CD9 and prostate cancer: The highly sensitive time resolved-fluorescence immunoassay (TR-FIA) for capture/detection of CD9 EV and CD63 EV has been previously employed to assess the content of CD9 positive and CD63 positive EV in urine of prostate cancer patients [38], where levels of CD9 and CD63 positive EV were found to be higher in urine samples from prostate cancer patients.