[1] Sophia Childrens Univ Hosp, Erasmus MC, Dept Pediat Hematol Oncol, Rotterdam, Netherlands
[2] Erasmus Univ, Med Ctr, Rotterdam, Netherlands
[3] Dutch Childhood Oncol Grp, The Hague, Netherlands
[4] Hannover Med Sch, D-3000 Hannover, Germany
[5] Vrije Univ Amsterdam, Med Ctr, Amsterdam, Netherlands
[6] Charles Univ Prague, Univ Hosp Motol, Sch Med 2, Dept Pediat Hematol & Oncol, Prague, Czech Republic