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 interaction of the proto-oncogene c-kit product with its ligand (stem cell factor or SCF) is considered to play crucial roles in hematopoiesis. In a series of human acute myeloblastic leukemia (AML) cells, the effects of recombinant human (rh) SCF on AML cells were examined in short-term and long-term cultures. c-kit expression was detected in 26 of 31 AML cases, and short-term treatment of AML cells with rhSCF led to proliferation in 13 of 18 AML cases that expressed the c-kit product. In seven of the 13 cases showing proliferative response to rhSCF, AML cells were exclusively composed of immature blast cells. We therefore used the seven AML cases for examining the effect of rhSCF on the differentiation and proliferation of AML cells in a long-term culture. Proliferation of AML cells was found to be maintained with rhSCF more than 2 weeks in five of seven cases and 4 weeks in two cases, whereas most of the AML cells died before 2 weeks in the absence of rhSCF. Further, in four of five AML cases, all of which expressed the CD34 antigen and showed a proliferative response to rhSCF in a long-term culture, rhSCF appeared to promote differentiation of blast cells toward lineages of various cell types, such as granulocytic and/or monocytic and mast-cell lineages. These results suggest that, at least in a fraction of AML cases, rhSCF can induce not only proliferation but also differentiation of AML cells, and also that phenotypic manifestation of AML cells may not mean definite cell commitment but can be changed by stimulation with rhSCF.
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PMID:Changes in phenotype and proliferative potential of human acute myeloblastic leukemia cells in culture with stem cell factor. 769 69

The diagnostic and prognostic value of immunophenotyping with 18 murine monoclonal antibodies (MoAbs) to a variety of leukocyte differentiation antigens was assessed in 168 adults aged 15 to 60 years with acute myeloid leukemia (AML). Patients were entered on the multicentre Australian Leukaemia Study Group M4 protocol, and were randomized to receive either standard or high-dose Ara-C together with daunorubicin and etoposide as induction chemotherapy, followed by standard consolidation and maintenance therapy. Diagnostic bone marrow aspirate (152 cases) or peripheral blood samples (16) were analyzed by indirect immunofluorescence and flow cytometry. MoAbs used were directed at myeloid (CD11b, CD13, CD14, CD15, CD33, CD41), lymphoid (CD2, CD3, CD7, CD9, CD10, CD19), or stem cell (HLA-DR, CD34, c-kit receptor) antigens, as well as the leukocyte integrins CD18 and CD49e, and the transferrin receptor CD71. Of the myeloid markers, CD13 and CD33 were the most useful diagnostically (71% and 79% of cases positive, respectively), with CD11b, CD14, and CD15 less commonly positive. A minority of cases expressed lymphoid antigens, either T cell (CD2 16%, CD3 7%, CD7 28%) or B cell (CD10 2%, CD19 7%). CD34 was detected on 42% and c-kit receptor on 48%. When patients were analyzed for response to treatment, CD2, CD9, and CD14 were significantly associated with complete remission rate: cases expressing these antigens had a poorer response than negative cases. In univariate analysis, CD11b+ cases had shorter periods of remission (relative risk of relapse, 2.33; P = .003) and shorter survival (relative death rate, 1.91; P = .006). In multivariate analysis, adjusting for other prognostic factors, CD9 and CD11b were significantly predictive of shorter survival. No other marker had a significant predictive effect. We conclude that myeloid MoAbs are useful in confirming the diagnosis of AML, but their prognostic value may be limited to CD11b. Lymphoid antigen expression is a consistent phenomenon in a minority of cases of AML, but appears to have little clinical significance.
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PMID:Prognostic value of immunophenotyping in acute myeloid leukemia. Australian Leukaemia Study Group. 804 37

