PSA was not significantly associated with the risk of overall ISUP 1 prostate cancer, with odds ratios ranging from 0.82 (95%CI: 0.68–1.00) for a man with PSA level from 3 to 4 ng/mL, 0.96 (95%CI: 0.79–1.16) for a man with PSA level from 4 to 6 ng/mL, 0.95 (95%CI: 0.75–1.21) for PSA 6–10 ng/mL, and 0.92 (95%CI: 0.58–1.45) for PSA 10–15 ng/mL compared to a man with PSA level from 2 to 3 ng/mL (Fig 1A). This evidence concerns the gene KLK3 and prostate cancer.