[Show abstract][Hide abstract] ABSTRACT: HPV-related HNSCC generally have a better prognosis than HPV-negative HNSCC. However, a subgroup of
HPV-positive tumors with poor prognosis has been recognized, particularly related to smoking, EGFR
overexpression and chromosomal instability. Viral integration into the host genome might contribute to
carcinogenesis, as is shown for cervical carcinomas. Therefore, all HPV16-positive HNSCC cell lines currently
available have been carefully analysed for viral and host genome parameters.
The viral integration status, viral load, viral gene expression and the presence of aneusomies was evaluated in the
cell lines UD-SCC-2, UM-SCC-047, UM-SCC-104, UPCI:SCC090, UPCI:SCC152, UPCI:SCC154 and
93VU147T. HPV integration was examined using FISH, APOT-PCR and DIPS-PCR. Viral load and the
expression of the viral genes E2, E6 and E7 were determined via quantitative PCR.
All cell lines showed integration-specific staining patterns and signals indicating transcriptional activity using
FISH. APOT- and DIPS-PCR identified integration-derived fusion products in six cell lines, and only episomal
products for UM-SCC-104. Despite the observed differences in viral load and the number of viral integration
sites, this did not relate to the identified viral oncogene expression. Furthermore, cell lines exhibited EGFR
expression, and aneusomy (except UPCI:SCC154).
In conclusion, all HPV16-positive HNSCC cell lines showed integrated and/or episomal viral DNA that is
transcriptionally active, although viral oncogene expression was independent of viral copy number and the
number of viral integration sites. Because these cell lines also contain EGFR expression and aneusomy, which
are parameters of poor prognosis, they should be considered suitable model systems for the development of new
International Journal of Cancer 10/2014; · 6.20 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: High-risk (hr) human papillomavirus (HPV) infections play a causal role in the development of cervical cancer. The detection of hrHPV is, therefore, advocated in cervical cancer screening programs.Objectives
The aim of this study was to determine the performance of a novel HPV typing assay, PapillomaFinder® SMART 20. This is a one-tube-per-sample method, to be performed on standard real-time PCR platforms, using melting curve analysis to distinguish targets. The assay detects all 14 hrHPV types, of which 16, 18, 31, 33, 35, 39, 45, 52, 56 and 58 individually. HrHPV types 51, 59, 66 and 68 are detected in an hrHPV pool, and low-risk (lr) HPV types 6, 11, 40, 42, 43 and 44 in an lrHPV pool.Study designThe method was tested on HPV plasmid models, WHO and QCMD proficiency panels and a series of clinical cytological samples (n = 45), the latter in comparison with a clinically validated real-time quantitative PCR.ResultsType-specificity of the test was 100% using plasmids, the WHO and QCMD panels. Sensitivity for hrHPV in single infections was 100% using the WHO and QCMD panels and cytological samples, with an analytical sensitivity of 10–25 copies per reaction for all HPV types tested. Of the 34 HPV types present in the 8 multiple infections in the WHO panel, 30 were detected. In all cytological samples at least one hrHPV type was found, in concordance with the clinically validated method. Only when the viral load of the dominant HPV types in multiple infections greatly exceeded that of the other types in the infection, those other types were not always detected.Conclusions
PapillomaFinder® SMART 20 is a rapid, easy to perform, single tube HPV typing assay. The assay detects the 14 hrHPV types, and the 6 most important lrHPV types with a high sensitivity and type-specificity.
[Show abstract][Hide abstract] ABSTRACT: Pulmonary carcinoids are neuroendocrine tumors histopathologically subclassified into typical (TC; no necrosis, <2 mitoses per 2 mm) and atypical (AC; necrosis or 2 to 10 mitoses per 2 mm). The reproducibility of lung carcinoid classification, however, has not been extensively studied and may be hampered by the presence of pyknotic apoptosis mimicking mitotic figures. Furthermore, prediction of prognosis based on histopathology varies, especially for ACs. We examined the presence of interobserver variation between 5 experienced pulmonary pathologists who reviewed 123 originally diagnosed pulmonary carcinoid cases. The tumors were subsequently redistributed over 3 groups: unanimously classified cases, consensus cases (4/5 pathologists rendered identical diagnosis), and disagreement cases (divergent diagnosis by ≥2 assessors). κ-values were calculated, and results were correlated with clinical follow-up and molecular data. When focusing on the 114/123 cases unanimously classified as pulmonary carcinoids, the interobserver agreement was only fair (κ=0.32). Of these 114 cases, 55% were unanimously classified, 25% reached consensus classification, and for 19% there was no consensus. ACs were significantly more often in the latter category (P=0.00038). The designation of TCs and ACs by ≥3 assessors was not associated with prognosis (P=0.11). However, when disagreement cases were allocated on the basis of Ki-67 proliferative index (<5%; ≥5%) or nuclear orthopedia homeobox immunostaining (+; -), correlation with prognosis improved significantly (P=0.00040 and 0.0024, respectively). In conclusion, there is a considerable interobserver variation in the histopathologic classification of lung carcinoids, in particular concerning ACs. Additional immunomarkers such as Ki-67 or orthopedia homeobox may improve classification and prediction of prognosis.
American Journal of Surgical Pathology 07/2014; · 4.87 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The histopathology of premalignant laryngeal lesions does not provide reliable information on the risk of malignant transformation, hence we examined new molecular markers which can easily be implemented in clinical practice.Dual-target fluorescence in situ hybridisation (FISH) for chromosome 1 and 7 centromeres was performed on tissue sections of laryngeal premalignancies in 69 patients. Chromosome instability was indicated by numerical imbalances and/or polysomy for chromosomes 1 and 7. Additionally, immunostainings for p53, Cyclin D1 and (p)FADD expression were evaluated. Malignant progression was recorded. Eighteen patients with carcinoma in situ (CIS) were treated after diagnosis and excluded from follow-up.Chromosome instability was strongly associated with a high risk of malignant transformation, especially in lower grade lesions (hyperplasia, mild and moderate dysplasia; odds ratio = 8.4, p = 0.004). Patients with lesions containing chromosome instability showed a significantly worse 5-year progression-free survival than those with premalignancies without chromosome instability (p = 0.002). Neither histopathology nor the protein markers predicted progression in univariate analysis, although histopathological diagnosis, p53 and FADD contributed positively to chromosome instability in multivariate analysis.Chromosome instability is associated with malignant progression of laryngeal premalignancies, especially in lower grade lesions. These results may contribute to better risk counselling, provided that they can be validated in a larger patient set.
[Show abstract][Hide abstract] ABSTRACT: Not long after the discovery of lamin proteins, it became clear that not all lamin subtypes are ubiquitously expressed in cells and tissues. Especially, A-type lamins showed an inverse correlation with proliferation and were thus initially called statins. Here we compare the findings of both A- and B-type lamin expression in various normal tissues and their neoplastic counterparts. Based on immunocytochemistry it becomes clear that lamin expression patterns are much more complicated than initially assumed: while normally proliferative cells are devoid of A-type lamin expression, many neoplastic tissues do show prominent A-type lamin expression. Conversely, cells that do not proliferate can be devoid of lamin expression. Yet, within the different types of tissues and tumors, lamins can be used to distinguish between tumor subtypes. The link between the appearance of A-type lamins in differentiation and the appearance of A-type lamins in a tumor likely relates the proliferative capacity of the tumor to its differentiation state.While lamins are targets for degradation in the apoptotic process, and accordingly are often used as markers for apoptosis, intriguing studies on an active role of lamins in the initiation or the prevention of apoptosis have been published recently and give rise to a renewed interest in the role of lamins in cancer.
