1. Dpt of Hospital and Territory, Gastroenterology Unit, St Anthony Hospital, Padua
2. Dpt of Medicine, Oncology Unit, San Donà di Piave, Venice
3. Dpt of Medicine, Chioggia Hospital, Venice
4. Dpt of Medicine, Gastroenterology Unit, San Bassiano Hospital, Bassano del Grappa, Vicenza
5. Dpt of Medicine, Endoscopy Unit, Dolo Hospital
6. Division of Endoscopy, European Institute of Oncology, Milan
7. Dept. of Molecular Medicine, Laboratory of Public Health and Population Studies, University of Padua, Padua, Italy