Prostate stem cell antigen mRNA expression in preoperatively negative biopsy specimens predicts subsequent cancer...

Recent data showed that prostate stem cell antigen (PSCA) mRNA expression in transurethral resection of the prostate (TURP)-resected tissues predicted the subsequent prostate cancer after TURP in benign prostatic hyperplasia (BPH) patients with both PSA < 4.0 ng/ml and normal DRE findings. This study was to determine whether PSCA mRNA positivity in preoperatively negative prostatic biopsy samples from BPH men with PSA > 4.0 ng/ml and/or suspicious DRE findings had predictive performance following TURP.

PSCA in situ hybridization was performed on negative prostatic biopsies taken before TURP from 166 enrolled symptomatic BPH patients, who were continuously followed for 5 years postoperatively. Predictive performance of PSCA mRNA for subsequent cancer onset was evaluated by univariate and multivariate Cox proportional hazards models with bootstrapping and concordance indices.

PSCA mRNA was detected in 42/166 (25.3%) of the preoperatively negative biopsy specimens, with a mean positive-labeling cells of 31.6%, in which 31 patients were identified as having subsequent PCa on follow-up. Of 124 patients with negative expression for PSCA mRNA none were subsequently diagnosed with PCa. The examination of Spearman's rank correlation coefficient showed that PSCA mRNA expression levels were positively and statistically correlated with higher Gleason score (r = 0.88, P < 0.001) and clinical T stage (r = 0.84, P < 0.001). A final multivariate Cox proportional hazards model demonstrated that only PSCA mRNA expression in negative prostatic biopsies was predictive of the subsequent cancer development after TURP (hazard ratio = 3.49; 95% CI: 2.02-4.75; P < 0.001), with the concordance index of 0.893.

This prospective study identifies PSCA mRNA in preoperatively negative prostatic biopsies as a significant predictor of subsequent cancer after TURP.