Evaluation of methylation changes and the expression of RASSF۲ gene in tumor tissue and tumor margins of colorectal cancer patients

Colorectal cancer or CRC is one of the most common cancers with increasing rate of mortality and morbidity. RASSF۲ is one of the ۱۰ members of RASSF. Through interaction with Ras GTPase, these proteins regulate diverse cellular processes including membrane transport, apoptosis, migration and proliferation. RASSF۲ can inhibit cell growth and induce apoptosis. Accordingly, loss of RASSF۲ expression has been observed in various tumors and cancer cell lines, and such phenomena are often associated with RASSF۲ promoter hypermethylation and poor prognosis for patients. In this study, the level of expression of this gene and its methylation in patients with colorectal cancer and their relationship with the variables of age, smoking, family history, stage and metastasis were investigated. In this research, ۷۵ tumor tissue samples and ۷۵ tumor margin samples from patients with colorectal cancer were examined. After extracting RNA (trizol) from tissues, cDNA synthesis was performed and it was used to evaluate changes in RASSF۲ gene expression by Real Time PCR. Also, DNA was extracted from tissue samples and the methylation pattern of RASSF۲ promoter regions was investigated using bisulfite treatment. Statistical analysis was performed to investigate the changes in the expression and methylation of the RASSF۲ gene and their effects on the clinical characteristics of the patients, and P value<۰.۰۵ was considered as a significant level. Using the statistical method of ROC curve analysis, the biomarker potential of RASSF۲ gene expression and methylation was evaluated as a factor in colorectal cancer diagnosis. The obtained results have determined that there is a significant relationship between the gene expression level in cancerous tissue and marginal tissue, so that the expression of RASSF۲ gene in colorectal cancer tissues is lower than in tumor marginal tissues. Also, methylation in colorectal cancer tissues is clearly higher than marginal tissues. The results of this study show that RASSF۲ gene expression and methylation changes have relatively high potential as colorectal cancer biomarkers and can be used in early diagnosis, treatment, and monitoring of the disease process and prognosis.

کلیدواژه ها:

colorectal cancer ، RASSF۲ expression ، RASSF۲ methylation