Helicobacter pylori infection promotes gastric carcinogenesis in a mice model.
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.
Han
Sang-Uk
SU
Department of Surgery, Ajou University School of Medicine, Suwon, Korea.
Kim
Young-Bae
YB
Joo
Hee-Jae
HJ
Hahm
Ki-Baik
KB
Lee
Won-Heung
WH
Cho
Yong-Kwan
YK
Kim
Dae-Yong
DY
Kim
Myung-Wook
MW
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
D018809:Proliferating Cell Nuclear Antigen; D008770:Methylnitrosourea