COMPARATIVE-STUDY OF 4 EXTRACTION PROCEDURES FOR UROKINASE-TYPE PLASMINOGEN-ACTIVATOR AND PLASMINOGEN-ACTIVATOR INHIBITOR-1 IN BREAST-CANCER TISSUES

The urokinase type plasminogen activator (u-PA) and the plasminogen ac tivator inhibitor-1 (PAI-1) are among the best second-generation progn ostic tissue factors in breast cancer. However, different extraction p rocedures and assay kits are used in different laboratories. A total o f 79 breast tumour tissues stored in liquid nitrogen were analysed in this study. We compared u-PA and PAI-1 levels determined with the Amer ican Diagnostics (AD) kit after Various extraction procedures. The med ian cytosolic extraction yield in the presence of 0.4 mol/l KCl, calcu lated relative to extraction in the presence of 10 ml/l Triton X100 wh en adapted to standard laboratory working hours (incubation for 2 h in stead of 12 h) was 74.4% for u-PA and 85.8% for PAI-1. In addition, th e correlations were acceptable. Cytosolic extracts prepared with KCl c ould permit optimal u-PA and PAI-1 assays while also enabling hormone receptors to be determined with the same specimens. Further studies wi th clinical data are now necessary to determine the prognostic relevan ce of this extraction procedure.