1. From the Laboratory of Pathology, National Cancer Institute, National Institutes of Health, Bethesda, MD, the Mount Sinai School of Medicine of the City University of New York, NY, the Section on Diseases of the Liver, National Institute of Arthritis, Metabolism and Digestive Diseases, National Institutes of Health, Bethesda, MD, and the Cancer and Birth Defects Division, Bureau of Epidemiology, Center for Disease Control, Atlanta, GA (address reprint requests to Dr. Thomas at the National Cancer...