Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023467 (acute myeloid leukemia)
 35,200 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The quantitative levels of intracellular cytokines IL-4, IL-10, and IFN-gamma (ie, the number of bound PE-conjugated antibody molecules/cell) of leukemic cells and bone marrow T cells (bmT cells) of acute leukemia patients were analyzed by flow cytometry. One hundred, thirty-one (95 AML, 25 ALL, 11 ABL) patients were studied. The leukemic cell IL-4 level was highest in the monocytic AML group (1735 +/- 1056) and lowest in the dysplastic AML group (960 +/- 545). The IFN-gamma level was highest in the acute promyelocytic leukemia (APL) group (495 +/- 159), and lowest in the ALL group (252 +/- 119). The IL-10 level was not significantly different among the diagnosis groups. In bmT cells, the IL-10 level was highest in the dysplastic AML group (972 +/- 1049) and lowest in the APL group (397 +/- 352). The leukemic cell cytokine levels were lowest and bmT cell cytokine levels were highest in the dysplastic AML group. There were no significant correlations of these cytokine levels with 2-yr survival rate, complete remission (CR) rate, or relapse rate. The cytokine levels of bmT cells at the time of CR became normal and were not different among the diagnosis groups. In summary, leukemic cell and bmT cell cytoplasmic expression profiles of IL-4, IL-10, and IFN-gamma are characteristic for each diagnostic group of acute leukemia patients and the profiles of bmT cells are normal at the time of CR.
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PMID:Intracellular IL-4, IL-10, and IFN-gamma levels of leukemic cells and bone marrow T cells in acute leukemia. 1650 Dec 31

To clarify whether expression of the programmed cell death 5 (PDCD5) gene in leukemic cells is abnormal, real-time quantitative reverse transcription polymerase chain reaction (RQ-RT-PCR) was used to examine its expression in marrow cells from leukemia patients. We found lower PDCD5 in both AML and CML marrow cells than in normal donor marrow cells. A negative correlation was found between relative levels of PDCD5 and BCR/ABL expression in all CML patients and in CML patients in the advanced phase. Treatment with the ABL tyrosine kinase inhibitor Imatinib mesylate increased PDCD5 expression in K562 and MEG-01 cells. These findings suggest that abnormal expression of PDCD5 in leukemia may be involved in the pathomechanism of AML and CML.
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PMID:Abnormal expression of the programmed cell death 5 gene in acute and chronic myeloid leukemia. 1650 20

In the present study, we analyzed the involvement of the BCR-ABL protein in the induction of antigen-specific CTL in order to develop an immunotherapeutic approach in patients with chronic myelogenous leukemia (CML). To accomplish this, we generated dendritic cells (DC) in vitro and electroporated them with various sources of RNA harboring the chimeric bcr-abl transcript. These genetically engineered DCs were used as antigen-presenting cells for the induction of CTLs. By applying this approach, we found that the CTLs induced by DCs transfected with RNA extracted from bcr-abl-positive K-562 cells or CML blasts lysed DCs transfected with the corresponding RNA, but failed to recognize epitopes derived from the chimeric BCR-ABL fusion protein in (51)Cr-release assays. In contrast, they were able to lyse autologous DCs electroporated with RNA isolated from patients with acute myeloid leukemia, indicating that antigens shared among these malignant cells are involved and recognized by these CTLs. In patients with CML in complete cytogenetic remission during IFN-alpha treatment, we detected some reactivity of CD8(+) T cells against BCR-ABL in IFN-gamma ELISPOT assays, which was weaker as compared with proteinase 3 (PR3)- or prame-directed responses, suggesting that the BCR-ABL protein is less immunogenic as compared with other CML-derived antigens.
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PMID:BCR-ABL is not an immunodominant antigen in chronic myelogenous leukemia. 1674 Jul 29

