Polymorphism detection of K-Ras mutations using high-resolution melting analysis in Mexican patients with metastatic colorectal cancer (mCRC)

Abstract

e15135 Background: Metastatic carcinoma of the colorectum remains a major problem. Nowadays the mutational polymorphism detection of K-ras gene is useful for patients with diagnosis of mCRC especially when an anti-EGFR biological therapy is considered to be used. The purpose of this study was to analyze and establish a molecular method to detect the mutational polymorphism of K-Ras gene in paraffin-embedded biopsies from Mexican patients with mCRC. Methods: The presence and polymorphism of K-ras gene mutations were analyzed in paraffin-embedded biopsies from 156 patients using a real time PCR technique with target specific oligomer competitor shifting the PCR amplification towards the mutated target, thus yielding an enriched PCR product containing variations. Results: K-ras mutations were detected in 89 of 156 patients (59%). There was not evaluated a relationship between the presence of a K-ras mutations and clinicopathological features. 39 of the 89 (42.85%) biopsies with a positive K- ras mutation had a 12G mutation polymorphism, 11 of the 89 (12.08%) biopsies had a 12D mutation polymorphism and 10 of the 89 (10.98%) biopsies had a 12S mutation polymorphism. Of the 64 biopsies without K-ras mutation (wild type), none clinicopathological correlation was determine in this group. The rate of the K-ras mutation was higher than that of the K-ras mutation negative group (wild type). Conclusions: This study demonstrates that the determination of mutational polymorphism of k-ras gene is possible and could be implemented as a predictor response in patients with mCRC to benefit from antibody based anti-EGFR therapies. No significant financial relationships to disclose.