In prostate cancer (PCa) patients, the expression of prostate specific antigen (PSA) [14-16], prostate-specific membrane antigen (PSMA) [17,18], and human glandular kallikrein 2 (hK2) [19] along with other epithelial cell markers has been investigated individually or in combination [20] for their ability to detect CTCs in patients with localized and metastatic PCa. This evidence concerns the gene KLK3 and prostate carcinoma.