title: Childhood acute lymphoblastic leukemia with equivocal chromosome markers of the t(1;19) translocation.
abstract: The t(1;19)(q23;p13) or its derivative encodes an E2A-PBXI fusion transcript and protein that has been shown to have important prognostic and therapeutic implications in patients with acute lymphoblastic leukemia (ALL). We describe two childhood cases in which a der(22)t(1;22)(q21-23;p13) cytogenetically mimicked a der(19)t(1;19)(q23;p13). In one case, which was phenotyped as early pre-B ALL with hyperdiploidy but lacked evidence of an E2A-PBX1 gene fusion by molecular study, the poor banding quality of chromosomes led to misinterpretation of the cytogenetic findings; a correct diagnosis was established only after analysis by the fluorescence in situ hybridization (FISH) method. The second case, which was classified as pseudodiploid pre-B ALL, had both a derivative 19 and a derivative 22 but lacked sufficient cells for evaluation of E2A-PBX1 gene fusion. This case was included in order to compare the der(19)t(1;19) and the der(22)t(1;22) and to pinpoint the difficulty in distinguishing these markers. FISH analysis can resolve diagnostic uncertainty in cases of ALL with equivocal chromosome 19 markers.
authors.affiliation: Department of Pathology and Laboratory Medicine, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA.
authors.forename: L V
authors.initials: LV
authors.lastname: Filatov
authors.forename: F G
authors.initials: FG
authors.lastname: Behm
authors.forename: C H
authors.initials: CH
authors.lastname: Pui
authors.forename: D R
authors.initials: DR
authors.lastname: Head
authors.forename: J R
authors.initials: JR
authors.lastname: Downing
authors.forename: S C
authors.initials: SC
authors.lastname: Raimondi
mesh_terms: D002675:Child, Preschool; D002878:Chromosomes, Human, Pair 1; D002888:Chromosomes, Human, Pair 19; D005260:Female; D005819:Genetic Markers / Q000235:genetics; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D008297:Male; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000235:genetics*; D014178:Translocation, Genetic
chemical_list: D005819:Genetic Markers