The secreted recombinant human UPAR consists of 292 amino acids with a molecular weight of 32.8 kDa. Recombinant human UPAR migrates as an about 48 kDa band in SDS-PAGE under reducing conditions due to glycosylation.Urokinase plasminogen activator surface receptor (U-PAR) is also known as PLAUR, Monocyte activation antigen Mo3, CD antigen CD87. U-PAR contains three UPAR/Ly6 domains and is expressed in neurons of the rolandic area of the brain (at protein level). PLAUR / UPAR acts as a receptor for urokinase plasminogen activator and plays a role in localizing and promoting plasmin formation. Urokinase plasminogen activator (uPA) and/or its receptor (uPAR) are essential for metastasis, and overexpression of these molecules is strongly correlated with poor prognosis in a variety of malignant tumours. Furthermore, the analysis of U-PAR expression has a potential role in the diagnostic or prognostic work-up of several hematological malignancies, particularly acute leukemia and multiple myeloma.