1. Gastroenterology, Toyoshima Endoscopy Clinic, Tokyo, Japan
2. Department of Gastroenterology and Hepatology, International University of Health and Welfare Narita Hospital, Chiba, Japan
3. Pathology and Cytology Laboratory Japan, Tokyo-Suginami, Japan
4. Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
5. Division of Gastroenterology and Hepatology, Toho University Omori Medical Center, Tokyo, Japan
6. Endoscopy Division, National Cancer Center Hospital, Tokyo, Japan