PSCA mRNA expression in preoperatively negative prostate biopsies predicts incidental prostate cancer in patients undergoing transurethral resection of the prostate for benign prostatic hyperplasia

Abstract

Recent data showed that prostate stem cell antigen (PSCA) mRNA expression is predictive of the subsequent cancer in BPH patients treated with TURP. This study was to determine whether PSCA mRNA expression in preoperatively negative biopsies identified the presence of incidental prostate cancer (IPCa) on TURP tissues analysis. PSCA in situ hybridization was performed in preoperatively negative prostatic biopsies taken from 592 enrolled BPH patients. Predictive performance of PSCA mRNA for IPCa was evaluated by the Cox proportional hazards models. PSCA mRNA positivity in negative biopsy specimens was detected in 84 (14.2%) of 592 men. Of those 84 patients, 57 were histopathologically identified as having PCa on their TURP tissues. None of the rest 508 men with negative PSCA mRNA expression were diagnosed with IPCa. Spearman's rank correlation coefficient showed that PSCA mRNA expression levels were correlated significantly and positively with Gleason score (r = 0.80, P < 0.001) and clinical stage (r = 0.86, P < 0.001). A multivariate Cox model demonstrated that only PSCA mRNA positivity was predictive of the IPCa presence on TURP (HR = 4.04; 95% CI: 2.12-5.42; P < 0.001), with the concordance index of 0.878. PSCA mRNA positivity in negative biopsies is a promising marker for the presence of IPCa in BPH patients.