Funding for this research was provided by:
Medical Scientific Research Foundation of Guangdong Province of China (No. A2019528)
Received: 27 January 2019
Accepted: 24 May 2019
First Online: 30 May 2019
Ethics approval and consent to participate
: The current study was approved by the Institutional Ethics Committee of the Affiliated Cancer Hospital&Institute of Guangzhou Medical University (No.2017003), and the need for signed informed consent was waived.
: Not applicable.
: The authors declare that they have no competing interests.