1. C. M. Knudson, W. G. Tourtellotte, G. A. J. Brown, S. J. Korsmeyer, Howard Hughes Medical Institute and Division of Molecular Oncology, Departments of Medicine and Pathology, Washington University School of Medicine, St. Louis, MO 63110, USA.
2. K. S. K. Tung, Department of Pathology, University of Virginia Health Sciences Center, Charlottesville, VA 22908, USA.