Sensitive High-Resolution Melting Analysis for Screening of KRAS and BRAF Mutations in Iranian Human Metastatic Colorectal Cancers

1.      Abstract 1.1.Background:investigations in the methods of mutation detection uncovered the major weaknesses of direct sequencing and pyrosequencing; they have high costs and low sensitivity for the screening of known or unknown mutations. High resolution melting (HRM) analysis seems to be an alternative tool for the rapid detection of mutations. Here we describe the accuracy of HRM in screening KRAS and BRAF mutations in metastatic colorectal cancer (mCRCs) samples. 1.2.Materials and methods:In this regard, we examined 1000 mCRC patients in Mehr Hospital, Tehran, Iran, from Feb. 2008 to May 2012 for KRAS mutations and 242 of them were selected for BRAF mutations by the HRM analysis. In order to calculate the sensitivity and specificity, HRM results were checked by pyrosequencing as the golden standard and Dxs Therascreen as another method. 1.3.Results:from the total of 1000 participants, there were 664 (66.4%) wild types and 336 (33.6%) mutants of KRAS gene in codon 12 and 13. Among 242 samples that randomly checked for BRAF gene, all were detected as wild type by HRM. Pyrosequencing and Dxs Therascreen results were in line with that of the HRM. In this regards, the sensitivity and specificity of HRM evaluated as 100%. 1.4.Conclusion:The findings suggest that the HRM, in comparison with DNA sequencing, is a more appropriate method for precise scanning of KRAS and BRAF mutations. It is also possible to state that HRM may be a more attractive technique for the detection of known or unknown somatic mutations of other genes.