1. Department of Surgery, Helsinki University Central Hospital, Haartmaninkatu 4, 00290 Helsinki, Finland
2. First Department of Medicine, University of Szeged, P.O. Box 427, Szeged 6701, Hungary
3. Department of Surgery, North Manchester General Hospital, Delaunays Road, Manchester M8 5RB, UK
4. Cancer Studies Research Group, The University of Manchester, Manchester Academic Health Science Centre, Manchester, UK