Abstract Disclosure: A. El-Kenawi: None. R. Putney: None. A. Berglund: None. K. Yamoah: None. African American men (AAM) experience disproportionately higher rates of both prostate cancer (PCa) incidence and mortality compared to their European American counterparts (EAM). To investigate some of the biological factors which contribute to these disparities, we carried out an unbiased genomic expression analysis of PCa by ancestry using the matched GRID and VANDAAM cohorts. In this analysis, we discovered aminopeptidase N (ANPEP, APN, CD13), to be the most differentially expressed functional gene in both self-identified and ancestry derived AAM compared with EAM. Further computational analyses revealed that ANPEP correlates with signatures of cholesterol transport, estrogen and androgen receptor (AR) signaling. The functional role of ANPEP in regulating cholesterol metabolism and AR signaling remains unclear. Further computational analyses demonstrate that expression of ANPEP predominantly correlates with various amino acid transporters. In addition, comprehensive metabolomic characterization revealed that ANPEP-overexpressing cells exhibit altered level of one-carbon metabolism metabolites. The one-carbon metabolic pathway regulates amino acids homeostasis and epigenetic mechanisms. Metabolomics-based approach to assess the consumption of over 15 amino acids in patient-derived explants validate enrichment of one-carbon metabolism circuits in AAM. Thus, we further investigated whether ANPEP impact high methylation capacity by performing genome-wide methylation profiling in cells. We unraveled that ANPEP overexpression is associated with elevated methylation of DNA. Our future studies will assess whether ANPEP regulation of methylation capacity have an impact on AR binding to DNA. Presentation: 6/3/2024