1. Department of Hepato-Pancreato-Biliary Surgery, Oslo University Hospital, Rikshospitalet, Oslo, Norway
2. Institute of Clinical Medicine, University of Oslo, Oslo, Norway
3. Department of Pathology, Oslo University Hospital, Radiumhospitalet, Oslo, Norway
4. Section of Gastroenterology, Department of Transplantation Medicine, Oslo University Hospital, Oslo, Norway
5. Department of Pathology, Oslo University Hospital, Rikshospitalet, Oslo, Norway