KRAS and BRAF mutation frequencies in a series of Turkish colorectal cancer patients

The prognostic value of KRAS and BRAF mutation in colorectal cancer (CRC) is very consistent. Several studies have demonstrated an association between these gene mutations and resistance to anti-EGFR based therapies. Wild type KRAS and BRAF is required for a response to CRC therapy. The aim of this study is to identify the frequency of KRAS and BRAF gene mutations in a series of Turkish CRC patients and to evaluate the relationship between the mutations and demographic features in the Turkish population. KRAS and BRAF mutations were analyzed in 220 colorectal tumor tissues. The mutation assays were performed with genomic DNA using automated microarray-based genotyping technology (Autogenomics Inc., Infinity Biofilm Chip Microarray, KRAS-BRAF Assay). Statistical analyses of the data were performed using SPSS (SPSS/Windows version 19.0, SPSS Inc., Chicago, IL, USA). In total, 33.2% of patients possessed a mutant KRAS genotype, and 6.7% of patients harbored BRAF mutations. The most common KRAS mutations were Gly12Asp and Gly12Val. All of the BRAF mutations were V600E. Patients with KRAS mutations did not harbor BRAF mutation. Female patients displayed an increased KRAS mutation frequency compared with male patients (P value =0.027). KRAS and BRAF gene alterations may determine the therapeutic response to anti-EGFR treatments. The utility of these markers was clarified by correlating genotyping studies with demographics and clinical findings. Cancer mutation profiles are influenced by cultural life style, environment and race/ethnicity. Genotype analysis could be used to select patients eligible for treatment. Patients should be classified according to genotypic subgroups for the selection of therapeutic agents.