Advances in experimental medicine and biology 01/2014; 773:27-48. · 1.83 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Infection with high-risk human papillomavirus (HPV) type 16 is an independent risk factor for the development of oropharyngeal squamous cell carcinomas (OSCC). However, it is unclear whether viral integration is an essential hallmark in the carcinogenic process of OSCC and whether HPV integration correlates with the level of viral gene transcription and influences the expression of disrupted host genes. We analyzed 75 patients with OSCC. HPV16-positivity was proven by p16(INK4A) immunohistochemistry, PCR and FISH. Viral integration was examined using DIPS- as well as APOT-PCR. Viral E2, E6 and E7 gene expression levels were quantified by quantitative reverse transcriptase (RT-q)PCR. Expression levels of 7 human genes disrupted by the virus were extracted from mRNA expression profiling data of 32 OSCCs. Viral copy numbers were assessed by qPCR in 73 tumors. We identified 37 HPV16-human fusion products indicating viral integration in 29 (39%) OSCC. In the remaining tumors (61%) only episome-derived PCR products were detected. When comparing OSCC with or without an integration-derived fusion product, we did not find significant differences in the mean RNA expression of viral genes E2, E6 and E7 or the viral copy numbers per cell, nor did the RNA expression of the HPV-disrupted genes differ from either group of OSCC. In conclusion, our data do not support the hypothesis that integration affects the levels of viral and/or HPV-disrupted human gene transcripts. Thus constitutive, rather than a high level, of expression of oncogene transcripts appears to be required in HPV-related OSCC.
PLoS ONE 01/2014; 9(2):e88718. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Context:MEN1 gene alterations have been implicated in lung carcinoids, but their effect on gene expression and disease outcome are unknown.Objective:To analyse MEN1 gene and expression anomalies in lung neuroendocrine neoplasms (NENs) and their correlations with clinicopathologic data and disease outcome.Design:We examined 74 lung NENs including 58 carcinoids and 16 high-grade neuroendocrine carcinomas (HGNECs) for MEN1 mutations (n=70) and allelic losses (n=69), promoter hypermethylation (n=65), and mRNA (n=74) expression. Results were correlated with disease outcome.Results:MEN1 mutations were found in 7/55 (13%) carcinoids and in 1 HGNEC, mostly associated with loss of the second allele. MEN1 decreased expression levels correlated with the presence of mutations (P=0.0060) and was also lower in HGNECs than carcinoids (P=0.0024). MEN1 methylation was not associated with mRNA expression levels. Patients with carcinoids harbouring MEN1 mutation and loss had shorter overall survival (P=0.039 and P=0.035, respectively), and low MEN1 mRNA levels correlated with distant metastasis (P=0.00010) and shorter survival (P=0.0071). In multivariate analysis, stage and MEN1 allelic loss were independent predictors of prognosis.Conclusion:Thirteen percent of pulmonary carcinoids harbour MEN1 mutation, associated with reduced mRNA expression and poor prognosis. Also in mutation-negative tumours, low MEN1 gene expression correlates with an adverse disease outcome. Hypermethylation was excluded as the underlying mechanism.
The Journal of Clinical Endocrinology and Metabolism 11/2013; · 6.31 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We evaluated the reliability of a novel multiplex ligation-dependent probe amplification (MLPA) assay in detecting integration of human papillomavirus (HPV) based on the viral E2/E6 copy number ratio in formalin-fixed and paraffin-embedded cervical lesions. The MLPA results were compared with those of amplification of papillomavirus oncogene transcripts for RNA, detection of integrated papillomavirus sequences for DNA, and HPV fluorescence in situ hybridization (FISH). DNA was isolated from 41 formalin-fixed and paraffin-embedded HPV-positive cervical lesions (cervical intraepithelial neoplasia grade 3 lesions, squamous cell carcinomas, and adenocarcinomas) for MLPA analysis. From 13 matching frozen samples, DNA and RNA were isolated for the detection of integrated papillomavirus sequences and/or the amplification of papillomavirus oncogene transcripts, respectively. Integrated HPV16, HPV18, or both were identified. The MLPA assay detected viral integration in 12 of these 13 cases, and episomal copies also were detected in 7 cases. In 20 of the 24 cases with exclusive viral integration or episomal viral copies as detected by FISH, MLPA confirmed the physical status of the virus. In the cases classified as mixed by FISH, the presence of excess episomal copies complicated the recognition of viral integration by MLPA. Furthermore, the feasibility of detecting gain of the telomerase genes with the HPV MLPA assay was evaluated. The MLPA confirmed the FISH data in 12 of 13 cases in which the status of copy number gain for telomerase RNA component was known. In conclusion, the HPV MLPA assay can be performed on routinely processed cervical lesions for the detection of viral load and HPV integration.
