Prognostic value of the urokinase-type plasminogen activator,and its inhibitors and receptor in breast cancer patients

Urokinase-type plasminogen activator (uPA), its inhibitors (PAI-1 and PAI-2), and its receptor (uPAR) play a key role in tumor invasion and metastasis. This study was designed to evaluate the prognostic impact of uPA, PAI-1, PAI-2, and uPAR and the combination of these factors in a group of 460 primary breast cancer patients. Concentrations of all 4 components of the uPA system were measured in tumor extracts using enzyme-linked immunosorbent assays (American Diagnostica, Inc, Greenwich, CT). After a median follow-up of 33 months, 18.5% of the patients had relapsed. The Cox proportional hazards model was applied for both univariate and multivariate analyses of disease-free survival (DFS). PAI-1 and PAI-2 were shown to provide independent prognostic information in breast cancer. Patients with either low levels of PAI-1 or high levels of PAI-2 were found to have better DFS (relative risk was 2.08 and 1.78, respectively). The prognostic value could be even further improved by a combination of both inhibitors. Aside from the uPA inhibitors, only nodal status and hormonal receptor status retained independent prognostic value. The other 2 invasion markers, uPA and uPAR, showed no statistically significant impact on DFS. In our patients, who were mostly treated with adjuvant therapy, uPA was not found to be an independent prognostic marker for DFS; this could be a consequence of the predictive value of uPA for response to adjuvant therapy and should be further investigated.