Glivec Phase II Pediatric Study

Inclusion Criteria: * Patients from 6 months to 21 years of age. * Malignant disease documented by conventional criteria to be refractory to standard, approved therapy, or for which no conventional therapies of definitive benefit exist. * Immunohistochemistry documentation of positivity of either Kit (CD117) or PDGF-R in tumor tissue relevant. Each positive tumor will be centrally reviewed before inclusion of the patient in the trial. * Measurable or evaluable disease. * WHO Performance status 0,1, or 2 or Lansky Play Scale \>= 50%. * Adequate organ function, defined as the following: total bilirubin \< 1.5 x ULN, SGOT and SGPT \< 2.5 x UNL (or \< 5 x ULN if hepatic disease involvement is present), creatinine \< 1.5 x ULN, ANC \> 1x 109/L, platelets \> 75 x 109/L. * Female patients of child-bearing potential must have negative pregnancy test within 7 days before initiation of study drug dosing. * Male and female patients of reproductive potential must agree to employ an effective barrier method of birth control throughout the study and for up to 3 months following discontinuation of study drug. * Life expectancy of more than 6 weeks. * Written, voluntary, informed consent, including consent for retrieval and investigational use of tissue samples for evaluation signed by parents or young adult patients. * National and, when needed, local ethical approval. Exclusion Criteria: * Patient with hematological disease positive for the chimeric BCR-ABL fusion protein or for c-kit. * Patient has received any other investigational agents within 28 days of first day of study drug dosing. * Female patients who are pregnant or breast-feeding. * Patient has another severe and/or life-threatening medical diseasePatient has an acute or known chronic liver disease (e.g., chronic active hepatitis, cirrhosis). * Patient has a known diagnosis of human immunodeficiency virus (HIV) infection. * Patient has received chemotherapy within 4 weeks (6 weeks for nitrosourea, mitomycin-C or any antibody therapy) prior to study entry unless urgent enrollment needed and approved by the study coordinator.