Timothy R. Rebbeck, PhD is Professor of Cancer Epidemiology at the Harvard TH Chan School of Public Health and Professor of Medical Oncology at the Dana Farber Cancer Institute. Dr. Rebbeck leads molecular epidemiology studies of cancer etiology, outcomes, health disparities, and global health. His research intends to identify and characterize cancer genes; to understand the relationship of allelic variation of these genes with cancer occurrence and cancer outcomes; and to evaluate the role of these genes in cancer etiology and outcomes in the context of the demographic, biochemical, environmental, and physiological risk factors. He has focused this research to address the following questions: 1) Why do men of African descent have higher incidence and poorer prognosis for prostate cancer compared to other groups? 2) How do we refine our understanding of cancer risk and prevention in high-risk individuals? 3) How do genes, environments, and other contextual factors interact in the etiology of commonly occurring cancers? He has primarily addressed these questions in cancer of the prostate, breast, and ovary.