Funding for this research was provided by:
National Natural Science Foundation of China (30470726)
The National Key Research and Development Program of China (2016YFC0905102)
Text and Data Mining valid from 2018-05-22
Received: 15 April 2017
Accepted: 9 May 2018
First Online: 22 May 2018
Ethics approval and consent to participate
: This study was approved by the ethical committee of Peking Union Medical College Hospital. The need for written informed consent was waived due to the non-interventional and retrospective nature of the study.
: The authors declare that they have no competing interests.
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