1 National Center for Pediatric Cancer Surveillance, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing 100045, China. Electronic address: ncpcs@bch.com.cn.
2 National Center for Pediatric Cancer Surveillance, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing 100045, China; School of Biological Science and Medical Engineering, Beihang University, Beijing, China.
3 National Center for Pediatric Cancer Surveillance, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing 100045, China; Department of Biostatistics, School of Public Health, Peking University, Beijing, China.
4 National Center for Pediatric Cancer Surveillance, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing 100045, China.