Race-specific patterns of epigenetic aging and age-associated differential methylation in normal rectal biopsies: Implications for the biology of aging and its relationship to rectal cancer

Approximately 90% of colorectal cancer (CRC) develop over the age of 50, highlighting the im-portant role of aging in CRC risk. African Americans (AAs) shoulder a greater CRC burden than European Americans (EA), and are more likely to develop CRC at a younger age. The effects of aging in AA and EA normal rectal tissue have yet to be defined. Here, we performed epige-nome-wide DNA methylation analysis in the first, large-scale biracial cohort of normal rectum (n=140 samples) Horvath clock was used to analyze epigenetic age acceleration in human rectum. DMRcate was performed to identify differences in DNA methylation associated with aging in AA and EA rectum. Differences were related to existing rectal cancer.