U-PAR/CD87

U-PAR, the CD87 antigen encoded by PLAUR, is a glycosylphosphatidylinositol-anchored three-domain receptor that concentrates urokinase-type plasminogen activator at the cell surface, localizing plasmin generation to the leading edge of migrating cells. Beyond proteolysis, its cleaved forms and association with integrins, vitronectin and LRP-1 transmit adhesion and chemotactic signals. Urokinase receptor expression correlates with invasion and poor prognosis in colorectal, breast, lung and gastric cancers, and it is among the most extensively validated prognostic markers in oncology. Soluble uPAR serves as a biomarker in cardiovascular and chronic kidney disease research, and receptor antagonists remain under development.