A non-invasive urine exosome gene expression assay (ExoIntelliScore Prostate) to predict pathologic stage and grade in the prostatectomy specimen.

46 Background: Non-invasive screening tools that add predictive value for identifying high-grade, Gleason score (GS) ≥7 should impact on the current diagnostic and subsequent treatment decision process. We have developed standardized processes to isolate exosomal-RNA from first-catch, non-DRE, urine specimens and have validated a three gene signature (ExoIntelliScore Prostate) that reliably differentiates GS7+ from GS6 and benign at the time of an initial biopsy. In addition to the biopsy outcomes, we sought to understand the performance of the assay in predicting objective pathology in the prostatectomy specimen. Methods: Pre-radical prostatectomy first-catch non-DRE urine specimens were collected from 5 urology practices (academic/community practices) without preservative, stored at 2-8C (up to 2 weeks) and shipped on ice to a central laboratory (Exosome Diagnostics, St. Paul, MN). Exosomes were isolated and RNA extraction performed. RT-qPCR RNA copy numbers of ERG and PCA3 were normalized to SPDEF. Spe...