[Show abstract][Hide abstract] ABSTRACT: Purpose
Infection with high-risk human papillomavirus (HPV) type 16 is an independent risk factor for the development of oropharyngeal squamous cell carcinomas (OSCC). However, it is unclear whether viral integration is an essential hallmark in the carcinogenic process of OSCC and whether HPV integration correlates to the level of viral gene transcription and influences the expression of disrupted genes.
Material and methods
HPV16 integration sites were assessed in 75 patients with HPV16-DNA- and p16INK4A-positive OSCC using Detection of Integrated Papillomavirus Sequences (DIPS)- as well as Amplification of Papillomavirus Oncogene Transcripts (APOT)-PCR. Quantitative RT-PCR assays were carried out to determine the viral E2/E4, E6 and E7 gene expression levels. Expression levels of 7 human genes disrupted by the virus were extracted from mRNA expression profiling data of 32 OSCC. Nuclear localization of HPV16 was visualized using Fluorescence In Situ Hybridization (FISH) in 59 OSCC, and corresponding viral copy numbers were assessed by quantitative RT-PCR in 61 tumors.
We identified 37 HPV16-human fusion products indicating viral integration in 29 (39%) OSCC. In the remaining tumors (61%) only episome-derived PCR products were detected.
When comparing OSCC with or without an integration-derived fusion product, we neither found significant differences in the mean expression of the viral genes E2/E4, E6 and E7, the nuclear FISH staining patters nor the viral copy numbers per cell. The expression of the HPV-invaded genes also did not significantly differ when comparing the expression in the affected tumor with the expression of that gene in either group of OSCC.
In conclusion, our data do not support the hypothesis that integration affects the levels of viral and/or HPV-disrupted human gene transcripts. Thus constitutive, rather than a high level, of expression of oncogene transcripts appears to be required in HPV-related OSCC.
Cancer Research 08/2013; 49:S6. · 8.65 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Pulmonary carcinoids comprise a well-differentiated subset of neuroendocrine tumors (NETs) usually associated with a favorable prognosis, but mechanisms underlying disease progression are poorly understood. In an explorative approach to identify pathways associated with progression, we compared gene expression profiles of tumors from 5 patients with a favorable and 5 with a poor disease outcome. Differentially expressed genes were validated using quantitative RT-PCR on 65 carcinoid tumors, in combination with survival analysis. One of the identified pathways was further examined using immunohistochemistry.As compared to other chromosomal locations, a significantly higher number of genes downregulated in carcinoids with a poor prognosis were located at chromosome 11q (P=0.00017), a region known to be frequently lost in carcinoids. In addition, a number of upregulated genes were found involved in the mitotic spindle checkpoint, the chromosomal passenger complex (CPC), mitotic kinase CDC2 activity, and the BRCA-Fanconi Anemia pathway. At the individual gene level, BIRC5 (survivin), BUB1, CD44, IL20RA, KLK12 and OTP were independent predictors of patient outcome. For survivin the number of positive nuclei was also related to poor prognosis within the group of carcinoids. Aurora B kinase and survivin, major components of the CPC, were particularly upregulated in high-grade carcinomas, and may therefore comprise therapeutic targets for these tumors.To our knowledge, this is the first expression profiling study focusing specifically on pulmonary carcinoids and progression. We have identified novel pathways underlying malignant progression and validated several genes as being strong prognostic indicators, some of which could serve as putative therapeutic targets.
