1. Cancer Research UK Epidemiology Unit, University of Oxford, Radcliffe Infirmary, Oxford OX2 6HE, United Kingdom
2. Diagnostics Division, Bayer HealthCare, Bayer House, Strawberry Hill, Newbury, Berks, and Department of Clinical Biochemistry, University of Oxford, Oxford, United Kingdom
3. 19 Kerwin Drive, Dore, Sheffield, United Kingdom