Text and Data Mining valid from 2017-08-07
Received: 18 April 2017
Revised: 30 June 2017
Accepted: 14 July 2017
First Online: 7 August 2017
Compliance with ethical standards
: The scientific guarantor of this publication is Ruijiang Li.
: The authors have no potential conflicts of interest.
: This research was partially supported by the NIH grant number R00 CA166186, R01 CA193730.
: No complex statistical methods were necessary for this paper.
: Written informed consent was waived by the Institutional Review Board.
: Institutional Review Board approval was obtained.
: • retrospective• cross-sectional study• multicentre study