[Show abstract][Hide abstract] ABSTRACT: Lung cancer is one of the leading causes of death from malignancy worldwide. In particular small cell lung cancers, which comprise about 15-20% of all lung cancers, are extremely aggressive and cure rates are extremely low. Therefore, new treatment modalities are needed and detection at an early stage of disease, as well as adequate monitoring of treatment response is essential in order to improve outcome. In this respect, the use of non-invasive tools for screening and monitoring has gained increasing interest and the clinical applicability of reliable, tumor-related substances that can be detected as tumor markers in easily accessible body fluids is subject of intense investigation. Some of these indicators, such as high LDH levels in serum as a reflection of the disease, have been in use for a long time as a general tumor marker. To allow for improved monitoring of the efficacy of new therapeutic modalities and for accurate subtyping, there is a strong need for specific and sensitive markers that are more directly related to the biology and behavior of small cell lung cancer. In this review the current status of these potential markers, like CEA, NSE, ProGRP, CK-BB, SCC, CgA, NCAM and several cytokeratins will be critically analyzed with respect to their performance in blood based assays. Based on known cleavage sites for cytoplasmic and extracellular proteases, a prediction of stable fragments can be obtained and used for optimal test design. Furthermore, insight into the synthesis of specific splice variants and neo-epitopes resulting from protein modification and cleavage, offers further opportunities for improvement of tumor assays. Finally, we discuss the possibility that detection of SCLC related autoantibodies in paraneoplastic disease can be used as a very early indicator of SCLC.
Biochimica et Biophysica Acta 06/2013; · 4.66 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Abstract Context: Small cell lung cancers (SCLC) are heterogeneous and tumours differ in growth characteristics and treatment resistance. Objective: To get insight into the underlying protein profiles responsible for this heterogeneity, two subtypes of SCLC cells mutually differing in chemo resistance properties and growth characteristics are analysed. Materials and methods: Two different electrophoresis approaches in combination with mass spectrometry were used to detect differences between the SCLC cell lines GLC1 and GLC1M13: IEF/SDS-PAGE as well as cetyltrimethylammonium bromide (CTAB)-SDS-PAGE. Results: Altogether 60 non redundant differentially expressed proteins were found of which 5 were verified by Western Blot analysis. Discussion: Most of these proteins identified are involved in processes of tumour progression. Therefore, these proteins are interesting candidates for further functional analysis. Conclusion: Additional CTAB-SDS page is a complementary method to IEF-SDS page revealing a complete new subset of proteins differentially expressed between GLC1 and GLC1 M13 cells SCLC subtypes.
[Show abstract][Hide abstract] ABSTRACT: PURPOSE: Pulmonary carcinoids are well-differentiated neuroendocrine tumors showing usually a favorable prognosis. However, there is a risk for late recurrence and/or distant metastasis. Because histological classification in typical and atypical (AC) carcinoids is difficult and its reliability to predict disease outcome varies, we evaluated three genes as potential prognostic markers, i.e., OTP, CD44 and RET. EXPERIMENTAL DESIGN: These genes were analyzed in 56 frozen carcinoids by quantitative RT-PCR. RET was further studied by methylation and mutation analysis. Immunohistochemistry for CD44 and OTP protein expression was performed on 292 carcinoids. RESULTS: Low mRNA expression levels of CD44 (p=1.8e-5) and OTP (p=0.00054), and high levels of RET (p=0.025), were strongly associated with a low 20-year survival of carcinoid patients. High RET expression was not related to promoter hypomethylation or gene mutations. A direct link between gene expression and protein levels was confirmed for CD44 and OTP, but not for RET. Within all carcinoids as well as ACs, absence of CD44 protein was significantly associated with low 20-year survival (p=0.00014 and p=0.00013, respectively). The absence of nuclear OTP followed by complete loss of expression was also significantly associated with unfavorable disease outcome in all carcinoids (p=5.2-6). Multivariate analyses revealed that age at diagnosis, histopathology, stage and cytoplasmic OTP immunoreactivity were independent predictors of prognosis. CONCLUSIONS: Our study indicates that CD44 and OTP are strong indicators of poor outcome. We therefore argue for implementation of these markers in routine diagnostics in addition to histopathology to improve subclassification of pulmonary carcinoids into prognostically relevant categories.
