Funding for this research was provided by:
National Natural Science Foundation of China (81704076)
Text and Data Mining valid from 2019-03-14
Received: 22 January 2019
Accepted: 7 March 2019
First Online: 14 March 2019
Compliance with ethical standards
: The authors have declared no conflicts of interest.
: The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.
: As the data used was from SEER dataset (public), Ethics approval and consent to participate could be checked in SEER.
: Not applicable.