[1] No & Yorkshire Clin Trials & Res Unit, Leeds LS16 6QB, W Yorkshire, England
[2] Univ Padua, Dept Paediat, Padua, Italy
[3] St Bartholomews Hosp, Dept Paediat Oncol, London, England
[4] Dept Paediat Pathol, Edinburgh, Midlothian, Scotland
[5] Inst Child Hlth, Dept Surg, London, England
[6] Univ Hosp Gasthuisberg, B-3000 Louvain, Belgium
[7] Kinderchirurg Centrum AMCVU, Amsterdam, Netherlands
[8] Univ Childrens Hosp, Dept Paediat Surg, Bern, Switzerland