title: Clinical features and outcome of T-cell acute lymphoblastic leukemia in childhood with respect to alterations at the TAL1 locus: a Pediatric Oncology Group study.
abstract: Alteration of the TAL1 locus is the most common nonrandom genetic defect in childhood T-cell acute lymphoblastic leukemia (T-ALL). To determine if rearrangements of the TAL1 proto-oncogene confer a distinct leukemic phenotype, we studied leukemic peripheral blood or bone marrow samples from 182 children with newly diagnosed T-ALL enrolled on Pediatric Oncology Group treatment protocols. Forty-eight (26%) of the samples had a local rearrangement of the TAL1 locus. Demographic and clinical features were compared for patient subgroups with and without TAL1 rearrangements. The only clinical correlates that were significantly associated with TAL1 gene rearrangements were higher white blood cell count (P = .017) and higher hemoglobin (P = .007) at diagnosis. Immunophenotypically, samples with altered TAL1 were more likely to be CD2+ (P = .001) and lack CD10 (cALLa) expression (P = .007) than those without the rearrangement. There was a trend toward improved event-free survival (EFS) in patients with TAL1 rearrangements (4-year EFS was 44% +/- 7% for patients without the rearrangements v 59% +/- 11% for those with rearrangements), but the difference was not significant (P = .34). The role of TAL1 in leukemogenesis has yet to be clearly defined, and the prognostic significance of TAL1 gene rearrangements in T-ALL deserves further study.
authors: Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas 75235-9048.
authors: R O
authors: RO
authors: Bash
authors: W M
authors: WM
authors: Crist
authors: J J
authors: JJ
authors: Shuster
authors: M P
authors: MP
authors: Link
authors: M
authors: M
authors: Amylon
authors: J
authors: J
authors: Pullen
authors: A J
authors: AJ
authors: Carroll
authors: G R
authors: GR
authors: Buchanan
authors: R G
authors: RG
authors: Smith
authors: R
authors: R
authors: Baer
mesh_terms: D000293:Adolescent; D000328:Adult; D001483:Base Sequence; D051792:Basic Helix-Loop-Helix Proteins; D002648:Child; D002675:Child, Preschool; D002878:Chromosomes, Human, Pair 1; D004268:DNA-Binding Proteins / Q000235:genetics*; D017353:Gene Deletion; D015321:Gene Rearrangement; D006801:Humans; D016130:Immunophenotyping; D007223:Infant; D015459:Leukemia-Lymphoma, Adult T-Cell / Q000235:genetics*; D008969:Molecular Sequence Data; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D012074:Remission Induction; D000073942:T-Cell Acute Lymphocytic Leukemia Protein 1; D014157:Transcription Factors
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D004268:DNA-Binding Proteins; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins; D000073942:T-Cell Acute Lymphocytic Leukemia Protein 1; D014157:Transcription Factors; C000715470:MAS1 protein, human; C067143:TAL1 protein, human