title: Eradication of Helicobacter pylori reduced the immunohistochemical detection of p53 and MDM2 in gastric mucosa.
abstract: BACKGROUND
  Although Helicobacter pylori has been regarded as a pathogen of gastric cancer, the mechanism by which H. pylori is involved in gastric carcinogenesis remains unknown. To clarify the role of H. pylori in carcinogenesis, the expression of tumor suppressor p53 and its regulator multiple double minute 2 (MDM2) in gastric mucosa were examined before and after H. pylori eradication.
  
  
  METHODS
  Biopsy specimens were obtained from 31 patients with H. pylori-infected gastric mucosa. Endoscopic biopsies were repeated 6 months after successful eradication. In addition, biopsy specimens from 12 patients with non-infected gastric mucosa were obtained. Immunohistochemical analysis was performed on the specimens using primary antibodies specific for p53 and MDM2.
  
  
  RESULTS
  Six months after H. pylori eradication, labeling indices for p53 were significantly reduced in the gastric corpus (2.3-fold; P < 0.01), and in the gastric antrum (2.0-fold; P < 0.01). Similarly, labeling indices for MDM2 were significantly reduced in the corpus (1.7-fold; P < 0.01), and in the antrum (3.5-fold; P < 0.01). In the non-infected group, labeling indices for p53 and MDM2 in the gastric mucosa were significantly lower (P < 0.01) than those of the H. pylori-infected group.
  
  
  CONCLUSIONS
  A significant increase is shown in p53 and MDM2 expression in H. pylori-infected gastric mucosa as compared to normal gastric mucosa; but successful eradication of H. pylori dramatically reduced the p53 and MDM2 levels. Therefore, H. pylori infection may be associated with alteration of cell proliferation and apoptosis.
authors.affiliation: Department of General Medicine, Faculty of Medicine, Oita University, Hasama-machi, Oita 879-5593, Japan. kodm@med.oita-u.ac.jp
authors.forename: Masaaki
authors.initials: M
authors.lastname: Kodama
authors.forename: Toshio
authors.initials: T
authors.lastname: Fujioka
authors.forename: Kazunari
authors.initials: K
authors.lastname: Murakami
authors.forename: Tadayoshi
authors.initials: T
authors.lastname: Okimoto
authors.forename: Ryugo
authors.initials: R
authors.lastname: Sato
authors.forename: Koichiro
authors.initials: K
authors.lastname: Watanabe
authors.forename: Masaru
authors.initials: M
authors.lastname: Nasu
mesh_terms: D000890:Anti-Infective Agents / Q000627:therapeutic use*; D015415:Biomarkers / Q000378:metabolism; D001706:Biopsy; D005260:Female; D005753:Gastric Mucosa / Q000378:metabolism* / Q000382:microbiology / Q000473:pathology; D005773:Gastroscopy; D016481:Helicobacter Infections / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D016480:Helicobacter pylori / Q000187:drug effects / Q000302:isolation & purification*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D051736:Proto-Oncogene Proteins c-mdm2 / Q000276:immunology* / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000276:immunology* / Q000378:metabolism
chemical_list: D000890:Anti-Infective Agents; D015415:Biomarkers; D016159:Tumor Suppressor Protein p53; D051736:Proto-Oncogene Proteins c-mdm2