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)

The very rapid development of techniques based on use of the polymerase chain reaction (PCR) for characterizing molecular lesions in leukaemia and lymphoma mow offers the opportunity for monitoring residual disease at a sensitivity of one malignant cell in 10(5) or 10(6) normal cells. Maximal specificity is achieved when the DNA sequences amplified are truly leukaemia-specific (i.e. BCR/ABL in CML, PML/RAR-alfa in APL, AML1/ETO in t(8; 21) AML and CBFB/MYH1 in inv(16) AML). A good level of sensitivity may also be achieved by using immunoglobin heavy chain (IGH) and T-cell receptor (TCR) gene rearrangements if a clonospecific probe can be generated. For clinical purposes the crucial issues are the following: can PCR techniques be used for confirmation of diagnosis and evaluation of extent of disease? Can PCR data obtained be developed to quantitate the PCR product and thereby increase its predictive value? These and other issues are still a matter of debate and several studies are presently in progress to address these points.
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PMID:Minimal residual disease detection in human leukemias: biologic and clinical significance. 765 31

A novel cell line SKNO-1 was established from the bone marrow cells of a 22-year-old male suffering from acute myeloblastic leukaemia (AML) M2 with t(8;21) whose disease became resistant to chemotherapy after acquisition of 17 monosomy. SKNO-1 has been maintained for more than 36 months as a granulocyte-macrophage colony-stimulating factor (GM-CSF) dependent line. Morphologically, SKNO-1 cells were myeloblasts somewhat matured. The cells grow in suspension with a doubling time of 48-72 h. The survival and growth of SKNO-1 cells was absolutely dependent on granulocyte-macrophage colony stimulating factor (GM-CSF). SKNO-1 cells possessed t(8;21) and monosomy 17 which were observed in original leukaemic cells. We confirmed that the AML1 gene, located on chromosome 21, was rearranged and the AML1-MTG8 fusion transcript was expressed in SKNO-1 cells. Over-expression and mutation of the p53 gene were also detected in SKNO-1. It is likely that alterations of AML1 or MTG8 gene and p53 gene contribute to a disease progression in this case. Since t(8;21) translocation is a common chromosome abnormality in AML, and inactivation of the p53 gene may play a crucial role in disease progression in AML, SKNO-1 would be a useful tool for analysing the molecular mechanisms in myeloid leukaemogenesis.
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PMID:Establishment of a myeloid leukaemic cell line (SKNO-1) from a patient with t(8;21) who acquired monosomy 17 during disease progression. 777 16

Fluorescence in situ hybridization (FISH) and/or RNA-based polymerase chain reaction (RT-PCR) were used to analyze the breakpoints within the AML1 gene and the AML1 fusion transcripts in t(8;21) acute myeloid leukemia (AML). Twenty-two patients presented with the simple t(8;21)(q22;q22) and one with a complex variant t(8;2;16;21). In eight cases we used FISH with AML1 cosmid probes on metaphase chromosomes as well as RT-PCR to detect the junctions of MAL1/CDR (ETO,MTG8). Five cases were analyzed by FISH alone and ten cases by RT-PCR alone. By FISH we could identify three groups according to the distribution of the fluorescent signal. Signals were found in group 1 on chromosomes 21 and 21q+, in group 2 on chromosomes 21, 21q+ and 8q- and in group 3 on chromosomes 21 and 8q-. In all groups we could detect an identical AML1/CDR fusion transcript. This transcript showed splicing of AML1 exon 5 onto CDR. Thus regardless of the heterogeneity suggested by FISH, all the breakpoints in the AML1 gene were clustered in the same intro between exons 5 and 6. Our results bring to over one hundred the number of t(8;21) cases in which an identical translocation could be detected at molecular level by RT-PCR. The high sensitivity of the technique makes it suitable for the diagnosis of this translocation in different stages of the disease. The impact of the molecular detection of t(8;21) cells in clinical remission as far as the treatment and the management of the disease are concerned deserves further discussion.
Leukemia 1995 Feb
PMID:Identical fusion transcript associated with different breakpoints in the AML1 gene in simple and variant t(8;21) acute myeloid leukemia. 786 65

