Tumor-associated calcium signal transducer 2, also known as Trop-2 and as epithelial glycoprotein-1 antigen (EGP-1), is a protein that in humans is encoded by the TACSTD2 gene. This intronless gene encodes a carcinoma-associated antigen defined by the monoclonal antibody GA733. This antigen is a member of a family including at least two type I membrane proteins. It transduces an intracellular calcium signal and acts as a cell surface receptor. Mutations of this gene result in gelatinous drop-like corneal dystrophy, an autosomal recessive disorder characterized by severe corneal amyloidosis leading to blindness. This antigen is the target of sacituzumab govitecan, an antibody-drug conjugate. TROP-2 is related to epithelial cell adhesion molecule (EpCAM), also called TROP-1, gp40, and KSA. Trop-1 and Trop-2 are homologous to serum IGF-II-binding proteins and appear as signal transducers. Thus, they likely represent novel cell-surface receptors and may play a role in regulating the growth of carcinoma cells. This human monoclonal chimeric antibody has been engineered from the mouse monoclonal parent antibody. By necessity, some mouse sequence is retained as part of the variable domain. When multiplexing with other mouse-derived antibodies, using cross absorbed Fc-reactive secondary antibodies are recommended.