[A comparison of proteomic analysis of Helicobacter pylori in patients with gastritis and gastric cancer between areas of high and low incidence of gastric cancer].

Objective: To identify the differentially expressed proteins of Helicobacter pylori (Hp) in patients with gastritis and gastric cancer from areas of high and low incidence of gastric cancer by 2-dimensional electrophoresis (2-DE), and to discuss the role of bacterial factor in pathogenesis.
Methods: Hp in the endoscopic biopsy specimens of gastric mucosa of patients with gastritis and gastric cancer from areas of high (Xining) and low (Beijing) incidence of gastric cancer, were separated, cultured and saved at -80°C. The bacteria were recovered. Then the whole-cell protein of the Hp were extracted and characterized by 2-DE. The different protein spots were analyzed by PDQuest analysis software and identified by electrospray ionization quadruple time-of-flight mass spectrometry (ESI-Q-TOF-MS), and searched by the Mascot database.
Results: Nine differentially expressed proteins were identified, and four protein spots were over expressed in the protein maps from gastric cancer in both areas, which were: Urease subunit alpha, chaperone protein dnaK, superoxide dismutase, DNA-directed RNA polymerase subunit alpha; two protein spots were over expressed in the protein maps from gastritis in both areas, which were: Probablethiol peroxidase, nucleoside diphosphate kinase; 60×10(3) chaperonin, and inorganic pyrophosphatase were over expressed only in the protein map from gastric cancer in Xining; S-ribosyl homocysteinelyase was over expressed only in the protein map from gastric cancer in Beijing.
Conclusion: There are differences between proteomic analyses of Hp in patients with gastritis and gastric cancer in areas of high and low incidents of gastric cancer, but 2/3 of the protein spots over expressed in the areas are consistent. The protein spots over expressed from gastric cancer in the area with high incidence of gastric cancer are more than in the area with low incidence of gastric cancer. For the Hp extracted from patients with gastric cancer, the mechanism of gastric cancer may be similar, but the role of the Hp from the area with high incidence of gastric cancer may be stronger.