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)

Because neither morphologic nor routine cytochemical features are pathognomonic, the diagnosis of acute megakaryoblastic leukemia (AML-M7) is difficult, requiring either specialized ultrastructural or immunologic techniques. Because the ultrastructural techniques are cumbersome, immunologic assays for expression of several platelet-specific antigens, such as CD41a (platelet glycoprotein IIb/IIIa), have become the primary method used to detect megakaryoblastic differentiation. In our flow cytometric analysis of the immunophenotypes of over 1,000 cases of AML from patients registered to Southwest Oncology Group (SWOG) Treatment Protocols, we found that 38% of cases demonstrated CD41a reactivity. Because this frequency of CD41a expression by flow cytometry greatly exceeded the number of morphologically defined cases of AML-M7, we postulated that the reaction may be caused by platelets adherent to leukemic blasts. To investigate this hypothesis, we performed a side-by-side comparison of flow cytometric and cytospin immunofluorescence studies on 37 cases of adult de novo AML that demonstrated a wide range of CD41a expression by flow cytometric analyses. We found that the expression of CD41a detected by flow cytometric techniques was secondary to adherent platelets or platelet fragments in 85% of cases. Many of these cases also expressed the lineage-specific carbohydrate, LNF III (CD15), which may mediate platelet adhesion to mature monocytes and neutrophils. Only 15% of the CD41a flow cytometrically positive cases demonstrated true diffuse membrane and cytoplasmic positivity on cytospin slides indicative of megakaryoblastic differentiation. Cytospin immunofluorescence for CD41a should be performed on all cases of suspected AML-M7. If only flow cytometric techniques are used, adherent platelets may result in the erroneous diagnosis of this AML subtype.
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PMID:False-positive flow cytometric platelet glycoprotein IIb/IIIa expression in myeloid leukemias secondary to platelet adherence to blasts. 134 44

A 63-year-old man was admitted because of anemia and thrombocytopenia. The bone marrow was hypercellular with 66.6% erythroblasts with dysplasia and 19.8% blasts. Cytogenetically, MAKA (major karyotypic aberrations) containing 5q-, -7, -17, with karyotypic instability was observed. A diagnosis of erythroleukemia (FAB M6) was made. Six months later, immature neutrophils increased in the peripheral blood, and blasts and promyelocytes increased to 25.8% and 20.0% of marrow cells, respectively. Three months later, blasts asts increased to 33.0% in the peripheral blood. They were ultrastructually positive for platelet peroxidase. Phenotypically, 69% and 63% of blasts were positive for CD41b (GPIIb/IIIa) and CD42a (GPIb), respectively. Bone marrow biopsy showed marked proliferation of blasts and dysplastic megakaryocytes accompanied by reticulin fibrosis. These findings suggested evolution to megakaryoblastic leukemia (FAB M7). In most cases, M6 defined by the FAB criteria is stem cell disorder with multilineage involvement and major erythroid component. M6-like features may be observed in the evolutive phase to acute leukemia from myelodysplastic syndrome (MDS).
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PMID:[Evolution to megakaryoblastic leukemia observed in myelodysplastic syndrome with erythrolekemia-like features]. 140 64

A 56-year-old man had a leiomyosarcoma of the small intestine in 1987. After surgery, he received cyclophosphamide for 2 years. In December, 1990, he exhibited severe pancytopenia. His hematological data were as follows: Hb 7.4g/dl, ret. 0.8%, WBC 1,700/microliters with leukoerythroblastosis and 2.8 x 10(4)/microliters platelets. A bone marrow aspiration was a dry tap. A bone marrow biopsy specimen showed a hypercellular marrow with myelofibrosis, leukemic infiltration (10.2%) and slight dyserythropoiesis. Both PPO and GPIIb/IIIa reaction were positive for blast cells and atypical megakaryoblasts. A diagnosis of MDS with an abnormality in megakaryocytic lineage was made. The patient was treated with 1,25-dihydroxy-vitamin D3, however this therapy was temporary and he developed into acute megakaryoblastic leukemia (M7). This report suggested that some cases of therapy-related leukemia (TRL) mainly involve megakaryocytic lineage and are diagnosed as MDS with myelofibrosis which transform to M7. The fact that PAS stain of erythroblasts in the patient reported here was positive may suggest involvement of development of more precise immunological markers of differentiation and EM study will permit better diagnosis of TRL and may therefore facilitate new therapeutic approaches.
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PMID:[Megakaryoblastic leukemia which developed from therapy-related MDS with myelofibrosis]. 147 98

