title: Microsatellite instability is associated with the macroscopic configuration of neoplasms in patients with multiple colorectal adenomas.
abstract: BACKGROUND
  The management of patients with multiple colorectal adenomas, 10-100 in number, is often troublesome clinically. To establish the reasonable management of such cases, genetic backgrounds should be made clear.
  
  
  METHODS
  For a total of 19 adenomas and four carcinomas from four patients with multiple colorectal adenomas, we analyzed genetic instability at four selected microsatellite loci and screened exon 1-4 of the APC gene with special reference to macroscopic configurations of adenomas and carcinomas.
  
  
  RESULTS
  RER-positive phenotypes were detected in none of 13 protruded type adenomas, two (33%) out of six superficial elevated type adenomas and two (50%) out of four carcinomas. We detected no mutation of exon 1-4 of the APC gene in any sample. In patients with multiple colorectral adenomas, the proportion of superficial elevated type adenomas exhibiting genetic instability was significantly higher than that of protruded type adenomas.
  
  
  CONCLUSIONS
  The results suggested that RER-positive phenotype was an early event in tumorigenesis through superficial elevated type adenomas.
authors.affiliation: Department of Surgery, University of Tokyo, Japan. sasaki_1su@h.u-tokyo.ac.jp
authors.forename: S
authors.initials: S
authors.lastname: Sasaki
authors.forename: T
authors.initials: T
authors.lastname: Masaki
authors.forename: N
authors.initials: N
authors.lastname: Umetani
authors.forename: M
authors.initials: M
authors.lastname: Shinozaki
authors.forename: T
authors.initials: T
authors.lastname: Yokoyama
authors.forename: M
authors.initials: M
authors.lastname: Ono
authors.forename: H
authors.initials: H
authors.lastname: Nagawa
authors.forename: T
authors.initials: T
authors.lastname: Muto
mesh_terms: D000236:Adenoma / Q000235:genetics* / Q000473:pathology; D011125:Adenomatous Polyposis Coli / Q000235:genetics; D001483:Base Sequence; D002277:Carcinoma / Q000235:genetics / Q000473:pathology; D003110:Colonic Neoplasms / Q000235:genetics* / Q000473:pathology; D005260:Female; D017491:Genes, APC / Q000235:genetics*; D006801:Humans; D008297:Male; D018895:Microsatellite Repeats; D008875:Middle Aged; D009154:Mutation; D010641:Phenotype; D012004:Rectal Neoplasms / Q000235:genetics* / Q000473:pathology