Epithelial Cellular Adhesion Molecule (EpCAM), also known as ECD326 and TROP-1 is a 36-41 kDa member of the TROP family of meolcules (1, 2). It is a type I transmembrane glycoprotein that is found on embryonic stem cells and adult non-squamous epithelium such as (respiratory) psuedostratified, (mammary) cuboid, and (colon) simple columnar epithelium. In mouse, the molecule has also been reported on T cells, Langerhans cells and thymic epithelium. Mature mouse EpCAM is 292 amino acids (aa) in length. It possesses a 243 aa extracellular region that contains one thyroglobulin type I domain. Such domains are associated with cathepsin binding and inhibition (2). On the cell surface, EpCAM is reported to participate in TEM (Tetraspanin-enriched microdomain) formation in concert with CD44v6, CD9, ADAM10, Claudin-7 and TS8. It is also noted to form homodimers in- cis and homotetramers in- trans. Although this would suggest the EpCAM acts as an adhesion molecule, in effect it does not, instead acting as a disruptor of the E-Cadherin:cytoskeleton interaction, and thus promoting cell migration (1, 2). The extracellular domain (ECD) of EpCAM undergoes multiple cleavages, principally between Ser200 and Ala210 (3). Cleavage at the Arg80-Arg81 site does not generate a soluble fragment, but rather a disulfide-linked "heterodimer" (3). Cleavage after Gly264 in the juxtamembrane region is followed by secretase cleavage of the transmembrane fragment, generating an ICD that translocates to the nucleus (4). The ECD of mouse EpCAM shares 81% and 90% aa sequence identity with human and rat EpCAM, respectively.