KLK3 and posterior cortical atrophy: Although a lower cut-off value for total PSA (i.e., 2 ng/ml) could better predict PCa risk in a four-year surveillance interval (43), we decided to use the most widely accepted cut-off value (4 ng/ml) for total PSA, then combined the ratio of free PSA to address the heterogeneity of PSA measurement across NHB and NHW individuals (37).