Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Surprisingly few cases of Down's syndrome with acute leukemia have been documented by chromosome banding studies of the leukemia cells. We studied a Down's syndrome child with acute myelomonocytic leukemia and found that, including this case, only 24 cases of Down's syndrome and acute leukemia have been reported with chromosome banding analysis. Twenty-three of the patients had a trisomy 21 chromosome complement, whereas, one had a translocation. The types of acute leukemia included acute myeloblastic leukemia, acute myelomonocytic leukemia, acute monoblastic leukemia, acute lymphoblastic leukemia, and erythroleukemia. Only three cases had chromosomes missing from the leukemic cells. Sixteen of the 24 patients had extra chromosomes in their malignant cells. Chromosomes #8 and #21 were extra in six cases each and chromosomes #19 and #22 were extra in four cases each. Chromosome rearrangements were observed in nine cases. Three of the nine cases had partial deletion of the long arm of chromosome #6. Cases of Down's syndrome with acute leukemia need to be reported with high-resolution chromosome banding of the leukemia cells. There is as yet no clear chromosome clue as to the precise basis of the etiologic association between Down's syndrome and acute leukemia.
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PMID:Chromosome clues to acute leukemia in Down's syndrome. 293 45

Four children with acute leukemia and Down syndrome received high-dose cyclophosphamide therapy and total body irradiation in preparation for bone marrow transplantation. Skin and mucous membrane toxicity was pronounced. Furthermore, three children died during the immediate posttransplantation period of infectious and hemorrhagic pulmonary complications. One patient had hematologic recovery and is surviving disease-free 1 year following transplantation. These preliminary observations are in agreement with previous data suggesting that children with Down syndrome are at higher risk for toxicity, pneumonitis, and, possibly, death following administration of intensive therapy for leukemia in comparison with children without Down syndrome. Improvements in the management of these children in the future will depend upon a better understanding of the biologic and pathophysiologic aspects of Down syndrome and additional clinical experience.
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PMID:Bone marrow transplantation for children with acute leukemia and Down syndrome. 294 56

In some infants with Down's syndrome, the circulating mononuclear population, when viewed with conventional and electron microscopy, contains many cells that closely resemble leukemic blast cells. In contrast with true leukemia, however, most of these infants with the "leukemia-like reaction in Down's syndrome" (LLR-DS) enter spontaneous remissions. We therefore investigated the natural resistance of such infants to hematological malignancy in vitro by means of natural killer cell assays. Mean natural killer cell determinations in four infants with LLR-DS were 17.5 +/- 9.2% and 37.6 +/- 18.5% against K-562 and Molt-4 target cells, respectively, at diagnosis. Later, during remission, these values were 34.3 +/- 14.3% against K-562 and 32.2 +/- 15.6% against Molt-4. The mean percentage lysis of Molt-4 both at diagnosis and during remission was greater (p less than 0.05) in LLR-DS than in children with acute lymphocytic leukemia and acute myelogenous leukemia at diagnosis. Natural killer cell activity levels in these LLR-DS patients were similar to levels obtained in other infants with Down's syndrome who were hematologically normal, as well as levels obtained in normal control specimens. Two of these LLR-DS patients progressively developed acute myelogenous leukemia with ultrastructural abnormalities several months later; one of these also developed another karyotype abnormality. Both remain in long-term remission exceeding 48 months.
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PMID:Natural killer cell activity and ultrastructure in myeloproliferative reactions in infants with Down's syndrome. 294 95

