ERG and Familial prostate cancer: Because the prevalence of the TMPRSS2-ERG fusion transcript in Chinese population is low, we detected the PRAC mRNA in urine-derived exosomes and discovered that the combination of urine exosome PCA3 and PRAC expressions enhanced the diagnostic value to predict the biopsy outcome for both any-grade and high-grade prostate cancer, which could potentially avoid unnecessary biopsy.