1. Division of Cancer Control, Research Institute, National Cancer Center, Goyang, Gyeonggi, Korea
2. Department of Internal Medicine, Kyung Hee University Hospital, Seoul, Korea
3. Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea
4. Center for Gastric Cancer, Research Institute and Hospital, National Cancer Center, Goyang, Gyeonggi, Korea
5. Department of Internal Medicine, Korea University Guro Hospital, Seoul, Korea