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

Very limited data exists in Thailand regarding the frequency of BCR-ABL leukemic gene and its prognostic implication in Thai CML patients. The objective of this study was to develop a rapid molecular assay for the detection of the two most commonly reported variants of BCR-ABL fusion gene, B2A2 and B3A2 in CML patients. Bone marrow or peripheral blood were used for RNA extraction and reverse-transcribed to cDNA for PCR amplification. 92 per cent of CML patients (91/99) were positive for BCR-ABL gene (61% B3A2 and 31% B2A2). 8/99 CML patients were BCR-ABL-negative. B3A2 and B2A2-positive patients did not have any different clinical and hematological features at presentation although B3A2 patients tended to be slightly older and had higher platelet counts. 71/71 non-CML including other MPD and leukemia cases were all negative for BCR-ABL gene. In conclusion, a rapid RT-PCR assay has now been developed for the detection of this hallmark gene in CML patients. It should be of great value in the differential diagnosis of CML from other diseases. Long-term follow-ups of CML patients with different variants are needed to determine the prognostic importance of each gene variant.
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PMID:Detection of molecular variants of BCR-ABL gene in bone marrow and blood of patients with chronic myeloid leukemia by reverse-transcriptase polymerase chain reaction (RT-PCR). 1099 48

Of the myeloproliferative/myelodysplastic disorders (MPD/MDS) that occur in childhood most, regarding the cytogenetic and molecular genetic basis, is known about the two purely paediatric disorders: juvenile myelomonocytic leukaemia (JMML) and transient myeloproliferative disorder (TMD). Although much has been published about these two disorders, their aetiology is by no means fully established. It would appear, however, that in this paediatric subset of MPDs a stage/developmentally specific vulnerability for proliferation and transformation exists. The study of the molecular basis of many other MPD-like syndromes that also occur in childhood, has been greatly accelerated by the identification of rare, but recurring, cytogenetic abnormalities involving 8p11 and 5q31-33. Good collaborative studies could result in similar progress being made in the understanding of JMML and TMD.
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PMID:Cytogenetic and molecular genetic aspects of childhood myeloproliferative/myelodysplastic disorders. 1243 14

Pluripotent hematopoietic stem cells have been defined as cells with extensive self-renewal capacity and lympho-hematopoietic differentiation potential. Clonal selection of a stem cell as a first step in the progression to neoplasia can be achieved by an alteration of this self-renewal potency. Our current understanding of the pathogenesis of the myeloproliferative disorders including acute myeloid leukemias, chronic myeloproliferative disorders (CMPD) and myelodysplastic syndromes (MDS), is based on the assumption that they represent a clonal disorder resulting from transformation of a hematopoietic stem cell. However, when performing methods for determining X-chromosome inactivation in female patients as a clonality marker, a significant minority of the patients with Philadelphia chromosome negative (Ph(-)) CMPD and MDS exhibit polyclonal proliferation. The implications of these results are not yet clarified and the lack of a proven target cell impairs the understanding of the underlying molecular defect. In this context, altered response to cytokine stimulation in vitro provides indirect information concerning molecular dysregulation. A subset of patients with MPD present with translocations that facilitate molecular investigation and clonality proof. They nearly always result in rearrangements of at least one transcription factor gene. Most of these fusion genes are constitutively active, sending out continuous proliferative and antiapoptotic signals or activate an overlapping set of signalling pathways. The classical example for a balanced translocation is the t(9;22) bcr-abl aberration in chronic myelogeneous leukemia. Many other karyotypic abnormalities have also been associated with CMPD and MDS and involve deletions of chromosomes 20q, 13q, 1q, 7q and 5q as well as trisomy of 8 and 9. Our increased understanding of the hematopoietic stem cell compartment and the molecular basis of regulation of its self-renewal and differentiation bears a direct impact on our understanding of leukemia evolution and progression.
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PMID:[Hematopoietic stem cells and hematopoietic neoplasias]. 1243 99

