[1] Univ Childrens Hosp Muenster, Munster, Germany
[2] Hannover Med Sch, D-3000 Hannover, Germany
[3] St Anna Childrens Hosp, A-1090 Vienna, Austria
[4] Univ Kinderklin Zurich, Div Pediat Oncol, Zurich, Switzerland
[5] Charles Univ Prague, Fac Med 2, Prague, Czech Republic