1. Department of Lower Gastrointestinal Medicine, The Cancer Institute Hospital of Japanese Foundation for Cancer Research, Tokyo, Japan
2. Department of Internal Medicine, Division of Gastroenterology and Hepatology, The Jikei University School of Medicine, Tokyo, Japan
3. Department of Endoscopy, The Jikei University School of Medicine, Tokyo, Japan
4. Department of Upper Gastrointestinal Medicine, The Cancer Institute Hospital of Japanese Foundation for Cancer Research, Tokyo, Japan