INS and carcinoma: For example, INS-GAS transgenic mice on the FVB genetic background that overexpress gastrin develop intramucosal carcinomas with submucosal and intravascular invasion in less than 1 year when infected by Helicobacter felis (H. felis) or H. pylori, with males showing a higher prevalence than females, indicating sex differences in GC tumorigenesis [72, 73].