1. Department of Gastroenterology, Takasaki General Medical Center, National Hospital Organization, Japan
2. Department of Gastroenterology and Hepatology, Gunma University Graduate School of Medicine, Japan
3. Department of Pathology, Japanese Red Cross Medical Center, Japan
4. Department of Hepato-Biliary-Pancreatic Surgery and Liver Transplantation, Japanese Red Cross Medical Center, Japan
5. Department of Surgery, Towa Hospital, Japan