KLK3 and prostate cancer: The current study excluded 717 men missing a Wave 1 PSA, men with Wave 1 PSA ≥ 4.0 ng/mL not followed by prostate biopsy, and men with prostate cancer detected at Wave 1, leaving 2547 screen-negative men at risk for prostate cancer at Wave 2 or Wave 3 (Figure 1).