Interleukin-8 serum levels in patients with benign prostatic hyperplasia and prostate cancer.
OBJECTIVE
Using arbitrarily primed polymerase chain reaction (AP-PCR) ribonucleic acid (RNA) fingerprinting, we discovered a messenger RNA (mRNA) that encoded the cytokine interleukin-8 (IL-8) that was up-regulated in the peripheral blood leukocytes (PBLs) of patients with metastatic prostate cancer (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 either biopsy-confirmed benign prostatic hyperplasia (BPH) or CaP.


METHODS
The sera from 35 apparently healthy normal volunteers and 146 patients with biopsy-confirmed BPH and CaP obtained from two academic centers were retrospectively examined to determine the serum levels of IL-8, total PSA (tPSA), and the f/t PSA ratio. Logistic regression and trend analysis statistical methods were used to assess the results.


RESULTS
Normals (n = 35), BPH patients (n = 53), patients with clinical Stages A to C CaP (n = 81), and patients with metastatic CaP (n = 1 2) had mean 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 differentiated BPH from clinical Stages A, B, C, or D CaP better than tPSA and performed similarly to the f/t PSA ratio. The combination of the IL-8 levels and f/t PSA ratios using multivariate logistic regression analysis distinguished BPH from Stages A, B, C, or D CaP or only Stages A and B with a receiver operating characteristic area under the curve of 89.8% and 87.5%, respectively (P <0.0001).


CONCLUSIONS
The IL-8 serum concentration in our clinically well-defined patient sample was independent of the f/t PSA ratio as a predictor of CaP. When test samples are controlled for extraneous clinical origin of inflammation or infection, the combination of the IL-8 and f/t PSA assay results may offer an improved approach for distinguishing BPH from CaP.
Veltri
R W
RW
UroScience Group, UroCor, Inc., Oklahoma City, Oklahoma 73104, USA.
Miller
M C
MC
Zhao
G
G
Ng
A
A
Marley
G M
GM
Wright
G L
GL
Vessella
R L
RL
Ralph
D
D
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006801:Humans; D016209:Interleukin-8 / Q000097:blood* / Q000235:genetics; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011470:Prostatic Hyperplasia / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood*; D012313:RNA / Q000032:analysis; D012372:ROC Curve; D012680:Sensitivity and Specificity
D016209:Interleukin-8; D012313:RNA