Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023473 (chronic myeloid leukemia)
 18,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A multicenter, immunohistochemical and morphometric study was performed on diagnostic pretreatment bone marrow biopsies in 614 adult patients with Ph1+ chronic myeloid leukemia (CML) to compare histological features with clinical findings. For identification of megakaryopoiesis we used the monoclonal antibody CD61 and additionally the PAS reaction to determine the subfraction of atypical micromegakaryocytes and precursors. Labelling of erythroid precursors was carried out by a monoclonal antibody directed against glycophorin C. In order to selectively stain macrophages and their activated subset we applied CD68 and the GSA-I lectin. Density of argyrophilic fibers (reticulin plus collagen) was measured following Gomori's silver impregnation method. In accordance with laboratory data morphological variables revealed a comparable amount of congruence in the various groups of CML patients derived from different sources. In about 26% of patients early (reticulin) to advanced (collagen) fibrosis was detectable. Significant correlations were calculated between the extent of myelofibrosis with splenomegaly, anemia and increasing numbers of erythroblasts and myeloblasts in the peripheral blood count. These features were assumed to indicate more advanced stages of the disease process with ensuing transition into myeloid metaplasia and consequently were associated with an unfavorable prognosis. Significant relationships were revealed between the number of CD61+ megakaryocytes and more important, also their precursor fraction with the degree of fibrosis. This result extends previous experimental findings regarding the impact of immature elements of this cell lineage for the generation of myelofibrosis. The significant association of erythroid precursors with the number of mature (resident) macrophages including their activated GSA-I subset may shed some light on their functional involvement in iron turnover and hemoglobin synthesis. A modified histological classification of predominant bone marrow features is introduced. This simplified synthesis staging system (Cologne Classification) is not only associated with certain sets of laboratory data, but also with different survival patterns.
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PMID:Bone marrow features and clinical findings in chronic myeloid leukemia--a comparative, multicenter, immunohistological and morphometric study on 614 patients. 1067 1

Megakaryocytes are platelet forming cells and are characterized by polyploidization, a phenomenon by which nuclear division occurs without corresponding cytoplasmic separation. Among the markers allowing to identify megakaryocytes, glycoprotein (GP) IIIa with GPIb and GPIIb are the most important. Using GPIIIa as a marker to recognize megakaryocytes in the bone marrow, we have estimated GPIIIa expression by flow cytometry in megakaryocyte populations from normal individuals and from patients with chronic myelogenous leukemia, immune thrombocytopenic purpura or polycythemia vera. We showed that the expression of GPIIIa is decreasing during megakaryocyte polyploidization in normal and pathological situations.
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PMID:Human megakaryocyte polyploidization is associated with a decrease in GPIIIA expression. 1069 32

In chronic myeloid leukemia (CML), it has been assumed that the number of CD34(+) progenitor cells (PGCs) provides useful diagnostic and prognostic information regarding the evolution of accelerated phase and blastic crisis. However, until now no information is available about changes of this peculiar precursor cell population during therapy or possible associations with the other bone marrow constituents. For this reason, a retrospective clinicopathological study was performed on 83 patients with CML including 209 sequential bone marrow biopsies (intervals ranging between 6 and 143 months) and immunohistological staining of CD34(+) cells (QBEND10), megakaryocyte precursors (CD61), and erythropoiesis (Ret 40f). According to treatment modalities, three different groups of patients could be distinguished that received either monotherapy by interferon-alpha2b (IFN-alpha2b) or hydroxyurea (HU) and a combination of both. In comparison with a control group, morphometry revealed a significant increase in the quantity of CD34(+) PGCs per hematopoiesis (cellularity) in the CML bone marrow before treatment. Independently of treatment modalities and presentation of clinical findings nonresponding patients were generally characterized by a higher amount of progenitors in the initial biopsy specimens. Furthermore, calculation of the CD34(+) cell growth index showed a significant and rapid progression in nonresponding patients and in those developing an accelerated or blastic phase during therapy. This feature was prominently expressed following IFN treatment and related to a failing regeneration of nucleated erythroid precursors. In patients with a myelofibrotic bone marrow at onset no differences in the number of CD34(+) PGCs were recognizable in the pretreatment biopsies. This finding contrasted a significant and gradual change in progenitor cell frequency under treatment and evolving myelofibrosis. Opposed to HU therapy, the latter feature was explicitly detectable in the IFN group. In conclusion, the incidence of CD34(+) PGCs in the CML bone marrow reflects therapeutic efficacy. By demonstrating a significant relationship between fiber content and quantity of CD34(+) cells during treatment, experimental findings concerning the complex functional interactions between the fibrous stroma compartment and progenitor cell differentiation and proliferation are elucidated.
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PMID:Therapy-related changes of CD34+ progenitor cells in chronic myeloid leukemia: a morphometric study on sequential trephine biopsies. 1179 9

