In leukemias, the monitoring techniques on the response after the treatment have clinical importance for evaluating new therapeutic approaches and identifying the risk of relapse. In this study, genetic changes before and after chemotherapy in interphase and metaphase nuclei of bone morrow of adults with provisional diagnosis of leukemia were compared to understand the molecular characterization and pathogenesis of the leukemia for the classification of diagnosis and prognosis. We examined bone morrow cells of 47 chronic myeloid leukemia (CML) cases (29 of 47 at the time of diagnosis, 31 of 47 after chemotherapy) with the bcr/abl translocation probes and of 10 acute promyelocytic leukemia (APL) cases (7 of 10 at the time of diagnosis, 4 of 10 after chemotherapy) with the PML/RARalpha translocation probes by using dual color-flourescence in situ hybridization (DC-FISH). For each case, 400 interphase nuclei and 11 to 25 metaphases nuclei were analysed. The ratios of translocations before and after chemotherapy were compared between interphase and metaphase nuclei. After chemotherapy, though, translocations were detected in interphase nuclei of 29 of the 31 CML and 4 of the 4 APL cases, these translocations were determined in metaphase nuclei of only 14 of the 31 CML and 1 of the 4 APL cases with very low ratios (p < 0.01). The results showed that the rates of translocation positive interphase nuclei were higher than the rates of translocation positive metaphase nuclei (p < 0.01) after chemotherapy, so there may be some factors effecting proliferative activity of metaphase formation in leukemias.

Chronic myeloid leukaemia is associated with a specific translocation between chromosomes 9 and 22 that results in the formation of a chimaeric gene. This gene, when transcribed, produces the BCR-Abl oncoprotein which has tyrosine kinase activity and the ability to prevent apoptosis, but has no effect on cellular proliferation. Imatinib mesylate, an inhibitor of the BCR-Abl transcript modelled on the ATP binding pocket of the Abl oncoprotein, prevents phosphorylation of effector molecules and induces apoptosis. Imatinib has limited effectiveness when BCR-Abl cells are in the quiescent cell-cycle state of G0. A life-long regimen of imatinib should reduce the risk of relapse from cells leaving G0. Up-regulation of BCR-Abl expression, ATP binding pocket mutations, up-regulation of MDR1 and over-expression of Pgp are all thought to limit the effectiveness of imatinib. Advanced BCR-Abl positivity is associated with complex mutations, which are thought to have a cumulative effect on the BCR-Abl oncoprotein in disrupting normal signal transduction, making these cells refractory to monotherapy alone. Combination therapy is thought to overcome this. Research studies have identified imatinib as a potential treatment option for a diverse range of malignancies associated with BCR-Abl, platelet-derived growth factor receptor (PDGFr) and c-Kit pathways. This may extend the application of this special therapy in the future.

OBJECTIVES: To evaluate the effectiveness of imatinib as first-line treatment for chronic myeloid leukaemia (CML) compared with interferon-alpha (IFN-alpha), hydroxyurea and bone marrow transplantation (BMT), and the cost-effectiveness of imatinib compared with IFN-alpha and hydroxyurea. DATA SOURCES: Electronic databases. REVIEW METHODS: Selected studies and full-text articles were screened and rigorously selected. Survival was the key outcome measure. Surrogate outcome measures included haematological (blood) response and cytogenetic (bone marrow) response (CR). As no published cost-effectiveness studies were found that compared imatinib and IFN-alpha, an independent Markov model was constructed and this was compared with models submitted to the National Institute for Clinical Excellence by the manufacturer of imatinib. RESULTS: Intention-to-treat analysis showed that imatinib was associated with complete CR at 12 months follow-up of 68% compared with 20% for the IFN-alpha plus Ara-C group. The estimated proportion of people taking imatinib who had not progressed to accelerated or blast phases at 12 months was 98.5%, and 93.1% for IFN-alpha plus Ara-C. Overall survival was not statistically significantly different. Withdrawal due to side-effects was 2% for imatinib and 5.6% for IFN-alpha plus Ara-C. Cross-over due to intolerance was 0.7% and 22.8% for imatinib and for IFN-alpha plus Ara-C, respectively. Quality of life was better in the imatinib group than the IFN-alpha group when assessed at 1, 3 and 6 months. Median survival across the four IFN-alpha versus hydroxyurea studies was 66 and 56.2 months, respectively. Median complete CR was 6% for IFN-alpha and 0 for hydroxyurea. Median withdrawal due to side-effects was 24% and 4% for IFN-alpha and hydroxyurea, respectively. Four out of the five studies comparing BMT and IFN-alpha showed a long-term survival advantage for BMT over IFN-alpha, but a short-term disadvantage. In four of the five studies comparing BMT and IFN-alpha, median survival had not yet been reached in the BMT groups in 6–10 years. Median survival in the IFN-alpha arms ranged from 5.2 to 7 years. The BMT group gained a survival advantage over IFN-alpha at 3–5.5 years. In the BMT group death due to transplant-related complications ranged from 36 to 45%. The incremental cost-effectiveness ratio (ICER) of imatinib compared with IFN-alpha from the independent model was GBP26,180 per quality-adjusted-life-years (QALY) gained and was relatively robust. Imatinib was less cost-effective than hydroxyurea with an ICER of GBP86,934. CONCLUSIONS: Imatinib appears to be more effective than current standard drug treatments in terms of cytogenetic response and progression-free survival, with fewer side-effects. However, there is uncertainty concerning longer term outcomes, the development of resistance to imatinib, the duration of response and the place of imatinib relative to BMT. New issues are continually arising, such as optimal management pathways and combination therapies. Recommendations for research include: long-term follow-up data from the first- and second-line imatinib trials; investigation into specific subgroups, e.g. high-risk patients, the elderly, children or those eligible for BMT; long-term comparisons of imatinib with BMT performed in early stages of CML; the use of imatinib in combination with other therapies, and further detailed economic studies. Investigation of the impact of CML and imatinib on quality of life is also important.

Primary (nonreactive) eosinophilia is operationally classified as either a “clonal” or an “idiopathic” process. Clonal eosinophilia stipulates the presence of cytogenetic, molecular, or bone marrow histologic evidence of acute leukemia or a chronic myeloid disorder. Idiopathic eosinophilia is a diagnosis of exclusion that is made after ruling out both “secondary” (reactive) and clonal eosinophilia. Hypereosinophilic syndrome is a subclass of idiopathic eosinophilia that requires the documentation of both sustained eosinophilia (> or = 1500/microL for at least 6 months) and target-organ damage. A series of novel observations in the last 5 years have warranted a refined approach to the diagnosis as well as the treatment of clonal eosinophilic disorders, including systemic mastocytosis. At the center of these new developments are mutations involving the platelet-derived growth factor receptor genes (PDGFRA and PDGFRB), which have been pathogenetically linked to clonal eosinophilia, and their presence predicts complete as well as durable treatment responses to imatinib mesylate. The bone marrow histologic phenotype of these imatinib-sensitive eosinophilic disorders includes systemic mastocytosis, chronic eosinophilic leukemia, chronic myelomonocytic leukemia, and atypical chronic myeloproliferative disorder.

To determine the optimal dose, dose-limiting toxicities, and pharmacokinetics of imatinib mesylate in children with refractory or recurrent Philadelphia chromosome-positive (Ph+) leukemias. Oral imatinib mesylate was administered daily at dose levels ranging from 260-570 mg/m2 in consecutive 28-day courses of therapy. Serial blood samples for plasma pharmacokinetic studies were collected on days 1 and 8 of course 1. Thirty-one patients between 3-20 years of age with refractory Ph+ leukemias received 479 courses (median 6, range 1-46) of imatinib. The most common toxicities associated with imatinib administration, which occurred in < 5% of courses, were grade 1 or 2 nausea, vomiting, fatigue, diarrhea and reversible increases in serum transaminases. One patient at the 440 mg/m2 dose level had dose-limiting weight gain. There were no other first course dose-limiting toxicities. A maximum tolerated dosage was not defined. Among twelve CML patients evaluable for cytogenetic response, 10 had a complete response and 1 had a partial response. Among ten ALL patients evaluable for morphologic response, seven achieved an M1 and one achieved an M2 bone marrow. Pharmacokinetic analyses revealed that there was marked interpatient variability in the pharmacokinetic parameters. Daily oral imatinib mesylate is well tolerated in children with Ph+ leukemias at doses ranging from 260 to 570 mg/m2. Doses of 260 and 340 mg/m2 provide systemic exposures similar to those of adults who are treated with daily doses of 400 and 600 mg, respectively.

Topotecan, a topoisomerase-I inhibitor is an active drug in the treatment of AML and MDS. To evaluate its toxicity and efficacy in a combination regimen with cytarabine, we conducted a clinical phase I/II trial in patients with relapsed acute myeloid leukemia (AML) or relapsed or newly diagnosed MDS RAEB, RAEB-t or CMML. Twenty-one patients (11 AML, 10 MDS/CMML) entered the study and were treated with 1.25 mg/m2 topotecan as continuous intravenous infusion daily for 5 days and cytarabine 1.0 g/m2 by infusion over 2 h daily for 5 days (TA). Cycles were repeated on day 28. The median observation time was 131 weeks (range: 36-196 weeks). A total of 37 cycles of TA were administered. In 1 patient, the dose of TA had to be reduced and in 1 patient, there was a treatment delay for the second cycle, both because of hematologic toxicity. The most frequent non-hematologic side-effect of TA was fever, which occurred in 17 patients (89%) with temperatures over 38 degrees C. None of the patients died due to any treatment-related toxicities, but 2 patients (10%) died within 1 month due to disease progression. A CR was achieved in 7 patients (33%), 3 of whom were MDS and 4 AML. A partial remission was reported in 8 patients (38%), no change of disease in 2 patients (10%) and progressive disease in 4 patients (19%). The median remission duration was 18 weeks (range 2-161 weeks) for MDS patients and 11 weeks (range 2-49 weeks) for AML patients. The time to progression for patients of 60 years and older (n = 10) was 16 weeks (range 2-49 weeks) and the survival was 32 weeks (range 2-119 weeks). TA is a feasible and efficacious chemotherapeutic combination for the treatment of MDS RAEB, RAEB-t, CMML and AML. For patients of 60 years and older, this regimen is also a safe option.

