1 Centre for Tumour Biology, Barts Cancer Institute, Barts and the London School of Medicine and Dentistry, London EC1M 6BQ, UK.
2 Institute of Cancer Sciences-Pathology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G61 1QH, UK.
3 National Cancer Research Institute, London EC1V 4AD, UK.
4 Northern Ireland Molecular Pathology Laboratory, Centre for Cancer Research and Cell Biology, Queen's University Belfast, Belfast BT7 1NN, Northern Ireland.