The human genome project has revolutionized technology for the study of DNA. Several of this year's papers have applied these techniques to the study of testicular cancer, especially the use of double-fluorescence in situ hybridization to identify the germ cell tumor marker isochrome 12p in tissue sections, and loss-of-heterozygosity studies to demonstrate a candidate suppressor gene on the long arm of the same chromosome that may be a ligand for the c-kit protooncogene. The report of a solitary case of a patient with a tumor (in a solitary testis) who was treated by partial orchiectomy and then fathered two children emphasizes the need for more information on fertility of patients with carcinoma in situ before the highly effective low-dose radiation to the testis can be accepted. The confirmation of the occurrence of acute myeloid leukemia as a late effect of etoposide and stomach cancer as a late effect of radiotherapy for stage I seminoma has drawn attention to the need to reduce treatment in good-risk patients. Results of trials substituting cisplatin with carboplatin and a trial eliminating bleomycin are particularly disappointing, and the 10% lower cures with the experimental regimen in these studies is an object lesson of the risks involved in such studies. Two other issues that continue to be debated include the increasing recognition of the value of lactate dehydrogenase-1 for identifying poor-risk patients, and the benefits of referral to a unit specializing in testicular cancer. There is an increasing trend to use high-dose chemotherapy for previously untreated patients who have poor risk factors. who have poor risk factors.
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PMID:Testicular cancer. 808 Aug 58

The proto-oncogenes c-fms and c-kit belong to a family of growth factor receptors possessing protein kinase activity. It has been shown that transfection of a c-fms gene carrying a point mutation at codon 301, leads to a ligand-independent transformation of mouse NIH3T3 cells. In human acute myeloid leukemia (AML), point mutations at codon 301 of the c-fms gene have been observed implying an important role in the transformation process. The possibility of a point mutation of the c-kit proto-oncogene was investigated. We sequenced a segment of the c-kit proto-oncogene coding for a part of the extracellular domain. This segment was 40.7% homologous to the c-fms region encompassing codon 301. c-DNA was prepared from peripheral blood or bone marrow cells from 25 patients with AML, from four patients with myelodysplastic syndrome (MDS) and from three human myeloid cell lines. The region of interest was amplified with two rounds of polymerase chain reactions (PCR) with nested primers and directly sequenced. No point mutations were found in the investigated samples. Thus, point mutations in this segment of the c-kit gene do not seem to play an important role in the transformation process of human acute leukemia.
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PMID:Absence of point mutations in a functionally important part of the extracellular domain of the c-kit proto-oncogene in a series of patients with acute myeloid leukemia (AML). 812 54

Similar to two other hematopoietic growth factor receptors, the c-fms (macrophage colony-stimulating factor receptor) and the c-kit genes, c-mpl has been discovered through the study of oncogenic retroviruses. Unlike c-fms and c-kit, which both belong to a subgroup of tyrosine kinase receptors, the c-mpl proto-oncogene encodes a new member of the cytokine receptor superfamily. We have studied the expression of c-mpl in a series of 105 patients with hematologic malignancies using Northern blot analysis. The levels of c-mpl transcripts in lymphoid malignancies and in chronic myeloproliferative disorders were not significantly different from those found in normal bone marrow cells, in which c-mpl was barely detectable. In contrast, c-mpl expression was increased in 26 of 51 patients with acute myeloblastic leukemia (AML) and in 5 of 16 patients with myelodysplastic syndromes. Amplification of the c-mpl gene was detected in genomic DNA of one M4 AML patient. There was no significant correlation between c-mpl expression and the French-American-British classification of AML. Patients with high c-mpl expression appeared to belong to a subgroup of AML with a low rate of complete remission and a poor prognosis, including secondary leukemia and AML with unfavorable cytogenetic abnormalities.
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PMID:Expression of the c-mpl proto-oncogene in human hematologic malignancies. 839 55

