PLAU and neoplasm: During tumor progression, cathepsins are secreted into the extracellular space to facilitate direct cleavage of the extracellular matrix and membrane, the migration of tumor cells from the primary lesion, the activation of other proteases such as matrix metalloproteinases and urokinase plasminogen activator, and cleavage of the cell adhesion protein E-cadherin to promote tumor migration and invasion (48).