A few examples of tissue-specific proteins are, among others: major histocompatibility complex MHC class II and CD86 for EVs derived from antigen-presenting cells in vitro [6], carcinoembryonic antigen (CEA) for EVs derived from colon carcinoma cell culture [7], human epidermal growth factor receptor 2 (HER2) from breast carcinoma cell lines [8] and prostate cancer antigen-3 (PCA-3) as well as TMPRSS2:ERG from EVs isolated from prostate cancer patients’ urinary samples [9]. Here, PCA3 is linked to prostate cancer.