1. B. Vogelstein is at the Howard Hughes Medical Institute, and the Kimmel Cancer Center at Johns Hopkins University, Baltimore, MD 21231, USA and chaired the recent National Research Council report on stem cells.
2. B. Alberts is president, National Academy of Sciences, and chair, National Research Council; Washington, DC 20418, USA.
3. K. Shine is president, Institute of Medicine; Washington, DC 20418, USA.