1. Division of Gastroenterology and Hepatology, Landspitali - The National University Hospital of Iceland, Reykjavik, Iceland
2. Department of Internal Medicine, Division of Gastroenterology and Hepatology, Sahlgrenska University Hospital, Gothenburg, Sweden
3. Faculty of Medicine, University of Iceland, Reykjavik, Iceland
4. Department of Oncology, Landspitali - The National University Hospital of Iceland, Reykjavik, Iceland