 The t(12;21) translocation resulting in TEL/AML1 gene fusion is present in approximately 25% of patients with precursor B-lineage pediatric acute lymphoblastic leukemia (ALL).     ///    "In conclusion, the presence of TEL/AML1 gene fusion in childhood precursor B-lineage ALL does not seem to be associated with a high in vitro drug sensitivity, except for ASP, indicating that these patients could benefit from treatment schedules with significant use of this drug.. "    ///    TEL/AML1 gene fusion is related to in vitro drug sensitivity for L-asparaginase in childhood acute lymphoblastic leukemia..     ///    "However, the TEL/AML1-positive patients were relatively more sensitive to L-asparaginase (ASP. "    ///    "The median LC(50) values did not differ significantly between TEL/AML1-positive and -negative samples for prednisolone, dexamethasone, daunorubicin, thiopurines, epipodophyllotoxins, and 4-HOO-ifosfamide. "    ///    "After matching for unevenly distributed patient characteristics-that is, excluding patients younger than 12 months, patients with CD10-negative immature B-lineage ALL, patients with Philadelphia chromosome, and patients who were hyperdiploid (more than 50 chromosomes) from the TEL/AML1 negative group-the only remaining difference was a relative sensitivity for ASP in the TEL/AML1-positive samples (10.8-fold. "