Dr. Castle received his Ph.D. in Biophysics from the Johns Hopkins University (JHU) in 1995. Dr. Castle then did a post-doctoral fellowship at the NIH on the molecular biology of the zona pellucida. In 1999, he joined the Cancer Prevention Fellowship at NCI and received his MPH from JHU in 2000. He conducted his Cancer Prevention Fellowship training with NCI's Hormonal and Reproductive Epidemiology Branch (2000-2003) and joined the branch as a principal investigator in 2003. His professional interests are (1) epidemiology of human papillomaviruses (HPV) and cervical/anogenital cancer; and (2) science and translation of cancer prevention strategies. He is the lead investigator on several epidemiologic studies, including the Mississippi Delta Project, The HPV Persistence and Progression Cohort at Kaiser Permanente Northern California, and the Low-Cost Molecular Cervical Cancer Screening Study in China.