title: Mutations in BRAF and KRAS differentially distinguish serrated versus non-serrated hyperplastic aberrant crypt foci in humans.
abstract: We previously reported that colon carcinomas, adenomas, and hyperplastic polyps exhibiting a serrated histology were very likely to possess BRAF mutations, whereas when these same advanced colonic lesions exhibited non-serrated histology, they were wild type for BRAF; among hyperplastic polyps, KRAS mutations were found mainly in a non-serrated variant. On this basis, we predicted that hyperplastic aberrant crypt foci (ACF), a putative precancerous lesion found in the colon, exhibiting a serrated phenotype would also harbor BRAF mutations and that non-serrated ACF would not. In contrast, KRAS mutations would be found more often in the non-serrated ACF. We examined 55 ACF collected during screening colonoscopy from a total of 28 patients. Following laser capture microdissection, DNA was isolated, and mutations in BRAF and KRAS were determined by direct PCR sequencing. When hyperplastic lesions were further classified into serrated and non-serrated histologies, there was a strong inverse relationship between BRAF and KRAS mutations: a BRAF(V600E) mutation was identified in 10 of 16 serrated compared with 1 of 33 non-serrated lesions (P = 0.001); conversely, KRAS mutations were present in 3 of 16 serrated compared with 14 of 33 non-serrated lesions. Our finding of a strong association between BRAF mutations and serrated histology in hyperplastic ACF supports the idea that these lesions are an early, sentinel, or a potentially initiating step on the serrated pathway to colorectal carcinoma.
authors: Colon Cancer Prevention Program, NEAG Comprehensive Cancer Center, and Center for Molecular Medicine, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030, USA. Rosenberg@nso2.uchc.edu
authors: Daniel W
authors: DW
authors: Rosenberg
authors: Shi
authors: S
authors: Yang
authors: Devon C
authors: DC
authors: Pleau
authors: Emily J
authors: EJ
authors: Greenspan
authors: Richard G
authors: RG
authors: Stevens
authors: Thiruchandurai V
authors: TV
authors: Rajan
authors: Christopher D
authors: CD
authors: Heinen
authors: Joel
authors: J
authors: Levine
authors: Yijian
authors: Y
authors: Zhou
authors: Michael J
authors: MJ
authors: O'Brien
mesh_terms: D025601:Adenomatous Polyposis Coli Protein / Q000235:genetics; D000595:Amino Acid Sequence; D003110:Colonic Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D005455:Fluorescent Antibody Technique; D017491:Genes, APC; D011905:Genes, ras; D045325:HCT116 Cells; D006801:Humans; D006965:Hyperplasia; D053842:Microsatellite Instability; D008969:Molecular Sequence Data; D009154:Mutation; D011230:Precancerous Conditions / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics*; D051176:beta Catenin / Q000378:metabolism
chemical_list: D025601:Adenomatous Polyposis Coli Protein; D051176:beta Catenin; C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf