1. Department of Gastroenterology, Graduate School of Medicine, University of Tokyo, Tokyo, Japan
2. Department of Gastroenterology, Ishikawa Prefectural Central Hospital, Kanazawa, Japan
3. Department of Internal Medicine, Hitachi General Hospital, Hitachi, Japan
4. Gastroenterology Center, Cancer Institute Hospital of JFCR, Tokyo, Japan
5. Department of Gastroenterology, Mitoyo General Hospital, Kanonji, Japan
6. Department of Gastroenterology, Niigata Prefectural Central Hospital, Niigata, Japan