title: Histological and genetic changes in malignant transformation of gallbladder adenoma.
abstract: METHODS
  Elucidate the histological and genetic changes in malignant transformation of adenoma of the gallbladder.
  
  
  METHODS
  Forty-three adenomas and 20 intramucosal tumors of carcinoma-in-adenomas were studied for histological and genetic changes (particularly K-ras mutation and p53 protein overexpression by immunohistochemistry) in malignant transformation. The genetic changes were compared with those of 164 carcinomas without anomalous union and 17 carcinomas with anomalous union of pancreatico-biliary duct.
  
  
  RESULTS
  Atypical cell foci, i.e. spindle cell foci, were observed only in the adenoma area, with a frequency of 23% in 39 adenomas, and of 45% in 20 tumors of carcinoma-in-adenoma. 129 of 130 spindle cell foci examined were negative for Ki-67 staining and all the spindle cell foci were negative for p53 stain. K-ras mutation and p53 overexpression were not found in all adenomas, pure and with carcinoma i.s., and only one carcinoma (1/16, 6%) with adenoma showed p53 overexpression. K-ras mutation was low (10%, 4/40) in carcinomas without adenoma, but high in carcinomas with anomalous union of pancreatico-biliary duct. While, p53 overexpression was high and similar in carcinomas with and without anomalous union.
  
  
  CONCLUSIONS
  These results suggest that there are three distinct pathways in gallbladder carcinogenesis; that is, de novo carcinoma develops from a predominant p53 alteration with low K-ras mutation, de novo carcinoma with anomalous union from K-ras mutation and p53 mutation, and carcinoma-in-adenoma from K-ras-, p53-, and probably APC-gene-related, as yet unknown, alteration.
authors.affiliation: Department of Pathology, Niigata University School of Medicine, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Watanabe
authors.forename: K
authors.initials: K
authors.lastname: Date
authors.forename: T
authors.initials: T
authors.lastname: Itoi
authors.forename: H
authors.initials: H
authors.lastname: Matsubayashi
authors.forename: N
authors.initials: N
authors.lastname: Yokoyama
authors.forename: M
authors.initials: M
authors.lastname: Yamano
authors.forename: Y
authors.initials: Y
authors.lastname: Ajioka
authors.forename: K
authors.initials: K
authors.lastname: Nishikura
mesh_terms: D000236:Adenoma / Q000235:genetics / Q000473:pathology*; D000818:Animals; D005706:Gallbladder Neoplasms / Q000235:genetics / Q000473:pathology*; D017491:Genes, APC; D011905:Genes, ras; D006801:Humans; D051379:Mice; D009154:Mutation; D016159:Tumor Suppressor Protein p53 / Q000032:analysis
chemical_list: D016159:Tumor Suppressor Protein p53