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PubMed2006

Gene expression changes associated with progression and response in chronic myeloid leukemia.

Chronic myeloid leukemia (CML) is a hematopoietic stem cell disease with distinct biological and clinical features. The biologic basis of the stereotypical progression from chronic phase through accelerated phase to blast crisis is poorly understood. We used DNA microarrays to compare gene expression in 91 cases of CML in chronic (42 cases), accelerated (17 cases), and blast phases (32 cases). Three thousand genes were found to be significantly (P < 10(-10)) associated with phase of disease. A comparison of the gene signatures of chronic, accelerated, and blast phases suggest that the progression of chronic phase CML to advanced phase (accelerated and blast crisis) CML is a two-step rather than a three-step process, with new gene expression changes occurring early in accelerated phase before the accumulation of increased numbers of leukemia blast cells. Especially noteworthy and potentially significant in the progression program were the deregulation of the WNT/beta-catenin pathway, the decreased expression of Jun B and Fos, alternative kinase deregulation, such as Arg (Abl2), and an increased expression of PRAME. Studies of CML patients who relapsed after initially successful treatment with imatinib demonstrated a gene expression pattern closely related to advanced phase disease. These studies point to specific gene pathways that might be exploited for both prognostic indicators as well as new targets for therapy.

Antineoplastic Agents↗
PubMed2006

Chronic myeloid leukemia: why does it evolve from chronic phase to blast transformation?

Clinically chronic myeloid leukemia is a biphasic or triphasic disease that is usually diagnosed in the initial 'chronic', 'indolent' or 'stable' phase and then spontaneously evolves after some years into an advanced phase. This advanced phase can sometimes be subdivided into an earlier accelerated phase and a later blast phase or blast transformation--in about one-half of patients the chronic phase transforms unpredictably and abruptly to a blast phase, while in the other half of patients, the disease evolves somewhat more gradually, through an accelerated phase, which may last for months or years, before a blast phase ensues; this may have myeloblastic or lymphoblastic features. Although much is now known about the molecular biology of the disease, the molecular basis of disease progression is still obscure. The popular thinking has been that one or more probably a sequence of additional genetic events occurs in the BCR-ABL positive clone. When the critical combination of additional events is achieved, clinically definable transformation occurs. Here we review what is known of the mechanisms underlying the evolution of chronic myeloid leukemia from a chronic phase to a blast transformation.

Animals↗
PubMed1996

Unrelated allogeneic bone marrow transplantation using high-dose busulfan and cyclophosphamide (BU-CY) for the preparative regimen.

This study reviews results of a radiation-free preparative regimen consisting of busulfan and cyclophosphamide in 65 unrelated allogeneic bone marrow transplant recipients. Thirty-eight patients had chronic myelogenous leukemia (17 patients chronic phase, 13 patients accelerated phase, eight patients blast phase), 19 patients had acute leukemia (second complete remission or relapse) and eight patients had myelodysplasia. The patients were transplanted at four different medical centers from July 1988 to November 1992. Ages ranged 4-48 years (median 32). Fifty-seven patients received busulfan 16 mg/kg and cyclophosphamide 120 mg/kg, and eight received busulfan at doses between 15 and 17 mg/kg and cyclophosphamide at doses 100-200 mg/kg as preparative regimens. All patients received cyclosporine for graft-versus-host disease prophylaxis; in addition 46 patients received corticosteroid, 38 methotrexate, six anti-CD5 ricin A-immunotoxin, and four T cell-depleted bone marrow. Median follow-up of survivors was 53 months (range 15-68 months). Four year actuarial survival was 24 +/- 12%. Four-year survival based on disease was 29 +/- 27% for chronic myelogenous leukemia (CML) in chronic phase, 20 +/- 9% for chronic myelogenous leukemia in accelerated phase, 0% for chronic myelogenous leukemia in blast phase, 32 +/- 40% for acute leukemia, and 38 +/- 34% for myelodysplasia. Actuarial survival was 66 +/- 40% in patients age < 20 years, vs 23 +/- 13% for patients ages 20 to 40, and 10 +/- 14% for patients age > 40 years. Fifty patients (88%) engrafted. Graft failure occurred in eight patients. Acute graft-versus-host disease grade II-IV occurred in 36 (72%). Two patients relapsed after engraftment with the donor cells and died of leukemia within a month of relapse. The most common causes of death were graft-versus-host disease (37%), and transplant-related toxicity (59%); relapse (4%) was a rare cause of death. Busulfan/cyclophosphamide is an effective preparative regimen in unrelated bone marrow transplantation permitting adequate engraftment and a low relapse rate. Best results are observed in patients less than 20 years old.

Adolescent↗
PubMed1994

High frequency of RAS oncogene mutation in chronic myeloid leukemia patients with myeloblastoma.

To determine the role of the mutated RAS oncogene during development into the blast phase, we sequentially analysed RAS oncogene mutations in the bone marrow of 27 patients with chronic myeloid leukemia (CML). DNA from CML patients in chronic and blast phases and nude mouse tumor DNA formed by a tumorigenicity assay (in vivo selection assay) were subjected to the polymerase chain reaction (PCR) and oligonucleotide hybridization. In addition, one patient in the chronic phase and five in the blast phase were also analysed. PCR analysis of DNA from the leukemic patients revealed that 3.6% (1 of 28) and 15.6% (5 of 32) of the patients in the chronic and blast phases, respectively, had RAS mutations. N- or K-RAS oncogene mutations were found mostly in the blast phase (4 of the 5 patients with the RAS oncogene mutation). Of the 5 patients with the RAS oncogene mutation, three developed myeloblastoma, a myeloblast cell tumor, in the blast phase. None of the 28 patients without the RAS mutation developed myeloblastoma. These results suggest that the RAS oncogene mutation occurred in the late stage of the disease and contributed to transformation to the blast phase in some CML patients. The findings also indicate an association between the presence of the RAS mutation and the formation of myeloblastoma.

3T3 Cells↗
PubMed1987

Chronic myelogenous leukemia: amplification of a rearranged c-abl oncogene in both chronic phase and blast crisis.

The specific genetic events that distinguish the blast crisis from the chronic phase cells of chronic myelogenous leukemia (CML) are unknown. The most common karyotypic change that occurs as CML evolves from chronic phase to blast crisis is the development of multiple Philadelphia (Ph1) chromosomes, each of which is presumably harboring a translocated c-abl oncogene. We describe here a patient with CML who presented in lymphoid blast crisis with three Ph1 chromosomes/metaphase associated with an amplified, rearranged c-abl oncogene fragment and high levels of the aberrant 8-kilobase bcr-abl transcript. This rearranged c-abl fragment was amplified to a similar degree in both the patient's blast crisis cells and in his terminally differentiated granulocytes, but the level of the aberrant CML-specific bcr-abl transcript was some eight- to 16-fold higher in the blast crisis cells v the granulocytes. This analysis indicates that genomic amplification of a translocated c-abl oncogene, although perhaps important in the evolution of CML, nevertheless cannot, by itself, be the sole genetic event giving rise to blast crisis.

Adult↗
PubMed2000

Telomere dynamics and genetic instability in disease progression of chronic myeloid leukemia.

Chronic myeloid leukemia (CML) is characterized by a Philadelphia (Ph) translocation creating a novel BCR-ABL oncoprotein, and CML patients have a chronic phase for several years followed by an intractable blast cell proliferation, called blast transformation. In the blast phase, more than 60% of patients show additional cytogenetic changes, e. g., double Ph, +8, i(17q). In this review, we would like to address genetic changes, including genome instability, cytogenetic changes, and telomere dynamics that relate to karyotypic instability. In the chronic phase, approximately 60% of CML patients show reduced telomere length without highly elevated telomerase activity or microsatellite alterations, indicating that telomere reduction may be linked to cell replication. Therefore, the Ph translocation might be a first event to immortalize cell proliferation. In the blast phase, 50% of CML patients have high levels of elevated telomerase activity and the same number of patients had microsatellite changes. Of note is that most patients with telomerase up-regulation in the blast phase had additional cytogenetic changes and >60% of them showed microsatellite changes at least at one locus. In contrast, most patients without telomerase activity did not show microsatellite changes. These findings may indicate that telomerase up-regulation in the blast phase of CML patients is closely associated with microsatellite changes (representative of genome instability), while blast cells in the remaining patients (30%) maintain their proliferative capability without microsatellite changes and telomerase up-regulation. This further suggests that there is also an unknown mechanism for genome stability without the process of telomerase up-regulation in some patients with CML in blast crisis.

Cell Transformation, Neoplastic↗
PubMed1997

Telomerase activity and cytogenetic changes in chronic myeloid leukemia with disease progression.

Progressive telomere shortening is thought to be important in the regulation of cellular senescence and that the upregulation or reactivation of telomerase activity may be a critical if not rate limiting step in the development of neoplastic cells. To obtain information about telomeres and telomerase activity in hematopoietic neoplasia at various disease stages, we evaluated 54 samples obtained from 41 patients with chronic myeloid leukemia (CML) using a combination of fluorescent-telomeric repeat amplification protocol and an internal telomerase assay standard. The terminal restriction fragment (TRF) lengths in the blast phase was reduced compared to that in the chronic phase (4.53 +/- 0.72 kb vs 6.13 +/- 1.68 kb; P = 0.0005). All samples obtained from CML in the chronic phase (n = 33) had detectable telomerase activity above background, regardless of age. In the blast phase (n = 21), a significant increase of telomerase activity was detected compared to that in the chronic phase (33.84 +/- 37.86% vs 6.08 +/- 3.21; P = 0.016). Among patients in the blastic phase, 50% of patients had moderate to high telomerase activity (>10 relative value), and the remaining patients had telomerase activity higher than that in the normal peripheral blood cells. No significant differences in hematologic findings, duration of chronic phase or blast phase, and telomere length in the blastic phase were noted between these two groups separated by telomerase activity. CML patients with moderate to high telomerase activity had a high frequency of additional cytogenetic changes (P = 0.01).

Adolescent↗
PubMed2006

[Combination of imatinib and anagrelide in treatment of chronic myeloid leukemia in blastic phase].

Chronic myeloid leukemia in blast phase (BP) is resistant to chemotherapy and majority of patients die within 6 months. Inhibitor Bcr-Abl tyrosine kinase imatinib mesylate dramatically improved outcome of patients in chronic phase (CP) and is also effective in BP of CML. The prognosis of patients treated with imatinib in BP is worse than in CP. High platelet counts are often observed at diagnosis or in the subsequent course of the CML in about 25% of patients. Thrombohemorrhagic complications associated with the thrombocythemia may be serious. Anagrelide selectively reduces circulating platelets and is used in treatment of thrombocythemia in chronic myeloproliferative disorders. Efficacy and safety of combination imatinib mesylate with anagrelide was demonstrated in chronic and accelerated phase of CML. No study about the use of imatinib with anagrelide in BP has been found. 51-year-old white man with CML presented in blast phase was followed for 4 years. Imatinib mesylate in dose of 600 mg p.o. qd. was administered after the failure of initial chemotherapy. The patient was treated with imatinib for 45 months, 14.5 months in combination with anagrelide. Partial hematologic response in duration of 33 months was induced by imatinib, cytogenetic response was not reached. Imatinib-resistant thrombocythemia was controlled with anagrelide in dose of 0.5-1 mg p.o. qd. No thrombohemorrhagic complications were observed. The patient tolerated the combination of imatinib and anagrelide well and long-term survival gave him the chance of treatment with the new tyrosin kinase inhibitor (dasatinib).

Antineoplastic Agents↗
PubMed1990

Rearrangement and expression of p53 in the chronic phase and blast crisis of chronic myelogenous leukemia.

We tested a population of over 60 patients with chronic myelogenous leukemia (CML) for changes in the structure and expression of the p53 gene, which is located on chromosome 17. Six of 27 (22%) blast crisis samples and 3 of 5 (60%) accelerated phase samples had rearrangements of chromosome 17, whereas only 3 of 42 (7%) chronic phase patients had cytogenetic changes in chromosome 17. There was no loss of heterozygosity during the transition to blastic crisis among seven individuals who were informative for polymorphic probes for regions in or around the p53 gene on 17p. One patient in the chronic phase and one patient in the blastic phase of the 61 CML patients studied exhibited rearrangements of the p53 gene that were detectable by Southern analysis. One p53 allele was rearranged in the chronic phase patient and both p53 alleles were rearranged in the blastic phase patient. The p53 messenger RNA (mRNA) was of normal size (2.8 kb) in chronic phase and blast crisis, and the expression of the p53 gene was at least as high or higher in blast crisis as in the chronic phase of CML. The high incidence of abnormalities of chromosome 17 in blast-crisis CML found in our studies and the discovery of rearrangements of the p53 gene in two CML patients studied suggest that further study with probes for the p53 gene and anonymous polymorphic sites in chromosome 17 should be conducted in CML.

Blast Crisis↗
PubMed1992

Effect of dipyridamole, theophyllamine and verapamil on spontaneous in vitro proliferation of myelogenous leukaemia cells.

Dipyridamole strongly inhibited spontaneous in vitro proliferation of peripheral blood mononuclear cells from patients with acute myelogenous leukaemia (n = 9), chronic myelogenous leukaemia in first chronic phase (n = 4) and blast phase (n = 1). Theophyllamine and verapamil also inhibited proliferation of leukaemia cells from all patients except the CML patient in blast phase where only minimal inhibition was seen. Only dipyridamole caused strong inhibition in concentrations corresponding to the therapeutic serum level, and this inhibition was not influenced by the presence of high levels of interleukin 2.

Aminophylline↗
PubMedDate not supplied

[Patient's age as a risk factor for central nervous system involvement in chronic myeloid leukemia].

Clinical and neuropathological examinations were carried out in 32 cases of chronic myeloid leukaemia dying in the blast phase. The hypothesis is put forward that in chronic myeloid leukaemia lower age of the patient (below 45 years) is a risk factor for development of central nervous system involvement which may be related possibly to high leucocytosis occurring more frequently in these cases in the blast phase leading to leucostasis and leukaemic infiltrations in the brain. The duration of the chronic phase and blast phase, and the pattern of leucocytosis in the chronic phase were similar in younger and older patients.

Adolescent↗
PubMed1999

Telomere length shortening is associated with disease evolution in chronic myelogenous leukemia.

We studied telomere length in the peripheral blood leukocyte samples of a large group of patients with chronic myelogenous leukemia (CML) by Southern blot hybridization using the (TTAGGG)4 probe. The average telomere length expressed as the peak telomere repeat array (TRA) of the peripheral blood samples obtained from a group of 34 healthy age-matched controls ranged between 7.6 and 10.0 kb and the mean peak TRA was 8.7 kb. Forty-one patients in the chronic phase of CML were studied; 32/41 (78%) showed telomere reduction (<7.6 kb) relative to age-matched controls and the mean peak TRA was 6.4 kb (range 4.0-10.6 kb). Serial samples were analysed from 12 patients at both chronic phase and during disease progression. The leukocyte DNA of all 12 patients in accelerated phase and/or blast crisis showed telomere reduction relative to age-matched controls and the mean peak TRA was 4.1 kb (range 3.0-5.4 kb). The peak TRA in the accelerated or blast phase was reduced compared with the corresponding paired sample in the chronic phase in all cases studied. These data show that a marked reduction in telomere length is associated with disease progression in CML.

Adult↗
PubMed2000

Prognostic implications of differences in telomere length between normal and malignant cells from patients with chronic myeloid leukemia measured by flow cytometry.

Chronic myeloid leukemia (CML) is a clonal, multilineage myeloproliferative disorder characterized by the Philadelphia chromosome (Ph) and a marked expansion of myeloid cells. Previous studies have indicated that the telomere length in blood cells may indicate their replicative history. However, the large variation in telomere length between individuals complicates the use of this parameter in CML and other hematologic disorders. To circumvent this problem, we compared the telomere length in peripheral blood or bone marrow cells with purified normal (Ph(-)) T lymphocytes from the same CML patient using fluorescence in situ hybridization and flow cytometry. Overall telomere fluorescence was significantly reduced in Ph(+) cells from patients with CML compared to blood leukocytes from normal individuals (P < 0.001) or normal (Ph(-)) T lymphocytes from the same individuals (n = 51, P < 0.001). Cells from patients in accelerated phase or blast phase (AP/BP) showed significantly shorter average telomere length than cells from patients in chronic phase (CP, P = 0.02) or cytogenetic remission (CR, P = 0.03). Patients in CP who subsequently developed BP within 2 years had significantly shorter telomeres than those who did not develop BP for at least 2 years (P < 0.05). Accelerated replication-dependent telomere shortening in Ph(+ )versus Ph(-) leukocytes supports previous evidence that Ph(+) stem cells cycle more actively than their counterparts in normal individuals. Our data further suggest that telomere shortening may serve as a surrogate marker of disease progression in patients with CP CML, supporting a mechanistic link between CML stem cell turnover, genetic instability, and malignant evolution in this disease. (Blood. 2000;95:1883-1890) (Blood. 2000;95:1883-1890)

Adolescent↗
PubMed1991

Platelet factor 4 mRNA expression in cells from a patient with megakaryoblastic crisis of chronic myelogenous leukemia.

A 61-year-old man with Philadelphia chromosome-positive chronic myelogenous leukemia developed megakaryoblastic leukemia. In the blast phase, his blast cells showed undifferentiated megakaryoblastic characteristics with no alpha-granules or demarcation membranes but with detectable platelet peroxidase (PPO) activity and surface glycoprotein (GP) IIb/IIIa. The patient has remained reasonably well for at least 12 months after blastic crisis, and 6-mercaptopurine alone has been effective in controlling leukocytosis and megakaryoblast proliferation. The expression of mRNA for platelet-specific proteins, such as GPIIb and platelet factor 4 (PF4), was studied in the patient's blast cells by the Northern blot analysis. Both GPIIb and PF4 mRNA were detected in the blast cells. Cytoplasmic maturation occurs later than the synthesis of the surface GP during megakaryocyte maturation. Therefore, PF4 mRNA expression should be a marker of mature megakaryoblasts. The PF4 mRNA expression in megakaryoblastic leukemia may indicate that a patient will have long survival and a good response to chemotherapy.

Antibodies, Monoclonal↗
PubMed1997

Activation of hematopoietic growth factor signal transduction pathways by the human oncogene BCR/ABL.

BCR/ABL is a human chimeric oncogene that causes chronic myelogenous leukemia (CML). The BCR/ABL oncogene is generated from the Philadelphia chromosome (Ph) translocation, t(9;22)(q34;q11), and creates a constitutively active tyrosine kinase. There is clonal expansion of hematopoietic stem cells of several different lineages in CML. CML patients in stable phase usually have high white blood counts and immature cells of granulocytic lineages. Stable phase CML evolves to a more aggressive phase typically within 3.5-5 years, where differentiation is blocked and acute leukemia ensues. The transition of CML stable phase to blast phase is reflected in the loss of growth factor requirement of CML cells and correlates with additional cytogenetic alterations. Some biological effects reported in primary CML cells include reduced apoptosis and altered adhesion to fibronectin; however, the cells are dependent on hematopoietic growth factors. On a molecular level, the BCR/ABL translocation is well characterized. However, the actual mechanism of transformation by the BCR/ABL oncogene of hematopoietic cells is largely unknown. Enhancement of the c-ABL tyrosine kinase activity in BCR/ABL appears to be crucial for transformation. This tyrosine kinase activity leads to activation of several signal transduction pathways that are also utilized by hematopoietic growth factors, including steel factor, thrombopoietin, interleukin-3, and granulocyte/macrophage-colony stimulating factor. In several model systems, BCR/ABL has overlapping biological effects with hematopoietic growth factors, and transformation of hematopoietic growth factor-dependent cell lines leads to growth factor independence. In this review, we will describe the molecular and biological abnormalities in CML and several signal transduction mechanisms utilized by BCR/ABL as compared to hematopoietic growth factors.

Adaptor Proteins, Signal Transducing↗
PubMed2006

Frequency and clinical significance of BCR-ABL mutations in patients with chronic myeloid leukemia treated with imatinib mesylate.

