Graduate School in Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China.|Graduate School in Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China.|Graduate School in Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China.|Graduate School in Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China.|Graduate School in Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China.