Funding for this research was provided by:
National Natural Science Foundation of China (81802564, 81472375)
China Postdoctoral Science Foundation (2018M632489)
Text and Data Mining valid from 2019-02-13
Received: 19 September 2018
Accepted: 27 January 2019
First Online: 13 February 2019
Ethics approval and consent to participate
: All analyses were based on previous published studies thus no ethical approval and patient consent are required.
: Not applicable.
: The authors declare that they have no competing interests.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.