The WT1 gene encoding a zinc finger polypeptide is a tumor suppressor gene that plays a key role in the carcinogenesis of Wilms' tumor. Reverse transcriptase-polymerase chain reaction (RT-PCR) was used to examine relative levels of WT1 gene expression (defined in K562 cells as 1.00) in 45 patients with acute myelogenous leukemia (AML), 22 with acute lymphocytic leukemia (ALL), 6 with acute mixed lineage leukemia (AMLL), 23 with chronic myelogenous leukemia (CML), and 24 with non-Hodgkin's lymphoma. Significant levels of WT1 gene were expressed in all leukemia patients and for CML the levels increased as the clinical phase progressed. In striking contrast with acute leukemia, the levels of WT1 gene expression for NHL were significantly lower or even undetectable. Clear correlation was observed between the relative levels of WT1 gene expression (< 0.6 v > or = 0.6) and the prognosis for acute leukemia (AML, ALL, and AMLL). Patients with less than 0.6 levels had significantly higher rates of complete remission (CR), disease-free survival, and overall survival than those with > or = 0.6 levels, whereas CR could not be induced in any of the 7 patients with acute leukemia having greater than 1.0 levels of WT1 gene expression. The quantitation of the WT1 gene expression made it possible to detect minimal residual disease (MRD) in acute leukemia regardless of the presence or absence of tumor-specific DNA markers. Continuous monitoring of the WT1 mRNA was performed for 9 patients with acute leukemia. In 4 patients, MRD was detected 2 to 8 months before clinical relapse became apparent. In 2 other patients, the WT1 mRNA gradually increased after discontinuation of chemotherapy. No MRD was detected in the remaining 3 patients with AML who received intensive induction and consolidation therapy. Simultaneous monitoring of MRD by RT-PCR using primers for specific DNA markers in 3 patients (2 AML-M3 with PML/RAR alpha, and 1 AML-M2 with AML1/ETO) among these 9 patients detected MRD comparable with that obtained from quantitation of WT1 gene expression. In a patient with acute promyelocytic leukemia, the limits of leukemic cell detection by RT-PCR using either WT1 or promyelocytic leukemia/retinoic acid receptor-alpha gene primers were 10(-3) to 10(-4) and 10(-4) for bone marrow, and 10(-5) and 10(-4) for peripheral blood, respectively. Therefore, we conclude that WT1 is a new prognostic factor and a new marker for the detection of MRD in acute leukemia.
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PMID:WT1 as a new prognostic factor and a new marker for the detection of minimal residual disease in acute leukemia. 794 79

A large number of AML cases is reviewed in order to clarify biological characteristics of t(8;21) AML cells. The incidence of positivities for stem cell antigens, CD34 and HLA-DR, on blasts in t(8;21) AML is higher in comparison with those in other M2 or M3 categories. Frequent expression of CD34 and HLA-DR is indicative of the stem cell derivation of t(8;21) AML cells. The non-blastic leukemic cells in t(8;21) AML tend to lose the immature phenotype with discordant maturation such as low CD33 expression. Further, the blasts show frequent expression of the B-cell antigen, CD19, without other B-cell antigens and immunoglobulin gene rearrangements. AML cells with t(8;21) showed poorer response to granulocyte-macrophage colony-stimulating factor (GM-CSF) due to a decreased number of GM-CSF binding sites. The absence of monocytic differentiation in t(8;21) AML cells might represent the abnormal response to growth factors at the bifurcation stage of granulocyte and monocyte differentiation. Recently, breakpoint region genes for the 8;21 translocation in chromosome 8 and 21 have been isolated, 48-50 and have been named AML1 and ETO, respectively. The AML1 gene showed a strong homology with the Drosophila segmentation gene, runt, which is thought to be necessary for the Sex lethal gene expression. Since the GM-CSF receptor alpha chain gene locates in the pseudoautosomal region of the sex chromosome, the decrease of GM-CSF binding sites might be related to the AML1/ETO fusion gene expression. Further molecular genetic investigations of the breakpoint genes in the future are expected to clarify the unique biological events seen in this type of leukemia.
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PMID:Cellular characteristics of acute myeloblastic leukemia associated with t(8;21)(q22;q22). The Japanese Cooperative Group of Leukemia/Lymphoma. 804 46

The chromosomal translocation, t(8;21), is found frequently in acute myeloid leukemia (AML) with maturation (FAB-M2). We have previously mapped the translocation breakpoints of t(8;21) in a specific intron of the AML1 gene on chromosome 21. In this study, we cloned cDNAs synthesized from a cell line carrying t(8;21) by reverse transcription polymerase chain reaction (RT-PCR) using an AML1-specific primer. The analysis of the cDNAs structure has led to the identification of the fusion of AML1 with a gene named MTG8 on chromosome 8, which seems to be identical to ETO. Northern analysis using MTG8 (ETO) probes detected 7.8-kb and 6.2-kb RNAs and several minor RNAs in the cell line with t(8;21), but failed to detect any transcripts in a cell line without t(8;21). A set of primers were designed to detect the AML1/MTG8(ETO) fusion by PCR. The PCR amplified identical products in all 6 patients and one cell line with t(8;21), suggesting that the AML1/MTG8(ETO) fusion is a constant feature associated with t(8;21) and the junctions of the AML1/MTG8(ETO) fusion are restricted in a unique site. Because the PCR detection of the AML1/MTG8(ETO) fusion at the RNA level is highly sensitive, it can be used as a sensitive method for diagnosis and detection of minimal residual disease in t(8;21) leukemia.
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PMID:Junctions of the AML1/MTG8(ETO) fusion are constant in t(8;21) acute myeloid leukemia detected by reverse transcription polymerase chain reaction. 835 89

