KLK3 and prostate cancer: The group most different from that above, defined by PSA low/Ki67 quartile 4-high (68/331, 21% of all cases) was characterized by high Gleason score, high tumor volume and stage, many cases with bone metastases already at diagnosis, and in this group 74% of the patient died from prostate cancer (Tables 2 and 3, Fig. 2).