COMBINED NESTED RT-PCR ASSAY FOR PROSTATE-SPECIFIC ANTIGEN AND PROSTATE-SPECIFIC MEMBRANE ANTIGEN IN PROSTATE-CANCER PATIENTS - CORRELATIONWITH PATHOLOGICAL STAGE

Nested reverse transcription (RT)-PCR for prostate-specific antigen (P SA) and prostate-specific membrane antigen (PSM) can detect circulatin g prostatic cells in patients with prostate cancer. We evaluated the r ole of a combined screening approach for PSA and PSM in prostate cance r staging, We examined the peripheral blood samples from 136 patients with adenocarcinoma of the prostate (PCA), 15 patients with benign pro static hyperplasia, 15 normal male subjects, and 5 female subjects, Th e controls (benign prostatic hyperplasias, normal males, and normal fe males) were negative for both PSA and PSM. In patients with metastatic PCA (n = 11), 100% were positive by combined PSA/PSM (64% by PSA and 91% by PSM), in biochemical failure PCB patients (n = 18), 39% were po sitive by PSM, compared to only 6% by PSA. In patients with clinically localized PCA (n = 107), 48% were positive bg combined PSA/PSM approa ch (43% by PSM and 14% by PSA). These results show that PSM is a more sensitive marker than PSA in detecting circulating prostatic cells (P < 0.0001). We correlated preoperative RT-PCR results with final pathol ogical stages in 67 prostatectomy patients. RT-PCR positivity was 81.5 % in patients with non-organ-confined disease versus 37.5% in organ-co nfined disease (P = 0.001), PSA/PSM RT-PCR had an odds ratio of 7.3 (9 5% confidence interval, 2.3-23.4; P = 0.001) in predicting tumor extra capsular extension, PSA/PSM RT-PCR was a better predictor of tumor ext racapsular extension than initial serum PSA, clinical stage, and biops y Gleason score, Our data show that PSA/PSM nested RT-PCR map provide the staging information unavailable from the current modalities. The u ltimate impact of this technique in the management of patients with pr ostate cancer will require continued investigation.