1. Gastroenterology and Endoscopy Unit, S. Elia-Raimondi Hospital, Caltanissetta, Italy
2. Diagnostic and Interventional Endoscopy, Candiolo Cancer Institute, FPO - IRCCS - Candiolo, Torino, Italy
3. Internal Medicine, Villa Sofia - V. Cervello Hospital, Palermo, Italy
4. Gastroenterology and Endoscopy Unit, Istituto San Raffaele Giglio, Cefalù, Italy
5. Digestive Diseases Endoscopy Unit, Policlinico G. Martino Hospital, University of Messina, Messina, Italy