KLK3 and prostate cancer: In the group with PSA low/Ki67 quartile 4-low where 51% died from prostate cancer, the men who died from prostate cancer had higher Gleason score (8 vs. 6, P < 0.001), higher tumor volume (75 vs. 30 %, P < 0.01), higher stage (3 vs. 1, P <0.001), and more commonly metastases at diagnosis (25 vs. 3%, P < 0.01), but their PSA or Ki67 staining scores did not differ from those alive or dying from other causes.