1. Screening Technologies Branch, Developmental Therapeutics Program, Division of Cancer Treatment and Diagnosis, National Cancer Institute at Frederick, National Institutes of Health, Frederick, Maryland 21702, Winship Cancer Institute, Emory University School of Medicine, Atlanta, Georgia 30322, Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois 30322, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Cientificas, 28006 Madrid, Spain, and Science...