Tumor-associated urokinase-type plasminogen activator: significance in breast cancer

Urokinase-type plasminogen activator (u-PA), a proteolitic enzyme, capable of degrading type 4 collagen, is supposed to be involved in degradation of extracellular matrix during cancer invasion. Evidence has been presented that primary breast cancer patients with tumors containing high levels of u-PA experience a worse prognosis. u-PA and its inhibitor, type 1 plasminogen activator inhibitor (PAI-1), are potentially important prognostic factors in breast cancer to identify patients at high risk for recurrence and also in the classification of clinically important subgroups.