There was no difference in the count of white blood cells in preoperative urine, preoperative total IPSS score, hypertension, diabetes mellitus, initial prostate-specific antigen (PSA) level, and Gleason score between the Mg-positive and Mg-negative patients, whereas the rate of extensive disease (pT2c–3b) was higher in Mg-positive patients than in Mg-negative patients (77% vs. 44%, P = 0.027). This evidence concerns the gene KLK3 and diabetes mellitus.