CDH17 (cadherin 17) is a calcium-dependent cell adhesion protein primarily expressed in intestinal and pancreatic epithelial cells that serves as both a normal physiological adhesion molecule and an emerging therapeutic target in cancer 1. In normal tissues, CDH17 exhibits membranous expression predominantly in intestinal epithelium and pancreatic excretory ducts, where it contributes to cell-cell adhesion and tissue organization 1. The protein's mechanism involves calcium-dependent homophilic interactions that facilitate cell adhesion, with its expression restricted to tight junctions between normal intestinal epithelial cells 2. CDH17 has significant disease relevance in gastrointestinal cancers, being highly expressed in 50-100% of colorectal neoplasms, other gastrointestinal adenocarcinomas, and various neuroendocrine tumors 1. Importantly, while CDH17 is expressed in both normal intestinal tissue and tumors, its differential localization makes it an attractive therapeutic target - it is exposed on the entire tumor cell surface but restricted to lateral junctions in healthy tissue 3. Clinically, CDH17 serves as a diagnostic biomarker for distinguishing gastrointestinal cancers from other tumor types and represents a promising target for novel therapies including CAR-T cells, antibody-drug conjugates, and immunoPET imaging 245. In colorectal cancer, reduced CDH17 expression correlates with advanced tumor features and microsatellite instability 1.