title: Late-developing Philadelphia chromosomes in a case of T-cell acute lymphoblastic leukemia.
abstract: A child with T-cell acute lymphoblastic leukemia (ALL) is presented who at relapse acquired two Philadelphia chromosomes (Ph). Molecular studies at relapse revealed a rearrangement of the major breakpoint cluster region (M-bcr) on chromosome 22. No rearrangements of the immunoglobulin heavy chain or T-cell beta receptor gene loci were demonstrated. This case supports the hypothesis that leukemogenesis in Ph-positive malignancies is a multi-step process, the first step of which may not necessarily involve acquisition of the Ph.
authors.affiliation: Department of Laboratory Medicine and Pathology, University of Minnesota School of Medicine, Minneapolis.
authors.forename: J E
authors.initials: JE
authors.lastname: Coad
authors.forename: D C
authors.initials: DC
authors.lastname: Arthur
authors.forename: K J
authors.initials: KJ
authors.lastname: Gajl-Peczalska
authors.forename: C E
authors.initials: CE
authors.lastname: Litz
mesh_terms: D002648:Child; D002873:Chromosome Fragility; D002892:Chromosomes, Human, Pair 22; D016044:Fusion Proteins, bcr-abl / Q000235:genetics; D015321:Gene Rearrangement; D006801:Humans; D016130:Immunophenotyping; D007621:Karyotyping; D015459:Leukemia-Lymphoma, Adult T-Cell / Q000235:genetics* / Q000276:immunology / Q000473:pathology; D008297:Male; D005810:Multigene Family / Q000235:genetics; D010677:Philadelphia Chromosome; D012008:Recurrence
chemical_list: D016044:Fusion Proteins, bcr-abl