1. Department of Interdisciplinary Endoscopy, University Hospital Hamburg-Eppendorf, Hamburg, Germany
2. Department of Surgery, Montreal General Hospital, McGill University, Montreal, Quebec, Canada
3. Department of Surgery, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA
4. Department of Pathology, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA
5. Imperial College, London University, London, United Kingdom
6. Section of Gastroenterology and Hepatology, Department of Medicine, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA