Multi-omic Analysis of Familial Adenomatous Polyposis Reveals Molecular Pathways and Polyclonal Spreading Associated with Early Tumorigenesis

Abstract Familial adenomatous polyposis (FAP) is a genetic disease causing hundreds of premalignant polyps in affected patients, leading to colorectal cancer (CRC), and is an ideal model to study early transition to CRC. We performed deep multi-omic profiling of 135 normal mucosal, benign and dysplastic polyps and adenocarcinoma samples from 6 FAP patients who consented to broad data sharing. Whole genome sequencing indicates that spatially separated polyps from the same donor harbor numerous mutations in common, but evolve independently, consistent with a model of polyclonal origin and spreading. Transcriptomic, proteomic, metabolomic and lipidomic analyses revealed a dynamic choreography of thousands of molecular and cellular events that occur during early hyperplasia, dysplasia and cancer formation. These involve processes such as cell proliferation, immune response, alterations in metabolism (including amino acids, lipids), hormones, and extracellular matrix proteins. Interestingly, activation of the arachidonic acid pathway was found to occur early in hyperplasia; this pathway is targeted by aspirin/NSAIDs, a common preventative treatment of FAP patients. Overall, our results reveal key genomic, cellular and molecular events during the earliest steps in cancer formation and potential mechanisms of pharmaceutical prophylaxis.