MCC

Gene Summary

Gene:MCC; mutated in colorectal cancers
Aliases: MCC1
Location:5q22.2
Summary:This gene is a candidate colorectal tumor suppressor gene that is thought to negatively regulate cell cycle progression. The orthologous gene in the mouse expresses a phosphoprotein associated with the plasma membrane and membrane organelles, and overexpression of the mouse protein inhibits entry into S phase. Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jul 2008]
Databases:VEGA, OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:colorectal mutant cancer protein
Source:NCBIAccessed: 16 March, 2017

Ontology:

What does this gene/protein do?
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Cancer Overview

Research Indicators

Publications Per Year (1992-2017)
Graph generated 16 March 2017 using data from PubMed using criteria.

Literature Analysis

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Tag cloud generated 16 March, 2017 using data from PubMed, MeSH and CancerIndex

Specific Cancers (6)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: MCC (cancer-related)

Gambichler T, Mohtezebsade S, Wieland U, et al.
Prognostic relevance of high atonal homolog-1 expression in Merkel cell carcinoma.
J Cancer Res Clin Oncol. 2017; 143(1):43-49 [PubMed] Related Publications
BACKGROUND: It has recently been reported that atonal homolog 1 (ATOH1) gene is down-regulated in Merkel cell carcinoma (MCC) and thus may represent a tumor suppressor gene.
OBJECTIVES: We aimed to test for ATOH1 gene mutations and expression levels in MCC tissues and cell lines.
METHODS: Genomic DNA isolation and amplification via PCR was successfully performed in 33 MCCs on formalin-fixed paraffin-embedded tissue and three MCC cell lines, followed by Sanger sequencing of the whole ATOH1 gene to detect genomic aberrations. ATOH1 mRNA levels were determined by RT-PCR. Immunohistochemistry of ATOH1 was performed to quantify protein expression in tumor samples and cell lines.
RESULTS: Neither in any of the 33 MCC tissue samples nor in the three cell lines ATOH1 mutations were present. ATOH1 was expressed in all lesions, albeit at different expression levels. Univariate analysis revealed that the total immunohistology score significantly correlated with the occurrence of tumor relapse (r = 0.57; P = 0.0008). This notion was confirmed in multivariate analysis suggesting that ATOH1 expression is a potential independent predictor for tumor relapse in MCC patients (P = 0.028). MCC-related death also correlated with ATOH1 expression (r = 0.4; P = 0.025); however, ATOH1 expression did not retain its predictive value in the regression model.
CONCLUSIONS: In contrast to anecdotal reports ATOH1 expression is not lost by genetic alterations in MCC. However, protein expression of ATOH1 is increased in advanced MCC indicating that ATOH1 is involved in MCC progression.

Li H, Yuan Z, Ji J, et al.
A novel Markov Blanket-based repeated-fishing strategy for capturing phenotype-related biomarkers in big omics data.
BMC Genet. 2016; 17:51 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: We propose a novel Markov Blanket-based repeated-fishing strategy (MBRFS) in attempt to increase the power of existing Markov Blanket method (DASSO-MB) and maintain its advantages in omic data analysis.
RESULTS: Both simulation and real data analysis were conducted to assess its performances by comparing with other methods including χ(2) test with Bonferroni and B-H adjustment, least absolute shrinkage and selection operator (LASSO) and DASSO-MB. A serious of simulation studies showed that the true discovery rate (TDR) of proposed MBRFS was always close to zero under null hypothesis (odds ratio = 1 for each SNPs) with excellent stability in all three scenarios of independent phenotype-related SNPs without linkage disequilibrium (LD) around them, correlated phenotype-related SNPs without LD around them, and phenotype-related SNPs with strong LD around them. As expected, under different odds ratio and minor allel frequency (MAFs), MBRFS always had the best performances in capturing the true phenotype-related biomarkers with higher matthews correlation coefficience (MCC) for all three scenarios above. More importantly, since proposed MBRFS using the repeated fishing strategy, it still captures more phenotype-related SNPs with minor effects when non-significant phenotype-related SNPs emerged under χ(2) test after Bonferroni multiple correction. The various real omics data analysis, including GWAS data, DNA methylation data, gene expression data and metabolites data, indicated that the proposed MBRFS always detected relatively reasonable biomarkers.
CONCLUSIONS: Our proposed MBRFS can exactly capture the true phenotype-related biomarkers with the reduction of false negative rate when the phenotype-related biomarkers are independent or correlated, as well as the circumstance that phenotype-related biomarkers are associated with non-phenotype-related ones.

Ritter C, Fan K, Paulson KG, et al.
Reversal of epigenetic silencing of MHC class I chain-related protein A and B improves immune recognition of Merkel cell carcinoma.
Sci Rep. 2016; 6:21678 [PubMed] Free Access to Full Article Related Publications
Merkel cell carcinoma (MCC) is a virally associated cancer characterized by its aggressive behavior and strong immunogenicity. Both viral infection and malignant transformation induce expression of MHC class I chain-related protein (MIC) A and B, which signal stress to cells of the immune system via Natural Killer group 2D (NKG2D) resulting in elimination of target cells. However, despite transformation and the continued presence of virally-encoded proteins, MICs are only expressed in a minority of MCC tumors in situ and are completely absent on MCC cell lines in vitro. This lack of MIC expression was due to epigenetic silencing via MIC promoter hypo-acetylation; indeed, MIC expression was re-induced by pharmacological inhibition of histone deacetylases (HDACs) both in vitro and in vivo. This re-induction of MICs rendered MCC cells more sensitive to immune-mediated lysis. Thus, epigenetic silencing of MICs is an important immune escape mechanism of MCCs.

