Epithelial Cell Adhesion Molecule (EpCAM) is a signal type I transmembrane glycoprotein that has an extracellular domain with one thyroglobulin type-1 domain and a short cytoplasmic domain. EpCAM is found on the surface of adenocarcinoma, but not on mesodermal or neural cell membranes. The EpCAM molecule has been shown to function as a homophilic Ca2+ independent adhesion molecule. It may act as a physical homophilic interaction molecule between intestinal epithelial cells (IECs) and intraepithelial lymphocytes (IELs) at the mucosal epithelium. Defects in EpCAM cause hereditary non-polyposis colorectal cancer type 8 (HNPCC8) and diarrhea type 5 (DIAR5). EpCAM plays a role in embryonic stem cell proliferation and differentiation, it up-regulates the expression of FABP5, MYC, and Cyclin A & Cyclin E. It is highly and selectively expressed by undifferentiated embryonic stem cells and in many types of epithelial carcinomas.
