TACSTD2 and breast carcinoma: Sacituzumab govitecan is composed of an antibody coupled to topoisomerase I inhibitor (SN-38) through a proprietary hydrolysable linker, and it targets human trophoblast cell-surface antigen 2 (TROP-2), which is overexpressed in many epithelial cancers, including a majority of breast cancers [6].