Reverse transcription-polymerase chain reaction detection of prostate-specific antigen, prostate-specific membrane antigen, and prostate stem cell antigen in one milliliter of peripheral blood: value for the staging of prostate cancer.

PURPOSE There have been several studies on the presence of circulating tumor cells in the peripheral blood of patients with malignant tumors including prostate cancer (PCa) using reverse transcription-PCR (RT-PCR). One of the aims of these studies was to obtain high sensitivity that would enable early-stage diagnosis. However, they varied in their detection rates, and the methods were rather complicated. We have improved the RT-PCR assay combining three prostate-associated molecules, prostate specific antigen (PSA), prostate specific membrane antigen (PSMA), and prostate stem cell antigen (PSCA) to reveal patients with poor prognosis. EXPERIMENTAL DESIGN Peripheral blood samples were obtained from 129 patients including 58 cases of PCa and 71 cases of nonmalignant disorders. Total RNA was extracted from 1 ml of whole blood using a commercially available kit. RESULTS The sensitivity of PSA-, PSMA-, and PSCA-nested RT-PCR was verified with positive signals of a single LNCaP cell in 1 ml of female blood sample. PSA-, PSMA-, and PSCA-mRNA were detected in 7 (12.1%), 12 (20.7%), and 8 (13.8%) PCa, and in 1, 2, and 0 samples in nonmalignant disorders, respectively. Among 58 PCa patients, each PCR indicated the prognostic value in the hierarchy of PSCA>PSA>PSMA RT-PCR, and extraprostatic cases with positive PSCA PCR indicated lower disease-progression-free survival than those with negative PSCA PCR. CONCLUSIONS The present findings suggest that PSCA PCR would be most promising for the molecular staging of PCa. The present RT-PCR is a highly cost-effective and rapid procedure, enabling the molecular staging of PCa with RT-PCR as a diagnostic routine.