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

Acute megakaryoblastic leukemia (FABM7) is an unusual but well recognized form of acute myelogenous leukemia in which the bone marrow blast cells are phenotypically recognized by the demonstration of cytoplasmic platelet peroxidase or surface staining for the IIb/IIIa platelet-specific glycoprotein. Herein, the authors report a case of acute megakaryoblastic leukemia that satisfies the accepted French-American-British criteria and in which the blast cells also exhibit evidence of myeloid differentiation, including surface MY7 (CD13) by flow cytometry and immunocytochemical positivity for myeloperoxidase. These findings suggest that megakaryoblasts may be closely related to myelomonoblasts, that they have the potential to partially differentiate along multiple phenotypic lines, and that aberrant phenotypes can occur that do not correspond to known stages of normal maturation. The authors illustrate the difficulty in classification of these aberrant phenotypes by standard cytochemical and morphologic criteria.
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PMID:Myeloperoxidase-positive acute megakaryoblastic leukemia. 254 7

The expression of the myeloperoxidase (MPO) gene was studied, by means of Northern blot analysis in 14 cases of acute myeloid leukemia (AML), 11 cases of chronic myeloid leukemia (CML), and 6 cases of CML blast crisis, and in HL60 cells before and after induction of terminal differentiation with retinoic acid (RA), phorbol esters (TPA), or vitamin D. The expression of a panel of cell cycle-related genes, namely C-MYC, histone H3, ornithine decarboxylase, P53, vimentin, and calcyclin, was also studied in the same cell populations. Our results indicate that: (a) MPO gene expression (steady state mRNA levels) is strictly confined to the first stages of myeloid differentiation, reaching its peak at the promyelocyte stage and becoming undetectable in mature granulocytes and monocytes; (b) cells devoid of any detectable MPO enzymatic activity such as leukemic basophils have a high content of MPO mRNA; and (c) MPO gene expression is not related to the growth activity of the cell population. Finally, our results show that the pattern of expression of growth-regulated genes in the neoplastic myeloid disorders AML, CML, and CML blast crisis is remarkably different.
Leukemia 1989 Jun
PMID:Expression of the myeloperoxidase gene in acute and chronic myeloid leukemias: relationship to the expression of cell cycle-related genes. 254

Nine cases of acute leukemia presenting unusual phenotype were studied by light microscopy (LM) cytochemistry and transmission electron microscopy (TEM) immunocytochemistry with the immunogold staining (IGS) method; in addition, cytogenetic and molecular analyses were performed. The presence of myeloperoxidase (MPO) was studied at TEM in combination with immunophenotype to identify minor populations not characterizable at LM. Four of nine cases had no TEM/MPO reactivity, whereas the remaining five showed variable percentages of positive cells. Of the MPO negative cases, one was a megakaryoblastic leukemia with a positive platelet peroxidase (PPO) reaction, and three were lymphoid. Among the peroxidase positive cases, the percentage of MPO reactive cells was higher at TEM than at LM examination. In case 5 TEM analysis indicated that cells with some MPO reactivity at LM were non neoplastic myeloid cells. With this combined technique in cases 1 and 2 we excluded the presence of the MPO enzyme in CD15 positive lymphoid cells and, in another case, we documented the existence of CD19/MPO positive cells. The value of cytochemistry and immunology at the ultrastructural level for the characterization of blast cells and for the precise diagnosis of leukemia with "unusual" phenotype is illustrated.
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PMID:Relevance of ultrastructural immunocytochemistry in the characterization of unclassifiable leukemias: correlation with phenotypic and genic studies. 254 74

