1. Center for Liver and Pancreatobiliary Cancer, National Cancer Center, Goyang-si, Korea
2. Department of Internal Medicine and Liver Research Institute, Seoul National University Hospital, Seoul National University College of Medicine, 101 Daehak-ro, Jongno-gu, Seoul 110-744, Korea
3. Division of Gastroenterology, Department of Internal Medicine, Liver Research Institute, College of Medicine, Seoul National University Hospital, Seoul National University, Seoul, Korea
4. Department of Gastroenterology, Kyung Hee University Hospital at Gangdong, Seoul, Korea
5. Division of Gastroenterology, Department of Internal Medicine, Dongguk University Ilsan Hospital, Goyang-si, Korea