title: Low epithelial cell proliferation and absence of oncoprotein expression in juvenile polyposis of the stomach, with or without tumors.
abstract: OBJECTIVE
  To assess cell proliferation and analyze oncogenetic abnormalities in cases of juvenile polyposis of the stomach (JPs), with or without coexisting tumors.
  
  
  METHODS
  The Ki-67 labeling indices (KLI) were compared for juvenile polyps and coexisting tumors in three cases of JPs along with values for gastritis, foveolar epithelial hyperplastic polyps, adenomas, and carcinomas. Expression of p53, Bcl-2, and c-ErbB-2 in tumors was examined immunohistochemically, and a search for c-Ki-ras mutations was made by DNA direct sequencing.
  
  
  RESULTS
  The KLI for JPs did not significantly differ between cases, being consistently lower than the values for both hyperplastic polyps and gastritis. The KLI for the papillary tumors and a signet ring cell carcinoma found in association with JPs tended to be lower than those for their conventional counterparts. P53, but not Bcl-2 and c-ErbB-2, was focally expressed in the papillary tumors, whereas all three were absent in the signet ring cell carcinoma, in the JPs. No c-Ki-ras mutations were detected in the papillary tumors.
  
  
  CONCLUSIONS
  The cell proliferation of JPs is relatively low and the polyps can be considered hamartomatous. However, neoplastic change clearly can occur in association with a relative increase in proliferative activity being observed in coexisting tumors. Low cellular proliferative activity and absence of oncogenetic abnormalities in tumors of JPs, compared with their conventional counterpart tumors, suggest that pathways of tumorigenesis and genetic alteration in JPs may be different from those in their conventional counterparts.
authors.affiliation: Department of Pathology, School of Medicine, Kitasato University, Sagamihara, Kanagawa, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Mitomi
authors.forename: H
authors.initials: H
authors.lastname: Uesugi
authors.forename: Y
authors.initials: Y
authors.lastname: Nishiyama
authors.forename: M
authors.initials: M
authors.lastname: Ohida
authors.forename: N
authors.initials: N
authors.lastname: Arai
authors.forename: N
authors.initials: N
authors.lastname: Kobayashi
authors.forename: I
authors.initials: I
authors.lastname: Okayasu
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics / Q000473:pathology*; D018256:Adenomatous Polyps / Q000235:genetics / Q000473:pathology*; D000328:Adult; D004847:Epithelial Cells; D004848:Epithelium / Q000473:pathology; D005260:Female; D005753:Gastric Mucosa / Q000378:metabolism; D006801:Humans; D008297:Male; D015513:Oncogene Proteins / Q000235:genetics; D011127:Polyps / Q000235:genetics / Q000473:pathology*; D013270:Stomach / Q000473:pathology*; D013272:Stomach Diseases / Q000235:genetics / Q000473:pathology; D013274:Stomach Neoplasms / Q000235:genetics / Q000473:pathology*
chemical_list: D015513:Oncogene Proteins