Clinical Cancer Research 02/2013; · 7.84 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A clearcut definition of the transition from the cervix to the lower uterine segment is lacking. We therefore evaluated the location of the anatomic border between the cervix and the uterine corpus. Using both morphometry and immunohistochemisty, we examined the epithelial and stromal cell types in this transition zone. In 26 patients, longitudinal sections from the cervix uteri up to the fundus uteri were paraffin embedded and immunohistochemically stained for BCL2, keratin 5, Ki-67, CD10, and CD34. Examination of the slides resulted in the identification of a junctional zone in the cranial portion of the cervix, which is characterized by a usually abrupt morphologic and immunohistochemical transition from an endocervical-type mucinous epithelium to a ciliated tubal-like epithelium and a slow transition in stromal marker expression patterns. This epithelial transition was characterized by its intense keratin 5 and BCL2 staining with accompanying Ki-67 expression in the tubal-like epithelium, whereas the endocervical epithelium was largely negative for these markers. CD10 expression was usually quite intense directly around endocervical invaginations, but the remaining stroma was negative. Toward the endometrial cavity, expression increased and endometrial stroma displayed full thickness expression for CD10. CD34 showed a reverse pattern to CD10, with moderate expression in the endocervical stroma, which disappeared in the endometrial stoma. The immunohistochemical identification of this transition may allow a more objective determination of the extension of endometrial carcinoma into the cervix in cases that are morphologically problematic. Furthermore, as ciliated tubal-like epithelium is invariably found cranial to the uterine-cervix-isthmus junction, a diagnosis of tubal metaplasia should not be made in this region and tubal-like epithelium is not indicative of a metaplastic process.
International journal of gynecological pathology: official journal of the International Society of Gynecological Pathologists 11/2012; · 2.07 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Tonsillar squamous cell carcinoma (TSCC) is frequently associated with human papillomavirus (HPV) and chromosome instability. Data from cellular model systems are, however, controversial concerning a relation between HPV and chromosome instability development. Here we studied this association in 77 primary TSCC with known clinical outcome and cell cycle protein expression profiles. Thirty-two tumors (42%) showed HPV16-integration. All 77 cases were analyzed by fluorescence in situ hybridization using chromosome 1- and 7-specific centromere DNA probes to detect chromosome instability, indicated by the presence of chromosome imbalances and/or polyploidization for these chromosomes. In addition, eight HPV-positive dysplasias, seven of which were adjacent to a carcinoma, were analyzed. Disomy for chromosome 1 and 7 was present in 29 out of 77 TSCC (38%), of which 19 were HPV16-positive (p = 0.002). Aneusomy was observed in the remaining 48 TSCC, of which 13 were HPV-positive. Aneusomies correlated significantly with tobacco- and alcohol consumption (p = 0.001 and p = 0.016, respectively) and a higher T-stage (p = 0.018). Both HPV-positivity and chromosome disomy were significantly associated with a favorable disease-free survival (p = 0.001 and p = 0.025, respectively). Particularly in the HPV16-positive group chromosome instability is a very strong indicator for an unfavorable prognosis (p = 0.032). In the dysplasias an identical HPV and chromosome copy number status was identified as in the adjacent tumors. We conclude that HPV-positive TSCC and their precursor lesions are more often genetically stable than HPV-negative lesions and that these tumors are associated with a favorable prognosis. Chromosome instability is an indicator for unfavorable prognosis, particularly in the HPV-positive patient group.
