[1] Childrens Hosp Agia Sofia, Dept Neurosurg, Athens, Greece
[2] Childrens Hosp Agia Sofia, Dept Pathol, Athens, Greece
[3] Univ Hosp Ioannina, Mol Biol Unit, Haematol Lab, Ioannina, Greece
[4] Univ Athens, Dept Pediat 1, Hematol Oncol Unit, Athens, Greece