Elevation of serum transforming growth factor-β1 Level in patients with metastatic prostate cancer

We measured serum transforming growth factor β1 (TGF-b1) levels in patients with untreated prostate cancer and compared them with other prognostic indicators, specifically serum prostate-specific antigen (PSA) and the Gleason histopathologic grading score. Prior to treatment, the Sandwich enzyme-linked immunosorbent assay (ELISA) was used to measure TGF-b1 concentrations directly in sera from 55 patients with prostate cancer (21 localized and 34 metastatic), 13 age-matched healthy male control subjects, and 8 patients with benign prostatic hyperplasia (BPH). Serum TGF-b1 levels in patients with lymph node and/or distant metastases were significantly higher than in patients with localized disease (p = 0.0003), but did not differ significantly among localized cancers as to tumor extension. Ten of 11 prostate cancer patients whose serum TGF-b1 was higher than an arbitrary cut-off value of 60 ng/ml had lymph node or distant metastasis (specificity 95.20, although in 24 of 34 metastatic patients serum TGF-b1 levels were less (sensitivity 29.4%). The correlation between serum TGF-b1 and tumor grade as assessed by the Gleason scoring system was weak (r = 0.340). Moreover, serum TGF-b1 was not correlated with the serum PSA level. Interestingly, there was an inverse correlation between serum TGF-b1 in the prostate cancer patients and patient age at diagnosis (r = -0.406). These findings suggest that elevation of the serum TGF-b1 levels reflects certain malignant potentials associated with metastasis that are unpredictable by PSA and the Gleason scoring system.