title: [Molecular biological diagnostics of KRAS and BRAF mutations in patients with colorectal cancer - laboratory experience].
abstract: BACKGROUND
  Targeted biological therapy based on blocking growth factor receptors and inhibition of cancer-inducing signaling pathways is a new treatment facility for patients with colorectal cancer (CRC). Therapeutic agents are monoclonal antibodies targeting epidermal growth factor receptor (EGFR). Gene aberrations in the EGFR-induced pathways are negative predictors of therapeutic response. Determination of -non-mutated KRAS is a requirement for the indication of targeted anti-EGFR therapy in the present time, BRAF mutation analysis is recommended. Comparison of our results with published data and verification of routine laboratory methods in relation to diagnostic kits were the purposes of this study.
  
  
  METHODS
  In addition to routine methods based on PCR, direct sequencing as well as two diagnostic kits for KRAS (codon 12 and 13) and BRAF (codon 600) mutation analysis were used for 132 patients.
  
  
  RESULTS
  KRAS mutations were detected in 45 patients (34%), V600E mutation of the BRAF gene in 9 patients (7%). Both mutations simultaneously were not detected. Tissues from primary tumor and metastases were available from 33 patients. KRAS mutation was detected in 13 cases of this group. KRAS mutations in tumor and metastasis were of the same type in 9 patients; types of mutation in both tissues were different in one case. KRAS mutation only in one tissue was detected in 3 cases. BRAF mutation in both tissues was detected in the 4 patients. A low percentage of tumor cells in 17 patients specimen did not allow performance of routine analysis and diagnostic kit was used.
  
  
  CONCLUSIONS
  The frequency of KRAS and BRAF mutations in our cohort of patients corresponds to published data. The suitability of metastatic tissue analysis due to tumor heterogeneity was confirmed. KRAS analysis requires a comprehensive methodological approach with regard to reduced DNA quality and different percentage of tumor cells in tissue. For this reason, commercial diagnostic kits constitute a suitable supplement to standard methods.
authors.affiliation: Centrum Molekulámí Biologie a Gernové Terapie, Interní Hematokogická a Onkologická Klinika LF MU a FN Brno. blanka.robesova@fnbeno.cz
authors.forename: B
authors.initials: B
authors.lastname: Robešová
authors.forename: M
authors.initials: M
authors.lastname: Bajerová
authors.forename: A
authors.initials: A
authors.lastname: Vašíková
authors.forename: L
authors.initials: L
authors.lastname: Ostřížková
authors.forename: J
authors.initials: J
authors.lastname: Hausnerová
authors.forename: J
authors.initials: J
authors.lastname: Kyclová
authors.forename: S
authors.initials: S
authors.lastname: Pospíšilová
authors.forename: J
authors.initials: J
authors.lastname: Mayer
authors.forename: D
authors.initials: D
authors.lastname: Dvořáková
mesh_terms: D015179:Colorectal Neoplasms / Q000235:genetics* / Q000628:therapy; D006801:Humans; D058990:Molecular Targeted Therapy; D009154:Mutation; 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