1. Department of Basic Sciences, College of Dentistry, New York University, New York, NY 10010
2. Institut National de la Santé et de la Recherche Médicale, Centre de Lutte Contre le Cancer Bergonié and Institut Européen de Chimie et Biologie, 33600 Pessac, France
3. Howard Hughes Medical Institute, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115
4. Serono Pharmaceutical Research Institute, Serono International S. A., Geneva, Switzerland
5. Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520