Helicobacter pylori: a ROS-inducing bacterial species in the stomach

Reactive oxygen species (ROS) and reactive nitrogen species (RNS) have been reported to impact gastric inflammation and carcinogenesis. However, the precise mechanism by which Helicobacter pylori induces gastric carcinogenesis is presently unclear. This review focuses on H. pylori-induced ROS/RNS production in the host stomach, and its relationship with gastric carcinogenesis. Activated neutrophils are the main source of ROS/RNS production in the H. pylori-infected stomach, but H. pylori itself also produces ROS. In addition, extensive recent studies have revealed that H. pylori-induced ROS production in gastric epithelial cells might affect gastric epithelial cell signal transduction, resulting in gastric carcinogenesis. Excessive ROS/RNS production in the stomach can damage DNA in gastric epithelial cells, implying its involvement in gastric carcinogenesis. Understanding the molecular mechanism behind H. pylori-induced ROS, and its involvement in gastric carcinogenesis, is important for developing new strategies for gastric cancer chemoprevention.