The cytotoxin of Helicobacter pylori( Hp) plays an important role in the initiation and development of gastric cancer. Both the cytotoxin-associated gene pathogenicity island( CagPAI) and the vacuolating cytotoxin A( vacA) are the most typical virulence factors in Hp. CagPAI which may induce the release of pro-inflammatory factors overly promote epithelial cell's proliferation and mobility,even show a hummingbird phenotype. CagPAI is also related to the abnormal mitosis and the destructure of apical junctio...