title: Frequent somatic mutations of mitochondrial DNA in traditional serrated adenomas but not in sessile serrated adenomas of the colorectum.
abstract: OBJECTIVE
  Serrated adenomas (SAs), recently subdivided into traditional SAs (TSAs) and sessile SAs (SSAs), are recognized as a distinct form of neoplasia of the colorectum. One of the characteristics of SAs is hypermaturation of the gland epithelium due to the low extent of cell loss by apoptosis. Mutations of mitochondrial DNA (mtDNA) are closely associated with abnormality in apoptosis. We therefore examined mtDNA mutations in colorectal lesions including hyperplastic polyps (HPs), SSAs, TSAs, and carcinomas.
  
  
  METHODS
  Examined were 25 HPs, 32 SSAs, 19 TSAs, and 138 carcinomas. The D310 region of the mtDNAs was examined by microsatellite assay.
  
  
  RESULTS
  mtDNA mutations were detected in none of 25 (0%) HPs, one of 32 (3%) SSAs, six of 19 (32%) TSAs, and eleven of 133 (8%) carcinomas (five of the 138 carcinomas were not informative). The frequency of mtDNA mutations in the TSAs was significantly higher than that in the HPs, SSAs, and carcinomas (P = 0.004, P = 0.008, and P = 0.009, respectively). The frequency of mtDNA mutations in carcinomas was not significantly higher than that in HPs and SSAs (P = 0.14 and P = 0.28, respectively).
  
  
  CONCLUSIONS
  Our data suggest that mtDNA mutations may play an important role in the development of TSAs and could be used as a genetic marker to aid in the diagnosis of colorectal lesions.
authors.affiliation: Departments of Gastroenterology and Metabolism, Hiroshima University Hospital, Hiroshima, Higashihiroshima, Japan.
authors.forename: Takako
authors.initials: T
authors.lastname: Shimomura
authors.forename: Toru
authors.initials: T
authors.lastname: Hiyama
authors.forename: Shiro
authors.initials: S
authors.lastname: Oka
authors.forename: Shinji
authors.initials: S
authors.lastname: Tanaka
authors.forename: Masaharu
authors.initials: M
authors.lastname: Yoshihara
authors.forename: Fumio
authors.initials: F
authors.lastname: Shimamoto
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Chayama
mesh_terms: D000236:Adenoma / Q000235:genetics* / Q000473:pathology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000235:genetics*; D002277:Carcinoma / Q000235:genetics* / Q000473:pathology; D003111:Colonic Polyps / Q000235:genetics* / Q000473:pathology; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000473:pathology; D004252:DNA Mutational Analysis; D004272:DNA, Mitochondrial; D005819:Genetic Markers; D006801:Humans; D006965:Hyperplasia; D007564:Japan; D008875:Middle Aged; D009154:Mutation
chemical_list: D014408:Biomarkers, Tumor; D004272:DNA, Mitochondrial; D005819:Genetic Markers