Chronic myelogenous leukemia (CML) is a biphasic neoplasm of the bone marrow that is precipitated by the Philadelphia chromosome, a t(9;22) balanced translocation that encodes a constitutively activated nonreceptor tyrosine kinase termed P210(BCR-ABL). This oncoprotein has several intracellular functions; however, the most important effect of P210(BCR-ABL) leading to cell transformation is phosphorylation of signaling molecules through a constitutively active tyrosine kinase domain. Despite extensive knowledge of the structure and functional domains of BCR-ABL, its precise function in transformation is not known. Progress has been hampered, in part, by the lack of relevant CML models, as cell culture and in vitro assays do not mimic the pathogenesis of CML. Recently, there has been significant progress toward improving murine models that closely resemble human CML. This has allowed researchers to evaluate critical functions of BCR-ABL and has provided a model to test the efficacy of therapeutic medications that block these pathways. Our laboratory has developed two intersecting research programs to better understand the functioning of P210(BCR-ABL) in leukemogenesis. In one approach, we have developed a murine CML model by transferring HSCs that express BCR-ABL from a retroviral vector. All recipients develop a rapidly fatal MPD that shares several important features with CML. This model has been extremely useful for studying the function of BCR-ABL in the pathogenesis of CML. A second approach utilizes a quantitative cell detachment apparatus capable of measuring small changes in cell adhesion to investigate the mechanism by which P210(BCR-ABL) causes abnormal cell binding. Altered cell adhesion may contribute to the imbalance between proliferation and self-renewal in the hematopoietic progenitor compartment. To better understand the role abnormal adhesion may play in the development of leukemia, we have attempted to correlate the effects of functional P210(BCR-ABL) mutants in regulating adhesion and oncogenicity.
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PMID:The biology of chronic myelogenous leukemia:mouse models and cell adhesion. 1247 8

The incidence of chronic MPD and MDS could be reduced considerably if relevant environmental factors could be identified and eliminated, but this seems an unlikely prospect for the foreseeable future. More probable is the likelihood that the molecular basis of the various chronic MPD gradually will be elucidated such that specific inhibitory molecules analogous to imatinib may be designed for each disease or each subtype of disease. Combinations of inhibitory molecules may prove especially useful. There is ample scope for improving the clinical results of allogeneic stem cell transplantation, which in theory could "cure" most patients with MPD or MDS. In this regard, reduced-intensity conditioning allogeneic stem cell transplants seem promising. One possibility is identification and exploitation of the basic mechanism underlying the graft-versus-leukemia effect for eradication of minimal residual disease without the need for allografting.
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PMID:Myeloproliferative and myelodysplastic syndromes: the future. 1456 Jul 86

Overexpression of SGTP and/or MT may contribute to various carcinogenic processes and to resistance to anticancer treatment. The importance of these proteins, although clearly established in solid tumours, has not been fully understood in haematopoietic neoplasm. The aim of this study was to determine the expression of MT and SGTP in the bone marrow of patients with MPD. Twenty paraffin-embedded bone marrow core biopsy specimens from newly diagnosed patients with MPD were evaluated -- osteomyelofibrosis (OMF), n = 9 and chronic myelocytic leukaemia (CML), n = 11. We demonstrate increased SGTP and MT expression in the bone marrow of MPD patients. In our study levels of MT in OMF patients were higher than in CML. This suggests that MT expression may correlate with bone marrow fibrosis. These data, although based on a relatively small number of patients, raise the possibility that SGTP and MT may play a role in the pathogenesis of MPD. The clinical significance of this phenomenon needs further investigation.
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PMID:Expression of metallothionein (MT) and gluthatione s-transferase pi (SGTP) in the bone marrow of patients with myeloproliferative disorders (MPD). 1503 19

