Prostate cancer incidence has increased dramatically over the post 20 years (Majeed et al, 2000; Cancer Research UK, 2009) and much of this is because of prostate-specific antigen (PSA) testing, which has resulted in many diagnoses of prostate cancer that would not have previously been diagnosed (Brewster et al, 2000; Evans and Moller, 2003). The gene discussed is KLK3; the disease is prostate cancer.