Abstract 4742: Familial adenomatous polyposis epigenetic landscape as a precancer model of colorectal cancer

Abstract Aberrant shifts in DNA methylation have long been regarded as an early biomarker for cancer onset and progression. However, it is unclear when methylation aberrance starts and how it interacts with other epigenomic modifications. To address how epigenomic changes occur and interact during the transformation from normal healthy colon tissue to malignant colorectal cancer (CRC), we collected 51 samples from 15 familial adenomatous polyposis (FAP) and non-FAP colorectal cancer patients. We generated 30-70x of whole-genome enzymatic methylation sequencing (WGEM-seq) data via the novel Ultima Genomics ultra high-throughput sequencing platform. We observed hypermethylation and hypomethylation emerge early in the malignant transformation process in gene promoters and distal regulatory elements. We performed multifaceted analysis on methylation alterations with whole-genome sequencing (WGS), transposase accessibility (ATAC-seq), high-resolution chromatin accessibility (Tri-C), and gene expression (RNA-seq) data. Our multidimensional analysis demonstrates how collectively epigenomic alterations have affected gene expression throughout normal colon mucosa, benign and dysplasia polyps to adenocarcinoma. Epigenomic changes start as early as benign polyps, followed by other epigenomic shifts, including bivalent domains. Various epigenomic aberrances are associated with concomitant gene expression level changes. Our integrative analysis of multi-epigenomics data implicates collective and cumulative epigenomic instability in the early onset of colon carcinogenesis. Citation Format: Hayan Lee, Gat Krieger, Tyson Clark, Yizhou Zhu, Aziz Khan, Casey R. Hanson, Aaron Horning, Edward D. Esplin, Mohan Badu, Kristina Paul, Roxanne Chiu, Bahareh Bahmani, Stephanie Nevins, Annika K. Weimer, Ariel Jaimovich, Christina Curtis, William Greenleaf, James M. Ford, Doron Lipson, Zohar Shipony, Michael P. Snyder. Familial adenomatous polyposis epigenetic landscape as a precancer model of colorectal cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4742.