Corcoran et al. 6 have shown that even after adjusting for known preoperative variables (including clinical stage, prostate-specific antigen (PSA), number of positive cores and percentage of positive cores) upgrade to a higher Gleason Score (GS) remained a strong and independent predictor of biochemical recurrence after attempted local curative therapy, this underscores the importance of gaining more information to predict upgrading of biopsy GS in men diagnosed with prostate cancer as this may serve as a marker of biologically aggressive disease. The gene discussed is KLK3; the disease is prostate cancer.