PROGNOSTIC IMPORTANCE OF PLASMINOGEN INHI BITOR-1 (PAI-1) IN PRIMARY BREAST-CANCER

The plasminogen activator system plays a key role in the proteolysis o f malignant tumours. In 155 patients with primary breast cancer levels from PAI-1 and uPA were measured in cytosol with monoclonal antibodie s and by an enzyme-linked immunosorbent assay. 35 tumour tissue sample s form benign breast were also examined. Malignant tumours contain hig her levels of PAI-1 (8.6 ng/mg) than benign tumours (1.28 ng/mg) (p < 0.01). Also the median level of uPA was significantly higher (p < 0.01 ) in malignant tissue (2.38 ng/mg) in comparison to benign disease (0. 54 ng/mg). No correlation was found between the proteases and the clas sical prognostic parameters like axillary lymph node involvement, tumo ur size and menopausal status. However, a significant correlation (p < 0.01) was found in tumours with lymphangiosis carcinomatosa, negative hormone receptors, grade III tumour cells and high S-phase fractions (> 5%). After a median follow-up of 46 months we found that high level s of PAI-1 correlated with short DFS (p = 0.0005) and OAS (p = 0.003). However, in the Cox multivariate regression analysis only PAI-1 was s ignificantly independent for OAS and could therefore give additional i nformation. We conclude that levels from PAI-1 antigen measured in cyt osol of primary breast cancer is an independent prognostic parameter t o identify patients with high and low risk for relapse and for individ ualised treatment.