Combined overexpression of urokinase, urokinase receptor, and plasminogen activator inhibitor-1 is associated with breast cancer progression: An immunohistochemical comparison of normal, benign, and malignant breast tissues

Abstract

We showed that overexpression of uPAR, uPA, and its main inhibitor, PAI-1, is a constant feature of invasive ductal breast carcinomas. However, the expression of the above fibrinolytic reactants is not specific for breast cancer since positive staining for these molecules was frequently observed in benign breast lesions as well as in normal breast tissues. The combined increased expression of uPA and its cellular receptor, uPAR on the surface of tumor epithelial cells may account for the activation of the proteolytic system which occurs in breast cancer.