1. Department of Internal Medicine, Seoul Metropolitan Government Seoul National University Boramae Medical Center, Seoul National University College of Medicine, Seoul, Korea
2. Department of Internal Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea
3. Department of Pathology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea
4. Department of Pathology, Seoul Metropolitan Government Seoul National University Boramae Medical Center, Seoul National University College of Medicine, Seoul, Korea
5. Department of Gastroenterology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea