KLK3 and Familial prostate cancer: Asymptomatic men may also be found to have raised prostate-specific antigen (PSA) levels and need to be referred for further investigation.3 However, the use of PSA as a screening and prognostic biomarker remains controversial,4 5 and GPs6–9 and patients10 have mixed views about its utility in informing investigation and treatment decisions for prostate cancer.