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)

The number of genetic lesions necessary to generate leukemia in humans is unknown, but it is possible that certain specific abnormalities, eg, fusion genes, known to be associated with acute and chronic leukemia are produced relatively frequently in human cells but require other events to occur before the leukemia becomes manifest. We investigated this possibility by studying peripheral blood leukocytes from normal individuals and various hematopoietic cell lines for the presence and expression of the p210 and the p190 types of the BCR-ABL gene associated with chronic myeloid leukemia (CML) and acute lymphoblastic leukemia. We used two-step reverse transcriptase-polymerase chain reaction (RT-PCR) assays in which batches of 10(8) cells per sample were tested in 40 replicate reactions. We estimate that this assay is 1.5 logs more sensitive than the two-step RT-PCR assays that we use routinely to assess minimal residual disease. BCR-ABL fusion gene transcripts of various configurations were found in circulating leukocytes from 12 of the 16 healthy adults analyzed. Transcripts with an e1a2 junction (p190 BCR-ABL) were present in 11 and p210-type transcripts with b2a2 and/or b3a2 junctions were detected in 4 individuals. The same RT-PCR assays in non-CML cell lines showed the presence of classical or aberrant p210-type mRNA in 3 of 7 lines and of p190-type transcripts in all 7 lines of hematopoietic origin (HL60, KG1, U937, Kasumi, Jurkat, JVM13, and JVM25), whereas the NIH3T3 murine fibroblast line was reproducibly negative for these fusion genes. These findings confirm and extend previous reports on the detection of leukemia-associated genes in normal leukocytes and suggest that certain fusion genes are generated relatively frequently in hematopoietic cells, but only infrequently do the cells acquire the additional changes necessary to produce leukemia in humans. Although there is only a small probability that such innocent BCR-ABL-carrying leukocytes are detected by conventional RT-PCR assays, they may be the source of some sporadically positive tests in leukemia patients in long-term remission.
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PMID:The presence of typical and atypical BCR-ABL fusion genes in leukocytes of normal individuals: biologic significance and implications for the assessment of minimal residual disease. 978 74

Interferon-alpha (IFN-alpha) can be considered as treatment of choice for patients with chronic myeloid leukaemia (CML) in chronic phase. With this treatment major cytogenetic responses can be achieved in 30% to 50% of patients. Regular monitoring of cytogenetic response is essential for the therapeutic management of these patients. As conventional cytogenetics is not always successful, especially under IFN-alpha treatment, molecular cytogenetic methods have been established for the examination of interphase nuclei for the presence of the BCR-ABL fusion gene, the molecular counterpart of the Philadelphia chromosome. To demonstrate the value of these new methods we have analysed interphase nuclei from sequentially cultured bone marrow cells from 14 CML patients who were treated with IFN-alpha and whose bone marrow was investigated regularly during therapy. Dual-colour FISH with a breakpoint spanning BCR-YAC and a flanking cosmid from the ABL region was applied. When compared with conventional cytogenetics the results achieved by FISH were favourable. The most evident advantage of FISH analysis is that in case of failure of conventional cytogenetics a reliable determination of the remission status can be done. Together with other recent studies our results illustrate the advantages and limitations of the interphase FISH method for monitoring CML patients.
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PMID:Monitoring of remission status by fluorescence in situ hybridisation in chronic myeloid leukaemia patients treated with interferon-alpha. 986 21

