Eui Joo Kim, Yoon Jae Kim, Department of Internal Medicine, Gachon University Gil Medical Center, Incheon 405-760, South Korea
Author contributions: Kim EJ and Kim YJ solely contributed to this paper.
Supported by Basic Science Research Program through the National Research Foundation of Korea funded by the Ministry of Science, ICT and Future Planning, No. 2014R1A1A1A05008202.
Conflict-of-interest statement: The authors have no potential conflict of interest to declare.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (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. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Yoon Jae Kim, MD, PhD, Department of Internal Medicine, Gachon University Gil Medical Center, 21 Namdong-daero 774 beon-gil, Namdong-gu, Incheon 405-760, South Korea. email@example.com
Telephone: +82-32-4603778 Fax: +82-32-4603408
Received: April 28, 2015
Peer-review started: May 7, 2015
First decision: September 29, 2015
Revised: October 22, 2015
Accepted: November 19, 2015
Article in press: November 19, 2015
Published online: January 14, 2016