PROJECT SUMMARY Gastro-intestinal (GI) cancer is a significant public health burden in the US. Among GI cancers, colorectal cancer (CRC) has been a focus of attention because it is the third most common cancer in the US. CRC arises through a polyp to cancer progression sequence, driven by molecular alterations (gene mutations and epigenetic alterations) in the normal colon cells, as well as by other factors including the tumor microenvironment, gut microbiome, etc. The identification of these molecular alterations and determination of their role in the etiology and behavior of CRC is incomplete and under active investigation. Another GI cancer that has received considerable attention recently is esophageal adenocarcinoma (EAC) because of its three-fold increase in the last few decades and because of its poor prognosis (20% 5-year survival). Like CRC, EAC arises secondary to gene mutations and epigenetic alterations that drive the formation of a pre-malignant condition called Barretts esophagus (BE) that can then progress to EAC. Although progress has been made in the prevention and management of GI cancers, there remains a substantial need to advance our understanding of the molecular pathology of GI cancers and to develop biomarkers that will translate into improved cancer screening programs, better patient management and outcomes. In order to address this need, the Research Specialist Dr. Ming Yu has developed this research plan to achieve the following objectives: 1) Characterize and functionally interrogate epigenetic alterations, in particular DNA methylation changes, during the initiation and progression of GI cancer; 2) Assess methylated genes as potential molecular biomarkers. This research plan is an integral part of the research programs that the Unit Director, Dr. William Grady, has developed at the Fred Hutchinson Cancer Research Center (FHCRC) (PQC1R01CA194663; PQ6R01CA220004), and several multi-disciplinary NCI funded research networks (the Early Detection Research Network (EDRN; U01 CA086389- 08), the Barrett’s Esophagus Translational Research Network (BETRNet; 5U54CA163060), and a Bridging the Gap UO1 (5U01CA182940)). Furthermore, this plan represents unique lines of investigation that Dr. Yu has initiated and will be leading in the next five years. These new investigations include the characterization of enhancer methylomes, the DNA methylation changes at gene enhancer elements, during GI cancer imitation and progression; the identification and the functional validation of onco-enhancers, and development of organoids derived from normal and cancerous gastrointestinal tissues to study DNA methylation during cancer initiation and progression. These approaches will provide an exciting addition to the existing research programs. Dr. Yu, the Research Specialist in this proposal, is the principal scientist successfully leading the studies of these research programs in the Grady laboratory at the FHCRC and has been the central determina...