1. Gastroenterology, Portsmouth Hospital University NHS Trust, Portsmouth, United Kingdom
2. Endoscopy Unit, Humanitas Clinical and Research Center IRCCS, Rozzano, Milan, Italy
3. Department of Biomedical Sciences, Humanitas University, Rozzano, Milan, Italy
4. GastroZentrum Hirslanden, Zürich, Switzerland
5. The Maria Sklodowska-Curie National Research Institute of Oncology, Warsaw, Poland
6. Statsconsultancy Ltd, Amersham, United Kingdom