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)

We investigated the impact of carrying more than one BCR-ABL1 mutation in 207 patients with chronic myeloid leukemia (102 chronic, 61 accelerated, and 44 blast phase) post-imatinib failure. Seven (8%) of 92 patients carrying mutations had more than one mutation: 4 (4%) in chronic phase, 2 (2%) in accelerated phase, and one (1 %) in blast phase. The cytogenetic response rate to second generation TKIs for patients with no, one, or more than one mutation was 88%, 69%, 50% (P=0.03) in chronic phase, 54%, 42%, 50% in accelerated phase (P=0.67), and 35%, 25%, 0% (P=0.63) in blast phase, respectively. No differences were observed in event free survival or overall survival in accelerated or blast phase according to their mutational status. However, the 4-year event free survival rates among patients in chronic phase with no, one, or more than one BCR-ABL1 mutation were 56%, 49%, and 0%, respectively (P=0.02), with overall survival rates of 91%, 69%, and 75%, respectively (P=0.13). In conclusion, patients with more than one BCR-ABL1 mutation fare worse than those with no or one mutation.
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PMID:Outcome of patients with chronic myeloid leukemia with multiple ABL1 kinase domain mutations receiving tyrosine kinase inhibitor therapy. 2135 4

Molecular monitoring is a key component of the management of patients with chronic myeloid leukemia. The current recommendation is that molecular monitoring be performed in place of cytogenetic assessment when a major molecular response (MMR) is achieved. With the more potent kinase inhibitors nilotinib and dasatinib now approved as front-line therapy, more patients will achieve an MMR and will benefit from molecular monitoring. There is a strong correlation between certain BCR-ABL1 levels and the cytogenetic response, which means that molecular monitoring may act as a surrogate for cytogenetic response, but only if the BCR-ABL1 values are converted to the international reporting scale. Furthermore, improvements in the limit of BCR-ABL1 detection and reduction of intra-assay variability are ongoing issues of importance for molecular monitoring. Standardization of molecular methods to accurately assess the patient response also remains a challenge, despite the recent certification of international scale reference materials.
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PMID:Chronic myelogenous leukemia: monitoring response to therapy. 2136 71

Molecular testing for the BCR-ABL1 fusion gene by real time quantitative polymerase chain reaction (RT-qPCR) is the most sensitive routine approach for monitoring the response to therapy of patients with chronic myeloid leukaemia. In the context of tyrosine kinase inhibitor (TKI) therapy, the technique is most appropriate for patients who have achieved complete cytogenetic remission and can be used to define specific therapeutic milestones. To achieve this effectively, standardization of the laboratory procedures and the interpretation of results are essential. We present here consensus best practice guidelines for RT-qPCR testing, data interpretation and reporting that have been drawn up and agreed by a consortium of 21 testing laboratories in the United Kingdom and Ireland in accordance with the procedures of the UK Clinical Molecular Genetics Society.
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PMID:Guidelines for the measurement of BCR-ABL1 transcripts in chronic myeloid leukaemia. 2138 19

Chronic myeloid leukemia (CML) is a clonal myeloproliferative disease caused by recombination between the BCR gene on chromosome 22 and the ABL1 gene on chromosome 9. This rearrangement generates the BCR-ABL1 fusion gene that characterizes leukemic cells in all CML cases. In about 90% of cases, the BCR-ABL1 rearrangement is manifest cytogenetically by the Philadelphia (Ph) chromosome, a derivative of the reciprocal translocation t(9;22)(q34;q11.2). For the remaining cases, recombination may be more complex, involving BCR, ABL1, and genomic sites on one or more other chromosomal regions, or it may occur cryptically within an apparently normal karyotype. Detection of the Ph and associated t(9;22) translocation is a recognized clinical hallmark for CML diagnosis. The disease has a natural multistep pathogenesis, and during chronic phase CML, the t(9;22) or complex variant is usually the sole abnormality. In 60-80% of cases, additional cytogenetic changes appear and often forecast progression to an accelerated disease phase or a terminal blast crisis. Because new frontline therapies such as imatinib specifically target the abnormal protein product of the BCR-ABL1 fusion gene to eliminate BCR-ABL1 positive cells, there is a new reliance on the cytogenetic evaluation of bone marrow cells at diagnosis, then at regular posttreatment intervals. Combined with other parameters, presence or absence of Ph-positive cells in the bone marrow is a powerful early indicator for clinical risk stratification. Cytogenetic changes detected at any stage during treatment, including in the BCR-ABL1-negative cells, may also provide useful prognostic information. Laboratory methods detailed here extend from initial collection of peripheral blood or bone marrow samples through cell culture with or without synchronization, metaphase or interphase harvest, hypotonic treatment and fixation, slide preparation for G-banding or fluorescent in situ hybridization (FISH), and final interpretation.
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PMID:Chronic myeloid leukemia: cytogenetic methods and applications for diagnosis and treatment. 2143 33

