Prognostic importance of the uPA/PAI-1 complex in breast cancer

The complex between urokinase-lype plasminogen activator (uPA) and its inhibitor PAI-1 (plasminogen activator inhibitor 1) has been prognostically evaluated in patients with breast cancer. The concentrations of uPA antigen, PAI-1 antigen and the uPA/PAI-1 complex were analysed in extracts from breast cancer tumours from 233 patients (median follow-tip of patients: 71 months). The uPA/PAI-1 complex typically constituted about 5% of the uPA antigen (total uPA). The concentration of complex was found to correlate more strongly to the concentration of PAI-1 (r = 0.72; p < 0.0001) than to the concentration of uPA (r = 0.55, p < 0.0001). Interestingly, in this material the uPA/PAI-1 complex (using an optimised cutoff level of 0.22 ng mug(-1) DNA) had a stronger prognostic value than optimised cut-off values for uPA or PAI-1. The data suggest that activation of prourokinase within the tumour, which is a prerequisite for the formation of the uPA/PAI-1 complex, is of better prognostic value than the production of prourokinase or PAI-1 in the breast cancer tumour.