Evaluation of correlation of miR-141 expression changes with common mutations of K-Ras gene and its relationship with prognosis in tumor tissue of colorectal cancer in Iranian patients

In many human malignant tumors, the expression of micro RNA molecules is dysfunctional. The purpose of this study was to investigate the miR-141 marker as a possible prognostic marker in colorectal cancer in order to screen patients with K-Ras mutation.

In this case- control study, 100 patients with colorectal cancer aged over 50 years were studied. The pathologist confirmed colorectal cancer among samples of paraffin-embedded colon tissue in the pathology department of Imam Hossein Hospital in Tehran. People who have codon 12 and 13 mutations in exon 2 of K-Ras gene were selected as case group and tumor samples of people without codon 12 and 13 mutation in exon 2 of K-Ras gene were selected as control group. Changes in miR-141 expression were investigated in both groups.

The results showed that 20% of patients were positive for codon 12 mutation and 10% of patients had codon 13 mutation. miR-141 gene expression in K-Ras positive tumor samples was 1.5 times its expression level in K-Ras negative samples and this increase in expression was statistically significant.

The results of the present study showed that the frequency of common K-Ras gene mutations in the population of colorectal cancer patients under study is consistent with the average of the Iranian population. It seems that miR-141 can be used as a biomarker to help in the diagnosis and prognosis of colorectal cancer.