Urokinase-type plasminogen activator and plasminogen activator inhibitor type-1 mRNA assessment in breast cancer by means of NASBA: correlation with protein expression

Urokinase plasminogen activator (uPA) and its main inhibitor, plasminogen activator inhibitor type-1 (PAI-1) determined in tumor tissue by means of enzyme-linked immunosorbent assay (ELISA) can discriminate patients with primary breast cancer at high risk vs low risk for recurrence. The aim of this study was to analyze uPA and PAI-1 messenger RNA (mRNA) expression by means of quantitative nucleic acid sequence-based amplification (NASBA) on 77 primary breast tumor samples and to correlate this expression with the uPA and PAI-1 protein content. We observed that the 2 markers were significantly overexpressed (uPA, P < .0001; PAI-1, P = .0042) in mRNA in the ELISA+ group. The receiver operating characteristic (ROC) curves demonstrated high concordance between NASBA and ELISA (area under the ROC curve of 0.84 and 0.70 for uPA and PAI-1, respectively) and showed that uPA and PAI-1 status could be predicted by using the molecular assay with sensitivity and specificity values of 80.8% and 82.4% and sensitivity and specificity values of 66.7% and 74.0%, respectively.