title: Conversion of childhood acute lymphocytic leukemia (L2) with a double t(12;21) to juvenile myelomonocytic leukemia with a novel t(4;11)(p12;q23): a cytogenetic, morphologic, and immunophenotypic study.
abstract: Here we describe a cytogenetic and flow-cytometric study of a case in which a conversion of childhood acute lymphocytic leukemia (ALL) into juvenile myelomonocytic leukemia (JMML) occurred. A 3-year-old boy diagnosed CALLA+, pre-B-ALL with double t(12;21) (by fluorescence in situ hybridization analysis), was treated as per the BFM protocol. A cytogenetic analysis performed at 17 months into treatment showed no t(12;21) in bone marrow (BM) cells; however, a novel translocation, namely, t(4;11), involving the p12 locus on chromosome 4 and the MLL gene at 11q23 was detected in monocytes. No cytogenetic abnormalities were found either in Epstein-Barr virus-transformed B cells or in phytohemagglutinin-stimulated T-lymphoid cells. Flow-cytometric analysis demonstrated an asynchronous expression of the antigenic determinants in populations of granulocytic and monocytoid cells: 60% of monocytes expressed low levels of CD14, an unusually high level of CD15, and no CD13 or HLA-DR antigens; 74% of myeloid cells expressed no CD13. Our results indicate that the transformation from B-cell ALL to JMML in this case occurred most probably in the granulocyte-erythroid-macrophage-megakaryocyte progenitor cells without involving the lymphoid cell line. To date, the child is 10 months off therapy and asymptomatic, with t(4;11) in only 3% of the cells.
authors: Cytogenetic Laboratory, Genetic Institute, Soroka University Medical Center, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel. manore@bgumail.bgu.ac.il
authors: Esther
authors: E
authors: Manor
authors: George
authors: G
authors: Shubinsky
authors: Asher M
authors: AM
authors: Moser
authors: Dora
authors: D
authors: Gurevitch
authors: Fanny
authors: F
authors: Chatach
authors: Tikva
authors: T
authors: Yermiahu
authors: Joseph
authors: J
authors: Kapelushnik
mesh_terms: D001853:Bone Marrow / Q000378:metabolism; D002471:Cell Transformation, Neoplastic / Q000235:genetics; D002648:Child; D002675:Child, Preschool; D002880:Chromosomes, Human, Pair 11; D002881:Chromosomes, Human, Pair 12; D002891:Chromosomes, Human, Pair 21; D002894:Chromosomes, Human, Pair 4; D004247:DNA / Q000378:metabolism; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007951:Leukemia, Myeloid / Q000235:genetics*; D008297:Male; D009000:Monocytes / Q000378:metabolism; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000235:genetics*; D014178:Translocation, Genetic
chemical_list: D004247:DNA