title: Oncogene Mutations in Colorectal Polyps Identified in the Norwegian Colorectal Cancer Prevention (NORCCAP) Screening Study.
abstract: Data are limited on oncogene mutation frequencies in polyps from principally asymptomatic participants of population-based colorectal cancer screening studies. In this study, DNA from 204 polyps, 5 mm or larger, were collected from 176 participants of the NORCCAP screening study and analyzed for mutations in KRAS, BRAF, and PIK3CA including the rarely studied KRAS exons 3 and 4 mutations. KRAS mutations were identified in 23.0% of the lesions and were significantly associated with tubulovillous adenomas and large size. A significantly higher frequency of KRAS mutations in females was associated with mutations in codon 12. The KRAS exon 3 and 4 mutations constituted 23.4% of the KRAS positive lesions, which is a larger proportion compared to previous observations in colorectal cancer. BRAF mutations were identified in 11.3% and were associated with serrated polyps. None of the individuals were diagnosed with de novo or recurrent colorectal cancer during the follow-up time (median 11.2 years). Revealing differences in mutation-spectra according to gender and stages in tumorigenesis might be important for optimal use of oncogenes as therapeutic targets and biomarkers.
authors.affiliation: Department of Pathology, Oslo University Hospital, Oslo, Norway.; University of Oslo, Oslo, Norway.
authors.forename: Jon A
authors.initials: JA
authors.lastname: Lorentzen
authors.affiliation: Department of Pathology, Oslo University Hospital, Oslo, Norway.
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Grzyb
authors.affiliation: Department of Pathology, Oslo University Hospital, Oslo, Norway.
authors.forename: Paula M
authors.initials: PM
authors.lastname: De Angelis
authors.affiliation: University of Oslo, Oslo, Norway.; Department of Medicine, Telemark Hospital, Skien, Norway.; Cancer Registry of Norway, Oslo, Norway.
authors.forename: Geir
authors.initials: G
authors.lastname: Hoff
authors.affiliation: Department of Pathology, Oslo University Hospital, Oslo, Norway.; University of Oslo, Oslo, Norway.
authors.forename: Tor J
authors.initials: TJ
authors.lastname: Eide
authors.affiliation: Department of Pathology, Oslo University Hospital, Oslo, Norway.
authors.forename: Per Arne
authors.initials: PA
authors.lastname: Andresen
keywords: colonic polyps; colorectal cancer screening; oncogenes