title: A comparability study of 5 commercial KRAS tests.
abstract: BACKGROUND
  Activating mutations in the KRAS gene occur frequently in human tumors, including colorectal carcinomas; most mutations occur in codons 12 and 13. Mutations in KRAS have been associated with poor response to anti-epidermal growth factor receptor antibodies. Therefore, an accurate and readily available analysis of KRAS mutational status is needed. The aim of this study was to evaluate concordance between KRAS assays performed by 6 different laboratories.
  
  
  METHODS
  Forty formalin-fixed paraffin-embedded colorectal cancer tumor samples were obtained. Sample sections were submitted for KRAS mutation analysis to 5 independent commercial laboratories (Agencourt, Gentris, Genzyme, HistoGeneX, and Invitek) and to the Amgen DNA Sequencing Laboratory for direct polymerase chain reaction sequencing. The assay used by Invitek is no longer commercially available and has been replaced by an alternative technique. Results from the commercial services were compared with those from Amgen direct sequencing by kappa statistics.
  
  
  RESULTS
  KRAS mutations were observed in codon 12 and/or 13 in 20 of 40 (50%) samples in Amgen direct sequencing assays. Results from HistoGeneX (kappa = 0.95), Genzyme (kappa = 0.94), and Agencourt (kappa = 0.94) were in almost perfect agreement with these results, and the results from Gentris were in substantial agreement with the results from Amgen (kappa = 0.75). The Invitek allele-specific assay demonstrated slight agreement (kappa = 0.13).
  
  
  CONCLUSIONS
  This study provides data on the comparability of KRAS mutational analyses. The results suggest that most (but not all) commercial services provide analysis that is accurate and comparable with direct sequencing.
authors.affiliation: Department of Molecular Sciences, Amgen Inc., Thousand Oaks, CA, USA.
authors.forename: Kelly
authors.initials: K
authors.lastname: Oliner
authors.forename: Todd
authors.initials: T
authors.lastname: Juan
authors.forename: Sid
authors.initials: S
authors.lastname: Suggs
authors.forename: Michael
authors.initials: M
authors.lastname: Wolf
authors.forename: Ildiko
authors.initials: I
authors.lastname: Sarosi
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Freeman
authors.forename: Tibor
authors.initials: T
authors.lastname: Gyuris
authors.forename: Will
authors.initials: W
authors.lastname: Baron
authors.forename: Andreas
authors.initials: A
authors.lastname: Bakker
authors.forename: Alex
authors.initials: A
authors.lastname: Parker
authors.forename: Scott D
authors.initials: SD
authors.lastname: Patterson
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics* / Q000473:pathology / Q000628:therapy; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002277:Carcinoma / Q000235:genetics* / Q000473:pathology / Q000628:therapy; D003062:Codon; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000473:pathology / Q000628:therapy; D004252:DNA Mutational Analysis; D005260:Female; D005404:Fixatives; D005557:Formaldehyde; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D015588:Observer Variation; D016612:Paraffin Embedding; D016133:Polymerase Chain Reaction; D011237:Predictive Value of Tests; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D016283:Proto-Oncogene Proteins p21(ras); D011933:Reagent Kits, Diagnostic; D015203:Reproducibility of Results; D016707:Tissue Fixation; D018631:ras Proteins / Q000235:genetics*
chemical_list: D003062:Codon; D005404:Fixatives; C117307:KRAS protein, human; D011518:Proto-Oncogene Proteins; D011933:Reagent Kits, Diagnostic; D005557:Formaldehyde; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins
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