A number of previous studies have already reported the association of EGFR, Her-2 and ErbB3 with PSA biochemical recurrence in prostate cancer patients (Visakorpi et al, 1992; Kuhn et al, 1993; Fox et al, 1994; Di Lorenzo et al, 2004; Hernes et al, 2004; Zellweger et al, 2005; Shah et al, 2006; Schlomm et al, 2007). Here, KLK3 is linked to prostate cancer.