The CagA-SHP-2 complex is predominantly located in atrophic gastric mucosa and is associated with the transition to atrophic gastritis and possibly intestinal metaplasia.41 Deregulation of the SHP-2 role by CagA is functionally similar to the effect of the gain-of-function mutation of the SHP-2 gene observed in other human malignancies.44 CagA interference with intracellular signaling may thus lead to deregulation of cellular growth, apoptosis, and elevated cell motility. This evidence concerns the gene PTPN11 and chronic atrophic gastritis.