The short segments of cDNA encoding glycoprotein (GP)Ib alpha, GPIIb, GPIIIa and platelet factor (PF) 4 were amplified using reverse transcriptase-polymerase chain reaction (RT-PCR) in order to characterize various types of megakaryoblasts. Cell lines with megakaryocytic features (K562, CMK and HEL) were tested. GPIb alpha, GPIIb and GPIIIa mRNAs were found to be present in K562, CMK and HEL cells, while only HEL cells expressed PF4 or mRNA. These results suggested that megakaryoblastic cell lines could be categorized into two groups, one with the PF4 transcript and the other without it. PF4 mRNA was present in the cells obtained from one Down's syndrome patient with transient myeloproliferative disorder and in one patient with primary myelofibrosis and megakaryoblastosis. On the other hand, one patient with acute megakaryoblastic leukemia transformed from refractory anemia had a poor prognosis with megakaryoblastic leukemia cells which expressed no PF4 mRNA. These observations suggested that the expression of PF4 mRNA in peripheral blood megakaryoblasts may indicate the absence of a true leukemic process.
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PMID:Detection of platelet-specific protein mRNAs in different megakaryoblasts using the reverse transcriptase polymerase chain reaction. 149 50

smg p21A and -B (smg p21s) are ras p21-like small GTP-binding proteins (G proteins) with the same putative effector domain as ras p21s. Both smg p21A mRNA and smg p21B mRNA were detected in CMK, a human megakaryocytic leukemia cell line, and their levels were markedly elevated by treatment with 12-O-tetradecanoyl-phorbol-13-acetate (TPA), which caused the differentiation of this cell line into more mature megakaryocytes. The smg p21 protein molecules also increased during the TPA-induced differentiation of CMK cells. The mRNA level of glycoprotein IIb (GPIIb), a typical marker of the megakaryocytes, was increased by this treatment, but the time course of the increase in the smg p21 mRNA levels as more rapid than that of the increase in the GPIIb mRNA level. Ha-ras p21 mRNA was undetectable, but both Ki- and N-ras p21 mRNAs were detected in CMK cells and their levels were also increased during TPA-induced differentiation of CMK cells, although to a lesser extent than those of smg p21 mRNAs. Protein kinase C inhibitors inhibited the basal and TPA-induced smg p21A mRNA level, but cyclic AMP-elevating prostaglandin E1 or Ca(2+)-mobilizing ionomycin did not inhibit them. Cycloheximide enhanced the basal and TPA-induced smg p21A mRNA levels. Actinomycin D blocked the TPA-induced smg p21A mRNA levels, but showed no detectable effect on the elevated smg p21A mRNA level which was induced by pretreatment with TPA. A dramatic increase in the smg p21 mRNA levels was also observed in other leukemia cell lines during TPA-induced differentiation. These results suggest that TPA stimulated expression of the smg p21A gene, presumably through the action of protein kinase C at the transcriptional level rather than at the post-transcriptional level, in hematopoietic leukemia cells.
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PMID:Induction of smg p21/rap1A p21/krev-1 p21 gene expression during phorbol ester-induced differentiation of a human megakaryocytic leukemia cell line. 154 53

A 57-year-old male who had suffered from polycythemia vera (PV) and had been treated with pipobroman, carbazilquinon and busulfan for ten years presented with fever. CBC revealed anemia and thrombocytopenia without an increase of leukemic blasts (WBC, 7,700/microliters, RBC 294 x 10(4)/microliters, Hb 9.1 g/dl, Plt 1.5 x 10(4)/microliters). Bone marrow aspiration resulted in dry tap. Bone marrow biopsy showed hyperplastic marrow with fibrosis and no increase in leukemic blasts. Eleven days later the patient became leukemic and he died of DIC. Blast cells showed a high nucleo-cytoplasmic ratio, basophilic cytoplasm and cytoplasmic blebs. Cytochemical and immunophenotype analysis of the blast cells showed the following results; myeloperoxidase (-), chloroacetate esterase (-), Sudan black (-), acid phosphatase (+), acetate esterase (+), PAS (+), HLA-DR (+) and GPIIb/IIIa (+). Platelet peroxidase reaction on electron microscopy was positive in perinuclear spaces and endoplasmic reticulum. A diagnosis of megakaryoblastic transformation of PV was made. Although acute myelogenous leukemia has been shown to develop occasionally in the course of PV, acute megakaryoblastic leukemia with DIC following PV is a very rare condition.
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PMID:[Megakaryoblastic transformation associated with disseminated intravascular coagulation in the course of polycythemia vera: a case report]. 160 15

A megakaryoblastic cell line (MKPL-1) was newly established from the bone marrow of an adult patient with acute megakaryoblastic leukemia. This cell line grew in single cell suspension with a doubling time of 30 h and consisted of large primitive blasts with persistent development of giant cells carrying multilobed nuclei. MKPL-1 cells were positive for platelet GPIIb/IIIa (CD41) and GPIIIa (CD61), and expressed OKM5 (CD36), MY7 (CD13), and MY9 (CD33) antigens in the absence of erythroid and lymphoid markers. The cytochemical and morphologic characteristics of MKPL-1 were also consistent with those of megakaryoblasts. The cells did not, however, express ultrastructural platelet peroxidase which is considered to be another marker of the megakaryocytic lineage. Cytogenetic analysis of MKPL-1 revealed a model chromosome number of 92 with abnormal chromosomes including those found in the patient's bone marrow cells. Furthermore, MKPL-1 cells were serially transplanted into nude mice for nine passages with production of lethal tumors and leukemic manifestation. Thus, our megakaryoblastic cell line which can be maintained both in vitro and in vivo would be useful for further studies of the biology of megakaryopoiesis and megakaryoblastic leukemia.
Leukemia 1992 Jun
PMID:Acute megakaryoblastic leukemia: establishment of a new cell line (MKPL-1) in vitro and in vivo. 160 96

