PLAU and cancer: Of these proteases, urokinase-type plasminogen activator (u-PA), matrix metalloproteinase (MMP)-2 (gelatinase A, 72 kDa), and MMP-9 (gelatinase B, 92 kDa) are considered to be the most crucial enzymes for controlling the degradation of the main constituent of the ECM, and they are substantially involved in cancer invasion and metastasis [10,11].