Dr. Markham is an Assistant Professor of Medicine in the Division of Gastroenterology. His laboratory program is focused on understanding C. difficile toxin pathogenesis and how the gut microbiome affects colorectal cancer. As a gastroenterologist and cell biologist, he has a firm commitment to developing this area of study for the benefit of patients. He is funded by the U.S. Department of Veterans Affairs to investigate how C. difficile toxins affect receptor tyrosine kinase signaling pathways during human infection. Stemming from this project and other collaborations, his lab is testing the hypothesis that prolonged exposure to C. difficile and subsequent colitis increases the risk of colon cancer tumorigenesis. Multiomic experiments in the lab are aimed at understanding how the spatial organization of the gut microbiota affects tumorigenesis. As a member of the National Cancer Institute’s Human Tumor Atlas Network (HTAN), Dr. Markham has applied an integrated approach for creating an atlas of human colorectal cancer with specific attention to intra-tumoral bacteria as a component of the tumor microenvironment. Together, his research program and clinical experience have coalesced into a passion for studying colorectal cancer and new opportunities for prevention and treatment.