1. Gastroenterology, Shonan Kamakura General Hospital, Kamakura, Japan
2. Gastroenterology, Saitama Medical University International Medical Center, Hidaka, Japan
3. Division of Medical Oncology/Hematology, Department of Medicine, Kobe University, Kobe, Japan
4. Department of Gastroenterology, Internal Medicine, Kitasato University School of Medicine, Sagamihara, Japan