The FIP1L1-PDGFRA fusion gene has been described in patients with eosinophilia-associated myeloproliferative disorders (Eos-MPD). Here, we report on seven FIP1L1-PDGFRA-positive patients who presented with acute myeloid leukemia (AML, n=5) or lymphoblastic T-cell non-Hodgkin-lymphoma (n=2) in conjunction with AML or Eos-MPD. All patients were male, the median age was 58 years (range, 40-66). AML patients were negative for common mutations of FLT3, NRAS, NPM1, KIT, MLL and JAK2; one patient revealed a splice mutation of RUNX1 exon 7. Patients were treated with imatinib (100 mg, n=5; 400 mg, n=2) either as monotherapy (n=2), as maintenance treatment after intensive chemotherapy (n=3) or in overt relapse 43 and 72 months, respectively, after primary diagnosis and treatment of FIP1L1-PDGFRA-positive disease (n=2). All patients are alive, disease-free and in complete hematologic and complete molecular remission after a median time of 20 months (range, 9-36) on imatinib. The median time to achievement of complete molecular remission was 6 months (range, 1-14). We conclude that all eosinophilia-associated hematological malignancies should be screened for the presence of the FIP1L1-PDGFRA fusion gene as they are excellent candidates for treatment with tyrosine kinase inhibitors even if they present with an aggressive phenotype such as AML.
Leukemia 2007 Jun
PMID:Recurrent finding of the FIP1L1-PDGFRA fusion gene in eosinophilia-associated acute myeloid leukemia and lymphoblastic T-cell lymphoma. 1737 85

The term chronic myeloproliferative disorders was originally used by Damashek to describe the link amongst a group of acquired blood diseases. Recent molecular genetic analysis has provided a scientific basis for this observation. Underlying myeloproliferative disorders are acquired abnormalities of tyrosine kinase genes. These may be chromosomal translocations resulting in the creation of a fusion kinase gene, examples of which include ABL, FGFR, and PDGFR as seen in disorders CML, 8p11 myeloproliferative syndrome, atypical CML and chronic eosinophilic leukaemia. The second group of tyrosine kinase abnormalities are point mutations in JAK2, a cytosolic TK. This abnormality is seen in 30-97% of cases of MPD with the phenotype PV, ET or CIMF.
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PMID:Chronic myeloproliferative disorders: the role of tyrosine kinases in pathogenesis, diagnosis and therapy. 1758 79

The 2001 World Health Organization (WHO)-sponsored classification of hematopoietic tumors has, for the first time, clearly defined a group of rare myeloid neoplasms termed myelodysplastic/myeloproliferative diseases (MDS/MPDs). This group includes three main entities, chronic myelomonocytic leukemia, atypical chronic myeloid leukemia and juvenile myelomonocytic leukemia, and also several less well defined, 'unclassifiable' disorders with MDS/MPN-like features. In the upcoming fourth edition of the WHO fascicle, due out later this year, the term 'MPD' is replaced by 'myeloproliferative neoplasm (MPN)'. Accordingly, the term MDS/MPD is being replaced by 'MDS/MPN' that will be used in this review. Although much progress has been made in understanding the molecular pathogenesis of myeloid neoplasms, most of the diseases included in the group of MDS/MPN still remain 'clinicopathologically assigned'. In other words, they can only be accurately categorized by a careful multiparametric approach that is based on the integration of bone marrow and peripheral blood morphology with other laboratory and clinical findings. The current 'spotlight' review provides practical guidelines, which should allow for a reproducible classification of these uncommon neoplasms when encountered in clinical practice.
Leukemia 2008 Jul
PMID:The myelodysplastic/myeloproliferative neoplasms: myeloproliferative diseases with dysplastic features. 1848 Aug 33

The definition of 'atypical MPDs' includes all chronic myeloid disorders that defy classification as either MDS or classic MPDs. These can be both molecularly defined or clinicopathologically assigned: chronic myelomonocytic leukemia, juvenile myelomonocytic leukemia, chronic neutrophilic leukemia, chronic basophilic leukemia, chronic eosinophilic leukemia, idiopathic eosinophilia including hypereosinophilic syndrome, systemic mastocytosis, unclassified MPD, and eosinophilic/mast cell disorders associated with mutations of PDGFR, FGFR1, and KIT all fall under the category of atypical MPDs.
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PMID:Atypical myeloproliferative disorders in adults. 2140 12


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