Abraham KJ, Zhang X, Vidal R, et al.
Roles for miR-375 in Neuroendocrine Differentiation and Tumor Suppression via Notch Pathway Suppression in Merkel Cell Carcinoma.
Am J Pathol. 2016; 186(4):1025-35 [PubMed] Related Publications
Dysfunction of key miRNA pathways regulating basic cellular processes is a common driver of many cancers. However, the biological roles and/or clinical applications of such pathways in Merkel cell carcinoma (MCC), a rare but lethal cutaneous neuroendocrine (NE) malignancy, have yet to be determined. Previous work has established that miR-375 is highly expressed in MCC tumors, but its biological role in MCC remains unknown. Herein, we show that elevated miR-375 expression is a specific feature of well-differentiated MCC cell lines that express NE markers. In contrast, miR-375 is strikingly down-regulated in highly aggressive, undifferentiated MCC cell lines. Enforced miR-375 expression in these cells induced NE differentiation, and opposed cancer cell viability, migration, invasion, and survival, pointing to tumor-suppressive roles for miR-375. Mechanistically, miR-375-driven phenotypes were caused by the direct post-transcriptional repression of multiple Notch pathway proteins (Notch2 and RBPJ) linked to cancer and regulation of cell fate. Thus, we detail a novel molecular axis linking tumor-suppressive miR-375 and Notch with NE differentiation and cancer cell behavior in MCC. Our findings identify miR-375 as a putative regulator of NE differentiation, provide insight into the cell of origin of MCC, and suggest that miR-375 silencing may promote aggressive cancer cell behavior through Notch disinhibition.

Veija T, Sarhadi VK, Koljonen V, et al.
Hotspot mutations in polyomavirus positive and negative Merkel cell carcinomas.
Cancer Genet. 2016 Jan-Feb; 209(1-2):30-5 [PubMed] Related Publications
Merkel cell polyomavirus (MCV) infection underlies most Merkel cell carcinoma (MCC), a primary neuroendocrine carcinoma of the skin. While previous research has focused on MCV-positive MCC tumors, less is known about the oncogenesis in MCV-negative tumors. In this study, we analyzed mutational status of 27 MCC tumors with known MCV status for hotspot regions of 50 cancer-related genes by targeted next-generation sequencing using the Ion AmpliSeq Cancer Hotspot Panel. In addition to previously reported TP53, KIT, and PIK3CA gene mutations, we found somatic mutations in the tyrosine kinase domain of the EGFR gene in a small proportion of the cells in six tumor tissues. RB1 mutations were seen only in virus negative tumors. Hotspot mutations were more frequent in MCV-negative tumors, although the difference was not statistically significant. No clear hotspot mutation profile was observed. Novel RB1 mutations were detected only in MCV-negative tumors.

Goh G, Walradt T, Markarov V, et al.
Mutational landscape of MCPyV-positive and MCPyV-negative Merkel cell carcinomas with implications for immunotherapy.
Oncotarget. 2016; 7(3):3403-15 [PubMed] Free Access to Full Article Related Publications
Merkel cell carcinoma (MCC) is a rare but highly aggressive cutaneous neuroendocrine carcinoma, associated with the Merkel cell polyomavirus (MCPyV) in 80% of cases. To define the genetic basis of MCCs, we performed exome sequencing of 49 MCCs. We show that MCPyV-negative MCCs have a high mutation burden (median of 1121 somatic single nucleotide variants (SSNVs) per-exome with frequent mutations in RB1 and TP53 and additional damaging mutations in genes in the chromatin modification (ASXL1, MLL2, and MLL3), JNK (MAP3K1 and TRAF7), and DNA-damage pathways (ATM, MSH2, and BRCA1). In contrast, MCPyV-positive MCCs harbor few SSNVs (median of 12.5 SSNVs/tumor) with none in the genes listed above. In both subgroups, there are rare cancer-promoting mutations predicted to activate the PI3K pathway (HRAS, KRAS, PIK3CA, PTEN, and TSC1) and to inactivate the Notch pathway (Notch1 and Notch2). TP53 mutations appear to be clinically relevant in virus-negative MCCs as 37% of these tumors harbor potentially targetable gain-of-function mutations in TP53 at p.R248 and p.P278. Moreover, TP53 mutational status predicts death in early stage MCC (5-year survival in TP53 mutant vs wild-type stage I and II MCCs is 20% vs. 92%, respectively; P = 0.0036). Lastly, we identified the tumor neoantigens in MCPyV-negative and MCPyV-positive MCCs. We found that virus-negative MCCs harbor more tumor neoantigens than melanomas or non-small cell lung cancers (median of 173, 65, and 111 neoantigens/sample, respectively), two cancers for which immune checkpoint blockade can produce durable clinical responses. Collectively, these data support the use of immunotherapies for virus-negative MCCs.

Prieto-Granada CN, Wiesner T, Messina JL, et al.
Loss of H3K27me3 Expression Is a Highly Sensitive Marker for Sporadic and Radiation-induced MPNST.
Am J Surg Pathol. 2016; 40(4):479-89 [PubMed] Free Access to Full Article Related Publications
Most malignant peripheral nerve sheath tumors (MPNSTs) exhibit combined inactivation of NF1, CDKN2A, and polycomb repressive complex 2 component genes (Embryonic Ectoderm Development [EED] and Suppressor of Zeste 12 [SUZ12]). Mutations in EED and SUZ12 induce loss of trimethylation at lysine 27 of histone 3 (H3K27me3), with subsequent aberrant transcriptional activation of polycomb repressive complex 2-repressed homeobox master regulators. These findings prompted us to investigate the performance of an anti-H3K27me3 monoclonal antibody clone C36B11 as an immunohistochemical marker for MPNSTs. We assessed the C36B11 reactivity pattern in a pathologically and genetically well-characterized cohort of 68 MPNSTs, spanning various clinical presentations, such as type 1 neurofibromatosis (NF1), radiotherapy, and sporadic MPNSTs. We found that 69% (n=47) of all MPNSTs demonstrated loss of H3K27me3 expression, with 42 (61%) showing complete loss and 5 (7%) showing partial loss, whereas 31% (n=21) retained H3K27me3 expression. Among the NF1-related high-grade MPNSTs, 60% demonstrated loss of expression. In contrast, the majority of both sporadic (95%) and radiotherapy-related (91%) MPNSTs showed loss of H3K27me3 expression. Two of the 3 low-grade MPNSTs and all neurofibromas showed retained expression. Furthermore, all 5 epithelioid MPNSTs retained H3K27me3 labeling. The specificity of H3K27me3 loss as a marker for MPNSTs was studied by testing a large spectrum of lesions included in MPNST differential diagnosis, such as spindle/desmoplastic melanomas, synovial sarcomas, myoepithelial tumors, and other mesenchymal neoplasms, all of which retained expression of H3K27me3. We conclude that immunohistochemical analysis of H3K27me3 has good sensitivity and robust specificity for the diagnosis of MPNST, particularly outside of NF1 clinical history, which represents the most challenging diagnostic setting.

