title: Microsatellite instability in Korean patients with gastric adenocarcinoma.
abstract: OBJECTIVE
  Microsatellites are short repeated oligonucleotide sequences found throughout the human genome. High mutation rates in microsatellite sequences have been found in tumors from patients with hereditary non-polyposis colorectal carcinoma and some sporadic carcinomas. However, little information is available regarding RER-positive phenotype in gastric carcinomas, particularly in terms of age of onset and other pathologic features, such as histologic types, degree of differentiation, location or stage of the carcinoma.
  
  
  METHODS
  To obtain a better understanding of the molecular mechanism of gastric carcinogenesis, microsatellite instability was examined at 6 gene loci (D2S71, D2S119, D3S1067, D6S87, D8S87, D11S905) in 77 gastric carcinomas (40 cases of young patients and 37 cases of elderly patients).
  
  
  RESULTS
  RER-positive phenotypes were found in 17 (22.1%) of 77 cases. In young patients (under 40 years) RER-positive phenotype was found in 9 (22.5%) of 40 cases, and in elderly patients 8 (21.6%) of 37 cases. Moderately differentiated carcinoma revealed a significantly high frequency of RER-positive phenotype than well differentiated carcinoma(p < 0.001). Tumors arising from the middle third (p < 0.001) or lower third (p < 0.001) revealed higher frequency of RER-positive phenotype than the tumors arising from the upper third of the stomach. The RER-positive phenotype was not significantly affected by the sex, histologic type or stage of carcinoma.
  
  
  CONCLUSIONS
  RER-positive phenotype occurs frequently in gastric carcinoma, although the frequency of RER-positive phenotype between young and elderly patient was not significantly different. Thus, the acquisition of RER-positive phenotype might be an early event in gastric carcinogenesis.
authors.affiliation: Department of Internal Medicine & Pathology, Chonnam University Medical School, Kwangju, Korea.
authors.forename: M S
authors.initials: MS
authors.lastname: Jee
authors.forename: C
authors.initials: C
authors.lastname: Koo
authors.forename: M H
authors.initials: MH
authors.lastname: Kim
authors.forename: C
authors.initials: C
authors.lastname: Choi
authors.forename: K M
authors.initials: KM
authors.lastname: Lee
authors.forename: S K
authors.initials: SK
authors.lastname: Choi
authors.forename: J S
authors.initials: JS
authors.lastname: Rew
authors.forename: C M
authors.initials: CM
authors.lastname: Yoon
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D018895:Microsatellite Repeats; D008875:Middle Aged; D009154:Mutation; D013274:Stomach Neoplasms / Q000235:genetics*