A schematic illustration of the role of Noxo1 and NOX1 in the inflammation-associated gastric tumorigenesis. Helicobacter pylori infection causes chronic gastritis, which further induces expression of Noxo1 through TNF-α/NF-κB inflammatory cytokine pathway. Induction of Noxo1 as well as other NOX1 complex, such as NOX1, Noxa1 and Cyba, leads to activation of NOX1 complex and ROS production. Increased ROS level in the inflamed gastric mucosa results in expansion of SOX2-positive stem cell population, which induces gastritis-associated gastric metaplasia and hyperplasia. This Noxo1-involved inflammatory pathway contributes to gastric tumorigenesis in the H. pylori-infected stomach.