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Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Translocations involving the MLL gene on chromosome 11q23 occur in 5-10% of human leukemias, and involve fusion with more than 30 different partner genes. The MLL-AF10 fusion produced by the t(10;11)(p12;q23) or ins(10;11)(p12;q23q13) occurs in a small percentage of acute leukemias, most commonly acute myelogenous leukemia (AML) of the M5 FAB subtype. We report two cases of AML (M5a and M0) and one case of acute lymphoblastic leukemia containing MLL-AF10 fusion. Each case had varied clinical characteristics, despite expressing similar MLL-AF10 fusion transcripts. Including the three cases described in this report, we identified a total of 38 cases of leukemia with MLL-AF10 fusion. Approximately one-third of these are not M5 AML. Taken together, these findings emphasize that while the sentinel molecular event may be identical in a disease, the clinical presentation and outcome can vary widely.
Leukemia 2000 Dec
PMID:Protean clinical manifestations in children with leukemias containing MLL-AF10 fusion. 1118 95

Chromosomal analysis plays an important role in the diagnosis, treatment and prognosis of human leukemia. Currently, the GTG-banding technique (G-banding) is the most commonly used diagnostic method in clinical cytogenetics. G-banding analysis of subtle chromosomal rearrangements or complex karyotypes with multiple markers can be inadequate because of poor chromosome morphology and/or an insufficient yield of analyzable metaphases. Fluorescence in situ hybridization (FISH) is a highly sensitive and specific method to detect chromosomal alterations. Conventional FISH is used optimally in instances where only one or a few abnormalities are investigated. Spectral karyotyping (SKY), a novel cytogenetic technique, has been developed to unambiguously display and identify all chromosomes at one time using a spectrum of 24 different colors. This report presents the use of SKY for examination of the entire karyotype in specimens with complex chromosomal abnormalities from three leukemia patients. Conventional cytogenetic analysis (G-banding) showed complex hyperdiploid clones with multiple markers in each case. SKY was able to clarify and identify additional cryptic chromosomal translocations [e.g., t(2;10), t(3;10), t(5;7), t(7;18), t(9;17), t(10;12), t(13;16)] insertions [e.g., ins(17;9), ins(20;Y)], duplications [e.g., i(8)(q10), dup(4)(q31q35)] and marker chromosomes in each case. This study demonstrates that the combination of SKY and G-band techniques results in a more complete characterization of the complex chromosomal aberrations seen in leukemia.
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PMID:Spectral karyotyping study of chromosome abnormalities in human leukemia. 1142 54

The MLL (HRX, ALL-1 HTRX) gene at chromosome band 11q23 frequently is rearranged in acute lymphoblastic and myeloblastic leukemia. To date, more than 40 different 11q23 abnormalities have been described on the cytogenetic level, and at least 25 of the respective fusion partner genes are cloned. The vast majority of the respective reciprocal translocations generate a chimeric 5'-MLL/partner-3' gene on the derivative 11q23. In this work, we report a unique ins(X;11)(q24;q23) in an infant with acute myeloid leukemia (AML-M2) that fuses the human KIAA0128 gene at Xq24 with MLL. In contrast to the typical reciprocal MLL translocations, however, we provide evidence that the 5'-MLL/KIAA0128-3' fusion resides on Xq24 rather than on 11q23. The KIAA0128 gene encodes the human Septin 6 protein, which contains an ATP-GTP binding motif and three nuclear targeting sequences in its carboxy terminus. The maintenance of the reading frame of the 5'-MLL/KIAA0128-3' mRNA fusion allows for the formation of a novel chimeric protein. Septin 6 is the third member of the Septins that is fused to the MLL protein; the other two are hCDCrel at 22q11 and MSF at 17q25.
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PMID:An ins(X;11)(q24;q23) fuses the MLL and the Septin 6/KIAA0128 gene in an infant with AML-M2. 1147 64