Cytomorphology, cytochemistry, immunophenotyping, in addition to cytogenetic and molecular analyses have specific roles in the diagnosis and management of acute leukemias. This work was designed as a comparative study of different available methods for diagnosis of acute leukemia. The study comprised 47 cases with acute leukemia (21 cases with ALL and 26 cases with AML). Peripheral blood and bone marrow samples were subjected to through morphological examination of Leishman-stained smears, cytochemical analysis, immunophenotyping, conventional cytogenetic banding analysis, fluorescence in situ hybridization (FISH) for selected cases, and RT-PCR for detection of BCR-ABL rearrangement. The results of the study revealed that careful examination of Romanowsky-stained peripheral blood and BM films is fundamental in the diagnosis of acute leukemias, and when considered together with clinical and hematological features, indicates which of the more specialized techniques are most likely to be useful. The major role of cytochemistry was in the diagnosis of AML, while the major role of immunophenotyping was in the diagnosis of acute leukemia, which is not obviously myeloid. Apart from identification of chromosomal abnormalities unique to specific subtypes of leukemia, cytogenetic analysis had a salient impact on anticipating the prognosis and treatment outcome in acute leukemias. We could conclude that the techniques used in this study are considered complementary rather than alternatives and that stepwise employment of strategies is more cost effective than doing all the tests simultaneously.
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PMID:A study for evaluation of different diagnostic approaches in acute leukemia in Egypt. 1675 47

Recurring chromosome abnormalities are strongly associated with certain subtypes of leukemia, lymphoma and sarcomas. More recently, their potential involvement in carcinomas, i.e. prostate cancer, has been recognized. They are among the most important factors in determining disease prognosis, and in many cases, identification of these chromosome abnormalities is crucial in selecting appropriate treatment protocols. Chromosome translocations are frequently observed in both de novo and therapy-related acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS). The mechanisms that result in such chromosome translocations in leukemia and other cancers are largely unknown. Genomic breakpoints in all the common chromosome translocations in leukemia, including t(4;11), t(9;11), t(8;21), inv(16), t(15;17), t(12;21), t(1;19) and t(9;22), have been cloned. Genomic breakpoints tend to cluster in certain intronic regions of the relevant genes including MLL, AF4, AF9, AML1, ETO, CBFB, MYHI1, PML, RARA, TEL, E2A, PBX1, BCR and ABL. However, whereas the genomic breakpoints in MLL tend to cluster in the 5' portion of the 8.3 kb breakpoint cluster region (BCR) in de novo and adult patients and in the 3' portion in infant leukemia patients and t-AML patients, those in both the AML1 and ETO genes occur in the same clustered regions in both de novo and t-AML patients. These differences may reflect differences in the mechanisms involved in the formation of the translocations. Specific chromatin structural elements, such as in vivo topoisomerase II (topo II) cleavage sites, DNase I hypersensitive sites and scaffold attachment regions (SARs) have been mapped in the breakpoint regions of the relevant genes. Strong in vivo topo II cleavage sites and DNase I hypersensitive sites often co-localize with each other and also with many of the BCRs in most of these genes, whereas SARs are associated with BCRs in MLL, AF4, AF9, AML1, ETO and ABL, but not in the BCR gene. In addition, the BCRs in MLL, AML1 and ETO have the lowest free energy level for unwinding double strand DNA. Virtually all chromosome translocations in leukemia that have been analyzed to date show no consistent homologous sequences at the breakpoints, whereas a strong non-homologous end joining (NHEJ) repair signature exists at all of these chromosome translocation breakpoint junctions; this includes small deletions and duplications in each breakpoint, and micro-homologies and non-template insertions at genomic junctions of each chromosome translocation. Surprisingly, the size of these deletions and duplications in the same translocation is much larger in de novo leukemia than in therapy-related leukemia. We propose a non-homologous chromosome recombination model as one of the mechanisms that results in chromosome translocations in leukemia. The topo II cleavage sites at open chromatin regions (DNase I hypersensitive sites), SARs or the regions with low energy level are vulnerable to certain genotoxic or other agents and become the initial breakage sites, which are followed by an excision end joining repair process.
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PMID:Chromatin structural elements and chromosomal translocations in leukemia. 1689 85

