DETECTION OF CIRCULATING PROSTATE CELLS BY REVERSE-TRANSCRIPTASE POLYMERASE-CHAIN-REACTION OF HUMAN GLANDULAR KALLIKREIN (HK2) AND PROSTATE-SPECIFIC ANTIGEN (PSA) MESSAGES

Objectives. To investigate the clinical value of human glandular kalli krein (hK2) reverse transcriptase-polymerase chain reaction (RT-PCR) f or detection of prostate cells in circulation and to compare the resul ts with those obtained from prostate-specific antigen (PSA) RT-PCR. Me thods, We examined peripheral blood (PB) and bone marrow (BM) samples of 13 patients with advanced-stage prostate cancer and 63 patients wit h clinically localized disease for the presence of circulating prostat e cells. An RT-PCR protocol with a two-step amplification cycle and ho t-start conditions was used. Results. The limit of detection of the PC R portion is similar for PSA and hK2 (5 to 10 copies of the plasmid co ntaining the cDNA). The RT-PCR limit of detection is one LNCaP cell in 10(8) peripheral blood mononuclear cells (PMBC) for PSA, and one LNCa P cell in 10(7) PMBC for hK2. Of the BM samples obtained prior to radi cal prostatectomy, 71.4% were positive for PSA mRNA and 41.3% were pos itive for hK2 mtRNA. In PB, the PSA positivity was 19% and hK2 positiv ity 12.7%. In advanced-stage patients, there were 76.9% PSA-positive s amples in BM versus 38.5% hK2-positive samples; 46.2% of patients were positive in PB for PSA versus 30.8% for hK2. Conclusions. We have dev eloped a sensitive RT-PCR protocol for detection of hK2 mRNA and evalu ated the suitability of hK2 mRNA in comparison with PSA mRNA as an add itional marker for detection of prostate cells in circulation. Combini ng results of these two tests increased the sensitivity of detection. (C) 1997, Elsevier Science Inc. All rights reserved.