1. Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109
2. National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892
3. Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania 16802
4. Department of Radiation Oncology, University of Washington School of Medicine, Seattle, Washington 98195