Received: 19 September 2019
Accepted: 15 June 2020
First Online: 29 June 2020
Ethics approval and consent to participate
: All the patients in this study signed consents for the approval of use of their tissues and information in research. The institutional ethics committee of Sun Yat-sen University cancer center approved this study.
: Not applicable.
: The authors declare that they have no conflict of interest.