Cytogenetic studies of patients with therapy-induced acute myeloid leukemia (t-AML) have demonstrated whole chromosome loss or q-arm deletion of chromosomes 5 and/or 7 in a majority of cases. We have established two cell lines, SAML-1 and SAML-2, from two patients who developed t-AML after radiation and chemotherapy for Hodgkin disease. In both cases, the leukemia cells contained 5q deletions. SAML-1 has 58 chromosomes and numerous abnormalities, including der(1)(1qter-->1p22::5q31-->5qter), der(5)(5pter-->5q22::1p22-->1pter), +8, der(13)i(13)(q10)del(13)(q11q14.1), and t(10;11). Fluorescence in situ hybridization (FISH) with unique sequence probes for the 5q31 region showed loss of IL4, IL5, IRF1, and IL3, and translocation of IL9, DS5S89, EGR1, and CSFIR to 1p. SAML-2 has 45 chromosomes, del(5)(q11.2q31) with a t(12;13)ins(12;5), leading to the proximity of IRF1 and RB1, and complex translocations of chromosomes 8 and 11, resulting in amplification of MYC and MLL. Comparative genomic hybridization and spectral karyotyping were consistent with the G-banding karyotype and FISH analyses. Because a potential tumor suppressor(s) in the 5q31 region has yet to be identified, these cell lines should prove useful in the study of the mechanisms leading to the development of t-AML.
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PMID:Cytogenetic, spectral karyotyping, fluorescence in situ hybridization, and comparative genomic hybridization characterization of two new secondary leukemia cell lines with 5q deletions, and MYC and MLL amplification. 1275 25

We report on a 69-year-old woman with B-lineage acute lymphoblastic leukemia. Cytogenetic studies at diagnosis with R banding showed an insertion, ins(4;11)(q21;q13q23). Fluorescence in situ hybridization (FISH) with whole chromosome painting probes confirmed the insertion of chromosome 11 material into chromosome 4. FISH using the MLL probe showed the translocation of the 5' end of MLL into chromosome 4. Since the 5'MLL-3'AF4 fusion transcript was detected by a reverse transcriptase polymerase chain reaction, we concluded that the insertion of part of chromosome 11 split the AF4 gene in two, resulting in the presence of the 5'MLL-3'AF4 fusion gene on the der(4) instead of the der(11), as commonly observed. Our findings stress the value of combining banding cytogenetics with FISH and molecular techniques to better assess rearrangements in leukemia.
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PMID:Insertion of chromosome 11 in chromosome 4 resulting in a 5'MLL-3'AF4 fusion gene in a case of adult acute lymphoblastic leukemia. 1288 67

Accumulation of intracellular lipid by pancreatic islet beta-cells has been proposed to inhibit normal glucose-regulated insulin secretion ('glucolipotoxicity'). In the present study, we determine whether over-expression in rat islets of the lipogenic transcription factor SREBP1c (sterol-regulatory-element-binding protein-1c) affects insulin release, and whether changes in islet lipid content may be reversed by activation of AMPK (AMP-activated protein kinase). Infection with an adenovirus encoding the constitutively active nuclear fragment of SREBP1c resulted in expression of the protein in approx. 20% of islet cell nuclei, with a preference for beta-cells at the islet periphery. Real-time PCR (TaqMan) analysis showed that SREBP1c up-regulated the expression of FAS (fatty acid synthase; 6-fold), acetyl-CoA carboxylase-1 (2-fold), as well as peroxisomal-proliferator-activated receptor-gamma (7-fold), uncoupling protein-2 (1.4-fold) and Bcl2 (B-cell lymphocytic-leukaemia proto-oncogene 2; 1.3-fold). By contrast, levels of pre-proinsulin, pancreatic duodenal homeobox-1, glucokinase and GLUT2 (glucose transporter isoform-2) mRNAs were unaltered. SREBP1c-transduced islets displayed a 3-fold increase in triacylglycerol content, decreased glucose oxidation and ATP levels, and a profound inhibition of glucose-, but not depolarisation-, induced insulin secretion. Culture of islets with the AMPK activator 5-amino-4-imidazolecarboxamide riboside decreased the expression of the endogenous SREBP1c and FAS genes, and reversed the effect of over-expressing active SREBP1c on FAS mRNA levels and cellular triacylglycerol content. We conclude that SREBP1c over-expression, even when confined to a subset of beta-cells, leads to defective insulin secretion from islets and may contribute to some forms of Type II diabetes.
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PMID:Over-expression of sterol-regulatory-element-binding protein-1c (SREBP1c) in rat pancreatic islets induces lipogenesis and decreases glucose-stimulated insulin release: modulation by 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR). 1469 Apr 55

