A Survey on EphA5 Methylation Status in Gastric Adenocarcinoma Patients

Introduction & Aim: Gastric cancer is the fourth most common cancer in the world. It has a poor prognosis and mostly diagnosed at an advanced stage. Gastric adenocarcinoma (GAC) is the most common histological type of gastric cancer. Alterations of genes regulating epigenetic processes especially in DNA methylation of tumor suppressor gene promote cancer progression. EPHA5 (EPH Receptor A5) is a tumor suppressor gene which belongs to the ephrin receptor subfamily of the protein-tyrosine kinase family. The aim of this study is investigation of methylation status of EPHA5 in gastric cancer samples for the first time. Methods About 14 formalin-fixed paraffin-embedded (FFPE) gastric adenocarcinoma samples were obtained from department of Pathology of Imam Reza hospital, Tabriz, IRAN. DNA extraction was performed using a modified salting out method. The methylation status was verified by methylation-specific PCR (MSP) technique. DNA was converted by sodium bisulphite treatment using Epizen DNA Methylation Kit and used in PCR with specific primers for EPHA5 promoter region. Four normal samples were used as control. Results: The results showed that EPHA5 gene was methylated in 9 out of 14 tumors DNA samples (64.28%), whereas it was unmethylated in all normal samlpes. Conclusion: The results indicated that CG sites covering the EPHA5 promoter region are methylated in most of the gastric adenocarcinomas. It seems that, EPHA5 methylation status can be used as an independent prognostic biomarker for gastric adenocarcinomas.