Urokinase-type plasminogen activator expression in human prostate carcinomas.

The prostate gland is the most common site of cancer in men in the United States. The biologic behavior of an individual tumor, however, varies widely, with some cancers taking a relatively indolent course and other progressing rapidly to disseminated disease. Prognostic factors that might help predict a tumor's aggressiveness and invasiveness are limited. The expression of urokinase plasminogen activator was evaluated in 36 human prostate cancer specimens. Using an immunohistochemical method with monoclonal antibody #394, 70.6% (12 of 17) of cancer specimens with extracapsular extension showed increased expression of urokinase plasminogen activator, compared with 26.6% (4 of 15) of specimens without capsular invasion. Increased expression was localized to the glandular cytoplasm, with tumor stroma yielding predominantly negative results. These findings provide additional evidence of the role of urokinase in determining the biologic behavior and metastatic potential of prostate cancer.