1. University of California, San Francisco Medical Center, San Francisco, Calif., and the End Results Section, National Cancer Institute, National Institutes of Health, Bethesda, Md.
2. University of California, San Francisco Medical Center, San Francisco, Calif.
3. End Results Section, National Institutes of Health, National Cancer institute, Bethesda, Md.
4. M. D. Anderson Hospital and Tumor Institute, Houston, Texas; formerly at University of California, San Francisco Medical Center, San Francisco, Calif.