title: Molecular characteristics of colorectal serrated polyps and hyperplastic polyps: A STROBE compliant article.
abstract: The serrated neoplasia pathway of colorectal carcinogenesis is characterized by BRAF mutation and aberrant DNA methylation, which have not been reported on Korean patients. The aim of this study was to investigate BRAF mutation and DNA methylation in colorectal serrated polyps and the right colon.Between 2005 and 2013, 146 colon polyps (47 tubular adenomas [TAs], 53 traditional serrated adenomas [TSAs], 17 sessile serrated adenomas/polyps [SSAs], and 29 hyperplastic polyps in the proximal colon [PHPs]) were collected from patients. Paraffin-embedded colon polyp tissue was used for DNA extraction. BRAF V600E mutation was identified through polymerase chain reaction (PCR) and pyrosequencing assay. The methylation status of the long interspersed nucleotide element-1, insulin-like growth factor binding protein 7 (IGFBP7), mutL homolog 1 (hMLH1), and CD133 genes were evaluated through disulfite conversion, PCR, and pyrosequencing assay.BRAF V600E mutation was found in 2.1% of TAs, 47.2% of TSAs, 41.2% of SSAs, and 20.7% of PHPs. TSA and SSA had higher BRAF mutation rates than did TA (P < 0.0001). TSA had higher BRAF mutation rates than did PHP (P = 0.018). IGFBP7 hypermethylation was found in 17% of TAs, 37.7% of TSAs, 88.2% of SSAs, and 37.5% of PHPs. TSA and SSA had higher hypermethylation of IGFBP7 than did TA (P = 0.021 and P < 0.0001, respectively). SSA had higher hypermethylation of IGFBP7 than did PHP (P = 0.002). hMLH1 hypermethylation was found in 2.1% of TAs, 5.7% of TSAs, 0% of SSAs, and 0% of PHPs. CD133 hypermethylation was found in 21.3% of TAs, 9.4% of TSAs, 35.3% of SSAs, and 17.4% of PHPs.BRAF mutation and methylation in TSA and SSA are different from those in PHP in Koreans. These findings suggested that PHP may have different molecular characteristics compared with other serrated polyps.
authors.affiliation: Division of Gastroenterology and Hepatology, Department of Internal Medicine Department of Pathology, Yonsei University Wonju College of Medicine, Wonju, Republic of Korea.
authors.forename: Otgontuya
authors.initials: O
authors.lastname: Sambuudash
authors.forename: Hee Man
authors.initials: HM
authors.lastname: Kim
authors.forename: Hannah
authors.initials: H
authors.lastname: Jo
authors.forename: Hyun Sik
authors.initials: HS
authors.lastname: Kim
authors.forename: Kyong Joo
authors.initials: KJ
authors.lastname: Lee
authors.forename: Hong Jun
authors.initials: HJ
authors.lastname: Park
authors.forename: Jae Woo
authors.initials: JW
authors.lastname: Kim
authors.forename: Mee Yon
authors.initials: MY
authors.lastname: Cho
authors.forename: Hyun-Soo
authors.initials: HS
authors.lastname: Kim
mesh_terms: D000236:Adenoma / Q000235:genetics / Q000473:pathology; D000368:Aged; D000704:Analysis of Variance; D001707:Biopsy, Needle; D015331:Cohort Studies; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000473:pathology; D019175:DNA Methylation / Q000235:genetics; D005260:Female; D020022:Genetic Predisposition to Disease / Q000453:epidemiology*; D006801:Humans; D007150:Immunohistochemistry; D007417:Intestinal Polyps / Q000235:genetics* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D016133:Polymerase Chain Reaction / Q000379:methods; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics*; D012189:Retrospective Studies
chemical_list: C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf