title: Characteristics and prevalence of KRAS, BRAF, and PIK3CA mutations in colorectal cancer by high-resolution melting analysis in Taiwanese population.
abstract: BACKGROUND
  The identification of KRAS, BRAF, and PIK3CA mutations before the administration of anti-epidermal growth factor receptor therapy of colorectal cancer has become important. The aim of the present study was to investigate the occurrence of KRAS, BRAF, and PIK3CA mutations in the Taiwanese population with colorectal cancer. This study was undertaken to identify BRAF and PIK3CA mutations in patients with colorectal cancer by high-resolution melting (HRM) analysis. HRM analysis is a new gene scan tool that quickly performs the PCR and identifies sequence alterations without requiring post-PCR treatment.
  
  
  METHODS
  In the present study, DNAs were extracted from 182 cases of formalin-fixed, paraffin-embedded (FFPE) colorectal cancer samples for clinical KRAS mutational analysis by direct sequencing. All the samples were also tested for mutations within BRAF V600E and PIK3CA (exons 9 and 20) by HRM analysis.
  
  
  RESULTS
  The results were confirmed by direct sequencing. The frequency of BRAF and PIK3CA mutations is 1.1%, and 7.1%, respectively. Intriguingly, we found that nine patients (4.9%) with the KRAS mutation were coexistent with the PIK3CA mutation. Four patients (2.2%) without the KRAS mutation were existent with the PIK3CA mutation. Two patients (1.1%) without the KRAS mutation were existent with the BRAF mutation.
  
  
  CONCLUSIONS
  In the current study, we suppose that HRM analysis is rapid, feasible, and powerful diagnostic tool for the detection of BRAF and PIK3CA mutations in a clinical setting. Additionally, our results indicated the prevalence of KRAS, BRAF, and PIK3CA mutational status in the Taiwanese population.
authors.affiliation: Division of Molecular Diagnostics, Department of Laboratory Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan.
authors.forename: Li-Ling
authors.initials: LL
authors.lastname: Hsieh
authors.forename: Tze-Kiong
authors.initials: TK
authors.lastname: Er
authors.forename: Chih-Chieh
authors.initials: CC
authors.lastname: Chen
authors.forename: Jan-Sing
authors.initials: JS
authors.lastname: Hsieh
authors.forename: Jan-Gowth
authors.initials: JG
authors.lastname: Chang
authors.forename: Ta-Chih
authors.initials: TC
authors.lastname: Liu
mesh_terms: D044466:Asian People; D001483:Base Sequence; D058534:Class I Phosphatidylinositol 3-Kinases; D015179:Colorectal Neoplasms / Q000453:epidemiology / Q000235:genetics*; D005091:Exons; D006651:Histocytochemistry; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D009691:Nucleic Acid Denaturation; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics*; D016133:Polymerase Chain Reaction / Q000379:methods; D015995:Prevalence; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics*; D016283:Proto-Oncogene Proteins p21(ras); D017422:Sequence Analysis, DNA; D013624:Taiwan / Q000453:epidemiology; D018631:ras Proteins / Q000235:genetics*
chemical_list: D058534:Class I Phosphatidylinositol 3-Kinases; D019869:Phosphatidylinositol 3-Kinases; D011518:Proto-Oncogene Proteins; D048493:Proto-Oncogene Proteins B-raf; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins; C117307:KRAS protein, human; C484760:PIK3CA protein, human; C482119:BRAF protein, human