On the contrary, in the analysis of DSS we found an association between high uPAR antigen levels and an increased risk of cancer-related death with a trend towards significance for patients with organ-confined tumours in either univariate or multivariate Cox regression analysis with HRs of 3.15 (95% CI 0.97-10.2, P = 0.057) and 3.09 (95% CI 0.88-10.8, P = 0.077), respectively (Additional file 1 : Tables S2 and S3).
Hofmann et al. [ 24 , 25 ], who used the same strategy and analysed a similar number of patients as we did, measured comparable uPA levels in the corresponding renal tissue specimens, whereas Span et al. [ 32 ] obtained a similar trend of uPA levels in malignant and non-malignant renal tissues as in our study, which did not reach statistical significance ( P = 0.081).
Moreover, Zubac et al. [ 21 ] could show that PAI-1 immunoexpression turned out to be a highly significant predictor for metastatic relapse in patients with organ-confined RCC.