1. Molecular Oncology Group, Royal Victoria Hospital, 1 and
2. Departments of Medicine,2
3. Departments of Microbiology and Immunology 3 and
4. Pharmacology, 4 Kimmel Cancer Institute, Philadelphia, Pennsylvania 19107
5. Oncology, 5 and
6. Biochemistry, 6 McGill University, Montreal, Quebec, Canada H3A 1A1, and