The Philadelphia (Ph) chromosome, the main product of the (9;22)(q34;q11) translocation, is the cytogenetic hallmark of chronic myeloid leukemia (CML), a clonal myeloproliferative disorder of the hematopoietic stem cell; the Ph chromosome is also found in a sizeable portion of acute lymphoblastic leukemia (ALL) patients and in a small number of acute myeloid leukemia (AML) cases. At the molecular level, the t(9;22) leads to the fusion of the BCR gene (on chromosome 22) to the ABL gene (translocated from chromosome 9); this fusion gene BCR-ABL with its elevated tyrosine kinase activity must to be central to the pathogenesis of these disorders. Three different breakpoint cluster regions are discerned within the BCR gene on chromosome 22: M-bcr, m-bcr, and mu-bcr. Ph + leukemia cell lines are important tools in this research area. More than 20 ALL-and more than 40 CML-derived Ph + leukemia cell lines have been described. Furthermore, three Ph + B-lymphoblastoid cell lines, established from patients with Ph + ALL or CML, are available. Molecular analysis has documented BCR-ABL fusion genes in three apparently Ph chromosome-negative cell lines, all three derived from CML. Nearly all Ph + ALL cell lines have the m-bcr e1-a2 fusion gene (only two ALL cell lines have a b3-a2 fusion) whereas all CML cell lines, but one carry the M-bcr b2-a2, b3-a2 or both hybrids. The mu-bcr e19-a2 has been detected in one CML cell line. Four cell lines display a three-way translocation involving chromosomes 9, 22 and a third chromosome. Additional Ph chromosomes (up to five) have been found in four Ph + ALL cell lines and in 18 CML cell lines; though in some cell lines the extra Ph chromosome(s) might be caused by the polyploidy (tri- and tetraploidy) of the cells. Another modus to acquire additional copies of the BCR-ABL fusion gene is the formation of tandem repeats of the BCR-ABL hybrid as seen in CML cell line K-562. Both mechanisms, selective multiplication of the der(22) chromosome and tandem replication of the fusion gene BCR-ABL, presumably lead to enhanced levels of the fusion protein and its tyrosine kinase activity (genetic dosage effect). The availability of a panel of Ph + cell lines as highly informative leukemia models offers the unique opportunity to analyze the pathobiology of these malignancies and the role of the Ph chromosome in leukemogenesis.
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PMID:Leukemia cell lines: in vitro models for the study of Philadelphia chromosome-positive leukemia. 1007 Oct 72

Chronic myelogenous leukemia (CML) is characterized by the Philadelphia chromosome resulting from the translocation t(9-22) producing the chimeric 190 and 210 kDa BCR-ABL fusion proteins. Evolution of the CML to the more agressive acute myelogenous leukemia (AML) is accompanied by increased cellular proliferation and genomic instability at the cytogenetic level. We hypothezised that genomic instability at the nucleotide level and spontaneous error in DNA replication may also contribute to the evolution of CML to AML. Murine Ba/F3 cell line was transfected with the p190 and p210-encoding BCR-ABL oncogenes, and spontaneous mutation frequency at the Na-K-ATPase and the hypoxanthine guanine phosphoribosyl transferase (HPRT) loci were measured. A significant 3-5-fold increase in mutation frequency for the transfected cells relative to the untransfected control cells was found. Furthermore, we observed that BCR-ABL transfection induced an overexpression of DNA polymerase beta, the most inaccurate of the mammalian DNA polymerases, as well as an increase in its activity, suggesting that inaccuracy of DNA replication may account for the observed mutator phenotype. These data suggest that the Philadelphia abnormality confers a mutator phenotype and may have implications for the potential role of DNA polymerase beta in this process.
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PMID:Mutator phenotype of BCR--ABL transfected Ba/F3 cell lines and its association with enhanced expression of DNA polymerase beta. 1034 41

Quantitative competitive RT-PCR techniques have been developed to detect BCR-ABL fusion transcripts in CML but they are hardly reproducible. In this work, we have developed BCR-ABL quantification by real time RT-PCR using the ABI PRISM 7700 (Perkin Elmer), a new technique which allows simple and rapid quantification of a target sequence during the extension phase of PCR amplifications. A fluorogenic probe labeled with both a reporter dye at the 5' end and a quencher-dye at the 3' end hybridizes to the target sequence on the third exon of the ABL gene. The exonuclease activity of the Taq DNA polymerase cleaves the probe and releases the reporter dye, resulting in an increase in the fluorescence signal. The absolute copy number of the target sequence (BCR-ABL) or a control gene (ABL) in an unknown sample can then be calculated using a calibration curve prepared from a set of BCR-ABL RNA standards, and results are expressed as a BCR-ABL/ABL ratio. In our hands, the sensitivity of a serial dilution of total RNA from a positive cell line (K562) in a negative cell line (HL60) was 10(-4). Fifteen CML patients in cytogenetic CR, including 11 allografted patients, two autografted patients and two patients treated by IFN were studied sequentially by this new real time quantitative RT-PCR technique in parallel with conventional qualitative two round nested RT-PCR. The two autografted patients showed high BCR-ABL/ABL ratio in all samples. The two patients treated by IFN showed a progressive decrease in the ratio. In the 11 allografted patients, four were sequentially studied 2 years or more after allo-BMT, and all ratios were below 10(-4). The four patients remained in clinical and cytogenetic CR. The seven other allografted patients were studied immediately after the procedure. Three of them showed a progressive decrease in the BCR-ABL/ABL ratio which reached 10(-4) 7 months after allo-BMT. The three patients remained in hematologic and cytogenetic CR. The remaining four allografted patients had progressive increase of BCR-ABL ratio; three developed cytogenetic relapse 9, 11, 28 months after allo-BMT, and the last patient remained in cytogenetic CR in the bone marrow but developed granulocytic sarcoma. Results of real-time quantitative RT-PCR were in agreement with those of qualitative two round nested PCR. However, evolution changes in the results of real-time quantitative RT-PCR often preceded those of the conventional technique: a decrease of the BCR-ABL/ABL ratio preceded progression from first round to second round positivity and then negativity with the classical technique; conversely, an increase in the ratio preceded evolution with the classical technique. Thus, real-time quantitative RT-PCR may show better correlation with clinical and cytogenetic evolution than conventional qualitative techniques and may help in making early therapeutic decisions in CML, especially after molecular relapse.
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PMID:Detection of BCR-ABL transcripts in chronic myeloid leukemia (CML) using a 'real time' quantitative RT-PCR assay. 1036 Mar 86

Methods of minimal residual disease (MRD) detection in chronic myelogenous leukemia (CML) include chromosome analysis, reverse transcriptase polymerase chain reaction (RT-PCR) and fluorescence in situ hybridization (FISH) techniques. We report a novel method to detect intracellular BCR-ABL messenger on single cells using in situ RT-PCR, which can be performed on blood and marrow slides, without extraction of the nucleic acid. After cellular permeabilization and fixation, the mRNA BCR-ABL was reverse transcribed and amplified by PCR using digoxigenin-labelled dUTP. The reaction was revealed with the anti-digoxigenin FITC antibody. On the fluorescent microscope, a strong positive green fluorescence signal was observed in 98-99% cells in Ph1-positive cell lines. A faint signal was detected in 1.5% and 2% of negative cell lines. Likewise, a faint signal was found in 1.6-2.8% of the cells in five normal controls (mean 2.2 +/- 1.1%). The positive threshold for in situ RT-PCR was therefore determined as mean + 2 s.d. = 4.4% cells. We used in situ RT-PCR by comparison to cytogenetics (at least 30 mitoses examined), and two-step RT-PCR (10(-6) sensitivity in our hands) in bone marrow samples from 13 CML patients: two patients at diagnosis and 11 patients in hematological remission after alpha interferon (three patients), hydroxyurea (one patient) autologous bone marrow transplantation (BMT) (one patient) and allogeneic BMT (six patients). In the two diagnostic patients, 90 and 95% cells were respectively strongly positive by in situ RT-PCR. In the six patients treated by allogeneic BMT, the median percentage of positive cells was 2.4% (range 1.8-3.2). All six patients had normal karyotype and negative two-step RT-PCR results. In the five other patients, two were treated by hydroxyurea alone or autologous BMT, and 11 and 13% of the cells were strongly positive; three were treated with interferon and 14-62% of the cells were positive, generally weakly. All five patients had persistence of Ph1 (in 9-56% mitoses), and positive RT-PCR results after one round. In conclusion, in situ RT-PCR can specifically identify cells with BCR-ABL transcript and its results are concordant with those of karyotype and RT-PCR. Because of its limited sensitivity and specificity, however, it appears to have limited value in the analysis of MRD. On the other hand, it can evaluate the presence and intensity of BCR-ABL fusion transcript at the single cell level, and this could be useful in treatment monitoring.
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PMID:Detection of BCR-ABL transcripts in chronic myeloid leukemia (CML) using an in situ RT-PCR assay. 1037 89

Chronic myelogenous leukemia is a myeloproliferative disorder. It is characterized by a biphasic or triphasic clinical course in which a benign chronic phase is followed by transformation into an accelerated and blastic phase. On a cytogenetic and molecular level, most patients with chronic myelogenous leukemia demonstrate BCR-ABL fusion genes in hematopoietic progenitor cells, which result from a reciprocal translocation between chromosomes 9 and 22; this translocation leads to a shortened chromosome 22, called the Philadelphia chromosome. Translation of the fusion products yields chimeric proteins of variable size that have increased tyrosine kinase activity. Conventional chemotherapy with hydroxyurea or busulfan can achieve hematologic control but cannot modify the natural disease course, which inevitably terminates in a rapidly fatal blastic phase. Since its introduction in the 1980s, allogeneic stem-cell transplantation has provided the groundwork for a cure of chronic myelogenous leukemia. However, few patients are eligible for this treatment because of donor availability and age restrictions. Therapy with interferon-alpha alone or in combination with cytarabine suppresses the leukemic clone, produces cytogenetic remissions, and prolongs survival. It is an effective alternative first-line treatment for patients ineligible for transplantation. New drugs active against chronic myelogenous leukemia may show increased activity in the transformed phases of the disease. Novel therapies and concepts are developing rapidly; targeted molecules are tyrosine kinases, ras, and messenger RNA through antisense oligonucleotides. Alternative transplantation options, such as stem cells from autologous sources and matched unrelated donors, are expanding. Immunomodulation by adoptive immunotherapy and vaccine strategies hold significant promise for the cure of chronic myelogenous leukemia.
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PMID:Chronic myelogenous leukemia: biology and therapy. 1042 38

Chronic myelogenous leukemia (CML) is characterized by a balanced translocation that leads to the formation of the the BCR-ABL fusion gene. Although autografts can prolong the life of CML patients, patients relapse owing to malignant cells that persist in the graft and the host. This review discusses various experimental strategies that target the BCR-ABL gene or gene products that are downstream of it. Various strategies have been adopted to block BCR-ABL at the gene, mRNA and protein level. One promising strategy involves the cotransduction of a patient's hematopoietic stem cells (HSCs) with anti-BCR-ABL antisense sequences and a drug resistance gene. This might allow for the elimination of any residual disease in the graft or host by chemotherapy while rendering any drug-resistant, malignant CML HSCs functionally normal.
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PMID:Gene therapy for chronic myelogenous leukemia. 1043 Nov 69

The expression of the BCR-ABL fusion oncoprotein in primitive hematopoietic cells results in chronic myeloid leukemia. Over the past decade studies of several in vitro and in vivo cell systems revealed multiple signal transduction pathways activated by BCR-ABL. However, the precise function of BCR-ABL in the pathogenesis of CML is still unclear. The goal of this review is to synthesize data on intracellular signaling in the context of the diverse murine assay systems employed. We emphasize the importance of in vivo assays and assays using primary cells in understanding the biology of CML and the molecular mechanisms by which BCR-ABL exerts its effects.
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PMID:Growth factor independence and BCR/ABL transformation: promise and pitfalls of murine model systems and assays. 1045 Jul 47

A minority of chronic myeloid leukemia (CML) cases have breakpoint in the minor cluster region (m-bcr) of the BCR-ABL fusion gene. We report a patient with Ph-positive acute lymphoblastic leukemia and m-bcr breakpoint at diagnosis. The patient was treated with chemotherapy followed by an autologous peripheral blood stem cell transplantation, achieving a clinical and hematological complete remission but with persistence of the Philadelphia chromosome. One year later, she developed leukocytosis with a blood picture consistent with CML. She was treated with hydroxyurea and interferon alpha with no response. This is the second case of m-bcr CML reported presenting with features of lymphoid blast crisis or acute lymphoblastic leukemia.
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PMID:p190 BCR-ABL rearrangement in chronic myeloid leukemia and acute lymphoblastic leukemia. 1045 57


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