Estimation of frequency of common mutations in ras genes in a group of iranian colorectal cancer patients in khorasan province

Mutation analysis of the EGFR downstream has been a main part of colorectal carcinoma evaluation.Different large prospective clinical trials have shown that only CRCs with wild-type KRAS and NRASrespond to anti-epidermal growth factor receptor (EGFR) treatment. Hence, mutation analysis is needed before treatment to confirm KRAS and NRAS mutations. There are very few studies about K-ras mutations in colorectal cancer (CRC) from developing countries such as Iran. It is therefore essential to conduct studies to learn about the molecular signature of such tumors, allowing the determination of an appropriate management plan. The aim of this study was to evaluate the frequency of hotspot mutations in KRAS and NRAS genes in Iranian patients with colorectal cancer (CRC) and to exploretheir correlations with certain clinicopathological parameters. We detected mutations in codons 12 and 13 of the KRAS and NRAS genes using high resolution melting (HRM), Intplex design and Sangersequencing in 87 Iranian CRC patients. Genomic DNA was isolated from fresh tissue samples of CRC patients. Mutations were glycine to aspartate on codon 12 (p.G12D), and glycine to aspartate on codon13 (p.G13D). We did not find any mutations in NRAS gene in our patients. In the frequency of KRAS in our population seems to be similar to China, Japan, India, USA, France, and Germany (13- 66%)and NRAS are similar to Western Iran. Using HRM as a rapid screening method can be helpful in determining the mutational status