1. Department of Experimental Oncology, St. Jude Children's Research Hospital, Memphis, TN 38105.
2. Department of Hematology-Oncology, St. Jude Children's Research Hospital, Memphis, TN 38105.
3. Department of Pediatrics, University of Tennessee College of Medicine, Memphis, TN 38163, USA.
4. Genelabs Inc., Redwood City, CA 94063, USA.