Myeloid malignancies are frequently associated with translocations and mutations of tyrosine kinase genes. Fusion genes involving ABL, ARG, PDGFRs, JAK2, SYK, TRKC, and FGFRs, and gain-of-function mutations of FLT3, KIT and JAK2 have been detected at various rates in myeloproliferative disease and acute myeloid leukemia. Furthermore, abnormal overexpression of tyrosine kinases such as FLT3 has also been reported. These gene products are constitutively activated and potentially transform hematopoietic cells by augmentation of proliferation and enhanced viability. Since the fusion or mutation of tyrosine kinase is a primary and central event in chronic myeloproliferative diseases, targeting the kinase activity has been thought to be an ideal intervention to treat these diseases. The clinical success of imatinib for chronic myeloid leukemia has made this idea a reality, and has accelerated the development of new tyrosine kinase inhibitors (TKIs). Challenging studies with TKIs have also been reported for acute myeloid leukemia. This review will focus on recent trials of TKIs against oncogenic tyrosine kinases (ABL, PDGFRs, FLT3 and KIT) in myeloid malignancies.
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PMID:Developing target therapy against oncogenic tyrosine kinase in myeloid maliganacies. 1707 49

FLT3 is a receptor tyrosine kinase with important roles in hematopoietic stem/progenitor cell survival and proliferation. It is mutated in about 1/3 of acute myeloid leukemia (AML) patients, either by internal tandem duplications (ITD) of the juxtamembrane domain or by point mutations usually involving the kinase domain (KD). Both types of mutation constitutively activate FLT3. Many studies have shown that AML patients with FLT3/ITD mutations have poor cure rates due to relapse. This has led to the development of a number of small molecule tyrosine kinase inhibitors (TKI) with activity against FLT3. Many of these are still in preclinical development, but several have entered clinical phase I and II trials as monotherapy in patients with relapsed AML. Patients with FLT3 mutations in these trials have shown clinical responses, most often a clearing of peripheral blasts, but rarely major reductions of bone marrow blasts. Several studies have shown that FLT3 was successfully inhibited in most patients. However, complete remissions have rarely been achieved in these trials. The difference in responses of chronic myeloid leukemia (CML) patients to BCR-ABL inhibitors compared to FLT3 mutant AML patients to FLT3 inhibitors may be reflective of treating a single gene disease in CML versus multiply altered gene disease in AML. This has led to clinical testing of FLT3 TKI in combination with conventional chemotherapy, with trial designs based on preclinical testing showing synergistic effects between these agents in inducing cytotoxic responses. Several combination trials are ongoing or planned in both relapsed and newly diagnosed FLT3-mutant AML patients.
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PMID:FLT3 mutations: biology and treatment. 1712 58

JAK2V617F, a somatic gain-of-function mutation involving the JAK2 tyrosine kinase gene, occurs in nearly all patients with polycythemia vera (PV) but also in a variable proportion of patients with other myeloid disorders; mutational frequency is estimated at approximately 50% in both essential thrombocythemia (ET) and myelofibrosis (MF), up to 20% in certain subcategories of atypical myeloproliferative disorder (atypical MPD), less than 3% in de novo myelodysplastic syndrome (MDS) or acute myeloid leukemia, and 0% in chronic myeloid leukemia (CML). Accordingly, there is now molecular justification for grouping PV, ET, and MF together in a distinct MPD category (i.e., classic, BCR-ABL(-) MPD) that is separate from chronic myeloid leukemia (CML), MDS, and atypical MPD. To date, JAK2V617F has not been described in patients with reactive myeloproliferation, lymphoid disorders, or solid tumor. Therefore, the presence of JAK2V617F strongly suggests an underlying MPD and it is therefore reasonable to consider JAK2V617F-based laboratory tests for the evaluation of polycythemia, primary thrombocytosis, unexplained leukocytosis, bone marrow fibrosis, or abdominal vein thrombosis. Current information on disease-specific prognostic relevance of JAK2V617F is inconclusive and confounded by inter-study differences in the performance of mutation screening assays. Regardless, the discovery of JAK2V617F has reinforced the pathogenetic contribution of JAK-STAT signaling in MPD and identifies JAK2 as a valid drug target.
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PMID:Classification, diagnosis and management of myeloproliferative disorders in the JAK2V617F era. 1712 67

