1. Department of Head and Neck Surgery, National Cancer Center Hospital East, Kashiwa, Japan
2. Department of Gastroenterology, Kitasato University School of Medicine, Sagamihara, Japan
3. Department of Head and Neck Surgery, Iwate Medical University School of Medicine, Morioka, Japan
4. Department of Head and Neck Surgery, Tokyo Medical and Dental University, Tokyo, Japan
5. Department of Health Promotion, National Institute of Public Health, Wako, Japan
6. Department of Gastroenterology and Endoscopy, National Cancer Center Hospital East, Kashiwa, Japan
7. Endoscopy Division, National Cancer Center Hospital, Tokyo, Japan
8. Department of Gastroenterology, Hokkaido University Graduate School of Medicine, Sapporo, Japan
9. Department of Gastroenterology, Ishikawa Prefectural Central Hospital, Kanazawa, Japan
10. Department of Molecular-Targeting Cancer Prevention, Kyoto Prefectural University of Medicine, Kyoto, Japan
11. Clinical Research Unit, National Hospital Organization Kurihama Medical and Addiction Center, Yokosuka, Japan
12. Department of Therapeutic Oncology, Kyoto University Graduate School of Medicine, Kyoto, Japan