1. Prostate Research Group, Surgical Oncology, Medical School, Framlington Place, University of Newcastle upon Tyne, Newcastle upon Tyne, NE2 4HH, UK
2. YCR Cancer Research Unit (Area 13), Department of Biology, University of York, PO BOX 373, York, YO10 5DD, UK
3. Department of Oncology, Addenbrooke's Hospital, University of Cambridge, Hills Road, Cambridge, CB2 2QQ, UK