Cadherin-17 or LI-cadherin is a member of the cadherin superfamily, genes encoding calcium-dependent, membrane-associated glycoproteins. Cadherin-17/LI-cadherin is a cadherin-like protein consisting of an extracellular region, 7 cadherin domains, and a transmembrane region but lacking the conserved cytoplasmic domain. The protein is a component of the gastrointestinal tract and pancreatic ducts, acting as an intestinal proton-dependent peptide transporter in the first step in oral absorption of many medically important peptide-based drugs. The protein may also play a role in the morphological organization of liver and intestine. Alternative splicing of the encoding gene results in multiple transcript variants. Cadherin-17/LI-cadherin preferentially interact with themselves in a homophilic manner in connecting cells. Cadherin-17 may thus contribute to the sorting of heterogeneous cell types and have a role in the morphological organization of liver and intestine. It's also involved in intestinal peptide transport. Experiments have reported the association between Cadherin-17/LI-cadherin and gastric cancer. Cadherin-17/LI-cadherin expression was detected in 63/94 of gastric adenocarcinomas in addition to intestinal metaplasia. The expression of Cadherin-17 tended to be associated with intestinal type carcinoma, and carcinomas with Cadherin-17 expression was significantly more frequent in advanced stage cases than in early stage. Cadherin-17 is also a useful immunohistochemical marker for diagnosis of adenocarcinomas of the digestive system.