Mutations of the BCR-ABL kinase domain are a common mechanism of resistance to imatinib in chronic myeloid leukemia. We screened for mutations 171 patients failing imatinib therapy. Sixty-six mutations in 23 amino acids were identified in 62 (36%) patients not responding to imatinib. Phosphate-binding loop (P-loop) mutations were the most frequent (n=24; 36%). By multivariate analysis, factors associated with development of mutations were older age (P=0.026) prior interferon therapy (P=0.026), and accelerated phase or blast phase at time of imatinib failure (P=0.001). After a median follow-up of 38 months (range, 4-68 months) from the start of imatinib therapy, seven patients with non-P-loop and two with P-loop mutation died. By multivariate analysis, development of clonal evolution and higher percentage of peripheral blood basophils were associated with worse survival from the time of imatinib failure. Mutation status had no impact on survival. When survival was measured from the time therapy started, non-P-loop mutations together with duration of response and transformation at the time of failure to imatinib were associated with shorter survival. In conclusion, P-loop mutations were not associated with poor outcome, suggesting that the prognosis of patients who fail imatinib is multifactorial.

Adult↗
PubMed2005

Chronic myelogenous leukemia.

Chronic myelogenous leukemia (CML) represents about 14% of all leukemias and occurs with a frequency of about 1 in 100,000. It is rare in children. Symptoms include fatigue, weight loss, sweating, and abdominal discomfort from an enlarged spleen. The white blood cell count can range from 100-600 ul. CML has three phases: the chronic phase, accelerated phase, and blast phase. Most patients are diagnosed during the chronic phase. Ionizing radiation has been implicated in some cases of CML, but in most individuals no cause is known. The Philadelphia chromosome, an acquired genetic mutation represented by a translocation of chromosome 22 and chromosome 9, drives the leukemic changes in CML. Imatinib mesylate, a tyrosine kinase inhibitor, was approved in 2002 for the treatment of all phases of CML. Because of its effectiveness, imatinib has become the treatment of choice for most patients with CML. Stem cell transplantation also is an option for eligible patients. It is the only curative treatment for CML. Two drugs under study for patients who cannot tolerate or who become resistant to imatinib are BMS-354825 and AMN107. Oncology nurses who are knowledgeable about new therapies for CML can be effective resources for their patients.

Age Distribution↗
PubMed2003

Approval summary: imatinib mesylate capsules for treatment of adult patients with newly diagnosed philadelphia chromosome-positive chronic myelogenous leukemia in chronic phase.

PURPOSE: The purpose is to describe the Food and Drug Administration (FDA) review and approval of imatinib (Gleevec; Novartis Pharmaceuticals, East Hanover, NJ) for treatment of adult patients with newly diagnosed Philadelphia chromosome-positive chronic myelogenous leukemia (CML) in chronic phase. EXPERIMENTAL DESIGN: The FDA reviewed data in electronic format from a randomized controlled clinical trial of 1106 adult patients with newly diagnosed Philadelphia chromosome-positive CML in chronic phase, comparing imatinib with the combination of IFN-alpha and cytarabine. RESULTS: Imatinib showed clinically and statistically significantly better results for time-to-progression to accelerated phase or blast crisis, progression-free survival, complete hematological response rate, and cytogenetic response rate. With a median follow-up of 14 months, a maximum follow-up of 19.5 months, and an expected median survival of 5-6 years on the IFN-alpha/cytarabine control arm, few of the expected progressions to accelerated or blast phase or deaths have occurred. Imatinib was also better tolerated. Edema, nausea, rigors, neutropenia, and headache were more frequent in women. Only 57% of the IFN-alpha target dose was administered, and only 68% of patients received any cytarabine. However, this does not appear to adequately explain the superiority of imatinib observed in this trial. Results of a population pharmacokinetic study in a subgroup of 371 patients and a separate rifampin-imatinib drug-drug interaction study in healthy volunteers are presented. CONCLUSIONS: On December 20, 2002, imatinib was granted accelerated approval under subpart H, rather than regular approval. Follow-up is short compared with the natural history of chronic phase CML or more mature results with established therapies such as IFN-alpha or transplantation. If imatinib should stop working after 1.5-2 years, the results could be importantly different from the present analysis. As a Phase IV postmarketing commitment, the applicant has agreed to provide follow-up reports on this imatinib study annually for the next 6 years.

Adult↗