The prevalence of common mutation frequency in K-ras codons 12, 13 in Iranian Colorectal Cancer patients

Colorectal cancer (CRC) is the most gastrointestinal cancer in United States and Europe. It is the third most common cancer in Iranian men, and fourth in Iranian women. Codons 12 and 13 are the hot spots for mutations in colorectal cancer patients, which encodes the activated RAS protein. According to recent researches, somatic mutations in codons 12, 13 (exon1) of K-ras gene are discovered in 20% - 50% human CRCs. The aim of this study was to estimate the contribution of K-ras gene mutations in codons 12, 13 in the incidence, and its association with clinicopathologic information like age, sex, familial history, site of primary and histology in Iranian colorectal cancer patients. In this study, we have analyzed 59 tissue specimens of colorectal cancer patients using PCR/sequencing method for codons 12, 13 of K-ras gene. 20.3% of patients (10 in codon 12 and 2 in codon 13) have shown a point mutation. About 60% of mutations occur in rectum and 41.7% in colon. More than 80% of mutations were in adenocarcinomas and less mutations in mucinous. Most mutations were found over the age of 60. Only two patients (16.6%) had a familial history for cancer. According to low rates of k-ras mutations in codons 12, 13, we can say they are not common in Iranian patients. The mutation pattern for Iranian patients differs from other nationalities. Perhaps we can find point mutations in other exons, and we suggest whole genome sequencing for our patients.