Frequency of K-RAS and N-RAS Gene Mutations in Colorectal Cancers in Southeastern Iran.

Background: K-RAS and N-RAS gene mutations cause resistance to treatment in patients with colorectal cancer. Based on this, awareness of mutation of these genes is considered a clinically important step towards better diagnosis and appropriate treatment. Materials and Methods: Fifty paraffin-embedded blocks of colorectal cancer were obtained from Imam Reza Hospital of Birjand, Iran. Following DNA extraction, the samples were analyzed for common mutations of exons 2, 3 and 4 of KRAS and NRAS genes using real time PCR and pyrosequencing. Results: According to this study, the prevalence of mutations was respectively 28% (14 out of 50) and 2% (1 out of 50) in KRAS and NRAS genes. All the mutations were observed in patients >50 years old. Conclusions: Mutations were found in both KRAS and NRAS genes in colorectal cancers in Iranian patients. Determining the frequency of these mutations in each geographical region may be necessary to benefit from targeted cancer therapy.