1. Department of Pathology, Oslo University Hospital-Rikshospitalet, Oslo, Norway 1
2. Institute of Clinical Medicine, University of Oslo, Oslo, Norway 2
3. Department of Gastrointestinal Surgery, Akershus University Hospital, Lørenskog, Norway 3
4. Department of Pathology, Akershus University Hospital, Lørenskog, Norway 4
5. Department of Hepatobiliary Surgery, Oslo University Hospital, Oslo, Norway 5
6. Institute of Oral Biology, University of Oslo, Oslo, Norway 6