1. From St Jude Children'ps Research Hospital, Memphis, TN; St Vincent Children'ps Hospital, Indianapolis, IN, The M. D. Anderson Cancer Center; and Texas Children'ps Cancer Center, Houston, TX; Children'ps Hospital of Philadelphia, Philadelphia; and Children'ps Hospital of Pittsburgh, Pittsburgh, PA; Children'ps Hospital at Denver, Denver, CO; Children'ps Hospital of San Diego, San Diego; and Children'ps Hospital of Los Angeles, Los Angeles, CA; Washington University Medical School, St Louis, MO;...