1. Department of Epidemiology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
2. Department of Biology, University of Chicago, Illinois
3. Department of Pathology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
4. Department of Cytopathology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China