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)

Clinical, cytomorphologic, and cytogenetic investigations were carried out in a series of 76 secondary MDS and ANLL. Chromosome abnormalities were more frequent in patients with a history of multiple myeloma or macroglobulinemia (92%) and myeloproliferative disorders (82%) than in patients with previous breast cancer (40%). The secondary hematologic malignancies were mostly a trilineage bone marrow disorder. The most commonly found cytogenetic anomaly was monosomy 7, followed by total or partial loss of chromosome 5. In addition six other chromosomes, i.e., chromosome 3, 8, 9, 12, 17, and 21 seemed to be consistently involved in the pathogenetic mechanisms of secondary leukemia and MDS.
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PMID:Cytogenetic and clinical investigations in 76 cases with therapy-related leukemia and myelodysplastic syndrome. 259 67

Myelodysplastic and myeloproliferative disorders are rare in childhood and there is no widely accepted system for their diagnosis and classification. We propose minimal diagnostic criteria and a simple classification scheme which, while based on accepted morphological features and conforming with the recent suggestions of the WHO, allows for the special problems of myelodysplastic diseases in children. The classification recognizes three major diagnostic groups: (1) juvenile myelomonocytic leukemia (JMML), previously named chronic myelomonocytic leukemia (CMML) or juvenile chronic myeloid leukemia (JCML); (2) myeloid leukemia of Down syndrome, a disease with distinct clinical and biological features, encompassing both MDS and AML occurring in Down syndrome; and (3) MDS occurring both de novo and as a complication of previous therapy or pre-existing bone marrow disorder (secondary MDS). The main subtypes of MDS are refractory cytopenia (RC) and refractory anemia with excess of blasts (RAEB). It is suggested retaining the subtype of RAEB-T with 20-30% blasts in the marrow until more data are available. Cytogenetics and serial assessments of the patients are essential adjuncts to morphology both in diagnosis and classification.
Leukemia 2003 Feb
PMID:A pediatric approach to the WHO classification of myelodysplastic and myeloproliferative diseases. 1452 56

The immunophenotyping of leukaemia and non-Hodgkin's lymphoma cells is based on staining the cells with monoclonal antibodies against surface and cytoplasmic determinants followed with flow cytometry analysis. The problems of immuno-phenotyping are associated with technical difficulties, changes in expression of determinants and the rare types of leukaemia and haematological disorders typical for newborns and infants. The lack of blast cells within cell suspension obtained for test may be the result of bone marrow disorder (aplastic anaemia, preleukaemic cytopenia) or technical pitfall. The changed expression of determinants on blastic cells observed as weak expression or overexpression or atypical combination of determinants requires a careful interpretation. In the diagnosis of rare types of acute leukaemia (e.g. erythroleukaemia, megakaryoblastic leukaemia, mixed lineage or undifferentiated leukaemia) the additional monoclonal antibodies beyond routine set are needed. A special concern is necessary in diagnosis of newborns and infants leukaemia or bone marrow disorders like myelodisplastic syndrome particularly in children with other systemic diseases e.g. congenital immunological deficiencies, Down's syndrome. The problems of immunophenotyping in non-Hodgkin's lymphoma are frequently associated with obtaining a representative material e.g. surgical tumour biopsy, lymph node. In some case the differential diagnosis including small round cell tumours and anaplastic type of lymphoma is necessary what requires an additional set of monoclonal antibodies. Despite of modern technology, morphology, immunophenotyping and histopathology remain the standard of complex diagnosis of lymphoproliferative diseases and haematopoietic disorders in children.
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PMID:[The problems of immunological diagnosis of childhood acute leukemia and non-Hodgkin's lymphoma]. 1457

We report the rare case of a patient with leukaemia cutis first presenting only on the hand and fingers and then subsequently spreading over the trunk and face. The lesions heralded the transformation of a previously undiagnosed myelodysplastic syndrome type RAEB (refractory anaemia with blast excess) into frank myeloid leukaemia. The haematological disease was first detected by the dermatohistopathologist. This case underlines the need to look meticulously for skin changes and perform early skin biopsies in haematological patients, as the skin can reveal the first clinical signs of an otherwise not evident bone marrow disorder. Leukaemia cutis as the initial clinical presentation of a transforming myelodysplastic syndrome type RAEB into acute myeloid leukaemia has been reported only very rarely.
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PMID:Cutaneous leukaemic infiltrations in a patient with previously undiagnosed myelodysplastic syndrome. 1534 25

