Funding for this research was provided by:
National Key Research and Development Project (2017YFC0113805)
Article History
Received: 24 January 2020
Accepted: 23 March 2020
First Online: 6 April 2020
Compliance with ethical standards
:
: The authors declare that they have no conflicts of interest.
: This study was approved by the Internal Review Board of Peking Union Medical College Hospital. Investigations involving human participants in this study were performed in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments.
: Informed consent was not required because of the retrospective character of the study.