Wong SQ, Waldeck K, Vergara IA, et al.
UV-Associated Mutations Underlie the Etiology of MCV-Negative Merkel Cell Carcinomas.
Cancer Res. 2015; 75(24):5228-34 [PubMed] Related Publications
Merkel cell carcinoma (MCC) is an uncommon, but highly malignant, cutaneous tumor. Merkel cell polyoma virus (MCV) has been implicated in a majority of MCC tumors; however, viral-negative tumors have been reported to be more prevalent in some geographic regions subject to high sun exposure. While the impact of MCV and viral T-antigens on MCC development has been extensively investigated, little is known about the etiology of viral-negative tumors. We performed targeted capture and massively parallel DNA sequencing of 619 cancer genes to compare the gene mutations and copy number alterations in MCV-positive (n = 13) and -negative (n = 21) MCC tumors and cell lines. We found that MCV-positive tumors displayed very low mutation rates, but MCV-negative tumors exhibited a high mutation burden associated with a UV-induced DNA damage signature. All viral-negative tumors harbored mutations in RB1, TP53, and a high frequency of mutations in NOTCH1 and FAT1. Additional mutated or amplified cancer genes of potential clinical importance included PI3K (PIK3CA, AKT1, PIK3CG) and MAPK (HRAS, NF1) pathway members and the receptor tyrosine kinase FGFR2. Furthermore, looking ahead to potential therapeutic strategies encompassing immune checkpoint inhibitors such as anti-PD-L1, we also assessed the status of T-cell-infiltrating lymphocytes (TIL) and PD-L1 in MCC tumors. A subset of viral-negative tumors exhibited high TILs and PD-L1 expression, corresponding with the higher mutation load within these cancers. Taken together, this study provides new insights into the underlying biology of viral-negative MCC and paves the road for further investigation into new treatment opportunities.

Zheng SD, Bui K, Chiappori A, et al.
RRM1, ERCC1 and TS1 Immunofluorescence Expression in Leiomyosarcoma: A Tissue Microarray Study with Clinical Outcome Correlation Analysis.
Pathol Oncol Res. 2016; 22(3):477-82 [PubMed] Related Publications
UNLABELLED: ERCC1, RRM1 and TS1 are reportedly linked to chemotherapy resistance in lung and other cancers. However, there are currently no studies reporting the relationship between these genes and clinical parameters in leiomyosarcomas.
METHOD: This study investigated the expression pattern of ERCC1, RRM1 and TS1 in forty-four leiomyosarcoma samples by the use of tissue microarray (TMA), immunofluorescence and AQUA methods. The results were then analyzed for expression level and correlations were made with clinical outcome to determine their potential prognostic value in leiomyosarcoma.
RESULTS: In the forty-four samples studied, the expression level of these three proteins can be well quantified in the AQUA system and reflected by the AQUA score. RRM1 and ERCC1 expression levels did not show any relationship with overall survival. However, a correlation was found between TS1 expression in the cytoplasm and overall survival. The high expression group had a shorter overall survival time (log-rank p = 0.0498). This trend was confirmed by the Cox proportional hazards model.
DISCUSSION: The poor overall survival of leiomyosarcoma is linked to TS1 cytoplasm expression which may be useful in predicting prognoses of this tumor, methods targeting expression of TS1 may lead to improved overall survival in leiomyosarcoma, though more detailed information regarding treatment information and a larger sample size is needed to confirm this phenomenon.

Schrama D, Hesbacher S, Angermeyer S, et al.
Serine 220 phosphorylation of the Merkel cell polyomavirus large T antigen crucially supports growth of Merkel cell carcinoma cells.
Int J Cancer. 2016; 138(5):1153-62 [PubMed] Related Publications
Merkel cell polyomavirus (MCPyV) is regarded as a major causal factor for Merkel cell carcinoma (MCC). Indeed, tumor cell growth of MCPyV-positive MCC cells is dependent on the expression of a truncated viral Large T antigen (LT) with an intact retinoblastoma protein (RB)-binding site. Here we determined the phosphorylation pattern of a truncated MCPyV-LT characteristically for MCC by mass spectrometry revealing MCPyV-LT as multi-phospho-protein phosphorylated at several serine and threonine residues. Remarkably, disruption of most of these phosphorylation sites did not affect its ability to rescue knockdown of endogenous T antigens in MCC cells indicating that phosphorylation of the respective amino acids is not essential for the growth promoting function of MCPyV-LT. However, alteration of serine 220 to alanine completely abolished the ability of MCPyV-LT to support proliferation of MCC cells. Conversely, mimicking the phosphorylated state by mutation of serine 220 to glutamic acid resulted in a fully functional LT. Moreover, MCPyV-LT(S220A) demonstrated reduced binding to RB in co-immunoprecipitation experiments as well as weaker induction of RB target genes in MCC cells. In conclusion, we provide evidence that phosphorylation of serine 220 is required for efficient RB inactivation in MCC and may therefore be a potential target for future therapeutic approaches.

Niroula A, Vihinen M
Classification of Amino Acid Substitutions in Mismatch Repair Proteins Using PON-MMR2.
Hum Mutat. 2015; 36(12):1128-34 [PubMed] Related Publications
Variations in mismatch repair (MMR) system genes are causative of Lynch syndrome and other cancers. Thousands of variants have been identified in MMR genes, but the clinical relevance is known for only a small proportion. Recently, the InSiGHT group classified 2,360 MMR variants into five classes. One-third of variants, majority of which is nonsynonymous variants, remain to be of uncertain clinical relevance. Computational tools can be used to prioritize variants for disease relevance investigations. Previously, we classified 248 MMR variants as likely pathogenic and likely benign using PON-MMR. We have developed a novel tool, PON-MMR2, which is trained on a larger and more reliable dataset. In performance comparison, PON-MMR2 outperforms both generic tolerance prediction methods as well as methods optimized for MMR variants. It achieves accuracy and MCC of 0.89 and 0.78, respectively, in cross-validation and 0.86 and 0.69, respectively, on an independent test dataset. We classified 354 class 3 variants in InSiGHT database as well as all possible amino acid substitutions in four MMR proteins. Likely harmful variants mainly appear in the protein core, whereas likely benign variants are on the surface. PON-MMR2 is a highly reliable tool to prioritize variants for functional analysis. It is freely available at http://structure.bmc.lu.se/PON-MMR2/.