International Journal of Cancer 09/2012; · 6.20 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: There is growing evidence that laminopathies, diseases associated with mutations in the LMNA gene, are caused by a combination of mechanical and gene regulatory distortions. Strikingly, there is a large variability in disease symptoms between individual patients carrying an identical LMNA mutation. This is why classical genetic screens for mutations appear to have limited predictive value for disease development. Recently, the widespread occurrence of repetitive nuclear ruptures has been described in fibroblast cultures from various laminopathy patients. Since this phenomenon was strongly correlated with disease severity, the identification of biomarkers that report on these rupture events could have diagnostic relevance. One such candidate marker is the PML nuclear body, a structure that is normally confined to the nuclear interior, but leaks out of the nucleus upon nuclear rupture. Here, we show that a variety of laminopathies shows the presence of these cytoplasmic PML particles (PML CPs), and that the amount of these protein aggregates increases with severity of the disease. In addition, between clinically healthy individuals, carrying LMNA mutations, significant differences can be found. Therefore, we postulate that detection of PML CPs in patient fibroblasts could become a valuable marker for diagnosis of disease development.
[Show abstract][Hide abstract] ABSTRACT: Pulmonary neuroendocrine tumors (NETs) are traditionally described as comprising a spectrum of neoplasms, ranging from low grade typical carcinoids (TCs) via the intermediate grade atypical carcinoids (ACs) to the highly malignant small cell lung cancers (SCLCs) and large cell neuroendocrine carcinomas (LCNECs). Recent data, however, suggests that two categories can be distinguished on basis of molecular and clinical data, i.e. the high grade neuroendocrine (NE) carcinomas and the carcinoid tumors. Bronchial carcinoids and SCLCs may originate from the same pulmonary NE precursor cells, but a precursor lesion has only been observed in association with carcinoids, termed diffuse idiopathic pulmonary neuroendocrine cell hyperplasia. The occurrence of mixed tumors exclusively comprising high grade NE carcinomas also supports a different carcinogenesis for these two groups. Histopathologically, high grade NE lung tumors are characterized by high mitotic and proliferative indices, while carcinoids are defined by maximally 10 mitoses per 2mm(2) (10 high-power fields) and rarely have Ki67-proliferative indices over 10%. High grade NE carcinomas are chemosensitive tumors, although they usually relapse. Surgery is often not an option due to extensive disease at presentation and early metastasis, especially in SCLC. Conversely, carcinoids are often insensitive to chemo- and radiation therapy, but cure can usually be achieved by surgery. A meta-analysis of comparative genomic hybridization studies performed for this review, as well as gene expression profiling data indicates separate clustering of carcinoids and carcinomas. Chromosomal aberrations are much more frequent in carcinomas, except for deletion of 11q, which is involved in the whole spectrum of NE lung tumors. Deletions of chromosome 3p are rare in carcinoids but are a hallmark of the high grade pulmonary NE carcinomas. On the contrary, mutations of the multiple endocrine neoplasia type 1 (MEN1) gene are restricted to carcinoid tumors. Many of the differences between carcinoids and high grade lung NETs can be ascribed to tobacco consumption, which is strongly linked to the occurrence of high grade NE carcinomas. Smoking causes p53 mutations, very frequently present in SCLCs and LCNECs, but rarely in carcinoids. It further results in other early genetic events in SCLCs and LCNECs, such as 3p and 17p deletions. Smoking induces downregulation of E-cadherin and associated epithelial to mesenchymal transition. Also, high grade lung NETs display higher frequencies of aberrations of the Rb pathway, and of the intrinsic and extrinsic apoptotic routes. Carcinoid biology on the other hand is not depending on cigarette smoke intake but rather characterized by aberrations of other specific genetic events, probably including Menin or its targets and interaction partners. This results in a gradual evolution, most likely from proliferating pulmonary NE cells via hyperplasia and tumorlets towards classical carcinoid tumors. We conclude that carcinoids and high grade NE lung carcinomas are separate biological entities and do not comprise one spectrum of pulmonary NETs. This implies the need to reconsider both diagnostic as well as therapeutic approaches for these different groups of malignancies.
Biochimica et Biophysica Acta (BBA) - Reviews on Cancer 05/2012; 1826(12):255-71. · 9.03 Impact Factor