Effect of eradication of Helicobacter pylori on genetic instabilities in gastric intestinal metaplasia

Abstract

Background: There is little evidence of changes in genetic variations in gastric intestinal metaplasia (GIM) after the eradication of Helicobacter pylori (H. pylori). Aim: To investigate the effects of H. pylori eradication on genetic GIM variability in patients with and without gastric cancer in a one-year prospective study. Methods: We analysed microsatellite instability (MSI) and loss of heterozygosity (LOH) in GIM. Subjects included Gr. A (n = 39): chronic gastritis, and Gr. B (n = 53): intestinal-type early gastric cancer patients who underwent endoscopic mucosal resection (n = 25) and surgical resection (n = 28). Results: The frequency of incidence of MSI in GIM was 10.3% and 28.3% for Gr. A and Gr. B, respectively. Gr. B showed a significantly (p = 0.03) higher incidence rate than Gr. A for MSI, but not for LOH. The frequency of MSI declined in both groups post-eradication, and patients that were positive for MSI before treatment were negative after H. pylori eradication. Unfortunately, however, GIM scores did not decline significantly post-treatment for either group. Conclusions: MSI in GIM may be associated with gastric carcinogenesis. H. pylori eradication reduced MSI during the one-year post-treatment period, although no histological improvement in GIM was observed. These changes in MSI may explain the decrease in gastric cancer incidence after the eradication of H. pylori. © 2006 The Authors.