Interim performance of a non-DRE urine exosome gene signature to predict Gleason ≥7 prostate cancer on initial prostate needle biopsy from patients enrolled in a prospective observational trial.

5064 Background: PSA and DRE are used for biopsy decisions; however, limited sensitivity and specificity have resulted in the over-diagnosis and treatment of low risk prostate cancer (PCa). Non-invasive screening tools that add predictive value for identifying high-grade, Gleason score (GS) ≥ 7, should impact the current paradigm. We sought to evaluate performance of a gene signature that differentiated GS7+ from GS6 + benign disease by evaluating patients with first-time biopsy results and gray zone PSA (4-10ng/mL) from an ongoing prospective clinical trial. Methods: 499 sequentially obtained first-catch non-DRE urine specimens (standard cups) from 15 urology practices were collected from patients presenting for biopsy. Exosomes were isolated and RNA extraction performed. RT-qPCR RNA copy numbers of ERG and PCA3, normalized to SPDEF, were measured to generate a three-gene signature, defined to yield a score discriminating GS7+ vs. GS6 and benign lesions, evaluating NPV, Sensitivity and Specificity relati...