1. Departments of Oncology and Pharmacology, Johns Hopkins University School of Medicine, Baltimore, MD 21205.
2. Department of Pathology, Duke University Medical Center, Durham, NC 27710.
3. Department of Radiation Oncology, University of Arizona, Tucson, AZ 85724.
4. Eleanor Roosevelt Institute for Cancer Research and the Department of Pediatrics, University of Colorado, Denver, CO 80262.
5. Laboratory of Viral Carcinogenesis, National Cancer Institute, Frederick, MD 21701.