Funding for this research was provided by:
National Natural Science Foundation of China (81472441)
Received: 18 November 2019
Accepted: 8 June 2020
First Online: 16 June 2020
Ethics approval and consent to participate
: This retrospective study was approved by the institutional review board of Jiangsu Cancer Hospital, Nanjing Medical University, China. The informed consent requirement was waived. The committee’s reference number was Jiangsu Cancer Hospital’s Ethical Committee 2016-05-01.
: Not applicable.
: The authors declare that they have no competing interests.