This entry includes transmembrane glycoprotein EpCAM (epithelial cell adhesion molecule, also known as Trop-1) and Trop-2 (also known as tumor-associated calcium signal transducer 2, TACSTD2). They belong to the tumour-associated calcium signal transducer (TACSTD) family. They have been reported to directly interact with claudin-1 and claudin-7 [, , ]. EpCAM mediates homotypic cell contacts in epithelia tissues and regulates cell proliferation and cancer stemness. It has been used as a diagnostic marker for circulating tumour cells (CTCs) in the blood []. EpCAM has been shown to contribute to formation of intestinal barrier by recruiting claudins to cell-cell junctions []. Mutations in the EpCAM gene lead to congenital tufting enteropathy, severe intestinal epithelium homeostasis disorders, and Lynch syndrome []. Trop-2 is highly expressed in a variety of epithelial cancer cells. It has been identified as an oncogene leading to invasiveness and tumorigenesis []. It has been shown to regulate integrin-dependent signalling for cell-substrate adhesion and cell migration. It also modulates Rac1 GTPase activity and induces activation of PAK4 [].
