1. Gastroenterology, Hepatology & Digestive Endoscopy Section, Department of Medicine and Surgery, University of Perugia, 06123 Perugia, Italy
2. Pathology Institute, ASST-Spedali Civili, 25123 Brescia, Italy
3. National Institute for Health Research, Nottingham Biomedical Research Centre, Nottingham University Hospitals NHS Trust UK, School of Medicine, University of Nottingham and Nottingham Digestive Diseases Centre, University of Nottingham, Nottingham NG7 2RD, UK