The commitment process of a human megakaryoblastic cell line (MEG-O1) induced with phorbol ester, TPA, was investigated with special reference to glycoprotein (GP) IIb/IIIa expression, multinuclear formation, and DNA replication. TPA (10(-7) mol/L) completely inhibited cellular division in MEG-O1, but did not suppress de novo DNA synthesis. Two days' culture with 10(-7) mol/L TPA was sufficient for MEG-O1 cells to initiate an irreversible commitment process. These cells could not resume cell growth and expressed GP IIb/IIIa antigen; some of them showed multinuclear form and DNA polyploidy even after removal of TPA from the culture medium. DNA histogram analysis showed that, upon treatment with TPA, the percentage of cells whose DNA ploidy was more than 8N was 5 to 10 times higher than that of control cells. Precise analysis using cell size fractionation by centrifugal elutriation method showed that there was strong correlation between the percentage of multinuclear cells and DNA polyploidy in TPA-treated cells. The percentage and staining intensity of GP IIb/IIIa and other megakaryocytic phenotypes such as von Willebrand factor and PAS staining were highest in large multinuclear cell populations, suggesting that these cells are the most differentiated population in this system. In TPA-treated cells, the activity of DNA polymerase alpha, a marker for cell growth, remained at the same level as in control cells. Aphidicolin, a specific inhibitor of DNA polymerase alpha, completely inhibited the differentiation induction of MEG-O1 cells with TPA measured by either GP IIb/IIIa expression or multinuclear cell formation. Therefore, DNA replication appears to be involved in the process of phenotypic expression as well as endomitosis in megakaryocyte differentiation of MEG-O1 cells. Aphidicolin was also effective in inhibiting megakaryocytic differentiation of other leukemia cell lines such as human erythroleukemia (HEL) and K562 cell lines induced with TPA, suggesting the close interplay of DNA replication and phenotypic expression in megakaryopoiesis.
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PMID:Aphidicolin, an inhibitor of DNA replication, blocks the TPA-induced differentiation of a human megakaryoblastic cell line, MEG-O1. 174 84

A 64-year-old man was admitted to our hospital with leukopenia. On admission, leukocyte count in the peripheral blood was 1,600/microliters, containing 24.5% blasts of lymphoid appearance, which were negative for myeloperoxidase. A bone marrow aspiration showed hypoplasia with increased blasts (31.6%). The blasts were ultrastructurally positive for platelet peroxidase (PPO) and positive for platelet membrane glycoprotein IIb/IIIa complex. A diagnosis of acute megakaryoblastic leukemia was made. Chemotherapy with behenoyl-ara C (BH-AC) (150 mg/day) was transiently effective. However, after three months, numerous nodules without itching appeared over the entire body, particularly on the anterior chest. A biopsy of the skin lesion revealed a diffuse fibrosis with infiltrations of the blasts. Bone marrow aspirations were dry tap, and a bone marrow biopsy showed marked myelofibrosis. Then, severe headache, vomiting, and loss of consciousness developed, and a lumbar puncture revealed infiltrations of blasts. Although methotrexate was intrathecally injected, he died due to the respiratory failure. As far as we know, a case of acute megakaryoblastic leukemia with leukemia cutis and meningeal leukemia is quite rare. In addition, it is interesting that megakaryoblastic leukemia was accompanied with both the fibrosis of skin and the myelofibrosis.
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PMID:[Acute megakaryoblastic leukemia with leukemia cutis, meningeal leukemia, and myelofibrosis]. 175 56

A 61-year-old man with Philadelphia chromosome-positive chronic myelogenous leukemia developed megakaryoblastic leukemia. In the blast phase, his blast cells showed undifferentiated megakaryoblastic characteristics with no alpha-granules or demarcation membranes but with detectable platelet peroxidase (PPO) activity and surface glycoprotein (GP) IIb/IIIa. The patient has remained reasonably well for at least 12 months after blastic crisis, and 6-mercaptopurine alone has been effective in controlling leukocytosis and megakaryoblast proliferation. The expression of mRNA for platelet-specific proteins, such as GPIIb and platelet factor 4 (PF4), was studied in the patient's blast cells by the Northern blot analysis. Both GPIIb and PF4 mRNA were detected in the blast cells. Cytoplasmic maturation occurs later than the synthesis of the surface GP during megakaryocyte maturation. Therefore, PF4 mRNA expression should be a marker of mature megakaryoblasts. The PF4 mRNA expression in megakaryoblastic leukemia may indicate that a patient will have long survival and a good response to chemotherapy.
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PMID:Platelet factor 4 mRNA expression in cells from a patient with megakaryoblastic crisis of chronic myelogenous leukemia. 199 Dec 66


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