Author contributions
(I) Conception and design: JW and YFZ; (II) Provision of study materials or patients: CCY, ZY, QJ and JJF; (III) Collection and assembly of data: XYF, JF and JX; (IV) Data analysis and interpretation: GH, LML and YFW; (V) Manuscript writing: All authors; (VI) Final approval of manuscript: All authors.