A Review on the role of helicobacter pylori in the pathogenesis of gastric cancer by focusing on the CagA pathogenicity factor

Background: Helicobacter pylori is a gram-negative bacterium and a successful pathogen in causing some of the gastric diseases from asymptomatic gastritis to gastric cancer. There are several pathogenicity factors in H. pylori that are known to be effective in causing gastric cancer. Among them, strains with positive cagA factors are the most potent risk factor of gastric cancer. This article aims to investigate the importance of Helicobacter pylori in the pathogenesis of gastric cancer by focusing on the cagA pathogenicity factor. Method: This study is a review of low-level laser therapy by analyzing articles from scientific databases, including Science Direct, PubMed, and Scopus with keywords gastric cancer, H.pylori, cagA from 2016 to 2019. Finding: The cagA protein (cytotoxin associated with gene A) has a key oncogenic role in Helicobacter pylori pathogenicity. After binding of H pylori to the host gastric cell surface receptors, cagA-related protein is injected into the gastric epithelial cells through the secretory system of type 4 H.pylori and immediately stimulates an oncogenic signal in the cell. The activity of the cagA protein, with the help of tyrosine phosphorylation and kinases of the hostcells, causes polar and binding defects in these cells and increases the risk of cancer. Despite the important role of cagA in the development of gastric cancer, this factor is not required for the maintenance of established cancer cells. Conclusion: The association between CagA and gastric cancer suggests that the eradication of Helicobacter pylori in infected individuals can be considered a tool of preventing gastric cancer, however many questions remain regarding the effectiveness of this strategy.

کلیدواژه ها:

gastric cancer ، Helicobacter pylori ، cagA