Analysis of hypermethylation and expression profiles of APC and ATM genes in patients with oral squamous cell carcinoma

Eighty-four OSCC tissues that have been fixed in paraffin along with 57 control oral samples have been used for analyzing promoter methylation of ATM and APC genes by Methylation Specific Polymerase Chain Reaction (MS-PCR). In addition, 10 cases of OSCC and the same of matched controls were examined for estimating expression of the above mentioned genes using Real-Time Reverse-Transcription PCR.Observed promoter methylations were 71.42% and 87.71% for the APC gene and 88.09% and 77.19% for the ATM gene in cases and controls, respectively. Analysis of these data showed that promoter methylation at APC was significantly different in cases compared to healthy controls (p = 0.01), but no difference was detected for the ATM gene. Furthermore, the mRNA expression levels did not differ statistically between cases and controls for both ATM (cases = 9, controls = 10) and APC (cases = 11, controls = 10) genes.Our results, for the first time, provide methylation profiles of ATM and APC genes in a sample of patients with OSCC in a southeast Iranian population. The present data support related evidence of APC methylation effect on OSCC development.Oral squamous cell carcinoma (OSCC) is one of the most frequently diagnosed types of head and neck cancers based on epidemiological reports [1]. It has been suggested that OSCC can arise in the course of accumulation of multiple genetic alterations [2], for which accurate molecular mechanisms regarding its pathogenesis remain to be understood.In addition to genetic changes, any alteration in epigenetic information such as DNA methylation, histone modifications, chromatin structure, microRNA, and other genomic functions may make an individual susceptible to developing cancer [3]. Hyper-methylation of promoter CpG islands and repetitive DNA sequences has been recognized as one of the most important variations in the progression of the cancer [4]. Growing data points to the critical role of CpG island hypermethylation in genes implicated