Stangeland B, Mughal AA, Grieg Z, et al.
Combined expressional analysis, bioinformatics and targeted proteomics identify new potential therapeutic targets in glioblastoma stem cells.
Oncotarget. 2015; 6(28):26192-215 [PubMed] Free Access to Full Article Related Publications
Glioblastoma (GBM) is both the most common and the most lethal primary brain tumor. It is thought that GBM stem cells (GSCs) are critically important in resistance to therapy. Therefore, there is a strong rationale to target these cells in order to develop new molecular therapies.To identify molecular targets in GSCs, we compared gene expression in GSCs to that in neural stem cells (NSCs) from the adult human brain, using microarrays. Bioinformatic filtering identified 20 genes (PBK/TOPK, CENPA, KIF15, DEPDC1, CDC6, DLG7/DLGAP5/HURP, KIF18A, EZH2, HMMR/RHAMM/CD168, NOL4, MPP6, MDM1, RAPGEF4, RHBDD1, FNDC3B, FILIP1L, MCC, ATXN7L4/ATXN7L1, P2RY5/LPAR6 and FAM118A) that were consistently expressed in GSC cultures and consistently not expressed in NSC cultures. The expression of these genes was confirmed in clinical samples (TCGA and REMBRANDT). The first nine genes were highly co-expressed in all GBM subtypes and were part of the same protein-protein interaction network. Furthermore, their combined up-regulation correlated negatively with patient survival in the mesenchymal GBM subtype. Using targeted proteomics and the COGNOSCENTE database we linked these genes to GBM signalling pathways.Nine genes: PBK, CENPA, KIF15, DEPDC1, CDC6, DLG7, KIF18A, EZH2 and HMMR should be further explored as targets for treatment of GBM.

Harms PW, Vats P, Verhaegen ME, et al.
The Distinctive Mutational Spectra of Polyomavirus-Negative Merkel Cell Carcinoma.
Cancer Res. 2015; 75(18):3720-7 [PubMed] Free Access to Full Article Related Publications
Merkel cell carcinoma (MCC) is a rare but highly aggressive cutaneous neuroendocrine tumor. Merkel cell polyomavirus (MCPyV) may contribute to tumorigenesis in a subset of tumors via inhibition of tumor suppressors such as retinoblastoma (RB1) by mutated viral T antigens, but the molecular pathogenesis of MCPyV-negative MCC is largely unexplored. Through our MI-ONCOSEQ precision oncology study, we performed integrative sequencing on two cases of MCPyV-negative MCC, as well as a validation cohort of 14 additional MCC cases (n = 16). In addition to previously identified mutations in TP53, RB1, and PIK3CA, we discovered activating mutations of oncogenes, including HRAS and loss-of-function mutations in PRUNE2 and NOTCH family genes in MCPyV-negative MCC. MCPyV-negative tumors also displayed high overall mutation burden (10.09 ± 2.32 mutations/Mb) and were characterized by a prominent UV-signature pattern with C > T transitions comprising 85% of mutations. In contrast, mutation burden was low in MCPyV-positive tumors (0.40 ± 0.09 mutations/Mb) and lacked a UV signature. These findings suggest a potential ontologic dichotomy in MCC, characterized by either viral-dependent or UV-dependent tumorigenic pathways.

Correa D, Somoza RA, Lin P, et al.
Mesenchymal stem cells regulate melanoma cancer cells extravasation to bone and liver at their perivascular niche.
Int J Cancer. 2016; 138(2):417-27 [PubMed] Free Access to Full Article Related Publications
Skeleton and liver are preferred organs for cancer dissemination in metastatic melanoma negatively impacting quality of life, therapeutic success and overall survival rates. At the target organ, the local microenvironment and cell-to-cell interactions between invading and resident stromal cells constitute critical components during the establishment and progression of metastasis. Mesenchymal stem cells (MSCs) possess, in addition to their cell progenitor function, a secretory capacity based on cooperativity with other cell types in injury sites including primary tumors (PT). However, their role at the target organ microenvironment during cancer dissemination is not known. We report that local MSCs, acting as pericytes, regulate the extravasation of melanoma cancer cells (MCC) specifically to murine bone marrow (BM) and liver. Intra-arterially injected wild-type MCC fail to invade those selective organs in a genetic model of perturbed pericyte coverage of the vasculature (PDGF-B(ret/ret)), similar to CD146-deficient MCC injected into wild type mice. Invading MCC interact with resident MSCs/pericytes at the perivascular space through co-expressed CD146 and Sdf-1/CXCL12-CXCR4 signaling. Implanted engineered bone structures with MSCs/pericytes deficient of either Sdf-1/CXCL12 or CD146 become resistant to invasion by circulating MCC. Collectively, the presence of MSCs/pericytes surrounding the target organ vasculature is required for efficient melanoma metastasis to BM and liver.

