title: [BRAF gene mutation in wild-type KRAS patients with colorectal cancers].
abstract: BACKGROUND
  In colorectal cancer, BRAF and KRAS mutation are mutually exclusive, but both are independent prognostic factors for the disease.
  
  
  OBJECTIVE
  To determine the frequency of BRAF V600E mutation in colorectal cancer.
  
  
  METHODS
  A KRAS mutation study was carried out in 100 tissue samples of primary and metastatic adenocarcinomas of colon and rectum from patients aged 61.1 ± 62 years (56 women). Negative KRAS mutation cases underwent study of BRAF V600E mutation by restriction fragment length polymorphism (RFLP) and direct sequencing.
  
  
  RESULTS
  Primary tumors were located in the colon and rectum in 88 and six cases respectively. Five were liver metastases and in one case, the sample location was undetermined. Forty two samples were KRAS positive (mutated). In 12 of the 58 KRAS negative (wild type) samples, the V600E mutation in codon 15 of the BRAF gene was demonstrated. No differences in the frequency and distribution of mutations, stratified by gender, age, primary tumor versus metastasis, or tumor location were observed.
  
  
  CONCLUSIONS
  Twelve percent of KRAS negative colorectal cancer samples showed BRAF gene mutation. Considering that 42% of samples have a KRAS mutation, 54% of patients should not respond to therapies with monoclonal antibodies directed against epidermic growth factor (EGFR) pathway.
authors.forename: Iván
authors.initials: I
authors.lastname: Roa
authors.forename: Anakaren
authors.initials: A
authors.lastname: Game
authors.forename: Carolina
authors.initials: C
authors.lastname: Bizama
authors.forename: Kurt
authors.initials: K
authors.lastname: Schalper
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics*; D015179:Colorectal Neoplasms / Q000235:genetics*; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D009367:Neoplasm Staging; D012150:Polymorphism, Restriction Fragment Length; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics*; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins / Q000235:genetics*
chemical_list: C117307:KRAS protein, human; D011518:Proto-Oncogene Proteins; C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins