1. Department of Medicine and Gastroenterology, Gemeinschaftskrankenhaus Bonn, Bonn, Germany
2. Institute für Pathology Bonn-Duisdorf, Bonn, Germany
3. Department of Endoscopy, Saku Central Hospital Advanced Care Center, Nagano, Japan
4. Department of General and Abdominal Surgery, Gemeinschaftskrankenhaus Bonn, Bonn, Germany
5. Division of Research and Development for Minimally Invasive Treatment, Cancer Center, Keio University School of Medicine, Tokyo, Japan