. 2020 Dec 27;12(12):1299–1313. doi: 10.4254/wjh.v12.i12.1299
©The Author(s) 2020. Published by Baishideng Publishing Group Inc. All rights reserved.
This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial.