperative examination are not well understood.
Methods:
The prevalence of PAX8/PPARγ rearrangement was analyzed in a series of 2015 consecutive thyroid nodules that underwent molecular analysis on cytology specimens and in 446 surgically removed PTCs. For all PAX8/PPARγ positive cases, cytology and surgical pathology slides were examined and the available clinical records were reviewed.
Results:
Twenty-two PAX8/PPARγ rearrangements were identified, including 16 detected preoperatively and 6 postoperatively. The incidence of PAX8/PPARγ in PTC was 1.1%. Cytologically, most of these nodules were diagnosed as a follicular neoplasm (73%), followed by the diagnosis of atypia of undetermined significance (19%), and none of the cases was diagnosed as cytologically malignant. All nodules with PAX8/PPARγ detected preoperatively and surgical follow-up available were found to be malignant, among which the most common diagnosis was the encapsulated follicular variant of PTC. Overall, among 20 PAX8/PPARγ-positive tumors that were surgically excised, 17 (85%) were PTC and 3 (15%) were FTC. On follow-up available for 17 patients (mean, 22.4 months), 16 PAX8/PPARγ-positive cancers showed no evidence of biochemical or structural recurrence, whereas 1 patient with FTC developed bone metastasis.
Conclusions:
In this series, PAX8/PPARγ rearrangement found in thyroid nodules had a 100% predictive value for differentiated thyroid cancer, and was more predictive of PTC than FTC. However, almost all PTC carrying PAX8/PPARγ were encapsulated follicular-pattern tumors, distinguished from FTC only by nuclear features. Although most tumors carrying this mutation appear to be clinically indolent, at least on short-term follow-up, distant metastasis can develop from FTC positive for PAX8/PPARγ.
Context:
Development of novel strategies in the treatment of advanced thyroid cancer are needed. Our laboratory has previously identified a role for nuclear factor κB (NF-κB) signaling in human thyroid cancer cell growth, survival, and invasion.
Objective:
Our goal was to establish the role of NF-κB signaling on thyroid cancer growth and metastases in vivo and to begin to dissect mechanisms regulating this effect.
Setting and design:
We examined tumor formation of five thyroid cancer cell lines in an in vivo model of thyroid cancer and observed tumor establishment in two of the cell lines (8505C and BCPAP).
Results:
Inhibition of NF-κB signaling by overexpression of a dominant-negative IκBα (mIκBα) significantly inhibited thyroid tumor growth in tumors derived from both cell lines. Further studies in an experimental metastasis model demonstrated that NF-κB inhibition impaired growth of tumor metastasis and prolonged mouse survival. Proliferation (mitotic index) was decreased in 8505C tumors, but not in BCPAP tumors, while in vitro angiogenesis and in vivo tumor vascularity were significantly inhibited by mIkBα only in the BCPAP cells. Cytokine antibody array analysis demonstrated that IL-8 secretion was blocked by mIκBα expression. Interestingly, basal NF-κB activity and IL-8 levels were significantly higher in the two tumorigenic cell lines compared with the nontumorigenic lines. Furthermore, IL-8 transcript levels were elevated in high-risk human tumors, suggesting that NF-κB and IL-8 are associated with more aggressive tumor behavior.
Conclusions:
These studies suggest that NF-κB signaling is a key regulator of angiogenesis and growth of primary and metastatic thyroid cancer, and that IL-8 may be an important downstream mediator of NF-κB signaling in advanced thyroid cancer growth and progression.
Significance
We generated a thyroid-specific CreER transgenic mouse and used this strain to model progression of v-raf murine sarcoma viral oncogene homolog B ( BRAF )-mutant papillary thyroid cancer to anaplastic thyroid cancer (ATC). These murine tumors recapitulated the temporal progression and molecular hallmarks of human ATC. We demonstrated that combined mapk/Erk kinase (MEK) and BRAF inhibition resulted in enhanced antitumor activity vs. single-agent BRAF inhibitors in this preclinical model. This model represents a previously lacking mouse model of BRAF -mutant ATC and adds to the experimental armamentarium of a highly lethal disease in need of scientific advances. These data also suggest that potent inhibition of the MAPK pathway may improve outcomes in advanced thyroid cancers.
The Wnt/βcatenin pathway has been associated with thyroid cell growth and tumorigenesis. However, little is known regarding its involvement in the response to the key regulators of thyroid cell proliferation and differentiation. Here we show that thyroid stimulating hormone (TSH) and Insulin-like growth factor I (IGF-I) increase βcatenin nuclear accumulation and its transcriptional activity in differentiated thyroid cells. This effect takes place in a Wnt-independent manner as TSH and IGF-I, through the activation of protein kinase A (PKA) and protein kinase B (PKB)/Akt (AKT), phosphorylate βcatenin at S552 and S675 which results in βcatenin release from E-cadherin at the adherens junctions. Nuclear βcatenin regulates thyroid cell proliferation, since its silencing or the overexpression of a dominant negative form of the T-cell factor 4 (TCF), resulted in reduced levels of Cyclin D1 and DNA synthesis. Furthermore, the βcatenin silencing markedly reduced the expression of Pax8, the main transcription factor involved in epithelial thyroid cell differentiation. Finally, we observed that βcatenin physically interacts with the transcription factor Pax8, increasing its transcriptional activity on the Sodium Iodide Symporter (NIS) gene, a critical gene required for the thyroid cell physiology. Altogether, our findings show that βcatenin plays a not yet described role in thyroid function including a functional interaction with Pax8.
Context:
Aberrant DNA methylation is known to be a major factor in oncogenesis and cancer progression, but effects of methylation in papillary thyroid cancer (PTC) are not well defined.
Objective:
The objective of the study was to identify altered methylation patterns, which may be associated with PTC disease behavior.
Design:
This study was a genome-wide methylation analysis of PTC.
Setting:
The study was conducted at the National Institutes of Health Clinical Center.
Patients:
PTC tissue from 51 patients were analyzed and compared with normal thyroid tissue from seven patients.
Interventions:
CpG methylation status was assessed using advanced genome-wide methylation bead chips.
Outcome measures:
Altered methylation patterns in PTC were analyzed by stage, recurrence, histological subtype of tumor, and tumor genotype.
Results:
PTC is globally hypomethylated compared with normal thyroid with 2837 differentially methylated CpG sites. The follicular variant of PTC demonstrated less differential methylation with only 569 differentially methylated CpG sites. Tumors with mutations in BRAF, RET/PTC, and RAS demonstrated a 3.6-fold increase in the number of differentially methylated sites compared with wild-type tumors. The differentially methylated genes were associated with oncological pathways including cellular movement, growth, and proliferation.
Conclusion:
PTC is epigenetically distinct from the follicular variant of PTC and by gene mutation status (BRAF, RET/PTC, and RAS).