KRAS gene mutations in correlation with clinicopathological features of colorectal carcinomas in Indian patient cohort

KRAS gene mutations have been identified as a predictive molecular marker to predict the sensitivity of tumors to anti-EGFR therapeutics. The variability of clinical response to anti-EGFR agents has highlighted the need to select the appropriate patients who can benefit from the treatment. We examined the prevalence of KRAS mutations in 1,323 colorectal cancer patients from different regions of India and its correlation with geographic distribution and clinicopathological characteristics. DNA was extracted from formalin-fixed, paraffin-embedded tissue samples and was amplified by nested polymerase chain reaction at KRAS exon 2 and subjected to nucleotide sequencing using ABI 3100 Genetic Analyzer. The frequency of KRAS mutations was found to be 20.5 % (271/1,323). There was significant association (p < 0.05) between KRAS mutations, age and the tumor differentiation. Statistical analysis revealed significantly higher prevalence of colorectal cancer with mutated KRAS gene in northern regions of the country. No significant association was observed between KRAS mutations and gender (p > 0.05). Our study indicates that KRAS mutations in Indian colorectal cancer patients occur at lower level compared to that of Western population.