Masaya Iwamuro1, Keisuke Hori2, Takehiro Tanaka3, Hiroyuki Okada4. 1. Department of Gastroenterology and Hepatology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan; Department of General Medicine, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan. 2. Department of Gastroenterology and Hepatology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan. 3. Department of Pathology, Okayama University Hospital, Okayama, Japan. 4. Department of Endoscopy, Okayama University Hospital, Okayama, Japan.