1. Department of Surgery, National Center for Global Health and Medicine, Tokyo, Japan
2. Department of Gastroenterology, The Research Center for Hepatitis and Immunology, Research Institute, National Center for Global Health and Medicine, Chiba, Japan
3. Course of Advanced and Specialized Medicine, Juntendo University Graduate School of Medicine, Tokyo, Japan
4. Pathology Division of Clinical Laboratory, National Center for Global Health and Medicine, Tokyo, Japan
5. Department of Gastroenterology and Hepatology, National Center for Global Health and Medicine, Tokyo, Japan