Myelodysplastic syndrome (MDS) is an acquired bone marrow disorder characterized by ineffective hematopoiesis and cellular dysfunction and has an increased risk of transforming into acute myeloid leukemia. Most patients are of advanced age with attendant comorbidities, making treatment difficult. Current treatment options have included supportive care and, in difficult cases, chemotherapy regimens designed for acute leukemia patients. A major effort has been made to determine the role of stem cell transplantation in adult MDS patients, currently the only curative option available for them. Based on relapse rates, studies indicate that allogeneic and autologous transplants provide better antileukemic activity than intensive chemotherapy schedules. Use of DNA methyltransferase inhibitors may assist in managing MDS patients while awaiting a transplant match, but the procedural mortality for transplant remains high. Reduced conditioning or nonmyeloablative conditioning, particularly in the elderly, has been attempted with some success. Reduced conditioning also increases the graft-versus-leukemia effect, allowing for a higher percentage of disease-free survival. Current use of peripheral blood as a source of stem cells for autotransplant is associated with an extremely low procedural mortality. Improvement in such transplant procedures as myeloablation, preparation of the autograft, and posttransplant prophylaxis are improving recovery rates for these patients. In addition, as the biology of this disease is being revealed, newer options will become available in the near future.
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PMID:Transplant strategies for myelodysplastic syndrome. 1549 94

Methylation of DNA at 5-position of cytosine, catalyzed by DNA methyltransferases, is the predominant epigenetic modification in mammals. Aberrations in methylation play a causal role in a variety of diseases, including cancer. Recent studies have established that like mutation, methylation-mediated gene silencing often leads to tumorigenesis. Paradoxically, genome-wide DNA hypomethylation may also play a causal role in carcinogenesis by inducing chromosomal instability and spurious gene expression. Since methylation does not alter DNA base sequence, much attention has been focused recently on developing small molecule inhibitors of DNA methyltransferases that can potentially be used as anticancer agents. Vidaza (5-azacytidine), marketed by Pharmion (Boulder, CO, USA), was the first DNA methyltransferase inhibitor approved by the U.S. Food and Drug Administration (FDA) for chemotherapy against myelodysplastic syndrome (MDS), a heterogeneous bone marrow disorder. Recently MGI Pharma Inc. (Bloomington, MN, USA) got FDA approval to market Dacogen (5-aza-2'-deoxycytidine, or decitabine) for treating MDS patients. These drugs were used earlier against certain anemias to induce expression of fetal globin genes. Interest in clinical trials of these drugs as anticancer agents has been renewed only recently because of reversal of methylation-mediated silencing of critical genes in cancer. Clinical trials have shown that both drugs have therapeutic potential against leukemia such as MDS, acute myeloid leukemia, chronic myelogenous leukemia and chronic myelomonocytic leukemia. In contrast, their effectiveness with solid tumors appears to be less promising, which challenges researchers to develop inhibitors with more efficacy and less toxicity. The major hindrance of their usage as anticancer agents is their instability in vivo as well as the toxicity secondary to their excessive incorporation into DNA, which causes cell cycle arrest. Gene expression profiling in cancer cells revealed that antineoplastic property of these drugs is mediated through both methylation-dependent and -independent pathways. Recently, we have shown that treatment of cancer cells with these cytidine analogues also induces proteasomal degradation of DNA methyltransferase 1, the ubiquitously expressed enzyme upregulated in almost all cancer cells. Development of related stable drugs that can facilitate gene activation in cancer cells by enhancing degradation of DNA methyltransferases without being incorporated into DNA would be ideal for chemotherapy. In this monograph we review historical perspective and recent advances on the molecular mechanisms of action and clinical applications of these DNA hypomethylating agents.
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PMID:DNA methyltransferases as targets for cancer therapy. 1761 10

The bone marrow is the major site of haemopoiesis in adult human. It contains cells that represent the stages in the development of different types of blood cells e.g. myelocytes, metamyelocytes, erythroblasts, reticulocytes, and other lymphoid progenies etc. Bone marrow failure is primarily the result of a specific failure of bone marrow precursor cells to produce mature cells. N-ethyl N-nitroso urea (ENU) is one of the most potent mutagens that can create an abnormal bone marrow microenvironment by causing defect in haematopoietic stem cell maturation cascade. ENU is easy to administer in mouse, and some probable mutations can be helpful to create models of human diseased conditions like Myelodysplastic syndrome (MDS). MDS is considered as an intravascular bone marrow disorder, a combined structural-functional abnormality wherein the differentiation procedure of the bone marrow stem cell is either incomplete or defective. We assumed that Myelodysplastic syndrome stands in between an inhibitory cellular pattern and a positive overshoot of abnormal differentiations representing an unknown juncture where the mystery of aplasia and leukemia hide back. Instead of using a transgenic mouse model, we attempted to develop an experimentally induced murine model of preleukemia or human MDS like disease model. In doing so ENU has been administered i.p and the animals were examined on thirtieth day and peripheral blood haemogram was documented. Upon registering the appearance of abnormal peripheral blood scenario, the changes in the intravascular bone marrow (BM) architecture, cell surface receptor expression, e.g. Sca-1, c-Kit and the early and late phase apoptic patterns were noted. The results represented an interesting correlation in between bone marrow architecture, early stem cell receptor and apoptic marker expression resembling human MDS.
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PMID:Sca-1 / c-Kit receptor expression and apoptosis pattern in ENU induced MDS mice. 2072 May 96