title: Helicobacter pylori infection promotes gastric carcinogenesis in a mice model.
abstract: OBJECTIVE
  Debate that Helicobacter pylori might play a causative role in gastric carcinogenesis still exists in spite of the World Health Organization's definition of H. pylori as a class I carcinogen. In order to define the exact role of H. pylori infection in gastric carcinogenesis, we established a mice model of H. pylori infection.
  
  
  METHODS
  One hundred and forty-four female C57BL/6 mice were divided into nine groups according to N-methyl-N-nitrosourea (MNU) treatment and H. pylori infection. All mice were killed at the 50th or 80th week after treatment, and their histopathological changes were evaluated according to group.
  
  
  RESULTS
  The incidence of gastric adenocarcinoma at the 50th week was 80% in mice treated with both MNU 240 microg/L and H. pylori infection, whereas the incidence was only 27% in mice treated with only MNU 240 microg/L. Although H. pylori caused marked expansion of the proliferative zone at the surface epithelium, H. pylori infection alone caused only chronic atrophic gastritis without any evidence of carcinomas until 80 weeks. The combination of MNU and H. pylori infection also resulted in a significantly higher incidence of gastric adenoma and adenocarcinoma. Significantly higher expressions of proliferating cell nuclear antigen were noted in the gastric mucosa infected with H. pylori compared to controls.
  
  
  CONCLUSIONS
  These results clearly demonstrated the role of H. pylori infection, rather than direct carcinogens, in promoting gastric carcinogenesis in a mice model.
authors: Department of Surgery, Ajou University School of Medicine, Suwon, Korea.
authors: Sang-Uk
authors: SU
authors: Han
authors: Young-Bae
authors: YB
authors: Kim
authors: Hee-Jae
authors: HJ
authors: Joo
authors: Ki-Baik
authors: KB
authors: Hahm
authors: Won-Heung
authors: WH
authors: Lee
authors: Yong-Kwan
authors: YK
authors: Cho
authors: Dae-Yong
authors: DY
authors: Kim
authors: Myung-Wook
authors: MW
authors: Kim
mesh_terms: D000230:Adenocarcinoma / Q000209:etiology* / Q000473:pathology; D000236:Adenoma / Q000209:etiology / Q000473:pathology; D000818:Animals; D005260:Female; D005753:Gastric Mucosa / Q000382:microbiology / Q000473:pathology; D005757:Gastritis, Atrophic / Q000382:microbiology / Q000473:pathology; D016481:Helicobacter Infections / Q000150:complications*; D016480:Helicobacter pylori; D008770:Methylnitrosourea; D051379:Mice; D008810:Mice, Inbred C57BL; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D013274:Stomach Neoplasms / Q000209:etiology* / Q000473:pathology
chemical_list: D018809:Proliferating Cell Nuclear Antigen; D008770:Methylnitrosourea