CDH17 and gastric cancer: In terms of biology, CDH17 is a cell-cell adhesion molecule reported to be expressed on the cell membrane of normal small and large intestinal epithelia, atrophic gastric mucosa with intestinal metaplasia, normal pancreatic ductal epithelium, and several types of tumors, e.g., colorectal cancer, gastric cancer, pancreaticobiliary adenocarcinoma, and hepatocellular carcinoma [19, 31–33].