KLK3 and prostate carcinoma: However, while a European trial demonstrated that screening using repeated PSA testing reduces prostate cancer specific mortality [3], the UK CAP trial suggested that there is little prostate cancer specific mortality benefit of a single PSA screen after 10 years of follow-up [4], and overall the weight of evidence does not indicate that any potential mortality benefit outweighs the risks of overdiagnosis of indolent disease and of overtreatment [5].