1. Department of Medical Biochemistry, Göteborg University, P.O. Box 440, 405 30 Gothenburg, Sweden
2. Institute of Biotechnology, Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany
3. Cancer Research UK, Breast Cancer Biology Group, Guy's Hospital, Thomas Guy House, London SE1 9RT, U.K.