1. Human Tumor Cell Biology Branch and the Medicine Branch, National Cancer Institute, National Institutes of Health, Bethesda, Md.
2. Department of Medicine, University of Utah School of Medicine, Salt Lake City, Utah; formerly Clinical Associate, Human Tumor Cell Biology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Md.
3. Medicine Branch, National Cancer Institute, National Institutes of Health, Bethesda, Md.
4. National Cancer Institute, National Institutes of Health, Bethesda, Md.
5. Human Tumor Cell Biology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Md.