Our results point to the fact that KLK1, KLK2, and KLK14 (only in recurrent prostate cancer tissues) are underexpressed in prostate cancer tissues, while KLK3, KLK4, KLK8, and KLK9 are overexpressed in both recurrent and non-recurrent tissues. The gene discussed is KLK2; the disease is Familial prostate cancer.