TROP2

Class

TROP2-directed antibody-drug conjugate (MMAE payload)

Pathway

TROP2-targeted delivery of monomethyl auristatin E cytotoxic payload to tumor cells

TROP2 (trophoblast cell-surface antigen 2) is a transmembrane glycoprotein expressed at low levels on many normal epithelial tissues but markedly overexpressed on the surface of numerous solid tumors, including cancers of the breast, lung, bladder, and gastrointestinal tract. Because of this differential expression, TROP2 serves less as a driver of tumor growth to be blocked and more as a docking point for targeted drug delivery. Antibody-drug conjugates (ADCs) exploit this by linking a monoclonal antibody that recognizes TROP2 to a cytotoxic payload, in this case monomethyl auristatin E (MMAE), a potent inhibitor of microtubule assembly. Upon binding, the antibody-payload complex is internalized by the tumor cell, and the payload is released intracellularly, causing cell-cycle arrest and death. This strategy aims to concentrate a highly toxic chemotherapeutic agent within tumor tissue while limiting systemic exposure, broadening the therapeutic window compared with administering the cytotoxic agent alone. TROP2-directed ADCs are being explored across a wide range of epithelial malignancies where the antigen is commonly overexpressed, reflecting a strategy of using tumor-selective surface markers as delivery vehicles rather than as direct signaling targets whose inhibition alone would be expected to slow tumor growth.