The aim of this study is to investigate how micro-RNAs in EVs would be effective in comparison with PSA, and we test three miRNAs, miR-21, miR-141, and miR-221 by isolating EVs from plasma, and compare the result with the level of PSA regarding their diagnostic performance in patients with prostate cancer [18, 19]. Here, KLK3 is linked to prostate carcinoma.