Urokinase plasminogen activator as a prognostic marker in different subgroups of patients with breast cancer.

Urokinase plasminogen activator (uPA) is a serine protease involved in cancer invasion and metastasis. Previously, uPA was shown to be an independent prognostic marker in breast cancer. The aim of this study were to evaluate uPA as a prognostic marker in different subgroups of patients with breast cancer. Urokinase plasminogen activator was assayed by enzyme-linked immunosorbent assay in detergent extracts of human breast tumors. Using both disease free interval (DFI) and overall survival (OS) as end points, uPA was an indicator of prognosis in the following groups of patients: those with positive axillary nodes, those who were estrogen receptor (ER)-positive, women younger than 50 years of age, and women older than 50 years of age. For patients with negative axillary lymph nodes, uPA was a significant prognostic marker using DFI as an end point and was almost statistically significant (P = 0.055) using OS as end point. In patients who were ER-negative, uPA levels showed no significant relationship with patient outcome. Urokinase plasminogen activator is a significant prognostic marker in most of the major subgroups of patients with breast cancer and may be a marker for patients with negative axillary lymph nodes.