The SR-1 monoclonal antibody (MoAb) recognizes an epitope of the c-kit receptor (KR), present on normal hemopoietic CD34+ stem cells as well as on blasts from patients with acute leukemia. Cytometric analysis by indirect immunofluorescence with the SR-1 MoAb was performed in 98 patients with acute myeloblastic leukemia (AML) and in 37 patients with acute lymphoblastic leukemia (ALL) in order to detect the presence of the KR and to examine its prognostic significance. Sixty-nine of 98 (70%) AML patients were SR-1 positive independently of the FAB subtype, although a higher incidence of SR-1 positive cases was observed in M4 and M5 AML and in those cases that also coexpressed lymphoid antigens. Fourteen AML samples were studied by Northern blot analysis and the KR mRNA was detected in the majority of SR-1 positive cases and also in 2 of 3 SR-1 negative samples. Furthermore, "in vitro" cultures from 15 cases showed that recombinant human Stem cell factor (rhSCF) induced an increased proliferative activity in most tested cases (11/15); this was further enhanced when rhSCF was combined with rhIL-3 + rhGM-CSF (p = 0.007) and with the GM-CSF/IL-3 fusion protein PIXY321 (p = 0.003). Thirty-seven ALL cases were also studied and all but one were SR-1 negative. Interestingly, the only SR-1 positive case also coexpressed myeloid antigens and showed an "in vitro" response when stimulated with rhSCF. Finally, the complete remission (CR) rate, survival and event-free survival were evaluated in 75 AML patients who received standard and identical chemotherapy; unlike previous studies which utilized a different anti-KR MoAb (YB5.B8) and which showed a poor prognosis for KR positive patients, we were unable to document any significant difference in CR rate, survival and event-free survival.
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PMID:Cytofluorimetric and functional analysis of c-kit receptor in acute leukemia. 852 52

Interleukin-11 is a stromal cells derived cytokine which stimulates the proliferation of primitive haemopoietic progenitor cells. For this paper we have studied the constitutive expression of IL-11 mRNA in a panel of wellknown leukaemic cell lines and samples from AML patients at diagnosis. Moreover, the same cellular populations were evaluated for their proliferative response to recombinant-human-(r-hu). IL-11 alone and combined with r-hu-IL-3, granulocyte-macrophage colony stimulating factor (GM-CSF) and stem cell factor (SCF, c-kit ligand). The colony-forming ability of HL60, K562, KG1 cells and eight fresh AML cell populations was assessed by a clonogenic assay in methylcellulose. In eight additional AML cases the number of S-phase leukaemic cells induced by IL-11 was determined by the bromodeoxyuridine (BRDU) incorporation assay after 3d of liquid culture. IL-11, as single cytokine, did not stimulate the colony formation of the three myeloid cell lines under serum-containing and serum-free conditions. In contrast, the proliferation of the leukaemic cells in response to IL-3, GM-CSF and SCF was enhanced by co-incubation with IL-11, and this effect was reversed in blocking experiments by the anti-IL-11 Moab. When tested on primary AML samples, IL-11 alone showed little, if any, proliferative activity. However, it increased the IL-3-dependent blast colony formation in eight out of eight cases and GM-CSF in seven cases. IL-11 also augmented synergistically the number of CFU-L stimulated by SCF in seven cases. A combination of three factors (IL-11, SCF and IL-3) yielded optimal colony formation. The BRDU studies showed the significant increase of AML cells in S-phase when IL-11 was combined with SCF, whereas the two CSF had no activity on their own. Positive interaction was also observed when IL-11 was added to IL-3 supplemented cultures in five out of eight cases tested. Reverse transcriptase-polymerase chain reaction amplification (RT-PCR) demonstrated the constitutive expression of IL-11 mRNA in all the cell lines and 11/12 AML samples studied at diagnosis. These results indicate that IL-11 is expressed in leukaemic myeloid cells and that their proliferation is regulated by the cytokine which acts as a synergistic factor.
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PMID:Interleukin-11 (IL-11) acts as a synergistic factor for the proliferation of human myeloid leukaemic cells. 854 68

