title: Pediatric T-cell acute lymphoblastic leukemia with aberrations of both MLL loci.
abstract: Translocations involving the MLL gene at 11q23 have been implicated in acute lymphoblastic leukemia (ALL), as well as acute myeloid leukemia (AML). Such translocations result in gain of function fusion proteins that drive cell proliferation. Except in cases of T-cell ALL, MLL rearrangement is typically associated with a poor prognosis. We report a case of T-cell ALL with a t(11;19)(q23;p13.3) and deletion of the other chromosome 11 homolog at band q23. Fluorescence in situ hybridization (FISH) analyses confirmed involvement of the MLL loci in both the translocation and deletion. This case is unique in that deletions of 11q23 reported in ALL generally do not involve MLL. We are unaware of a previous report showing rearrangement of the MLL loci on both chromosome 11 homologues.
authors.affiliation: Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC 29425, USA. quigleyd@musc.edu
authors.forename: Denise I
authors.initials: DI
authors.lastname: Quigley
authors.forename: Daynna J
authors.initials: DJ
authors.lastname: Wolff
mesh_terms: D002648:Child; D002871:Chromosome Banding; D002880:Chromosomes, Human, Pair 11 / Q000235:genetics*; D005260:Female; D017353:Gene Deletion; D011495:Histone-Lysine N-Methyltransferase; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D015459:Leukemia-Lymphoma, Adult T-Cell / Q000235:genetics*; D051788:Myeloid-Lymphoid Leukemia Protein / Q000235:genetics*; D014178:Translocation, Genetic / Q000235:genetics*
chemical_list: C497422:KMT2A protein, human; D051788:Myeloid-Lymphoid Leukemia Protein; D011495:Histone-Lysine N-Methyltransferase