In search for common genetic variants contributing to the risk of prostate cancer in men of African ancestry, we conducted a meta-analysis of GWAS summary statistics from the African Ancestry Prostate Cancer Consortium (AAPC; 12,643 cases and 16,627 controls) and the VA Million Veteran Program (6,107 cases and 47,412 controls). A total of 29,896,808 common (minor allele frequency (MAF) > 0.01) genotyped and imputed variants (r2 > 0.3) were meta-analyzed in a total of 18,750 prostate cancer cases and 64,039 controls. Of the 269 established risk variants for prostate cancer, 265 were polymorphic and 168 were nominally (P<0.05) associated with prostate cancer risk with directionally consistent effect estimates, of which 44 reached the genome-wide significance (P<5x10-8). Of the 3,018 genome-wide significant variants, eight were considered novel susceptibility loci for prostate cancer in men of African ancestry. Of the eight variants, five were only found in populations of African ancestry (MAF 2% - 34%) but not in European or Asian populations, and two were substantially more common in African ancestry populations (MAF 40%) than in other populations (MAF < 8%). One of the novel variants, rs60985508 (odds ratio (OR) = 1.12 [1.08 - 1.15]; P = 2.93×10-13; MAF = 34%), introduces a stop codon in exon 24 in the prostate-specific gene anoctamin 7 (ANO7), a known prostate cancer susceptibility gene. A polygenic risk score including 273 variants (265 of 269 established risk variants and 8 novel variants from this analysis) conferred an increased prostate cancer risk for men in the 90 - 100th percentile (OR = 3.91 [3.50 - 4.36]) and those in the 99 - 100th percentile (OR = 7.05 [5.51 - 9.02]), compared to men in the 40-60th percentile. These estimates were higher than what was observed with the PRS of 265 variants (90 - 100th percentile: OR = 3.49 [3.13 - 3.90]; 99 - 100th percentile: OR = 6.40 [4.99 - 8.21]). Our finding of 8 novel susceptibility loci for prostate cancer may improve risk prediction for men of African Ancestry and provide further insight into the underlying biology of prostate cancer.

Citation Format: Fei Chen, Ravi K. Madduri, Xin Sheng, Alex Rodriguez, Alisha Chou, Todd L. Edwards, Stephen K. Van Den Eeden, Rosalind A. Eeles, John S. Witte, Michael B. Cook, William J. Blot, David V. Conti, John M. Gaziano, Amy C. Justice, Christopher A. Haiman, VA Million Veteran Program and PRACTICAL/ELLIPSE Consortium. Meta-analysis in more than 80,000 men of African ancestry identified nine novel variants associated with prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr LB011.