Epithelial cell adhesion and activating molecule (EpCAM/CD326) is a transmembrane glycoprotein that mediates Ca2+-independent, homophilic adhesions on the basolateral surface of most epithelial cells. EpCAM is not expressed in adult squamous epithelium, but it is highly expressed in adeno and squamous cell carcinomas. Research studies identified EpCAM as one of the first tumor-associated antigens, and it has long been a marker of epithelial and tumor tissue. Investigators have shown that EpCAM is highly expressed in cancer cells.