Promoter Hypermethylation of the Eyes Absent 4 Gene is a Tumor-Specific Epigenetic Biomarker in Iranian Colorectal Cancer Patients

Abstract

The aim of this study was to investigate whether hypermethylation of Eyes Absent 4 (EYA4) is also implicated in Iranian Colorectal Cancer (CRC) patients or not. From fresh frozen tissues, samples from 38 paired (cancer and normal) CRC tissue specimens were used in this study, the DNA was isolated, sodium bisulfite treated and analyzed by methylation-specific polymerase (MSP) chain reaction using primers specific for unmethylated or methylated promoter sequences of the EYA4 gene. We also analyzed EYA4 mRNA expression using real time RT-PCR. Demographic characteristics of these patients including age, sex, tumor grade, location, stage, and TNM classification were evaluated and the relationship between methylation status of the gene and clinicopathological features was analyzed. Current study indicated that EYA4 promoter hypermethylation has a sensitivity of 81.57% and specificity of 78.94%. Findings showed lower expression of EYA-4 in methylated samples in comparison with its normal adjacent tissue, although it was not significant (P>0.05). No significant associations were observed between EYA4 hypermethylation and the clinicopathological characteristics. Although the clinical patient outcome of our 38 CRC patients was not associated with EYA4 promoter hypermethylation, the high frequency of this methylation and its high sensitivity and specificity to neoplastic cells may qualify EYA4 promoter methylation as a potential candidate screening marker in Iranian population and may help to improve early detection of CRC.

Keywords

• DNA methylation
• Colorectal cancer
• EYA4
• Screening