Aim: To determine the expression of DNA MMR proteins, including hMLH1 and hMSH2, in gastric epithelial cells of patients with or without H. pylori infected gastritis.
Background: Impairment of DNA mismatch repair (MMR) system is a known mechanism of carcinogenesis and tumor progression in both sporadic and hereditary human cancers.
Patients and methods: Fifty H.pylori-positive patients and 50 H.pylori-negative subjects were enrolled in the study. During endoscopy of patients with non-ulcer dyspepsia, 2 antral and 2 corpus biopsies were taken for histologic examination (Giemsa stain) and immunohistochemical staining on hMLH1 and hMSH2.
Results: The percentage of epithelial cell nuclei demonstrating positivity for hMLH1 staining was 84.14±7.32 in H.pylori-negative subjects in comparison of 73.34±10.10 in H.pylori-positive patients (p<0.0001). The percentage of epithelial cell nuclei demonstrating positivity for hMSH2 staining did not differ significantly (81.16±8.32 in H.pylori-negative versus 78.24±8.71 in H.pylori-positive patients; NS).
Conclusion: Study indicates that H.pylori might promote development of gastric carcinoma at least in part through the ability to affect the DNA MMR system.