Detection of DNA H.pylori and distribution of CagA genotype in cancerous and precancerous tissue


Helicobacter pylori (H. pylori) has been recognized as the causative agent of chronic gastric inflammation, which can progress further to a variety of diseases such as peptic ulcer and adenocarcinoma. The major bacterial virulence markers of H. pylori, the cytotoxin-associated gene (CagA), may play a role in determining the clinical outcome of Helicobacter infections. Aim of this study to investigate the presence of H.pylori DNA within gastric epithelial cells in patients with H.pylori infection and to determine the prevalence of CagA among patients with cancerous and precancerous lesion. Methods: A total of 92 gastric biopsy samples, 25 H.pylori negative and 67 H.pylori positive patients. H.pylori DNA in gastric epithelial cells and CagA gene of H. pylori was assessed by using the in situ hybridization test. Results: In H. pylori positive group, the positive rates of H.pylori DNA in the gastric epithelial cells were progressively increased in chronic superficial gastritis, precancerous changes and gastric cancer groups(P>0.01); The detection of CagA positive H. pylori was significantly higher in patients with gastric cancer compared to those with chronic superficial gastritis and atrophic gastritis(P<0.01). Conclusion: The pathological progression from chronic superficial gastritis, precancerous changes to gastric cancer is associated with higher positive rates of H.pylori DNA presence in the gastric epithelial cells, and there was a significant increase in CagA-positive H.pylori among patients with gastric cancer.


H. pylori, DNA, CagA, ISH