title: Mature B-cell acute lymphoblastic leukemia with t(9;11) translocation: a distinct subset of B-cell acute lymphoblastic leukemia.
abstract: Mature B-cell acute lymphoblastic leukemia (ALL) is typically associated with the FAB-L3 morphology and rearrangement of the MYC gene, features characteristic of the leukemic phase of Burkitt's lymphoma. However, the term 'mature' has also been used to describe other rare cases of B-ALL with light-chain surface immunoglobulin expression. In contrast, infantile B-cell ALL is generally characterized by rearrangement of the MLL gene, an immature pro-B-cell phenotype, and CD10 negativity. We describe two unusual cases of infantile B-ALL with non-L3 morphology, expressing a mature B-cell phenotype (lambda sIg+, CD19+, CD10-, TdT-, and CD34-), and showing MLL rearrangement without MYC rearrangement at presentation. Both infants relapsed after months of morphologic and genetic remission. At relapse, the t(9;11) translocation was detected in both cases by spectral karyotyping. After the initial relapse, both cases followed a rapid and aggressive course. Literature search identified few similar cases, all expressed lambda surface immunoglobulin and showed MLL rearrangement (majority with the t(9;11) translocation). These cases show that B-ALL with MLL rearrangement, especially the t(9;11) translocation, can express a 'mature' B-cell phenotype and may represent a distinct subset. Identification of additional cases will further clarify the significance of MLL rearrangements in mature B-ALL.
authors.affiliation: Department of Pathology, Columbia University, New York, NY 10032, USA.
authors.forename: Lawrence
authors.initials: L
authors.lastname: Tsao
authors.forename: Hediya Y
authors.initials: HY
authors.lastname: Draoua
authors.forename: Ifeyinwa
authors.initials: I
authors.lastname: Osunkwo
authors.forename: Subhadra V
authors.initials: SV
authors.lastname: Nandula
authors.forename: Vundavalli V S
authors.initials: VV
authors.lastname: Murty
authors.forename: Mahesh
authors.initials: M
authors.lastname: Mansukhani
authors.forename: Govind
authors.initials: G
authors.lastname: Bhagat
authors.forename: Bachir
authors.initials: B
authors.lastname: Alobeid
mesh_terms: D015703:Antigens, CD / Q000032:analysis; D002871:Chromosome Banding; D002880:Chromosomes, Human, Pair 11 / Q000235:genetics*; D002899:Chromosomes, Human, Pair 9 / Q000235:genetics*; D004253:DNA Nucleotidylexotransferase / Q000032:analysis; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007223:Infant; D007621:Karyotyping / Q000379:methods; D008297:Male; D015452:Precursor B-Cell Lymphoblastic Leukemia-Lymphoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D014178:Translocation, Genetic
chemical_list: D015703:Antigens, CD; D004253:DNA Nucleotidylexotransferase