1. Department of Gastroenterology, HM Montepríncipe University Hospital, HM Hospitales Group, Boadilla del Monte, Madrid, Spain
2. Department of Clinical Sciences, School of Medicine, University of CEU San Pablo, Boadilla del Monte, Madrid, Spain
3. Department of Gastroenterology, HM Puerta del Sur University Hospital, HM Hospitales Group, Móstoles, Madrid, Spain
4. Department of Pathological Anatomy, HM Puerta del Sur University Hospital, Móstoles, Madrid, Spain