種名： Helicobacter pylori
Stanford University Stanley Falkow
Helicobacter pylori lives in the human stomach. It causes gastritis, ulcer disease and even gastric cancer. Some H. pylori can inject a protein, CagA, into gastric epithelial cells. CagA interacts with the tight junctions that bind cells together and with signaling molecules affecting motility and proliferation. CagA is associated with ulcer disease and cancer but we don't understand how it works to favor malignancy. Not long ago in history most humans carried H. pylori ; the incidence of carriage and gastric cancer is dropping but there is evidence that this microbe also had a protective effect on human health.