1. Department of Epidemiology and Biostatistics; School of Public Health; Peking University Health Science Center; Beijing China
2. Center for Clinical Cancer Genetics and Global Health; Department of Medicine; University of Chicago; Chicago Illinois
3. Department of Public Health Sciences; University of Chicago; Chicago Illinois
4. Department of Surgery; College of Medicine; University of Ibadan; Ibadan Nigeria
5. Center for Population and Reproductive Health; College of Medicine; University of Ibadan; Ibadan Nigeria
6. Division of Epidemiology; Department of Medicine; Vanderbilt Epidemiology Center; Vanderbilt-Ingram Cancer Center; Vanderbilt University; Nashville Tennessee
7. Department of Medicine; University of Pennsylvania; Philadelphia Pennsylvania
8. Department of Preventive Medicine; State University of New York at Stony Brook; Stony Brook New York
9. Laboratory of Human Carcinogenesis; National Cancer Institute; Bethesda Maryland