Nine cases of early erythroblastic leukemia, unidentified by usual criteria, have been diagnosed using a panel of antibodies. Three cases arose in patients with Down's syndrome, one in a patient with therapy-related leukemia, and four patients were in blast crisis of chronic myeloid leukemia; only one case arose de novo. Blast cells could be assigned to two main stages of erythroid differentiation: presence of all erythroid-specific proteins in two patients, a phenotype corresponding to an immature erythroblast; absence of the erythroid markers such as glycophorin A and spectrin in the presence of carbonic anhydrase isoenzyme I, ABH group antigens, and the antigen defined by FA6 152 monoclonal antibody in six patients, a phenotype related to a late erythroid progenitor (CFU-E). One patient had an intermediate phenotype. All patients except one demonstrated a megakaryocytic component. In three patients, chromosomal abnormalities were present, detected both in blasts and in erythroid colonies. In conclusion, these findings indicate that most "cryptic erythroleukemias" are blocked at a "CFU-E-like" stage of differentiation, it may be a frequent event in Down's syndrome and chronic myeloid leukemia, and these erythroleukemias are phenotypically heterogeneous.
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PMID:Phenotype of early erythroblastic leukemias. 294 4

The many hematological abnormalities observed in patients with Down's syndrome have intrigued hematologists for many years. This review summarizes recent studies concerning the hematological findings in newborn infants with Down's syndrome, the transient leukemoid/leukemia-like proliferative disorders in these infants, the increased incidence of leukemia and types of leukemia in patients with Down's syndrome, and immunological studies of these patients. In addition, studies concerning the significance of the extra genetic material in chromosome 21 found in patients with Down's syndrome are discussed. It appears that the extra genetic material in chromosome 21 confers a proliferative advantage to hematopoietic stem cells, and may make them more prone to further karyotypic changes leading to leukemia. Megakaryocytic proliferative disorders are more common in patients with Down's syndrome. The spectrum of myeloproliferative disorders including myelofibrosis, myeloid metaplasia, and megakaryoblastic leukemia is seen in these patients. Studies of the genetic loci on chromosome 21 have demonstrated loci for enzymes involved in purine biosyntheses. Further studies of specific loci on chromosome 21 may help explain the hematopoietic growth advantages found in the stem cells with an extra chromosome 21.
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PMID:Hematological changes in Down's syndrome. 294 91

We used a micromethod for cytogenetic analysis from single haematopoietic colonies to study two adults with chronic myelomonocytic leukaemia (CMML) and a boy with juvenile chronic myeloid leukaemia (JCML) carrying distinct chromosome abnormalities, 7q-, der(21), and trisomy 21. We wanted to know if both granulocyte-macrophage (GM) and erythroid precursors are involved in the abnormal clone. In all three patients, their chromosome abnormality was seen in almost all metaphases obtained from GM-colonies and erythroid bursts. Peripheral blood leucocytes stimulated with phytohaemagglutinin exhibited only normal karyotypes. Clones of B-cell produced by Epstein-Barr virus had only normal karyotypes in the CMML patients. These findings indicate that CMML and JCML are clonal haemopathies that originate in a partially committed myeloid progenitor cell.
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PMID:Cytogenetic evidence for partially committed myeloid progenitor cell origin of chronic myelomonocytic leukaemia and juvenile chronic myeloid leukaemia: both granulocyte-macrophage precursors and erythroid precursors carry identical marker chromosome. 294 9

The phenotype and in vitro growth properties of blood and marrow blast cells detected in two neonates with Down's syndrome and a transient leukaemic picture are presented. In both patients, blast cells at diagnosis were heterogeneous and expressed predominantly megakaryocyte and erythroid markers identified by membrane fluorescence using monoclonal antibodies or ultrastructural detection of platelet peroxidase and ferritin. An additional trisomy involving chromosome 22 was detected in blast cells from one patient. Blood and marrow cells colony-assays performed at diagnosis revealed precursors with an abnormal differentiation capacity similar to those found in acute myelogenous leukaemia colony assays. However, an unusual feature was the persistence of high numbers of precursor cells (namely erythroid) following a normal differentiation pathway. Phenotypically and cytogenetically abnormal cells spontaneously disappeared by week 4-6, but overt relapse occurred in one patient 20 months later. These results bring strong arguments in favour of the neoplastic nature of the transient leukaemic picture observed in some neonates with Down's syndrome. Furthermore, we suggest that this disorder can be individualized as a separate entity with specific phenotypic and biological properties.
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PMID:Characterization of the blast cell population in two neonates with Down's syndrome and transient myeloproliferative disorder. 295 79

