Funding for this research was provided by:
Chinese Academy of Medical Sciences Innovation Fund for Medical Science (CAMS-2017-I2M-1-011)
Text and Data Mining valid from 2018-10-11
Received: 9 June 2018
Accepted: 1 October 2018
First Online: 11 October 2018
Compliance with ethical standards
: The authors declare that they have no conflict of interest.
: This study was approved by the Institutional Review Board of Peking Union Medical College Hospital, Chinese Academy of Medical Sciences.