Role of Helicobacter pylori Virulence Factor CagA in Gastric Cancer

Abstract

In 1983, Australian scientists Warren and Marshall identified Helicobacter pylori also known as H. pylori as the stomach bacteria responsible for peptic ulcer disease. For their discovery, they were awarded the 2005 Nobel Prize in Physiology or Medicine. Other studies conducted in the early 1990s demonstrated that H. pylori is also responsible for gastric cancer. As a prominent human infection, H. pylori established strong link between ulcers and cancer. It has been proposed that specific analysis of Helicobacter pylori virulence factor can be suitable for predicting of H. pylori infection disorders like Gastric Cancer (GC). Colonization by H. pylori is extremely common worldwide, affecting about half of the world’s population, and most carriers develop neither ulcers nor cancer. Gastric cancer is the third most common cause of cancer-related death in the world. This article is designed to evaluate the association between specific virulence factor of H. pylori and Gastric cancer. One major virulence factor in H. pylori is the cytotoxin-associated gene a (CagA). The carriage of CagA+ stain is proinflammatory and associated with increased risk of gastric cancer. The product of the CagA gene CagA enters gastric epithelial cells directly through the type IV secretion system. The overexpression of H. pylori CagA antigen results in dysregulation of cellular signalling, which increases the risk of gastric cancer. The review also discusses the epidemiological data linking H.pylori strains that are CagA positive to infection and a higher risk of gastric cancer including the eradication.