1. Department of Gastroenterology, The University of Tokyo, Tokyo, Japan
2. Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
3. Department of Gastroenterology, Center for Epidemiology and Preventive Medicine, The University of Tokyo, Tokyo, Japan
4. Department of Gastroenterology, Tokatsu-Tsujinaka Hospital, Chiba, Japan
5. Department of Pathology, Chiba University Hospital, Chiba, Japan
6. Department of Pathology, The University of Tokyo, Tokyo, Japan