BRAF Gene Mutation Analysis in Colorectal Cancer in South of Iran

Colorectal carcinoma is the third most commonly diagnosed cancer worldwide and many studies have focused on its molecular basis. BRAF V600E is the single most important mutation of this gene in cancers. It shows variable, but usually low, frequency in colorectal cancer, but is associated with distinct histologic, prognostic and molecular features. It is highly associated with MSI (microsatellite instability), CIMP-H (CpG island methylator phenotype), serrated pathway, poor prognosis and resistance to anti-EGFR (epidermal growth factor) drugs and interestingly absent in Lynch syndrome. In this study, we analyzed BRAF V600E mutation in colorectal cancer in Iranian patients. One hundred patients with colorectal cancer, operated in hospitals affiliated to Shiraz University of medical Sciences (Faghihi and Namazi Hospital) were selected. The cases were chosen from the pathology files of the above mentioned hospitals, during 2011-2013. Genomic DNA were extracted from the paraffin blocks, by the DNP TM kit, amplified using conventional PCR and DNA sequenced using the automated sequencer (Sanger method). Patients were 21-87 years old (mean = 59.8), 45% female and 55% male. Thirty percent of the cases had right-sided and 70% left-sided cancer, of which 83% were well and 17% moderately differentiated. No BRAF V600E mutation was detected in these 100 cases. The BRAF mutation is not common in colorectal cancer patients in the South of Iran. Our results are very similar to very few previous studies conducted in Iran, although we suggest further studies with larger numbers of patients to confirm these results.