In the blast crisis phase of chronic myelogenous leukemia (CML), Bcr-Abl(+) myeloblasts fail to undergo terminal maturation. The extracellular signal-regulated kinase (Erk) mitogen-activated protein (MAP) kinase has been shown to mediate terminal differentiation of myeloid cells. Interestingly, Bcr-Abl(+) CML cell lines established from blast crisis were found to have low Erk MAP kinase activity. In this study, we analyzed the role of the Gab2 docking protein in regulation of the Erk MAP kinase in Bcr-Abl(+) K562 human CML cells. Overexpression of Gab2 in K562 cells resulted in transcriptional activation of the c-fos serum response element (SRE) promoter, whereas overexpression of SHP2, Grb2, and CrkL had no effect. Activation of the c-fos SRE transcriptional activity by Gab2 required tyrosine 604, which is a SHP2 docking site on Gab2, and the SHP2 tyrosine phosphatase activity. Elk1, c-Jun, and CHOP trans-reporting assays indicated that overexpression of Gab2 selectively activated the Erk2-Elk1 signaling pathway. To determine cellular consequences of elevating the Gab2 level in K562 cells, stable cell lines for doxycycline-inducible expression of the wild-type Gab2 (Gab2WT) and an SHP2-binding defective Gab2 (Gab2Tyr604Phe) were established. Analysis of these cell lines indicated that induction of Gab2WT expression, but not Gab2Tyr604Phe expression, led to Erk activation, growth arrest, cell spreading, and enlargement; expression of megakaryocyte/platelet lineage-specific integrins alphaIIb/beta3 (CD41/CD61); and upregulation of RNA for megakaryocyte/platelet proteins. All of these changes are characteristics of megakaryocytic differentiation. Together, these results reveal Gab2 as a limiting signaling component for Erk MAP kinase activation and terminal differentiation of K562 CML cells.
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PMID:Regulation of the Erk2-Elk1 signaling pathway and megakaryocytic differentiation of Bcr-Abl(+) K562 leukemic cells by Gab2. 1183 Apr 91

Chronic myeloprolifeative diseases (CMPD) are clonal hematopoietic stem cell disorders characterized by excessive proliferation and production of one or more of the myeloid cells and are subclassified according to the predominant cells, such as chronic myelogenous leukemia (CNL), chronic eosinophilic leukemia (CEL), polycythemia vera (PV), essential thrombocythemia (ET) and chronic idiopathic myelofibrosis (CIMF). This brief review focuses on the characteristic morphology of each clinical entity and the useful cytochemical (including leukocyte alkaline phosphatase, myeloperoxidase, butyrate esterase, chloroacetate esterase and cyanide-resistant peroxidase) and immunohistochemical (including von Willebrand factor/CD61, keratin, tryptase, CD117, CD68 (PGM-1), c-Mpl and bFGF) stains for differential diagnosis.
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PMID:The role of morphology, cytochemistry and immunohistochemistry in the diagnosis of chronic myeloproliferative diseases. 1243 Aug 92

Until now, studies on mixed chimerism (MCh) after allogeneic bone marrow transplantation (BMT) have predominantly focused on the B- and T-lymphocyte population, but not on distinct myeloid cell lineages like nucleated erythroid precursors and megakaryocytes. To evaluate the lineage-restricted MCh more explicitly in 10 patients with chronic myelogenous leukemia (CML), a quantitative analysis was performed on bone marrow biopsies following a sex-mismatched host/donor constellation. Techniques included immunophenotyping (antiglycophorin C, CD61) for the identification of erythro- and megakaryopoiesis and a simultaneously conducted genotyping with x- and y-chromosome-specific DNA probes. Normal bone marrow and specimens taken before BMT served as controls. Contrasting a total gender-dependent sex-typing in the latter samples in the early and late posttransplant period (up to 586 days), 3-9% erythroid precursors and about 16% megakaryocytes revealed a host-type origin. This significantly higher number of host megakaryocytes is explained by their polyploidy generating an increased probability to detect positive signals at a certain section level of the corresponding biopsies. A striking conversion of MCh to a recipient cell type was found in leukemic relapse with a more than 90% host-derived erythroid and megakaryocytic cell population in 4 patients approximately 643 days after BMT.
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PMID:Mixed chimerism of erythro- and megakaryopoiesis following allogeneic bone marrow transplantation. 1285 89

In chronic myeloid leukemia following therapy with Imatinib (STI571) hematologic and cytogenetic response is associated with conspicuous changes of bone marrow morphology. However, it is not known to which extent these alterations are accompanied by a loss of the bcr/abl translocation. To study regression of the leukemic cell population we recruited 14 patients lacking pretreatment. Therapy resulted in a reduction of CD61(+) megakaryopoiesis. Dwarf megakaryocytes characteristic for this disorder were replaced by large, normally appearing cells of this lineage. Morphometric analysis confirmed the significant decrease in the number of micromegakaryocytes and yielded planimetric parameters in keeping with normalization. Moreover, a fluorescence in-situ hybridization study in five patients of this cohort revealed that before therapy 70% of all myeloid cells exhibited the bcr/abl gene. Regarding megakaryopoiesis about 65% of the micromegakaryocytes displayed positive signals. Following treatment these bcr/abl(+) cell populations decreased significantly while the emerging large megakaryocytes lacked a proper labeling. Because cytogenetic response and reduction of atypical micromegakaryocytes are linked, this feature may be useful to monitor therapeutic efficacy.
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PMID:[Regression of the Philadelphia chromosome (bcr/abl)-positive myelo- and megakaryopoiesis after Imatinib (STI571) therapy in chronic myelogenous leukemia (CML)]. 1517 23

