1. Polyposis Registry, St Mark's Hospital, City Road, London EC1V 2PS, UK
2. Imperial Cancer Research Fund Colorectal Unit, St Mark's Hospital, City Road, London EC1V 2PS, UK
3. Department of Pathology, St Mark's Hospital, City Road, London EC1V 2PS, UK
4. Family Cancer Clinic, St Mark's Hospital, City Road, London EC1V 2PS, UK