We investigated the effects of stem cell factor (SCF) on the growth of blast clonogenic cells from 27 patients with acute myeloblastic leukemia (AML) and 3 patients with chronic myelocytic leukemia in myeloid crisis. SCF alone showed a significant stimulatory activity in 15 of 30 patients (50%). A marked reduction in the number of blast cell colonies supported by SCF alone was noted by the addition of neutralizing antibody (Ab) against granulocyte-macrophage colony-stimulating factor (GM-CSF). Ab against interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) also moderately reduced the number of colonies, whereas Ab against granulocyte CSF (G-CSF) failed to do so. All four Ab together completely abolished the growth in 5 of 6 patients tested. c-kit antisense oligonucleotides reduced the colony formation supported by IL-3 or G-CSF or, in the absence of growth factor, in only 2 of 10 patients tested. SCF caused stimulation by acting synergistically with G-CSF, GM-CSF, IL-3, IL-6, IL-9, IL-11, and IL-12 in 20 of 27 (74%), 17 of 27 (63%), 14 of 28 (50%), 9 of 28 (32%), 1 of 15 (7%), 3 of 28 (11%), and 2 of 15 (13%) patients, respectively. Thus, SCF alone or in combination with some other factor stimulated the growth in 27 of 30 (90%) patients. Of 3 nonresponders, 2 were AML, M3 at presentation. G-CSF at the optimal concentration increased the sensitivity of blasts to SCF. Taken together, SCF acting in combination with other factors, but not alone, stimulates the growth of blast clonogenic cells. GM-CSF, IL-6, and TNF-alpha may be produced endogenously, whereas G-CSF and SCF may be supplied exogenously. Autocrine regulation of the growth of blasts seems to increase the responsiveness of the cells to any of these factors, allowing them to achieve a highly active growth state.
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PMID:Roles of stem cell factor in the in vitro growth of blast clonogenic cells from patients with acute myeloblastic leukemia. 856 3

There is increasing evidence for an interaction between acute leukemia cells and the microenvironment of the bone marrow. Blast cells from cases of acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) bind to cellular and extracellular matrix components of the bone marrow stroma. In AML, adhesion to stroma is mediated by the combined action of beta 1 (principally VLA-4) and beta 2 integrins, while in precursor-B ALL VLA-4 and VLA-5 integrins play a major role. Adhesion molecules such as CD31, CD44, non-beta 1, beta 2 integrins, growth factor receptors such as c-kit, and other molecules are also likely to play a role. Binding of acute leukemia blasts to ligands on stroma has several pathophysiological consequences. Stromal contact is able to inhibit programmed cell death (apoptosis) in a proportion of cases of both AML and ALL. In ALL, diffusible molecules derived from stroma appear to contribute. Marrow stroma also plays a part in regulating leukemic cell proliferation. While this is partly due to stromal production of hemopoietic growth factors, in soluble or transmembrane form or bound to extracellular matrix, signalling mediated directly by binding of adhesion molecules on leukemic cells may also have a role. Contact of ALL blasts with marrow fibroblasts is followed by migration of leukemic cells, utilizing VLA-4 and VLA-5 integrins, potentially allowing homing of blasts to favourable microenvironmental sites, or controlling egress into the circulation. AML cells compete for stromal binding sites with natural killer cells and cytotoxic lymphocytes, which are known to inhibit their clonogenic growth. We speculate that these complex interactions between leukemic blasts, cellular and matrix components of stroma, and cytotoxic lymphocytes, play a critical role in determining the fate of small numbers of leukemic cells surviving after cytotoxic chemotherapy.
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PMID:Interaction of acute leukemia cells with the bone marrow microenvironment: implications for control of minimal residual disease. 858 Aug 10

The murine monoclonal antibody YB5.B8 (CD117) identifies a transmembrane tyrosine kinase receptor encoded by the human c-kit proto-oncogene. In this study we investigated the expression of c-kit on different types of acute leukemia to determine the degree of specificity and sensitivity of this marker for the myeloid and lymphoid lineages. C-kit was positive in over half of the 115 cases of acute leukemia studied. Overall, two thirds of AML cases expressed c-kit, whereas only one of 23 ALL patients was c-kit positive. C-kit was also positive in 16 of 19 cases of myeloid blast crisis of myeloproliferative disorders and negative in four with a lymphoid phenotype. There was no correlation between c-kit expression and the degree of myeloid differentiation by FAB subtypes or other markers. We conclude that c-kit is a specific marker for the myeloid lineage, which is expressed early during hematopoietic differentiation and can aid the diagnosis of AML in difficult cases. More patients need to be tested to establish whether the expression of c-kit may define AML subgroups of prognostic significance.
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PMID:C-kit receptor (CD117) expression in acute leukemia. 860 74


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