Growth factors and mitogens use the Ras/Raf/MEK/ERK signaling cascade to transmit signals from their receptors to regulate gene expression and prevent apoptosis. Some components of these pathways are mutated or aberrantly expressed in human cancer (e.g., Ras, B-Raf). Mutations also occur at genes encoding upstream receptors (e.g., EGFR and Flt-3) and chimeric chromosomal translocations (e.g., BCR-ABL) which transmit their signals through these cascades. Even in the absence of obvious genetic mutations, this pathway has been reported to be activated in over 50% of acute myelogenous leukemia and acute lymphocytic leukemia and is also frequently activated in other cancer types (e.g., breast and prostate cancers). Importantly, this increased expression is associated with a poor prognosis. The Ras/Raf/MEK/ERK and Ras/PI3K/PTEN/Akt pathways interact with each other to regulate growth and in some cases tumorigenesis. For example, in some cells, PTEN mutation may contribute to suppression of the Raf/MEK/ERK cascade due to the ability of activated Akt to phosphorylate and inactivate different Rafs. Although both of these pathways are commonly thought to have anti-apoptotic and drug resistance effects on cells, they display different cell lineage specific effects. For example, Raf/MEK/ERK is usually associated with proliferation and drug resistance of hematopoietic cells, while activation of the Raf/MEK/ERK cascade is suppressed in some prostate cancer cell lines which have mutations at PTEN and express high levels of activated Akt. Furthermore the Ras/Raf/MEK/ERK and Ras/PI3K/PTEN/Akt pathways also interact with the p53 pathway. Some of these interactions can result in controlling the activity and subcellular localization of Bim, Bak, Bax, Puma and Noxa. Raf/MEK/ERK may promote cell cycle arrest in prostate cells and this may be regulated by p53 as restoration of wild-type p53 in p53 deficient prostate cancer cells results in their enhanced sensitivity to chemotherapeutic drugs and increased expression of Raf/MEK/ERK pathway. Thus in advanced prostate cancer, it may be advantageous to induce Raf/MEK/ERK expression to promote cell cycle arrest, while in hematopoietic cancers it may be beneficial to inhibit Raf/MEK/ERK induced proliferation and drug resistance. Thus the Raf/MEK/ERK pathway has different effects on growth, prevention of apoptosis, cell cycle arrest and induction of drug resistance in cells of various lineages which may be due to the presence of functional p53 and PTEN and the expression of lineage specific factors.
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PMID:Roles of the Raf/MEK/ERK pathway in cell growth, malignant transformation and drug resistance. 1712 25

The treatment of myeloid leukaemia has progressed in recent years with the advent of donor leukocyte infusions (DLI), haemopoietic stem cell transplants (HSCTs) and targeted therapies. However, relapse has a high associated morbidity rate and a method for removing diseased cells in first remission, when a minimal residual disease state is achieved and tumour load is low, has the potential to extend remission times and prevent relapse especially when used in combination with conventional treatments. Acute myeloid leukaemia (AML) and myelodysplastic syndrome (MDS) are heterogeneous diseases which lack one common molecular target while chronic myeloid leukaemia (CML) patients have experienced prolonged remissions through the use of targeted therapies which remove BCR-ABL(+) cells effectively in early chronic phase. However, escape mutants have arisen and this therapy has little effectivity in the late chronic phase. Here we review the immune therapies which are close to or in clinical trials for the myeloid leukaemias and describe their potential advantages and disadvantages.
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PMID:Immunotherapy of myeloid leukaemia. 1718 Jun 71


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