Recurrent chromosomal rearrangements involving the 11q23 region have been described in various hematologic malignancies. Among these rearrangements, translocations are the most common mechanism involving the mixed lineage leukemia gene (MLL). Few cases of insertion have been reported and, to our knowledge, none of them involved MLL and chromosome 1. We report a complex karyotype in a childhood acute myelomonocytic leukemia (AML M4) involving the 11q23 region with an insertion between chromosomes 1 and 11 in addition to a translocation between chromosomes 11 and 22. This translocation was clarified by fluorescence in situ hybridization (FISH) analysis: 46,XY,ins(1;11)(q22 approximately q23;q13q23),t(11;22)(q13;q11 approximately q12). This finding also underlines the complementary contribution of conventional cytogenetic and FISH analysis to detect karyotypic complex abnormalities.
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PMID:Chromosomal insertion involving MLL in childhood acute myeloblastic leukemia (M4). 1506 23

The CCAAT/enhancer-binding protein-alpha (CEBPA) is a transcription factor strongly implicated in myelopoiesis through control of proliferation and differentiation of myeloid progenitors. Recently, several works have reported the presence of CEBPA-acquired mutations in hematological malignancies. In this work, we analyzed characteristics of mutations and their correlation with disease characteristics described in previous studies. In the 1175 patients reported, 146 CEBPA mutations were identified in 96 patients. Mutations were found in the whole gene sequence, but cluster regions were clearly identified. Furthermore, two categories of mutations were reported: out-of-frame ins/del often in the N-terminal region, and in-frame ins/del often in the C-terminal region. CEBPA mutations were reported exclusively in acute myeloid leukemia (AML) (according to WHO classification criteria) and mutated patients preferentially belonged to M1, M2 and M4 FAB subtypes. All but one case belonged to the 'intermediate' prognostic subgroup of MRC classification. In the absence of poor prognostic factors, patients with CEBPA mutation had favorable outcome, very similar to that of the t(8;21), inv(16), t(15;17) subgroup. Systematic analysis of CEBPA mutations, in addition to that of alterations in master genes of hematopoiesis, may be useful to assess the prognosis of AML particularly in patients belonging to the 'intermediate' prognostic subgroup.
Leukemia 2005 Mar
PMID:CEBPA point mutations in hematological malignancies. 1567 66

We describe a premature neonate who was born with pancytopenia and a single subcutaneous nodule on her right lower extremity. A biopsy specimen from the nodule demonstrated a dense infiltrate of pleomorphic mononuclear cells that extended throughout the dermis and into the subcutaneous tissue. Immunohistochemical stains and bone marrow examination confirmed a diagnosis of acute myelogenous leukemia. Cytogenetic studies on peripheral blood by G-banding analysis revealed an abnormal karyotype of 46, XX, ins[inv(10)(p11.2q22.2);11](q22.2;q13.2q23.2). A split in the mixed lineage leukemia gene was identified by fluorescence in situ hybridization. Induction chemotherapy was started but was complicated by multiorgan failure. The patient died on the eleventh day of life. As leukemia cutis more typically presents as multiple infiltrative papules, nodules, or plaques, we stress the importance of including leukemia in the differential diagnosis of a solitary nodule in a neonate.
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PMID:Congenital leukemia cutis. 1830 50

The mixed-lineage leukemia 3 (MLL3) gene, which encodes an important component of a histone H3 lysine 4 methyltransferase complex named the ASC-2- and Mll3-containing complex (ASCOM), has been implicated as a tumor suppressor gene due to its frequent mutations in multiple types of human tumors as well as tumor induction upon targeted inactivation of the gene in mice. The role of MLL3 in breast cancer, however, remains unknown. In this study, we sequenced all 59 exons of MLL3 (14.7 Kb coding sequence) in 38 breast cancers from Chinese women, and found three somatic mutations in two of the cases, including one frameshift mutation (c.2687 ins A) that truncates the majority of the MLL3 protein, and two synonymous mutations. In addition to 24 known single nucleotide polymorphisms (SNPs), 5 novel SNPs were also detected in the 38 women; and interestingly, all the 5 novel SNPs alter amino acid sequences of MLL3 thus could have functional consequences. We also examined the expression of MLL3 mRNA in 30 breast tumors and their matched normal breast tissues. While no associations were found between expression change and clinicopathologic parameters, 40% of the samples showed reduced expression in cancer tissues. These results suggest that mutation of MLL3 plays a role in the development of breast cancer.
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PMID:Somatic mutations of the mixed-lineage leukemia 3 (MLL3) gene in primary breast cancers. 2111 61


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