CD87. also known as the urokinase plasminogen activator receptor (uPAR), is a glycosylphosphatidylinositol (GPI)-anchored cell surface protein encoded by the *PLAUR* gene. It plays a critical role in extracellular matrix remodeling by binding to urokinase-type plasminogen activator (uPA), facilitating the conversion of plasminogen to plasmin, a protease involved in fibrinolysis and tissue degradation. CD87 is implicated in pathological processes such as cancer metastasis, inflammation, and fibrosis, where its overexpression correlates with poor prognosis in malignancies like breast, lung, and colorectal cancers.
CD87 antibodies are tools developed to target this receptor for research and therapeutic purposes. In research, they are used to study uPAR's signaling mechanisms, cellular localization, and interactions with integrins or vitronectin in tumor microenvironments. Therapeutically, anti-CD87 agents aim to inhibit uPA/uPAR-driven pathways to suppress tumor invasion, angiogenesis, or metastasis. Some antibodies block ligand binding or induce receptor internalization, while others are conjugated to drugs for targeted delivery. Challenges include minimizing off-target effects and overcoming tumor heterogeneity.
Despite mixed clinical outcomes, CD87 remains a biomarker of interest. Antibodies are also applied in diagnostic assays to quantify uPAR levels in tissues or biofluids, aiding disease monitoring. Ongoing research explores bispecific antibodies and combination therapies to enhance efficacy.