1. Department of Gastroenterology, Gachon University Gil Medical Center, Gachon University of Medicine and Science, Incheon, Korea.
2. Center for Gastric Cancer, National Cancer Center, Goyang, Korea.
3. Department of Internal Medicine, Catholic University of Daegu School of Medicine, Daegu, Korea.
4. Division of Gastroenterology, Department of Internal Medicine, Kyung Hee University School of Medicine, Seoul, Korea.
5. Department of Gastroenterology, CHA Bundang Medical Center, CHA University, Seongnam, Korea.