The t(8;21) translocation breakpoint, which is observed in acute myeloid leukemia (AML), has recently been cloned and a fusion transcript identified. We have now designed primer sets capable of amplifying the breakpoint junction of the fusion transcript by the reverse transcription-polymerase chain reaction (RT-PCR). Primer set 821U/821D1 amplified a 200-bp DNA fragment, and primer set 821U/821D2 amplified a 1.2-kb DNA fragment in all t(8;21)-positive AML tested. Sequence analysis of the amplified DNA fragments demonstrated that all fusion transcripts were fused at exactly the same site, indicating that this translocation breakpoint occurs within a single intron of the AML1 and ETO genes. Forty-five cycles of RT-PCR were used to detect residual t(8;21)-positive leukemia cells in three patients who had been in complete remission for 1, 3 and 5 years. Minimal residual disease was found in all three samples. Northern blot analysis demonstrated that two fusion transcripts of 7 and 10 kb were expressed in the t(8;21)-positive AML and that the ETO gene is not normally expressed in the hematopoietic system. Expression of a normal 5.5-kb ETO mRNA was found in the lung. From these results we concluded that expression of the ETO gene in t(8;21)-positive AML was activated as a result of the translocation.
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PMID:Expression of AML1-ETO fusion transcripts and detection of minimal residual disease in t(8;21)-positive acute myeloid leukemia. 845 49

Acute leukemia (AL) is a relatively uncommon, but dreaded, complication occurring with increased frequency in individuals with Down syndrome (DS). This selective update includes aspects of AL in DS in which a change or advancement in our understanding of this disease has occurred. Despite previous reports describing a worse outcome for these individuals, more recent studies have suggested an improved response to current treatment strategies (including high-dose AraC) equaling, or even surpassing, the survival of non-DS individuals with AL. An increased toxicity to methotrexate in DS patients has also been recognized. While the leukemia of DS infants has been described as megakaryoblastic, the spectrum of in vitro differentiation is much broader including (in addition to megakaryocytic colonies) various myeloid, macrophage, and even erythroid colonies. Although the cause(s) of DS-AL remains unknown, potential candidate genes include those encoded on chromosome 21 that play a role in other defined leukemias in non-DS individuals. The AML1/PEBP2alpha gene maps to the DS critical region and is characteristically associated with two leukemia-associated chromosomal translocations: 1) the 8;21 translocation involving an AML1/ETO fusion transcript commonly seen in acute myelogenous leukemia (AML) and; 2) a 3;21 translocation identified in certain chemotherapy-related myelodysplasias/leukemias and occasionally in the blast crisis of chronic myelogenous leukemia cells. Similarly, the ETS-related gene, ERG, involved in the AML 16;21 maps to the q22 region of chromosome 21. Lastly, a familial platelet disorder with a propensity to develop myeloid leukemia has been linked to 21q22.1-22.2 and conceivably might involve AML1, ERG or yet another gene.
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PMID:Down syndrome and leukemia, an update. 854 49

AML1, a gene encoding a protein of the PEBP2/CBF family of transcription factors is disrupted by translocations associated with human leukemia. In the t(8;21) acute myelogenous leukemia (AML), AML1 was found fused to a gene on chromosome 8 that we designated CDR (also known as ETO and MTG8). Immunoprecipitation experiments followed by immunoblotting using a combination of antibodies against different epitopes of one of the predicted chimeric proteins encoded by a fully characterized fusion transcript enabled us to visualize a chimeric protein in the t(8;21) Kasumi-1 cell line. The estimated size of this protein is 64 kDa. Immunoblotting of leukemic blasts containing the t(8;21) detected a protein of the same size. Immunofluorescence experiments indicate that the chimeric protein is localized in the nucleus. A normal AML1 protein of 27 kDa was also detected in t(8;21) Kasumi-1 cells. It remains to be established by which mechanism the mutant AML1 isoform may contribute to the leukemogenesis process of t(8;21)-positive acute myeloid leukemia.
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PMID:Detection and subcellular localization of an AML1 chimeric protein in the t(8;21) positive acute myeloid leukemia. 857 Feb 22

For therapeutic purposes, two chimeric DNA/RNA hammerhead ribozymes were synthesized to cleave AML1/MTG8, the t(8;21)-associated fusion mRNA of acute myeloid leukemia. One ribozyme, A/MRZ-1, recognizes the area adjacent to the fusion point between AML1 and MTG8, and cleaves six bases downstream from this point. The other, MRZ-1, recognizes the MTG8 sequence. Both ribozymes cleaved synthetic chimeric DNA/RNA substrates at theoretical sites. Neither cleaved AML1 RNA. A/MRZ-1 cleaved only AML1/MTG8 RNA, and MRZ-1 cleaved both AML1/MTG8 and MTG8 RNAs. The two ribozymes showed growth inhibition of an acute myeloid leukemia cell line carrying t(8;21), SKNO-1 cells. The same extent of growth inhibition was attained by antisense oligonucleotides against AML1/MTG8 RNA. The results suggest that the ribozyme has the potential to be developed as a useful agent for gene therapy, in particular for leukemia with t(8;21).
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PMID:Designing of chimeric DNA/RNA hammerhead ribozymes to be targeted against AML1/MTG8 mRNA. 860 80


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