PROGNOSTIC VALUE OF UROKINASE PLASMINOGEN-ACTIVATOR IN PRIMARY BREAST-CARCINOMA - COMPARISON OF 2 IMMUNOASSAY METHODS

Urokinase-type plasminogen activator (uPA) is a potentially important prognostic factor in breast cancer for identifying patients at high ri sk of recurrence. This retrospective study assessed two enzyme-linked immunosorbent assay (ELISA) methods measuring uPA antigen levels in 49 9 primary breast cancer cytosols. Both uPA methods were applied to cyt osols used routinely for oestrogen (ER) and progesterone (PgR) recepto r assays. uPA was determined using a classical ELISA method (Imubind; American Diagnostica) and a novel automatic immunoluminometric assay ( Lia; Sangtec Medical). The uPA Imubind method revealed about twice as much uPA antigen (median 0.75 ng mg(-1) protein) as the uPA Lia method (median 0.38 ng mg(-1) protein). The correlation coefficient between the two methods was acceptable (r = 0.81), but the two techniques are not interchangeable. Univariate analyses confirmed the poor outcome of patients whose tumours contained large amounts of uPA, regardless of the technique used. Multivariate analyses showed that uPA Imubind and uPA Lia values were both strong independent prognostic factors.