We reported a 68-year-old woman with acute nonlymphocytic leukemia, in whom the leukemia transformed from poorly differentiated myeloperoxidase (MPO)-negative type into myelomonocytic type during the observation without chemotherapy. Hematological findings on admission revealed a leukocyte count of 3,500/microliters with 48% blasts and a platelet count of 9.2 x 10(4)/microliters. Bone marrow aspiration showed 68.2% infiltration of blasts negative for MPO. Sudan black B and esterase stains. By electron microscopy MPO was detected in the endoplasmic reticulum and nucleoenvelope of the blasts. Large vacuole-like granules were MPO-negative. She was observed without administration of any antileukemic agent or an immunopotentiator. The leukocyte count rose gradually, in association with increases in the relative and absolute counts of mature neutrophils and monocytic cells, and the platelet count. Twenty-six months after the initial diagnosis, a blood examination showed a leukocyte count of 74,300/microliters with 20.5% mature neutrophils and 15.5% monocytic and a platelet count of 31.4 x 10(4)/microliters. Cytological, cytochemical, ultrastructural and immunological studies of the bone marrow cells showed features compatible with acute myelomonocytic leukemia (FAB M4). This case is unusual in respect that poorly differentiated ANLL transformed spontaneously into moderately differentiated ANLL.
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PMID:[Spontaneous differentiation from myeloperoxidase-negative acute nonlymphocytic leukemia to acute myelomonocytic leukemia]. 255 92

Since myeloperoxidase (MPO) is considered to be a critical marker of differentiating acute myelogenous leukemia (AML) from acute lymphocytic leukemia (ALL), the analysis of MPO gene expression may provide further insight into the leukemia classification and the lineage fidelity of leukemia cells. By Northern blot hybridization using full-length MPO cDNA as a probe, approximately 66% of AML cells (3/4 M1 cases, 2/4 M2 cases, 15/15 M3 cases, 11/15 M4 cases, and 2/12 M5 cases) were found to express MPO mRNAs, whereas none of 18 ALL cases did. MPO mRNA was detectable when AML cells contained at least 10% peroxidase-positive cells. APL (M3) cells expressed high levels of mRNA in accordance with heavy staining for peroxidase.
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PMID:Myeloperoxidase gene expression in acute leukemias. 256 Aug 87

Mo5 is a 94-kd protein antigen expressed by human peripheral blood monocytes, neutrophils, and by all bone marrow myeloperoxidase-positive myeloid precursors (promyelocytes, myelocytes, metamyelocytes, and bands). Mo5 is borne by the malignant cells of 74% of patients (N = 27) with acute monocytic leukemia (French-American-British [FAB] group M4, M5), and 50% of patients (N = 38) with acute granulocytic leukemia (FAB M1, M2, and M3). Nonmyeloid cells in peripheral blood and bone marrow are Mo5-negative. The surface expression of Mo5 by myeloid cells is modulated by several experimental conditions: Exposure of neutrophils to calcium ionophore (1 mumol/L, 37 degrees C, ten minutes) under conditions resulting in degranulation of specific granules produces a three- to fourfold increase in the plasma membrane density of Mo5 antigen. This suggests that, in neutrophils, there is an intracellular pool of Mo5 antigen, which may be associated with specific granules, and that granule-associated Mo5 is translocated to the plasma membrane upon degranulation. Conversely, incubation of monocytes, neutrophils, U-937, and Mo5-positive leukemia cells in medium containing anti-Mo5 monoclonal antibody results in a significant decrease in surface Mo5 expression. This loss of surface Mo5 is a rapid, temperature-dependent process (occurring within 30 minutes at 37 degrees C) that is produced by divalent anti-Mo5 immunoglobulin [F(ab')2 but not F(ab)]. After down-modulation, Mo5 is reexpressed by monocytes within 48 hours. Mo5 is therefore a human myelomonocytic differentiation antigen whose expression is modulated up or down depending on the nature of extracellular stimuli.
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PMID:The modulated expression of Mo5, a human myelomonocytic plasma membrane antigen. 257 92

We report a case of acute myelofibrosis (AMF) developing into acute myelomegakaryoblastic leukemia. A 33-year-old woman was admitted to our hospital because of fever and chest pain. On physical examination, hepatosplenomegaly was not noticed. Pancytopenia and a small number of blast cells were observed in the peripheral blood. Poikilocytosis was not detected. Bone marrow examination revealed dry tap on aspiration, and moderate increase in reticulin fiber on biopsy. The diagnosis of AMF was made. Eight months later, blast cells markedly increased. Surface marker was investigated and MCS-2 (CD13), C17 (CDw41) and P2 (CDw41) were found to be positive. Electron microscopic examination revealed that blast cells were composed of PPO-positive cells and MPO-positive cells. Based on these findings, it was considered that the patient developed acute myelomegakaryoblastic leukemia. Recently AMF is thought to be a state to have the ability to develop into various types of acute leukemia. Adequate therapy may be required before the development of leukemia.
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PMID:[Acute myelofibrosis terminating in acute myelomegakaryoblastic leukemia]. 259 46

