1. Department of Pediatrics (B.C.P., A.Mer., L.R.M.) Emory University/Aflac Cancer and Blood Disorders Center of Children's Healthcare of Atlanta, Atlanta, Georgia 30322;
2. Department of Public Health Sciences (Y.C., Y.Y.), University of Alberta, Edmonton, Alberta, Canada T6G 1C9;
3. Department of Pediatrics (C.A.S.), Memorial Sloan-Kettering Cancer Center, New York, New York 10065;
4. Department of Pediatrics (J.N.), University of Minnesota Medical School, Minneapolis, Minnesota 55454;
5. Department of Epidemiology and Cancer Control (G.T.A., L.L.R.), St Jude Children's Research Hospital, Memphis, Tennessee 38105;
6. Division of Oncology (A.Mea.), The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104;
7. Department of Radiation Physics (M.S.), The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030