1. Department of Medical Biochemistry, University of Göteborg, SE 405 30 Göteborg, Sweden
2. Endothelial Cell Biology Laboratory, Imperial Cancer Research Fund, London WC2A 3PX, UK
3. Wolfson Institute for Biomedical Research, University College London, London WC1E 6AU, UK
4. Molecular/Cancer Biology Laboratory, Haartman Institute and Ludwig Institute for Cancer Research, Biomedicum, 00014 Helsinki, Finland
5. Department of Obstetrics and Gynaecology, University of Nottingham, City Hospital, Nottingham, NG5 1PB, UK