PLAU and breast cancer: Alternatively, the metastatic potential of node-positive and node-negative breast tumors is evaluated based on the protein levels of serine protease urokinase plasminogen activator (uPA) and the plasminogen activator inhibitor type-1 (PAI-1) in fresh or frozen tumor tissue of size not less than 0.125 cm3 which is impractical in unresected tumors of early breast cancer (EBC) [5, 6].