Urokinase-plasminogen activator in breast cancer: assay by both catalytic and immunoassay

Urokinase plasminogen activator (uPA) is a serine protease implicated in cancer spread and is thus a potential prognostic marker for human cancers. The aim of this investigation was therefore to compare uPA activity and uPA antigen as prognostic markers in breast cancer. Patients with tumours containing high levels of either uPA activity or antigen, had a significantly worse disease-free interval and survival pattern than patients with low levels. However, uPA antigen was a stronger prognostic marker than uPA activity. It is concluded that uPA should be assayed by immunoassay when using this protease as a prognostic marker in breast cancer.