Project Summary Cancer is the second most common cause of death in developed nations, where an estimated 70% of cancers are attributable to “modifiable” risk factors, including obesity, chronic inflammatory diseases, and poor diet, all of which have been associated with increased oxidative stress. Colorectal cancer (CRC) is the second leading cause of cancer-related deaths worldwide, with its incidence closely tied to these modifiable factors, particularly inflammation and metabolic disorders. Of increasing concern is the rise in early-onset CRC diagnoses in adults younger than 50, who are diagnosed over a decade sooner than the recommended age for routine screening. Studies have shown individuals who were overweight or obese in childhood are known to be at a higher risk of developing colorectal cancer (CRC) later in life. The parent grant focuses on determining the role of oxidative stress in cancer development, specifically targeting CRC influenced by lifestyle factors like obesity, chronic inflammation, and poor diet. Using advanced techniques such as whole genome sequencing (WGS) and computational analyses, the study aims to pinpoint mutational signatures associated with oxidative stress-induced DNA damage and their correlation with cancer-promoting lifestyle factors. In this diversity supplement, our central hypothesis is that CRC susceptibility in the context of obesity arises from somatic mutations occurring in functional loci, such as those located in accessible chromatin regions. We propose to leverage multi-omic profiling and computational tools to probe the relationship between reactive oxygen species (ROS)-mediated mutational signatures and inflammation-driven cancer risk factors using datasets from the NIH Common Fund (HuBMAP & GTEx). This supplement aligns with the parent grant's mission to investigate lifestyle risk factors, oxidative stress, and CRC risk, extending its focus to explore mutations in open chromatin sites under altered metabolic conditions and studying mutagenesis in colorectal stem progenitor cells. To elucidate the molecular pathways linking early-life obesity to CRC susceptibility, it is crucial to model and investigate the effects of hyperglycemic conditions and other mutagens during key developmental stages. Colonic organoids derived from induced pluripotent stem cells (iPSCs) will provide an excellent model system for studying CRC development in vitro. By exposing these organoids to mutagenic agents, we can mimic early-life exposures and assess their impact on mutagenesis and CRC risk. Additionally, leveraging developmental GTEx data will enable us to map chromatin accessibility across different developmental staging, allowing us to correlate the timing of mutagenesis and the effect on mutation accumulation and functional impact. The overarching objective of our study is to comprehend how early-life obesity and metabolic dysfunction increase susceptibility to mutagenesis leading to CRC development.