The serine proteinase urokinase-type plasminogen activator (uPA; EC 3.4.21.73) and its specific inhibitors (the plasminogen activator inhibitor type-1 and −2, PAI-1 and PAI-2, respectively), are involved in the control of extracellular matrix turnover, tissue remodeling, cell adhesion and migration during physiopathological processes, including breast cancer[50,51]. Here, PLAU is linked to breast cancer.