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High-Resolution Melting Analysis for Rapid Detection of KRAS, BRAF, and PIK3CA Gene Mutations in Colorectal Cancer

Lisa Simi PhD, Nicola Pratesi PhD, Marina Vignoli PhD, Roberta Sestini PhD, Fabio Cianchi MD, Rosa Valanzano MD, Stefania Nobili PhD, Enrico Mini MD, Mario Pazzagli PhD, Claudio Orlando PhD
DOI: http://dx.doi.org/10.1309/LWDY1AXHXUULNVHQ 247-253 First published online: 1 August 2008


High-resolution melting analysis (HRMA) provides a valid approach to efficiently detect DNA genetic and somatic mutations. In this study, HRMA was used for the screening of 116 colorectal cancers (CRCs) to detect hot-spot mutations in the KRAS and BRAF oncogenes. Mutational hot spots on the PIK3CA gene, exons 9 and 20, were also screened. Direct sequencing was used to confirm and characterize HRMA results. HRMA revealed abnormal melting profiles in 65 CRCs (56.0%), 16 of them harboring mutations in 2 different genes simultaneously. The frequency of mutations was 17.2% for PIK3CA (11.2% in exon 9 and 6.0% in exon 20), 43.1% for KRAS exon 2, and 9.5% in exon 15 of the BRAF gene. We found a significant association between PIK3CA and KRAS mutations (P = .008), whereas KRAS and BRAF mutations were mutually exclusive (P = .001). This report describes a novel approach for the detection of PIK3CA somatic mutations by HRMA.

Key Words:
  • Oncogenes
  • Somatic mutations
  • Colon cancer