Thank you Professor so much for your kind help

A number of mouse‐adapted H. pylori strains have now been developed, including the well‐characterized Sydney strain (SS1). After about 8 months of infection with this strain, mice develop severe gastritis and atrophy of the gastric epithelium, which may progress to high‐grade dysplasia, although adenocarcinomas do not usually develop. For this reason, H. pylori SS1 is typically used in conjunction with chemical agents or in genetically engineered mice to enable and promote gastric carcinogenesis. The inability of H. pylori SS1 to induce adenocarcinomas on its own is thought to be attributed to the loss of its cag pathogenicity island (CagA), which encodes a type IV secretion system that enables the bacterium to inject CagA, peptidoglycan, and other proteins into the host cell.

Thank you Professor Majid Eslami so much for your kind help