Following therapy with imatinib (STI571) hematologic and cytogenetic response in chronic myeloid leukemia (CML) is associated with conspicuous alterations of bone marrow (BM) morphology. Besides reduction of cellularity and fibrosis, small megakaryocytes characteristic for this disorder were replaced by large, normally appearing cells of this lineage. However, it is not known whether and to which extent these changes are accompanied by a loss of the bcr/abl translocation. Therefore an immunohistochemical (CD61) and fluorescence in-situ hybridization (FISH) study was performed on sequential BM biopsies in 5 patients with CML receiving STI571 without any pretreatment. Morphometric analysis revealed that the prevalent population of 47% micromegakaryocytes (size < or = 150 microm2) was significantly reduced (15%) during therapy and that a conspicuous shift to medium-sized and large megakaryocytes occurred. According to FISH analysis in the initial BM biopsy sections 71% of all myeloid cells exhibited the bcr/abl gene and concerning megakaryopoiesis about 65% of the prominent micromegakaryocytes displayed positive signals. After treatment this peculiar cell population decreased significantly while the emerging large megakaryocytes (52%) totally lacked a bcr/abl labeling. Because cytogenetic response and reduction of micromegakaryocytes seem to be linked, this feature may be useful to monitor therapeutic efficacy by evaluating BM morphology.
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PMID:Megakaryocyte features and bcr/abl translocation in chronic myeloid leukemia following imatinib mesylate (STI571) therapy--a fluorescence in-situ hybridization study. 1537 Feb 16

In chronic myeloid leukemia K562 cells, differentiation is also blocked because of low levels of ganglioside GM3, derived by the high expression of sialidase Neu3 active on GM3. In this article, we studied the effects of Neu3 silencing (40-70% and 63-93% decrease in protein content and activity, respectively) in these cells. The effects were as follows: (a) gangliosides GM3, GM1, and sialosylnorhexaosylceramide increased markedly; (b) cell growth and [(3)H]thymidine incorporation diminished relevantly; (c) as mRNA, cyclin D2, and Myc were much less expressed, whereas cyclin D1 was expressed more like its inhibitor p21; (d) as mRNA, pro-apoptotic proteins Bax and Bad increased with concurrent decrease and increase in the anti-apoptotic proteins Bcl-2 and Bcl-XL, respectively; (e) the apoptosis inducers etoposide and staurosporine were active on Neu3 silencing cells but not on mock cells; (f) as mRNA, the megakaryocytic markers CD10, CD44, CD41, and CD61 increased similar to the case of mock cells stimulated with PMA; (g) the signaling cascades mediated by PLC-beta2, PKC, RAF, ERK1/2, RSK90, and JNK were largely activated. The induction of a GM3-rich ganglioside pattern in K562 cells by treatment with brefeldin A elicited a phenotype similar to that of Neu3 silencing cells. In conclusion, upon Neu3 silencing, K562 cells show a decrease in proliferation, propensity to undergo apoptosis, and megakaryocytic differentiation.
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PMID:Silencing of membrane-associated sialidase Neu3 diminishes apoptosis resistance and triggers megakaryocytic differentiation of chronic myeloid leukemic cells K562 through the increase of ganglioside GM3. 1882 Jun 43

Imatinib has shown significant clinical and cytogenetic success in the treatment of chronic myeloid leukemia. Although resistance has been observed in a proportion of patients, sudden blastic crisis is a rare event during imatinib therapy. We describe a 24-year-old male patient with Philadelphia chromosome-positive chronic myeloid leukemia in chronic phase who developed sudden blastic crisis in the 24th month of imatinib therapy, with loss of complete cytogenetic response. At this time, the patient had splenomegaly, severe anemia, thrombocytopenia, and leukocytosis. Bone marrow aspirate revealed the presence of massive blastic infiltration with myeloid morphology. Flow cytometric analysis of the bone marrow cells showed positivity for CD45, CD34, CD13, CD33, CD19, CD41, CD61, and glycophorin-A. Trephine biopsy specimens showed 100% cellular marrow with diffuse infiltrate by blasts. A reticulin stain of the bone marrow biopsy section demonstrated severe diffuse fibrosis. Cytogenetic analysis by fluorescence in situ hybridization (FISH) revealed that 92% of the cells were positive for the BCR/ABL fusion signal and had increased copy numbers for chromosomes 8, 13, 19, and 21. The patient's prognosis was unfavorable. In conclusion, chronic myeloid leukemia remains complex and includes unanswered questions. The presented case with a rare event during imatinib therapy highlights the need for the continued monitoring of residual disease and the development of strategies to eliminate residual leukemia cells in patients showing a complete cytogenetic response.
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PMID:Sudden blastic crisis and additional chromosomal abnormalities during chronic myeloid leukemia in the imatinib era. 1996 94


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