1. Department of Internal Medicine, Hanyang University Guri Hospital, Hanyang University College of Medicine, Guri, Korea.
2. Department of Pathology, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea.
3. Department of Gastroenterology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
4. Department of Internal Medicine, Incheon St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Incheon, Korea.
5. Department of Pathology, Inha University Hospital, Inha University School of Medicine, Incheon, Korea.