The c-sis gene expression in leukemia cells from a patient with acute megakaryoblastic leukemia and Down's syndrome was studied. The leukemia blasts were identified as megakaryoblasts by the platelet peroxidase reaction and the reactivity against antiplatelet monoclonal antibodies. Leukemia cells obtained from peripheral blood or bone marrow specimens before and after initiation of chemotherapy were analyzed for c-sis gene expression by the RNA-DNA dot blot hybridization. Although the level varied, the mRNA of the c-sis gene was detected in all megakaryoblastic leukemia cells obtained at different clinical stages. The c-sis mRNA level in cells obtained after relapse was higher than that obtained before the initiation of therapy. The 25S c-sis mRNA was detected in a megakaryoblastic leukemia cell line established from this patient. The role of the expression of the c-sis gene in acute megakaryoblastic leukemia cells is discussed.
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PMID:The c-sis gene expression in cells from a patient with acute megakaryoblastic leukemia and Down's syndrome. 295 17

The association of Down's syndrome and leukemia has been documented for over 50 years. Multiple studies have established the incidence of leukemia in Down's syndrome patients to be 10- to 20-fold higher than that in the general population. The age of onset for leukemia in these children is bimodal, peaking first in the newborn period and again at 3-6 years. This increased risk extends into adulthood. All cytogenetic types of Down's syndrome apparently predispose to leukemia. The proportion of acute lymphoblastic leukemia and acute nonlymphoblastic leukemia in patients with Down's syndrome is similar to non-Down's syndrome leukemia patients matched for age. There are case reports in which leukemia, Down's syndrome, and other chromosomal aberrations cluster within a family. In these kindreds, there may be a familial tendency toward nondisjunction. Congenital leukemia also occurs with increased frequency in Down's syndrome patients, and is characterized by a preponderance of acute nonlymphoblastic leukemia (similar to non-Down's syndrome patients). Transient leukemoid reactions have been observed in Down's syndrome patients, as well as in phenotypically normal children with constitutional trisomy 21 mosaicism. The transient leukemoid reactions are characterized by a high spontaneous remission rate. However, in some Downs syndrome patients with apparent transient leukemoid reaction, leukemia relapse following periods of spontaneous remission have been reported. Cytogenetic studies of leukemic cells in Down's syndrome patients show a tendency toward hyperdiploidy. Besides trisomy 21, there is no other specific cytogenetic abnormality that is characteristic of the leukemia cells in Down's syndrome patients. The possible mechanisms for leukemogenesis in Down's syndrome patients may involve factors at the levels of the organism, the organ/system, the cell, the chromosomes or the DNA.
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PMID:Down's syndrome and leukemia: epidemiology, genetics, cytogenetics and mechanisms of leukemogenesis. 295 86

Twenty-four patients with Down syndrome and leukemia were studied. A strong male predominance (79%) was found. Age ranged between 18 months and 15 years (mean: 5 6/12); 54% of the patients were less than 4 years of age at the time of diagnosis. A preleukemic phase was noted in 6/24 patients. This phase, characterized essentially by thrombocytopenia, lasted from 2-8 months. Patients with preleukemia had unusual blast cell morphology and involvement of more than one cell line (dyserythropoiesis, hypolobulated megakaryocytes) and were probably M7 leukemias. All patients demonstrated severe methotrexate toxicity at standard methotrexate doses. Toxicity, manifesting as mouth ulcerations and bone marrow depression was seen regardless of the route of administration (oral, intrathecal or intravenous). A 30%-50% reduction of the standard dose was tolerated. Methotrexate absorption and clearance were studied in two patients and were found to be normal. We postulate that the observed toxicity of methotrexate may be due to a gene dosage effect for enzymes known to be on chromosome 21 and intervening in purine metabolism. Increased purine synthesis implies greater tetrahydrofolic acid demands and therefore greater sensitivity to an antifolate agent.
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PMID:Down syndrome and leukemia: unusual clinical aspects and unexpected methotrexate sensitivity. 295 83


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