In risk groups using Gleason score and baseline PSA, identified earlier as high (prostate cancer mortality at 10 years >30%), intermediate and low risk (prostate cancer mortality at 10 years <10%), Ki-67 was a significant independent prognostic factor for cause-specific survival in men at high risk (P=0.0001) or intermediate risk (P=0.049), but not among those at low risk of dying from prostate cancer, possibly because of the very few cases of men with a low Gleason score and high Ki-67 (P=0.99). This evidence concerns the gene KLK3 and prostate carcinoma.