KLK3 and prostate cancer: Rountree, et al. [97] developed an exosome-based anti-prostate cancer vaccine—MVA-BN-PRO—that contained two chimeric proteins derived from tumor-associated antigens, prostate-specific antigen (PSA), and prostatic acid phosphatase (PAP) fused to the C1C2 domain of lactadherin, targeting them specifically to the exosome.