UROKINASE PLASMINOGEN-ACTIVATOR, A STRONG INDEPENDENT PROGNOSTIC FACTOR IN BREAST-CANCER, ANALYZED IN STEROID-RECEPTOR CYTOSOLS WITH A LUMINOMETRIC IMMUNOASSAY

Urokinase plasminogen activator (uPA) is involved in the activation of different proteases which participate in the degradation of extracell ular matrix, thereby enhancing the invasive capacity of tumour cells. uPA has been shown to be of prognostic importance in breast cancer. We have analysed uPA with a new luminometric immunoassay (LIA), applicab le in cytosol samples routinely used for oestrogen-receptor (ER) and p rogesterone-receptor (PgR) analyses. At a cut-off value of 0.62 ng uPA /mg protein, 33% (230/688) samples were classified as representing hig h uPA tumours. High uPA content was found to be associated with shorte r recurrence-free survival (median observation time: 42 months), ER an d PgR negativity, increased p53 expression, DNA non-diploidy and a hig h S-phase fraction (SPF), but not with lymph node involvement or tumou r size (less than or equal to 20 mm versus >20 mm). In the subgroup of patients not treated with systemic adjuvant therapy, multivariate ana lysis showed uPA to be an independent prognostic factor together with lymph node status and SPF. If these results can be reproduced, uPA may be a factor suitable for inclusion in a prognostic index. Copyright ( C) 1996 Elsevier Science Ltd