ERG and cancer: One established role of LB in the diagnosis of early PC is the use of the ExoDxTM Prostate IntelliScore (EPI, Exosome Diagnostics, Inc., Waltham, MA, USA), a high-throughput, urine-based EV assay which tests for the presence of the mRNA transcript of three genes (ERG, PC3 and SPDEF) that can distinguish high-grade (≥Grade group 2) from low-grade (Grade group 1) cancer and benign tissue.