1. Department of Gastroenterology, Jyoban Hospital of Tokiwa Foundation, Iwaki, Japan
2. Division of Gastroenterology and Hepatology,, Kansai Medical University Medical Center, Moriguchi, Japan
3. Department of Medicine, Division of Gastroenterology, Jichi Medical University, Shimotsuke, Japan
4. Department of Coloproctology, Fukushima Medical University Aizu Medical Center, Fukushima, Japan
5. Royal Free Unit for Endoscopy, The Royal Free Hospital and University College London (UCL) Institute for Liver and Digestive Health, London, UK
6. Department of Pathology, Jichi Medical University, Shimotsuke, Japan