Summary: | Urokinase plasminogen activator (uPA) and its inhibitor (PAI-1) have shown to be of merit as biomarkers for a variety of cancers. The objective of this project was to assay for uPA and PAI-1 in prostate needle biopsy tissue from 217 patients using the FEMTELLE enzyme linked immunosorbent (ELISA) assay, and to examine the robustness of PAI-1 as a candidate marker in benign prostatic hyperplasia (BPH) and prostate cancer (PCa), as previously identified in a different cohort of 111 patients. These results validate the assertion that PAI-1 levels of >4.5 ng mg−1 protein in prostate biopsies are indicative of prostate malignancy in elderly men, but further show that tissue from BPH patients in the 70–80 year age interval express significantly high levels of this marker. To address this anomaly, a malignancy index, derived from the concentrations of prostate-specific antigen (PSA), uPA, and PAI-1, and patient age is proposed. This simple index discriminates prostate tissue from BPH and PCa patients with concordance indices of 0.59 and 0.69 when tissues are taken as biopsy or transurethral resection of the prostate (TURP), respectively. Corresponding indices for PSA as a predictor of prostate disease were 0.67 and 0.73. Further evaluation of the proposed malignancy index using specimens, such as venous blood, could prove valuable in the search for non-invasive predictive assays.
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