Lin CH, Hsu KH, Chang SN, et al.
Increased survival with the combination of stereotactic radiosurgery and gefitinib for non-small cell lung cancer brain metastasis patients: a nationwide study in Taiwan.
Radiat Oncol. 2015; 10:127 [PubMed] Free Access to Full Article Related Publications
PURPOSE: Whole brain irradiation (WBRT) either with or without resection has historically been the treatment for brain metastases from non-small cell lung cancer (NSCLC). The effect of gamma knife (GK) radiosurgery, chemotherapy, or the combination remains incompletely defined. In this study, we assessed the outcome of brain metastases from non-small cell lung cancer treated by WBRT followed by GK, gefitinib, or the combination of GK and gefitinib.
MATERIAL AND METHODS: We retrieved the records of NSCLC patients with brain metastases from the National Health Insurance Research Database (NHIRD) of Taiwan from 2004 to 2010. WBRT either with or without resection was the first line treatment for nearly all patients. The decision to add GK and/or gefitinib treatment was at the discretion of the treating physician and based upon a patient's medical records and imaging data. These patients were classified into four groups including WBRT, WBRT + gefitinib, WBRT + GK, WBRT + gefitinib + GK. These data was evaluated for difference in survival and factors that portended an extended survival from the time of brain metastasis diagnosis.
RESULTS: Of the 60194 patients with newly diagnosed NSCLC, 23874 (39.6 %) developed brain metastases. The distribution of patients for the groups was WBRT for 20241, WBRT + gefitinib for 3379, WBRT + GK for 155, and WBRT+ gefitinib + GK for 99 patients. The median survival for the time of brain metastasis diagnosis for WBRT, WBRT+ gefitinib, WBRT+ GK, WBRT+ gefitinib + GK groups was 0.53, 1.01, 1.46, and 2.25 years, respectively (p < 0.0001). The hazard ratio (95 % CI) for survival was 1, 0.56, 0.43, and 0.40, respectively (p < 0.001). The adjusted hazard ratio (95 % CI) by age, sex and Charlson comorbidity index (CCI) was 1, 0.73, 0.49, and 0.42, respectively (p < 0.001).
CONCLUSION: Patients with brain metastases from NSCLC receiving GK or gefitinib demonstrated extended survival. The improved survival seen with GK and gefitinib suggests a survival benefit in selected patients receiving the combined treatment. Further Phase II study should be conducted to assessment these influence.

Sengupta D, Kannan A, Kern M, et al.
Disruption of BRD4 at H3K27Ac-enriched enhancer region correlates with decreased c-Myc expression in Merkel cell carcinoma.
Epigenetics. 2015; 10(6):460-6 [PubMed] Free Access to Full Article Related Publications
Pathologic c-Myc expression is frequently detected in human cancers, including Merkel cell carcinoma (MCC), an aggressive skin cancer with no cure for metastatic disease. Bromodomain protein 4 (BRD4) regulates gene transcription by binding to acetylated histone H3 lysine 27 (H3K27Ac) on the chromatin. Super-enhancers of transcription are identified by enrichment of H3K27Ac. BET inhibitor JQ1 disrupts BRD4 association with super-enhancers, downregulates proto-oncogenes, such as c-Myc, and displays antitumor activity in preclinical animal models of human cancers. Here we show that an enhancer proximal to the c-Myc promoter is enriched in H3K27Ac and associated with high occupancy of BRD4, and coincides with a putative c-Myc super-enhancer in MCC cells. This observation is mirrored in tumors from MCC patients. Importantly, depleted BRD4 occupancy at the putative c-Myc super-enhancer region by JQ1 correlates with decreased c-Myc expression. Thus, our study provides initial evidence that super-enhancers regulate c-Myc expression in MCC.

Batinica M, Akgül B, Silling S, et al.
Correlation of Merkel cell polyomavirus positivity with PDGFRα mutations and survivin expression in Merkel cell carcinoma.
J Dermatol Sci. 2015; 79(1):43-9 [PubMed] Related Publications
BACKGROUND: Merkel cell carcinoma (MCC) is a neuroendocrine cancer of the skin postulated to originate through Merkel cell polyomavirus (MCPyV) oncogenesis and/or by mutations in molecules implicated in the regulation of cell growth and survival. Despite the fact that MCPvV is detected more broadly within the population, only a part of the infected people also develop MCC. It is thus conceivable that together, virus and for example mutations, are necessary for disease development. However, apart from a correlation between MCPyV positivity or mutations and MCC development, less is known about the association of these factors with progressive disease.
OBJECTIVES: To analyze MCPyV positivity, load and integration in MCC as well as presence of mutations in PDGFRα and TP53 genes and correlate these with clinical features and disease progression to identify features with prognostic value for clinical progression.
METHODS: This is a study on a MCC population group of 64 patients. MCPyV positivity, load and integration in parallel to mutations in the PDGFRα and TP53 were analyzed on genomic DNA from MCC specimens. In addition, expression of PDGFRα, survivin and p53 proteins was analyzed by immunodetection in tissues specimens. All these parameters were analyzed as function of patient's disease progression status.
RESULTS: 83% of MCCs were positive for the MCPyV and among these 36% also displayed virus-T integration. Viral load ranged from 0.006 to 943 viral DNA copies/β-globin gene and was highest in patients with progressive disease. We detected more than one mutation within the PDGFRα gene and identified two new SNPs in 36% of MCC patients, whereas no mutations were found in TP53 gene. Survivin was expressed in 78% of specimens. We could not correlate either mutations in PDGFR or expression of PDGFR, p53 and surviving either to the disease progression or to the MCPyV positivity.
CONCLUSIONS: In conclusion, our data indicate that the viral positivity when associated with high viral load, correlates with poor disease outcome. Frequent mutations in the PDGFRα gene and high survivin expression were found in MCC independent of the viral positivity. These data suggest that these three factors independently contribute to Merkel cell carcinoma development and that only the viral load can be used as indicator of disease progression in virus positive patients.

Jouhi L, Koljonen V, Böhling T, et al.
The expression of Toll-like receptors 2, 4, 5, 7 and 9 in Merkel cell carcinoma.
Anticancer Res. 2015; 35(4):1843-9 [PubMed] Related Publications
AIM: We sought to clarify whether the expression of toll-like receptors (TLR) in Merkel cell carcinoma (MCC) is linked to tumor and patient characteristics, especially the presence of Merkel cell polyoma virus (MCV).
MATERIALS AND METHODS: The study comprised of 128 patients with data on Merkel cell polyomavirus (MCV) status and clinical features were included in the study. Immunohistochemistry for TLR expression was performed on tissue microarray (TMA) slides.
RESULTS: TLR 2, 4, 5, 7 and 9 expression was noted in most of the tumor specimens. Decreased expression of TLR 9 correlated strongly with MCV positivity. Cytoplasmic TLR 2 expression correlated with small tumor size, while nuclear TLR 2 and TLR 5 expressions with larger tumors. Increased nuclear TLR 4 expression and decreased TLR 7 expression were associated with older age.
CONCLUSION: TLR 2, 4, 5, 7 and 9 appear to reflect certain clinicopathological variables and prognostic markers of MCC tumors.

