Interleukin-8 serum levels in patients with benign prostatic hyperplasia and prostate cancer

Objectives, Using arbitrarily primed polymerase chain reaction (AP-PCR) rib onucleic acid (RNA) fingerprinting, we discovered a messenger RNA (mRNA) th at encoded the cytokine interleukin-8 (IL-8) that was up-regulated in the p eripheral blood leukocytes (PBLs) of patients with metastatic prostate canc er (CaP) compared with similar cells from healthy individuals. We compared the total prostate-specific antigen (PSA) levels, the free/total (f/t) PSA ratios, and the immunoreactive IL-8 serum concentrations in patients with e ither biopsy-confirmed benign prostatic hyperplasia (BPH) or CaP. Methods. The sera from 35 apparently healthy normal volunteers and 146 pati ents with biopsy-confirmed BPH and CaP obtained from two academic centers w ere retrospectively examined to determine the serum levels of IL-8, total P SA (tPSA), and the f/t PSA ratio, Logistic regression and trend analysis st atistical methods were used to assess the results. Results. Normals (n = 35), BPH patients (n = 53), patients with clinical St ages A to C CaP (n = 81), and patients with metastatic CaP (n = 12) had mea n levels of IL-8 of 6.8, 6.5, 15.6, and 27.8 pg/mL, respectively. The IL-8 serum concentrations correlated with increasing CaP stage and also differen tiated BPH from clinical Stages A, B, C, or D CaP better than tPSA and perf ormed similarly to the f/t PSA ratio. The combination of the IL-8 levels an d f/t PSA ratios using multivariate logistic regression analysis distinguis hed BPH from Stages A, B, C, or D CaP or only Stages A and B with a receive r operating characteristic area under the curve of 89.8% and 87.5%, respect ively (P < 0.0001). Conclusions. The IL-8 serum concentration in our clinically well-defined pa tient sample was independent of the f/t PSA ratio as a predictor of CaP. Wh en test samples are controlled for extraneous clinical origin of inflammati on or infection, the combination of the IL-8 and f/t PSA assay results may offer an improved approach for distinguishing BPH from CaP. UROLOGY 53: 139 -147, 1999. (C) 1999, Elsevier Science Inc. All rights reserved.