Chromosomal rearrangements involving the ABL1 gene, leading to a BCR-ABL1 fusion gene, have been mainly associated with chronic myeloid leukemia and B-cell acute lymphoblastic leukemia (ALL). At present, six other genes have been shown to fuse to ABL1. The kinase domain of ABL1 is retained in all chimeric proteins that are also composed of the N-terminal part of the partner protein that often includes a coiled-coil or a helix-loop-helix domain. These latter domains allow oligomerization of the protein that is required for tyrosine kinase activation, cytoskeletal localization, and neoplastic transformation. Fusion genes that have a break in intron 1 or 2 (BCR-ABL1, ETV6-ABL1, ZMIZ1-ABL1, EML1-ABL1, and NUP214-ABL1) have transforming activity, although NUP214-ABL1 requires amplification to be efficient. The NUP214-ABL1 gene is the second most prevalent fusion gene involving ABL1 in malignant hemopathies, with a frequency of 5% in T-cell ALL. Both fusion genes (SFPQ-ABL1 and RCSD1-ABL1) characterized by a break in intron 4 of ABL1 are associated with B-cell ALL, as the chimeric proteins lacked the SH2 domain of ABL1. Screening for ABL1 chimeric genes could be performed in patients with ALL, more particularly in those with T-cell ALL because ABL1 modulates T-cell development and plays a role in cytoskeletal remodeling processes in T cells.
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PMID:ABL1 fusion genes in hematological malignancies: a review. 2143 2

Acquired resistance to ABL1 tyrosine kinase inhibitors (TKIs) through ABL1 kinase domain mutations, particularly the gatekeeper mutant T315I, is a significant problem for patients with chronic myeloid leukemia (CML). Using structure-based drug design, we developed compounds that bind to residues (Arg386/Glu282) ABL1 uses to switch between inactive and active conformations. The lead "switch-control" inhibitor, DCC-2036, potently inhibits both unphosphorylated and phosphorylated ABL1 by inducing a type II inactive conformation, and retains efficacy against the majority of clinically relevant CML-resistance mutants, including T315I. DCC-2036 inhibits BCR-ABL1(T315I)-expressing cell lines, prolongs survival in mouse models of T315I mutant CML and B-lymphoblastic leukemia, and inhibits primary patient leukemia cells expressing T315I in vitro and in vivo, supporting its clinical development in TKI-resistant Ph(+) leukemia.
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PMID:Conformational control inhibition of the BCR-ABL1 tyrosine kinase, including the gatekeeper T315I mutant, by the switch-control inhibitor DCC-2036. 2162 88

Prospective identification of patients whose chronic myeloid leukemia (CML) will progress to blast crisis is currently not possible. PP2A is a phosphatase and tumor suppressor that regulates cell proliferation, differentiation, and survival. Cancerous inhibitor of PP2A (CIP2A) is a recently described inhibitor of PP2A in breast and gastric cancer. The aim of this study was to investigate whether CIP2A played a role in CML and whether PP2A or its inhibitor proteins CIP2A or SET could predict clinical outcome. At the time of diagnosis of CML, patients who will later progress to blast crisis have significantly higher levels of CIP2A protein (P < .0001) than patients who do not progress, suggesting that PP2A is functionally inactive. We show that the potential mechanism for disease progression is via altered phosphorylation of the oncogene c-Myc. Knockdown of CIP2A results in increased PP2A activity, decreased c-Myc levels, and a decrease in BCR-ABL1 tyrosine kinase activity. We demonstrate that CIP2A levels at diagnosis can consistently predict patients who will progress to blast crisis. The data show that CIP2A is biologically and clinically important in CML and may be a novel therapeutic target.
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PMID:Cancerous inhibitor of PP2A (CIP2A) at diagnosis of chronic myeloid leukemia is a critical determinant of disease progression. 2149 Mar 38

A 65-year-old patient with a high hemoglobin and hematocrit was treated for 14 months with therapeutic phlebotomy when cytogenetics of bone marrow revealed 100% cells with the Ph chromosome and 45% of the Ph+ cells contained trisomy 8. Treatment with tyrosine kinase inhibitors did not reduce the BCR-ABL1 fusion positive clone. Instead, the Ph positive cells acquired further the t(8;21)/RUNX1-RUNX1T1, del(4q) and trisomy 15 chromosomal abnormalities which were resistant to further treatment. Literature review revealed eight other patients who either had t(9;22) and t(8;21) simultaneously or developed t(8;21) in the Ph positive clone. We conclude that there are rare patients with CML who either present in blast crisis with coexistence of t(9;22) and t(8;21) with or without +8, or progress to blast crisis with acquiring RUNX1-RUNX1T1 in the BCR-ABL1 clone which may or may not be therapy related and represent a later event in a multistep pathogenesis.
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PMID:Development of t(8;21) and RUNX1-RUNX1T1 in the Philadelphia-positive clone of a patient with chronic myelogenous leukemia: additional evidence for multiple steps involved in disease progression. 2150 17

Fanconi D2 (FANCD2) is monoubiquitinated on K561 (FANCD2-Ub) in response to DNA double-strand breaks (DSBs) to stimulate repair of these potentially lethal DNA lesions. FANCD2-Ub was upregulated in CD34+ chronic myeloid leukemia (CML) cells and in BCR-ABL1 kinase-positive cell lines in response to elevated levels of reactive oxygen species (ROS) and DNA cross-linking agent mitomycin C. Downregulation of FANCD2 and inhibition of FANCD2-Ub reduced the clonogenic potential of CD34+ CML cells and delayed BCR-ABL1 leukemogenesis in mice. Retarded proliferation of BCR-ABL1 positive FANCD2-/- leukemia cells could be rescued by FANCD2 expression. BCR-ABL1 positive FANCD2-/- cells accumulated more ROS-induced DSBs in comparison with BCR-ABL1 positive FANCD2+/+ cells. Antioxidants diminished the number of DSBs and enhanced proliferation of BCR-ABL1 positive FANCD2-/- cells. Expression of wild-type FANCD2 and FANCD2(S222A) phosphorylation-defective mutant (deficient in stimulation of intra-S phase checkpoint, but proficient in DSB repair), but not FANCD2(K561R) monoubiquitination-defective mutant (proficient in stimulation of intra-S phase checkpoint, but deficient in DSB repair) reduced the number of DSBs and facilitated proliferation of BCR-ABL1 positive FANCD2-/- cells. We hypothesize that FANCD2-Ub has an important role in BCR-ABL1 leukemogenesis because of its ability to facilitate the repair of numerous ROS-induced DSBs.
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PMID:Monoubiquitinated Fanconi anemia D2 (FANCD2-Ub) is required for BCR-ABL1 kinase-induced leukemogenesis. 2230 77

Activation-induced deaminase (AID), a cytidine deaminase, can accelerate the acquisition of BCR-ABL1 kinase domain mutations in human CML. In the present study, we investigated the expression of AID and Bcr-Abl in CML cells derived from 35 clinical patients. We found that both AID and Bcr-Abl were correlatively over-expressed in CML-LBC (lymphoid blast crisis) cells as compared with those in CML-CP (chronic phase) cells. AID expression was significantly decreased in CML-LBC cells after treated with arsenic trioxide, especially together with imatinib. We also observed satisfied therapy effects of As(2)O(3) and imatinib on patients with CML blast crisis. These data suggest that decreasing AID expression in CML-LBC by As(2)O(3) may be a promising approach to CML treatment.
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PMID:AID expression is correlated with Bcr-Abl expression in CML-LBC and can be down-regulated by As2O3 and/or imatinib. 2157 Jan 18


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