Detection of prostate-specific antigen RNA before and after radical retropubic prostatectomy and transurethral resection of the prostate using "light-cycler"-based quantitative real-time polymerase chain reaction

Objectives. To report our initial experience gained in establishing real-ti me reverse transcriptase-polymerase chain reaction (RT-PCR) detection of pr ostate-specific antigen (PSA) mRNA using the quantitative online PCR system LightCycler. Many studies have thus far failed to provide the desired proo f that the detection of circulating PSA-expressing tumor cells with RT-PCR in the blood samples of patients with prostate cancer (PCa) is a highly sen sitive prognostic and course marker. One of the possible reasons is the lac k of reliable quantification methods. Methods. Blood samples before and after surgery were obtained from 87 patie nts who underwent radical prostatectomy for locally confined PCa and 27 pat ients who underwent transurethral resection of the prostate for benign pros tatic hyperplasia. Eight days postoperatively, additional blood samples wer e obtained from the patients with PCa. Quantitative no-nested RT-PCR, for P SA mRNA (291 bp) was performed using the LightCycler system applying the SY BR Green protocol. The number of circulating LNCaP tumor cell-equivalents p er sample was estimated from the mean amplification Value measured in a giv en number of LNCaP cells. Results. PSA mRNA was detected preoperatively in 19 patients with Stage pT2 tumor (40%) and in 28 patients with tumor greater than Stage pT2 (72%), bu t in only 2 patients with benign prostatic hyperplasia (8%; analysis of var iance, P <0.001). Significant quantitative differences were observed among Stage pT2 disease (1034 LNCaP tumor cell-equivalents/mL), greater than Stag e pT2 disease (7830 cells/mL), and benign prostatic hyperplasia (58 cells/m L; analysis of variance for all groups, P <0.001). The correlation between the detection of PSA expression by RT-PCR and the Gleason score and serum P SA value was statistically significant. Conclusions. Our results show that the initial experience with the LightCyc ler system for PSA-assisted detection of circulating PSA mRNA in PCa by RT- PCR may be a promising preoperative prognostic marker for organ-confined or locally advanced PCa. Long-term follow-up of these patients with PCa must demonstrate the clinical value of molecular diagnostics with quantitative R T-PCR systems. (C) 2001, Elsevier Science Inc.