1. Department of Gastroenterology and Hematology, Hirosaki Graduate School of Medicine, Japan
2. Department of Internal Medicine, Hirosaki Municipal Hospital, Japan
3. Department of Gastroenterology, Aomori City Hospital, Japan
4. Department of Anatomic Pathology, Hirosaki Graduate School of Medicine, Japan
5. Department of Pathology and Bioscience, Hirosaki Graduate School of Medicine, Japan