Ninety-four consecutive patients with acute leukaemia were analysed using cytochemical stains and, in selected individuals, a panel of monoclonal antibodies combined with measurement of the enzyme terminal deoxynucleotidyl transferase. These results were correlated with the French-American-British morphological classification. Acute non-lymphoblastic leukaemia was diagnosed in 55 individuals on the basis of morphology and cytochemical criteria; 6 of this group were further studied with antibodies directed against specific myelomonocytic antigens, but no further clinically useful information was obtained. Blasts from 36 patients did not stain with either Sudan black or myeloperoxidase. These individuals were considered to have acute lymphoblastic leukaemia (ALL) and were further assessed with monoclonal antibodies directed against epitopes expressed on cells of lymphoid lineage; 10 were classified as arising from T precursors; 23 were of B lineage, of which 13 marked as common, 6 as null, 1 as pre-B, 2 as B-ALL and 1 to have a pattern characteristic of lymphoblastic lymphoma. Two cases could not be classified and 1 was found to have megakaryoblastic features. In a further 3 patients who had undergone lymphoblastic transformation as a terminal event in the course of chronic granulocytic leukaemia, 2 were immunophenotypically common and 1 was marked as a null cell. This study confirms the value of monoclonal antibodies for accurately assigning lineage to the acute leukaemias and particularly in those situations where conventional morphological criteria and cytochemical markers are inconclusive.
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PMID:Immunophenotyping in the diagnosis and classification of acute leukaemia. 259 3

A 21-year-old man was admitted to our hospital because of anorexia and general malaise in July, 1988. On admission, the white blood cell count of 18,600/microliters with 72% leukemic cells. The bone marrow aspirate showed 76.8% immature monocytes, 10% mature and immature eosinophils. Leukemic cells were 66.6% myeloperoxidase positive cells, and 20.6% naphthylbutyrate esterase positive cells. The lysozyme activity in urine was high. Cytogenetic analysis revealed the presence of 46 XY inv (16) (p13 q22). Under the diagnosis of acute myelomonocytic leukemia with eosinophilia (M4Eo) associated with inv (16) (p13 q22), one course of DCMP induction therapy was performed. After complete remission, the bone marrow aspirate showed disappearance of inv (16) (p13 q22), and associated with decreased residual leukemic cells.
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PMID:[Acute myelomonocytic leukemia with inv (16) (p13 q22) disappeared abnormal karyotype during complete remission]. 262

We have studied the immunophenotypic and genotypic features in 35 infants aged less than 1 year with acute lymphoblastic leukemia (ALL) or acute undifferentiated leukemia (AUL). A CD10 (common ALL antigen)-negative, CD19-positive pre-pre-B ALL phenotype was observed in 24 infants. Seventeen of them had blast cells coexpressing myeloid-associated markers such as CD15A (VIM-D5, MZ17) and/or VIM-2, but neither myeloperoxidase nor platelet peroxidase was detected in five of these cases analyzed by electron microscopy. Five patients showed a typical common ALL, five a pre-B ALL phenotype, and one infant was unclassifiable by surface-marker and morphologic analysis. Cytogenetic data, available in 21 of these patients, revealed chromosomal abnormalities involving 11q23 in 10 infants with a CD10-negative pre-pre-B ALL. Immunoglobulin (Ig) and T cell receptor (TCR) gamma, beta and delta gene analysis of 31 infants showed Ig heavy-chain gene rearrangement in all but one patient with evidence for clonal evolution in six and kappa-light-chain rearrangement in three infants. TCR beta-chain and TCR gamma-chain rearrangement occurred in six and five patients respectively, while TCR delta-chain rearrangement was identified in 15 patients. Our data indicate that ALL in infancy may present with heterogeneous immunophenotypic and genotypic features. The high frequency of coexpression of B-lineage and myeloid surface markers as well as of chromosomal rearrangement involving 11q23 suggests that the clonogenic cell of infant ALL may relate to a multipotent progenitor cell in most cases.
Leukemia 1989 Jun
PMID:Phenotypic and genotypic heterogeneity in infant acute leukemia. I. Acute lymphoblastic leukemia. 272 59


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