1. Department of Microbiology and Kaplan Cancer Center, New York University Medical Center, New York, NY 10016, USA.
2. Institute for Molecular and Cellular Biology, Osaka University, Osaka 565, Japan.
3. Amgen Institute, Ontario Cancer Institute-Princess Margaret Hospital, Departments of Medical Biophysics and Immunology, University of Toronto, Ontario M4X 1K9, Canada.
4. Institute of Environmental Medicine and Kaplan Cancer Center, New York University Medical Center, Tuxedo, NY 10987, USA.
5. EntreMed, Inc., Rockville, MD 20850, USA.