A large cross-sectional study from Japan noted that serum PSA levels were significantly reduced in men with T2DM on anti-diabetes drugs, higher glycated hemoglobin A1c (HbA1c), higher fasting SBG levels, obesity, and elevated alanine transaminase [26]. Such findings and associations should be carefully interpreted and individualized based on the clinical setting and the patient. This evidence concerns the gene KLK3 and diabetes mellitus.