Urokinase plasminogen activator receptor (CD87): Something old, something new

CD87 is a widely expressed receptor for urokinase plasminogen activator (uPA) and plays a critical role in regulation of cell-surface plasminogen activation. An expanding body of evidence suggests that CD87 is involved in regulation of diverse physiological and pathological processes, including cellular adhesion, cell motility, angiogenesis, tumor invasion, and tumor metastasis. These data characterize CD87 as a pleiotropic molecule that mediates a wide range of events beyond plasminogen activation through extensive and complex interactions with other cell-surface molecules, such as integrins and L-selectin. The association of CD87 overexpression in tumor cells with tumor invasion has attracted many researchers to exploration of the potential therapeutic utility of CD87 by targeting binding of CD87 to uPA, the interactions between CD87 and other surface and matrix molecules, CD87 gene expression, and posttranscriptional modification. Therapeutic strategies targeting CD87 as a key molecule of tumor invasion and metastasis have great potential for becoming valuable assets in therapy for malignant tumors.