[1] Hosp Sick Children, Div Haematol Oncol, Toronto, ON M5G 1X8, Canada
[2] Goethe Univ Frankfurt, Frankfurt, Germany
[3] Univ Childrens Hosp Muenster, Munster, Germany
[4] Leeds Gen Infirm, Leeds, W Yorkshire, England
[5] Univ York, York YO10 5DD, N Yorkshire, England
[6] Great Ormond St Hosp Sick Children, London WC1N 3JH, England
[7] London S Bank Univ, London, England
[8] John Hunter Childrens Hosp, Newcastle, NSW, Australia
[9] Univ Fed Sao Paulo, Sao Paulo, Brazil
[10] Childrens Hosp Philadelphia, Philadelphia, PA 19104 USA
[11] St Jude Childrens Res Hosp, Memphis, TN 38105 USA
[12] Hosp Ninos Luis Calvo Mackenna, Santiago, Chile
[13] Univ Chile, Santiago, Chile
[14] Ist Giannina Gaslini, I-16148 Genoa, Italy
[15] High Tor, Nassau, Bahamas
[16] Inst Rotary Canc Hosp, New Delhi, India
[17] All India Inst Med Sci, New Delhi, India
[18] Istanbul Univ, Istanbul, Turkey
[19] Duke Univ, Med Ctr, Durham, NC USA