PLAU and neoplasm: Upon binding to uPAR, uPA efficiently activates co-localized plasminogen to the potent broad-spectrum protease plasmin, which initiates a cascade of pericellular proteolysis that directly and indirectly (through the activation of pro-metalloproteinases, pro-MMPs) degrades integral ECM molecules including fibronectin, laminins, elastins, and collagens, thus enabling tumor cell invasion and dissemination (18, 22).