Zhang PW, Chen L, Huang T, et al.
Classifying ten types of major cancers based on reverse phase protein array profiles.
PLoS One. 2015; 10(3):e0123147 [PubMed] Free Access to Full Article Related Publications
Gathering vast data sets of cancer genomes requires more efficient and autonomous procedures to classify cancer types and to discover a few essential genes to distinguish different cancers. Because protein expression is more stable than gene expression, we chose reverse phase protein array (RPPA) data, a powerful and robust antibody-based high-throughput approach for targeted proteomics, to perform our research. In this study, we proposed a computational framework to classify the patient samples into ten major cancer types based on the RPPA data using the SMO (Sequential minimal optimization) method. A careful feature selection procedure was employed to select 23 important proteins from the total of 187 proteins by mRMR (minimum Redundancy Maximum Relevance Feature Selection) and IFS (Incremental Feature Selection) on the training set. By using the 23 proteins, we successfully classified the ten cancer types with an MCC (Matthews Correlation Coefficient) of 0.904 on the training set, evaluated by 10-fold cross-validation, and an MCC of 0.936 on an independent test set. Further analysis of these 23 proteins was performed. Most of these proteins can present the hallmarks of cancer; Chk2, for example, plays an important role in the proliferation of cancer cells. Our analysis of these 23 proteins lends credence to the importance of these genes as indicators of cancer classification. We also believe our methods and findings may shed light on the discoveries of specific biomarkers of different types of cancers.

Tan CL, Teissier S, Gunaratne J, et al.
Stranglehold on the spindle assembly checkpoint: the human papillomavirus E2 protein provokes BUBR1-dependent aneuploidy.
Cell Cycle. 2015; 14(9):1459-70 [PubMed] Free Access to Full Article Related Publications
The Human Papillomavirus (HPV) E2 protein, which inhibits the E6 and E7 viral oncogenes, is believed to have anti-oncogenic properties. Here, we challenge this view and show that HPV-18 E2 over-activates the Spindle Assembly Checkpoint (SAC) and induces DNA breaks in mitosis followed by aneuploidy. This phenotype is associated with interaction of E2 with the Mitotic Checkpoint Complex (MCC) proteins Cdc20, MAD2 and BUBR1. While BUBR1 silencing rescues the mitotic phenotype induced by E2, p53 silencing or presence of E6/E7 (inactivating p53 and increasing BUBR1 levels respectively) both amplify it. This work pinpoints E2 as a key protein in the initiation of HPV-induced cervical cancer and identifies the SAC as a target for oncogenic pathogens. Moreover, our results suggest a role of p53 in regulating the mitotic process itself and highlight SAC over-activation in a p53-negative context as a highly pathogenic event.

Castaño-Vinyals G, Aragonés N, Pérez-Gómez B, et al.
Population-based multicase-control study in common tumors in Spain (MCC-Spain): rationale and study design.
Gac Sanit. 2015 Jul-Aug; 29(4):308-15 [PubMed] Related Publications
INTRODUCTION: We present the protocol of a large population-based case-control study of 5 common tumors in Spain (MCC-Spain) that evaluates environmental exposures and genetic factors.
METHODS: Between 2008-2013, 10,183 persons aged 20-85 years were enrolled in 23 hospitals and primary care centres in 12 Spanish provinces including 1,115 cases of a new diagnosis of prostate cancer, 1,750 of breast cancer, 2,171 of colorectal cancer, 492 of gastro-oesophageal cancer, 554 cases of chronic lymphocytic leukaemia (CLL) and 4,101 population-based controls matched by frequency to cases by age, sex and region of residence. Participation rates ranged from 57% (stomach cancer) to 87% (CLL cases) and from 30% to 77% in controls. Participants completed a face-to-face computerized interview on sociodemographic factors, environmental exposures, occupation, medication, lifestyle, and personal and family medical history. In addition, participants completed a self-administered food-frequency questionnaire and telephone interviews. Blood samples were collected from 76% of participants while saliva samples were collected in CLL cases and participants refusing blood extractions. Clinical information was recorded for cases and paraffin blocks and/or fresh tumor samples are available in most collaborating hospitals. Genotyping was done through an exome array enriched with genetic markers in specific pathways. Multiple analyses are planned to assess the association of environmental, personal and genetic risk factors for each tumor and to identify pleiotropic effects.
DISCUSSION: This study, conducted within the Spanish Consortium for Biomedical Research in Epidemiology & Public Health (CIBERESP), is a unique initiative to evaluate etiological factors for common cancers and will promote cancer research and prevention in Spain.

Netter J, Lehmann-Che J, Lambert J, et al.
Functional TP53 mutations have no impact on response to cytotoxic agents in metastatic colon cancer.
Bull Cancer. 2015; 102(2):117-25 [PubMed] Related Publications
BACKGROUND: Survival of metastatic colon cancer (mCC) patients has considerably improved with optimization of new drugs regimen. Inactivation of TP53 pathway by TP53 mutations is observed in nearly half of colorectal tumors. The impact of such mutations has been poorly studied in the metastatic setting.
METHODS: The files of 254 mCC treated in a single institution at Saint-Louis hospital between January 1999 and April 2011 were retrospectively reviewed. Tissue samples for analysis of TP53 mutations were available for 68 patients, performed using FASAY. The prognostic value of TP53 status was evaluated by comparing progression free survival (PFS) and overall survival (OS) in the group of TP53-mutated and wild type patients.
RESULTS: PFS was 6.9 months and OS 21.7 months in the whole population. There was no statistical difference in TP53-mutated and wild type groups in term of PFS (HR=1.04; IC 95%=0.6-1.79) and OS (HR=0.99; IC 95%=0.53-1.55) whatever the chemotherapy regimen (oxaliplatin- or irinotecan-based). Only BRAF V600 mutation was demonstrated to be a poor prognostic factor for PFS and OS, and CEA level for OS.
CONCLUSIONS: Routine determination of TP53 mutations, even with a highly sensitive method, cannot be recommended to predict chemotherapy response in mCC.

