1. Gastroenterology and Gastrointestinal Endoscopy Unit; Vita Salute San Raffaele University; Scientific Institute San Raffaele; Milan; Italy
2. Department of Gastroenterology and Hepatology; Erasmus; University Medical Centre Rotterdam; The Netherlands
3. Research Centre of Epidemiology and Preventive Medicine; University of Insubria; Varese; Italy
4. Pathology Department; University Hospital of Santiago de Compostela; Spain
5. Pathology Department; Erasmus; University Medical Centre Rotterdam; The Netherlands
6. Pathology Department; Paoli-Calmettes Institute; Marseilles; France
7. Pathology Department; Catholic University; Rome; Italy
8. Pathology Department; Vita Salute San Raffaele University; Scientific Institute San Raffaele; Milan; Italy
9. Endoscopic Unit; Paoli-Calmettes Institute; Marseilles; France
10. Gastroenterology and Hepatology Department; University Hospital of Santiago de Compostela; Spain
11. Digestive Endoscopy Unit; Catholic University; Rome; Italy