KLK3 and Familial prostate cancer: Prostate cancer (PCa) disproportionately affects Black men in the US.30, 31 They tend to develop PCa at younger ages compared to other racial/ethnic groups, often present with a more aggressive form of PCa, and die at a higher rate than any other groups.31, 32 Additionally, Black men are less likely to undergo screening and treatment,32–34 which for PCa involves prostate-specific antigen (PSA) testing and digital rectal examination (DRE).