Cutcutache I, Suzuki Y, Tan IB, et al.
Exome-wide Sequencing Shows Low Mutation Rates and Identifies Novel Mutated Genes in Seminomas.
Eur Urol. 2015; 68(1):77-83 [PubMed] Related Publications
BACKGROUND: Testicular germ cell tumors are the most common cancer diagnosed in young men, and seminomas are the most common type of these cancers. There have been no exome-wide examinations of genes mutated in seminomas or of overall rates of nonsilent somatic mutations in these tumors.
OBJECTIVE: The objective was to analyze somatic mutations in seminomas to determine which genes are affected and to determine rates of nonsilent mutations.
DESIGN, SETTING, AND PARTICIPANTS: Eight seminomas and matched normal samples were surgically obtained from eight patients.
INTERVENTION: DNA was extracted from tissue samples and exome sequenced on massively parallel Illumina DNA sequencers. Single-nucleotide polymorphism chip-based copy number analysis was also performed to assess copy number alterations.
OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The DNA sequencing read data were analyzed to detect somatic mutations including single-nucleotide substitutions and short insertions and deletions. The detected mutations were validated by independent sequencing and further checked for subclonality.
RESULTS AND LIMITATIONS: The rate of nonsynonymous somatic mutations averaged 0.31 mutations/Mb. We detected nonsilent somatic mutations in 96 genes that were not previously known to be mutated in seminomas, of which some may be driver mutations. Many of the mutations appear to have been present in subclonal populations. In addition, two genes, KIT and KRAS, were affected in two tumors each with mutations that were previously observed in other cancers and are presumably oncogenic.
CONCLUSIONS: Our study, the first report on exome sequencing of seminomas, detected somatic mutations in 96 new genes, several of which may be targetable drivers. Furthermore, our results show that seminoma mutation rates are five times higher than previously thought, but are nevertheless low compared to other common cancers. Similar low rates are seen in other cancers that also have excellent rates of remission achieved with chemotherapy.
PATIENT SUMMARY: We examined the DNA sequences of seminomas, the most common type of testicular germ cell cancer. Our study identified 96 new genes in which mutations occurred during seminoma development, some of which might contribute to cancer development or progression. The study also showed that the rates of DNA mutations during seminoma development are higher than previously thought, but still lower than for other common solid-organ cancers. Such low rates are also observed among other cancers that, like seminomas, show excellent rates of disease remission after chemotherapy.

Graves CA, Jones A, Reynolds J, et al.
Neuroendocrine Merkel cell carcinoma is associated with mutations in key DNA repair, epigenetic and apoptosis pathways: a case-based study using targeted massively parallel sequencing.
Neuroendocrinology. 2015; 101(2):112-9 [PubMed] Free Access to Full Article Related Publications
INTRODUCTION: Merkel cell carcinoma (MCC) is a rare neuroendocrine carcinoma with a poorly understood molecular etiology. We implemented a comprehensive deep sequencing approach to identify mutations in the tumor DNA from a cohort of patients treated at our institution over the past 15 years. Our results indicate mutations that may constitute therapeutic targets in MCC.
METHODS: Five patients were treated for MCC within the study interval. Patients with adequate tissue (n = 4), positive neuroendocrine differentiation (chromogranin, synaptophysin, and cytokeratin 20), and histopathological confirmation of MCC were included in the study. DNA was extracted from archival tumor tissue samples and analyzed by massively parallel sequencing using a targeted, multiplex PCR approach followed by semiconductor sequencing.
RESULTS: We demonstrate high-penetrance nonsense mutations in PDE4DIP (n = 4) as well as various missense mutations in the DNA damage response (PRKDC, AURKB, ERCC5, ATR, and ATRX) and epigenetic modulating enzymes (MLL3).
CONCLUSION: We describe several mutations in potential disease-relevant genes and pathways. These targets should be evaluated in a larger cohort to determine their role in the molecular pathogenesis of MCC.

Daily K, Coxon A, Williams JS, et al.
Assessment of cancer cell line representativeness using microarrays for Merkel cell carcinoma.
J Invest Dermatol. 2015; 135(4):1138-46 [PubMed] Free Access to Full Article Related Publications
When using cell lines to study cancer, phenotypic similarity to the original tumor is paramount. Yet, little has been done to characterize how closely Merkel cell carcinoma (MCC) cell lines model native tumors. To determine their similarity to MCC tumor samples, we characterized MCC cell lines via gene expression microarrays. Using whole transcriptome gene expression signatures and a computational bioinformatic approach, we identified significant differences between variant cell lines (UISO, MCC13, and MCC26) and fresh frozen MCC tumors. Conversely, the classic WaGa and Mkl-1 cell lines more closely represented the global transcriptome of MCC tumors. When compared with publicly available cancer lines, WaGa and Mkl-1 cells were similar to other neuroendocrine tumors, but the variant cell lines were not. WaGa and Mkl-1 cells grown as xenografts in mice had histological and immunophenotypical features consistent with MCC, whereas UISO xenograft tumors were atypical for MCC. Spectral karyotyping and short tandem repeat analysis of the UISO cells matched the original cell line's description, ruling out contamination. Our results validate the use of transcriptome analysis to assess the cancer cell line representativeness and indicate that UISO, MCC13, and MCC26 cell lines are not representative of MCC tumors, whereas WaGa and Mkl-1 more closely model MCC.

Chen CJ, Cox JE, Azarm KD, et al.
Identification of a polyomavirus microRNA highly expressed in tumors.
Virology. 2015; 476:43-53 [PubMed] Free Access to Full Article Related Publications
Polyomaviruses (PyVs) are associated with tumors including Merkel cell carcinoma (MCC). Several PyVs encode microRNAs (miRNAs) but to date no abundant PyV miRNAs have been reported in tumors. To better understand the function of the Merkel cell PyV (MCPyV) miRNA, we examined phylogenetically-related viruses for miRNA expression. We show that two primate PyVs and the more distantly-related raccoon PyV (RacPyV) encode miRNAs that share genomic position and partial sequence identity with MCPyV miRNAs. Unlike MCPyV miRNA in MCC, RacPyV miRNA is highly abundant in raccoon tumors. RacPyV miRNA negatively regulates reporters of early viral (T antigen) transcripts, yet robust viral miRNA expression is tolerated in tumors. We also identify raccoon miRNAs expressed in RacPyV-associated neuroglial brain tumors, including several likely oncogenic miRNAs (oncomiRs). This work describes the first PyV miRNA abundantly expressed in tumors and is consistent with a possible role for both host and viral miRNAs in RacPyV-associated tumors.

