title: Helicobacter pylori infection and expression of DNA mismatch repair proteins.
abstract: OBJECTIVE
  To determine the expression of DNA (MMR) proteins, including hMLH1 and hMSH2, in gastric epithelial cells in the patients with or without Helicobacter pylori (H pylori)-infected gastritis.
  
  
  METHODS
  Fifty H pylori-positive patients and 50 H pylori-negative patients were enrolled in the study. During endoscopy of patients with non-ulcer dyspepsia, two antral and two corpus biopsies were taken for histological examination (Giemsa stain) and for immunohistochemical staining of hMLH1 and hMSH2.
  
  
  RESULTS
  The percentage of epithelial cell nuclei that demonstrated positivity for hMLH1 staining was 84.14 +/- 7.32% in H pylori-negative patients, while it was 73.34 +/- 10.10% in H pylori-positive patients (P < 0.0001). No significant difference was seen between the two groups regarding the percentage of epithelial cell nuclei that demonstrated positivity for hMSH2 staining (81.16 +/- 8.32% in H pylori-negative versus 78.24 +/- 8.71% in H pylori-positive patients; P = 0.09).
  
  
  CONCLUSIONS
  This study indicates that H pylori might promote development of gastric carcinoma at least in part through its ability to affect the DNA MMR system.
authors.affiliation: Department of Patholology, Research Center for Gastroenterology and Liver Disease, Shaheed Beheshti University, M.C., 19835-187, Tehran, Iran.
authors.forename: Vahid
authors.initials: V
authors.lastname: Mirzaee
authors.forename: Mahsa
authors.initials: M
authors.lastname: Molaei
authors.forename: Hamid-Mohaghegh
authors.initials: HM
authors.lastname: Shalmani
authors.forename: Mohammad-Reza
authors.initials: MR
authors.lastname: Zali
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism*; D000328:Adult; D001706:Biopsy; D053843:DNA Mismatch Repair / Q000502:physiology*; D004848:Epithelium / Q000378:metabolism / Q000473:pathology; D005260:Female; D005753:Gastric Mucosa / Q000378:metabolism; D005756:Gastritis / Q000378:metabolism* / Q000473:pathology; D016481:Helicobacter Infections / Q000378:metabolism* / Q000473:pathology; D016480:Helicobacter pylori; D006801:Humans; D008297:Male; D053842:Microsatellite Instability; D008875:Middle Aged; D000070957:MutL Protein Homolog 1; D000070956:MutL Proteins; D009363:Neoplasm Proteins / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism*; D013270:Stomach / Q000473:pathology
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C501486:MLH1 protein, human; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; C088996:PMS1 protein, human; D000070957:MutL Protein Homolog 1; D000070956:MutL Proteins