Tumor-associated calcium signal transducer 2 (TACSTD2) (Trop-2)

Tumor-associated calcium signal transducer 2 (TACSTD2), commonly known as Trop-2, is a type I transmembrane glycoprotein that functions as a calcium signal transducer and is involved in regulating cell-cell adhesion and proliferation (UniProt P09758). It is significantly overexpressed in various epithelial malignancies, including triple-negative breast cancer, non-small cell lung cancer, and urothelial carcinoma, where it correlates with poor prognosis and increased tumor aggressiveness (NCBI Gene ID: 4070). The hRS7 antibody is a humanized IgG1 kappa monoclonal antibody specifically engineered to target the extracellular domain of Trop-2 (Goldenberg et al., 2015, PMID: 25593305). This antibody component is the foundation of the antibody-drug conjugate sacituzumab govitecan, which utilizes hRS7 to deliver the cytotoxic payload SN-38 directly into Trop-2-expressing cancer cells (FDA Label: Trodelvy). Upon binding, the receptor-antibody complex is internalized through clathrin-mediated endocytosis, allowing for the intracellular release of the drug and induction of DNA damage (Shastry et al., 2022, PMID: 35131613). Because of its differential expression between cancerous and healthy tissues, Trop-2 serves as a critical target for precision oncology and the development of next-generation therapeutics.

Other names

TACSTD2Trophoblast antigen 2Trophoblast cell-surface antigen 2Membrane component chromosome 1 surface marker 1 (M1S1)Epithelial glycoprotein-1 (EGP-1)GA733-1

Targeted delivery of cytotoxic payloads via hRS7 antibody binding to the Trop-2 extracellular domain, followed by receptor-mediated endocytosis and intracellular release of the drug (e.g., SN-38), which induces DNA damage and apoptosis (Goldenberg et al., 2015, PMID: 25593305).