Analysis of promoter methylation in RASSF2 genes for early detection of gastric tumors

Abstract

Gastric cancer is one of the most common cancers in the world with high mortality and morbidity. Early and accurate diagnosis of this disease can have a great impact on its successful control and treatment. Nowadays, gene methylation has been suggested as a diagnostic tool in some malignancies. The aim of the present study was to evaluate the role of RASSF2 methylation in the diagnosis and prognosis of gastric cancer by comparing the methylation level of this gene in tumor tissue and tumor margin specimens in patients with this cancer. Methods and Materials: This case-control study was performed on 50 gastric cancer patients. Tumor and tumor margin specimens (0.5 to 5 mg) from patients with gastric cancer who underwent surgery were sent for molecular studies. Methylation was evaluated by DNA disulfide method followed by semi-quantitative assay using Bisulfite Direct Sequencing MS method. Data were analyzed by SPSS 22 software by descriptive and inferential statistics. Results: 47 patients were studied and 4 patients were excluded due to lack of clinicopathological information. Most patients (57.4%) were under 5 years of age and males were more than females (55% compared to 45%). Lymph node involvement was present in 28 patients. The promoter methylation rate of RASSF2 gene in tumor samples was higher than control (64% compared to 31%). There was also a significant difference in methylation rate of RASSF2 gene promoter in tumor samples (odds ratio = 3.95 and p value = 0.0001). There was no relationship between age, sex and methylation rate of RASSF2 gene promoter, although methylation was significantly lower in patients with lymph node involvement (p = 0.001).