Hypermethylation of RUNX3 but not WIF1 gene and its association with stage and nodal status of tongue cancers
ABSTRACT Recent studies indicate various molecular abnormalities in oral squamous cell carcinomas (OSCC), including DNA methylation of tumor-associated genes. Although promoter hypermethylation of Wnt pathway antagonists RUNX3 (Runt-related transcription factor 3) and Wnt inhibitory factor 1 (WIF1) has been identified as a common event in a number of carcinomas, methylation status and the role of RUNX3 as a possible tumor suppressor in oral and head and neck cancer are yet controversial. The aim of our study is to determine the occurrence of RUNX3 and WIF1 genes hypermethylation and correlation with tumor and host-related factors and prognosis in tongue carcinomas.
In 76 patients with tongue carcinoma, RUNX3 and WIF1 genes promoter hypermethylation analysis was assessed by nested methylation-specific PCR method.
Hypermethylation of WIF1 and RUNX3 genes promoters was observed in 35% and 25% of carcinomas, respectively. RUNX3 gene promoter hypermethylation was significantly associated with lymph node involvement (P = 0.013) and tumor stage (P = 0.006), but not with the overall survival. Occurrence of RUNX3 and WIF1 genes comethylation was associated with nodal status (P = 0.058) and tumor stage (P = 0.055).
Our findings indicate that RUNX3 and WIF1 are frequently aberrantly methylated and that RUNX3 promoter methylation could be considered as a potential prognostic marker in tongue carcinoma.
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ABSTRACT: Head and neck squamous cell carcinoma is a heterogeneous group of tumors with each subtype having a distinct histopathological and molecular profile. Most tumors share, to some extent, the same multistep carcinogenic pathways, which include a wide variety of genetic and epigenetic changes. Epigenetic alterations represent all changes in gene expression patterns that do not alter the actual DNA sequence. Recently, it has become clear that silencing of cancer related genes is not exclusively a result of genetic changes such as mutations or deletions, but it can also be regulated on epigenetic level, mostly by means of gene promoter hypermethylation. Results from recent studies have demonstrated that DNA methylation patterns contain tumor-type-specific signatures, which could serve as biomarkers for clinical outcome in the near future. The topic of this review discusses gene promoter hypermethylation in oral and oropharyngeal squamous cell carcinoma (OSCC). The main objective is to analyse the available data on gene promoter hypermethylation of the cell cycle regulatory proteins p16(INK4A) and p14(ARF) and to investigate their clinical significance as novel biomarkers in OSCC. Hypermethylation of both genes seems to possess predictive properties for several clinicopathological outcomes. We conclude that the methylation status of p16(INK4A) is definitely a promising candidate biomarker for predicting clinical outcome of OSCC, especially for recurrence-free survival.Disease markers 04/2014; 2014:260549. DOI:10.1155/2014/260549 · 2.17 Impact Factor
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ABSTRACT: The deregulation of Wnt signaling has recently emerged as one of the drivers of head and neck cancers. This is frequently related to the methylation of several antagonists of this pathway. This study aimed at the assessment of the profile of methylation of Wnt pathway antagonists and the determination of the prognostic value of the methylation of selected genes in oral carcinomas. The methylation of DACH1, DKK1, LKB1, PPP2R2B, RUNX3, SFRP2, and WIF-1 was analyzed in 16 oral squamous cell carcinoma cell lines using the methylation-specific polymerase chain reaction. The methylation of selected genes was further analyzed in tumor sections from 43 primary oral carcinoma patients. The analysis of oral carcinoma cell lines showed very frequent methylation of SFRP2 and WIF-1 and also a less frequent methylation of DACH1 and DKK1. On the other hand, RUNX3 was methylated only in one cell line, while LKB1 and PPP2R2B were not methylated in any of the cell lines. The biallelic methylation of DKK1 correlated with the low level of expression of this gene. Further evaluation of the methylation of DACH1, DKK1, and WIF1 in a clinical patient group confirmed the frequent methylation of WIF1 and intermediate or low frequency of methylation of DACH1 or DKK1, respectively. Importantly, the methylation of WIF-1 correlated with shorter survival in oral cancer patients. Overall, the methylation of the antagonists of Wnt pathway is frequently detected in oral squamous cell carcinomas. The methylation of WIF1 may be considered a prognostic marker in oral cancers.Tumor Biology 12/2014; DOI:10.1007/s13277-014-2913-x · 2.84 Impact Factor
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ABSTRACT: DNA hypermethylation is reported as a frequent event and prognostic marker in head and neck squamous cell carcinomas (HNSCC). Methylation has been commonly assessed with non-quantitative methodologies, such as methylation-specific PCR (MSP). We investigated previously reported hypermethylated genes with quantitative methodology in oral tongue squamous cell carcinomas (OTSCC). The methylation status of 12 genes in 115 OTSCC samples was assessed by one or more of three quantitative analyses: methylation sensitive high resolution melting (MS-HRM), sensitive-melting analysis after real time-methylation specific PCR (SMART-MSP), and bisulfite pyrosequencing. In contrast to much of the literature, either no or infrequent locus-specific methylation was identified by MS-HRM for DAPK1, RASSF1A, MGMT, MLH1, APC, CDH1, CDH13, BRCA1, ERCC1, and ATM. The most frequently methylated loci were RUNX3 (18/108 methylated) and ABO (22/107 methylated). Interrogation of the Cancer Genome Atlas (TCGA) HNSCC cohort confirmed the frequency of significant methylation for the loci investigated. Heterogeneous methylation of RUNX3 (18/108) and ABO (22/107) detected by MS-HRM, conferred significantly worse survival (P = 0.01, and P = 0.03). However, following quantification of methylation levels using pyrosequencing, only four tumors had significant quantities (>15%) of RUNX3 methylation which correlated with a worse patient outcome (P <0.001), while the prognostic significance of ABO hypermethylation was lost. RUNX3 methylation was not prognostic for the TCGA cohort (P = 0.76). We demonstrated the critical need for quantification of methylation levels and its impact on correlative analyses. In OTSCC, we found little evidence of significant or frequent hypermethylation of many loci reported to be commonly methylated. It is likely that previous reports have overestimated the frequency of significant methylation events as a consequence of the use of non-quantitative methodology.12/2014; 6(1):22. DOI:10.1186/1868-7083-6-22