Abstract A031: Methylomic Biomarkers Associated with Prostate Cancer in Black Men

Abstract Introduction: The prostate cancer (PCa) disparity remains the highest cancer disparity in the US, with Black men facing an estimated 78% higher incidence and 230% higher mortality than White men. However, current understanding of risk factors for PCa such as socioeconomic status (SES), diet, and genetics cannot fully explain these disparities. Our objective is to examine DNA methylation (DNAm) markers in a cohort of Black men and assess their associations with PCa status. Methods: We randomly selected 100 Black men for DNAm profiling (50 cases diagnosed with clinically significant (Gleason Grade 3+) prostate cancer and 50 age-matched controls) from two larger cohorts. The cohorts recruited 400 Black men who were newly diagnosed with sporadic PCa as well as 400 controls matched on age and race. All men were 40-79 at recruitment and were enrolled from urology clinics at five Chicago-area medical institutions. All PCa cases underwent a transrectal prostate biopsy for abnormal prostate-specific antigen (PSA) or digital rectal exam and had a histologically confirmed prostate cancer and were not previously diagnosed with PCa. All men in the control group had been recruited from community prostate cancer screening events or were referred to participating urology clinics and had a negative prostate biopsy for a PSA 10ng/ml and were not diagnosed with PCa for 2 years of follow-up. Men with prior PCa diagnosis or conditions known to affect PSA levels were excluded. After enrollment and informed consent, all men provided demographic and lifestyle data via three questionnaires, followed by venipuncture for DNA collection. These specimens were obtained using buffy coat extraction after red blood cell lysis, centrifugation, and pipetting off the overlying plasma and buffy coat for freezing followed by Illumina EPIC arrays for DNAm assays. We examined DNAm markers in gene promoter regions associated with PCa using logistic regression and adjusted for multiple testing using Bonferroni correction. All models controlled for age, BMI, smoking status, first degree family history of PCa, blood cell types, and technical control variables. Results: We found 2,180 CpG sites in gene promoter regions associated with any PCa in this population. The top ten strongest associations identified in our models include loci on genes that have already been associated with prostate cancer progression (MAFG, FAM65B, OSM, PRKAG2), risk (SLC11A1, LAT), and metastasis (S1PR4) as well as immune system functioning (RAP1GAP2). Conclusions: Our initial findings suggest that DNAm markers may be useful predictors of clinically significant PCa status among Black men. Additional research is currently ongoing to expand the sample size of the DNAm profiling and to explore links between these loci and social determinants of health, as well as associations with more advanced (i.e., higher Gleason Grade) PCa. Citation Format: Brian T. Joyce, Yishu Qu, Jun Wang, Kai Zhang, Zequn Sun, Lifang Hou, Adam B. Murphy. Methylomic Biomarkers Associated with Prostate Cancer in Black Men abstract. In: Proceedings of the 17th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr A031.