[1] Univ Oxford, Mol Haematol Unit, Weatherall Inst Mol Med, John Radcliffe Hosp, Oxford OX3 9DS, England
[2] Hannover Med Sch, Dept Pediat Hematol Oncol, D-30625 Hannover, Germany
[3] Comenius Univ, Sch Med, Dept Pediat Oncol, Bratislava, Slovakia
[4] Univ Childrens Hosp, Bratislava, Slovakia
[5] Univ London Imperial Coll Sci Technol & Med, Dept Haematol, London, England
[6] Aarhus Univ Hosp, Dept Pediat, Nord Soc Pediat Hematol & Oncol, Skejby, Denmark