Veija T, Sahi H, Koljonen V, et al.
miRNA-34a underexpressed in Merkel cell polyomavirus-negative Merkel cell carcinoma.
Virchows Arch. 2015; 466(3):289-95 [PubMed] Related Publications
Merkel cell polyomavirus (MCV) is frequently detectable in Merkel cell carcinoma (MCC) tumors, but the significance of MCV infection is not yet totally understood. Thus far, no key regulatory miRNA has been identified for MCC tumorigenesis. However, distinct miRNA expression profiles have been suggested for MCV-positive and MCV-negative tumors. We used microarray hybridization to identify miRNA expression differences in MCC tumor samples according to MCV status and further validated these results by quantitative reverse transcription polymerase chain reaction (qRT-PCR). When compared with MCV-negative tumors, we detected overexpression of miR-34a, miR-30a, miR-142-3p, and miR-1539 in those MCV positives. In addition, slight underexpression was detectable in MCV-positive tumors of miR-181d. We confirmed the distinct expression of miRNAs in MCV-positive and MCV-negative tumors and confirmed statistically significant underexpression of miR-34a in MCV-negative tumors by both array analysis and qRT-PCR. Neither tumor location nor development of metastases affected miRNA expression.

Fisher CA, Harms PW, McHugh JB, et al.
Small cell carcinoma in the parotid harboring Merkel cell polyomavirus.
Oral Surg Oral Med Oral Pathol Oral Radiol. 2014; 118(6):703-12 [PubMed] Related Publications
OBJECTIVE: This study aimed to document three new cases of primary small cell carcinoma (SmCC) of the parotid and examine immunohistochemical and quantitative real-time polymerase chain reaction (qPCR) data of the recently developed Merkel cell polyomavirus (MCPyV) within these tumors.
STUDY DESIGN: Immunohistochemistry for neuroendocrine markers (chromogranin A, CD56, CD57, neuron-specific enolase [NSE], thyroid transcription factor 1 [TTF-1]), epithelial markers (CK20, CK7, CAM 5.2), and MCPyV large T antigen (LTAg) were examined. qPCR and Sanger sequencing were performed to confirm the presence of the MCPyV LTAg gene.
RESULTS: Two males and one female, average age 76 years, presented with left parotid masses. Clinical examinations, histories, and imaging studies were negative for cutaneous Merkel cell carcinoma (MCC), pulmonary and extrapulmonary SmCC, or any other malignancy. Immunohistochemical analysis demonstrated positive immunoreactivity for CK20 in a perinuclear dotlike pattern (3/3), CAM 5.2 (3/3), (2/3), NSE (3/3), CD56 (2/3), and CD57 (3/3). Two cases stained positive for MCPyV, showing moderate to strong, diffuse positivity, confirmed with qPCR. PCR-Sanger sequencing of LTAg exon 2 showed greater than 97% similarity to the MCPyV reference genome in both cases.
CONCLUSION: Our findings expand the number of reported cases classified as primary parotid SmCC that harbors MCPyV and underscore the similarity between cutaneous MCC and parotid SmCC. Further investigation is needed to determine whether immune-based therapeutic strategies targeting MCPyV in MCC are also effective in the setting of parotid SmCC harboring MCPyV.

Murakami I, Takata K, Matsushita M, et al.
Immunoglobulin expressions are only associated with MCPyV-positive Merkel cell carcinomas but not with MCPyV-negative ones: comparison of prognosis.
Am J Surg Pathol. 2014; 38(12):1627-35 [PubMed] Related Publications
Merkel cell carcinoma (MCC) is an aggressive neuroendocrine skin cancer, often associated with Merkel cell polyomavirus (MCPyV). Recently, immunoglobulin (Ig) expression was reported in MCC, thereby suggesting that B cells might be their cellular ancestors. We tested 30 MCCs (20 MCPyV-positive and 10 MCPyV-negative) using immunohistochemistry for the expressions of IgG, IgA, IgM, Igκ, Igλ, terminal desoxynucleotidyl transferase, paired box gene 5 (PAX5), octamer transcription factor-2 (Oct-2), and sex-determining region Y-box 11 (SOX11). We performed in situ hybridization for Igκ-mRNA or Igλ-mRNA and Ig heavy chain (IgH) gene rearrangement (IgH-R) analyses. The expressions of PAX5, TdT, Oct-2, and SOX11 were not significantly different between MCPyV-positive and MCPyV-negative MCCs. At least 1 of IgG, IgA, IgM, or Igκ was expressed in MCPyV-positive (14/20, 70%) and none in MCPyV-negative MCCs (P=0.0003). There was a higher tendency for Igκ-mRNA expression (7/19, using in situ hybridization) and IgH-R (10/20, using polymerase chain reaction) in MCPyV-positive than in MCPyV-negative MCCs (0/10 and 2/10, respectively), thus suggesting a different Ig production pattern and pathogenesis between the 2 types of MCC. Ig expression or IgH-R in MCPyV-positive MCCs might be associated with MCPyV gene integration or expression in cancer cells but do not necessarily suggest a B-cell origin for MCCs. IgH expression or IgH-R nonsignificantly correlated with improved prognosis. However, these might be important factors that influence the survival of neoplastic cells and might allow the development of novel therapies for patients with MCPyV-positive MCCs.

Ariffin H, Chan AS, Oh L, et al.
Frequent occurrence of gastric cancer in Asian kindreds with Li-Fraumeni syndrome.
Clin Genet. 2015; 88(5):450-5 [PubMed] Related Publications
Type of cancer and age of onset in individuals with inherited aberrations in the tumour suppressor gene TP53 are variable, possibly influenced by genetic modifiers and different environmental exposure. Since 2009, the modified Chompret criteria (MCC) have been used to identify individuals for TP53 mutation screening. Using the TP53 mutation database maintained by the International Agency for Research on Cancer (IARC), we investigated if the MCC, mainly developed for a Caucasian population, was also applicable in Asia. We identified several differences in Asian families compared with similar Caucasian cohorts, suggesting that identification and management of Li-Fraumeni syndrome in Asia do not completely mirror that of North America and Western Europe. Early gastric cancer (<40 years) may be considered a new addition to the MCC especially for Asian families.

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