1. Department of Gastroenterology and Hepatology, Hokkaido University Hospital, Sapporo, Japan
2. Department of Gastroenterological Surgery II, Hokkaido University Faculty of Medicine, Sapporo, Japan
3. Center for Gastroenterology, Teine Keijinkai Hospital, Sapporo, Japan
4. Department of Surgery, Surgical Oncology and Science, Sapporo Medical University School of Medicine, Sapporo, Japan
5. Department of Medical Oncology, Sapporo Medical University School of Medicine, Sapporo, Japan
6. Department of Gastroenterology and Hepatology, Sapporo Medical University School of Medicine, Sapporo, Japan
7. Department of Surgery, Asahikawa Medical University, Asahikawa, Japan
8. Division of Metabolism and Biosystemic Science, Asahikawa Medical University, Asahikawa, Japan
9. Division of Gastroenterology and Hematology/Oncology, Asahikawa Medical University, Asahikawa, Japan