It has recently been postulated that the absence of a single tumor suppressor gene (TSG) allele can provide a selective advantage for an emerging tumor cell. We have characterized the precise extension of the deletion on der(9) in 20 chronic myeloid leukemia (CML) cases using FISH analysis with an appropriate set of BAC/PAC probes to attempt a better definition of TSGs encompassed by these genomic deletions. Chromosome 9 deletions on the der(9) were detected in 15 (75%) cases; the TSG PTGES gene was lost in 11 (73%) cases. Chromosome 22 deletions on der(9) were found in 18 (90%) of the analysed cases; two TSGs were found located inside the deleted sequences of chromosome 22: SMARCB1 and GSTT1. These TSGs were found deleted in 16 (89%) cases bearing deletions of chromosome 22. Fourteen (70%) patients were treated with IFN-alpha therapy: 12 did not obtain complete haematologic remission (CHR) and 2 were not evaluable for response. Therefore, the patients did not respond to the IFN-alpha treatment started Glivec obtaining CHR and major cytogenetic response (MCR). The observation that deletions on der(9) are associated with the loss of TSGs suggests their possible involvement in the CML outcome, mediated by a haplo-insufficiency mechanism.

To further elucidate the role of vascular endothelial growth factor (VEGF) in the pathogenesis of chronic myeloid leukemia (CML), we transfected K562 cells with a VEGF(121)cDNA sense vector (S), an antisense (AS) vector or vector (V) alone. The growth of transfected cells was investigated by MTT and colony-formation assays, and apoptosis was measured by flow cytometry (FCM) of Annexin-V-FITC/PI dual labeled cells. Transfected cells were subcutaneously transplanted into nude mice and the microvessel density (MVD) of tumor masses was determined by vWF immunohistochemistry staining. We tested the supernatant of different transfected K562 cells against human bone marrow endothelial cells (BMECs), and examined the synergic effects of antisense VEGF(121)cDNA and IFNalpha or STI571 on the proliferation and apoptosis of K562 cells. We found that K562/AS transfectants exhibited a 49% reduction in VEGF secretion, whereas K562/S transfectants exhibited a 3-fold increase in VEGF secretion, all in comparison to the vector controls. K562 cells transfected with antisense VEGF(121)cDNA showed growth retardation in vitro. In transplanted nude mice in vivo, transfection of implanted cells with antisense VEGF(121)cDNA resulted in decreased tumor MVD, and increased apoptosis in the presence of IFNalpha. Taken together, these results suggest that VEGF may be involved in the pathogenesis of CML through autocrine and paracrine mechanisms, and that anti-VEGF therapy alone or in combination with conventional treatment may be beneficial for CML patients.

BACKGROUND: Allogeneic bone marrow transplantation (BMT) or peripheral blood stem cell transplantation remains the only modality of treatment that can eradicate a leukaemia clone in the majority of patients with chronic myeloid leukaemia (CML). However, the advent of the targeted molecule imatinib mesylate (formerly STI-571) against the bcr-abl chimeric protein in the disease has brought the issue of managing newly diagnosed CML patients, especially those with available donors, to the crossroads. Although the curative potential of this agent remains unknown, it can produce complete cytogenetic response in > 60% of newly diagnosed patients. METHODS: From May 1991 to October 2002, a total of 55 Ph+ CML-chronic phase patients received oral busulphan 16 mg/kg and cyclophosphamide 120 mg/kg i.v. as a conditioning regimen. All patients received human leucocyte antigen (HLA)-identical sibling donor haematopoletic stem cells–bone marrow in 41 patients (74.5%) and peripheral blood stem cells in 14 (25.4%). Post-transplant prophylaxis for graft-versus-host disease included a short course of methotrexate (on days +1, +3, +6 and +11) and cyclosporin till day +180 in 38 patients (69.1%), while a combination of cyclosporin and methylprednisolone was used in the remaining 17 (29%). RESULTS: At a median follow up of 48 months (10-144 months), 26 patients (47.3%) are alive. Early mortality (100-day) occurred in 17 patients (30.9%). Acute graft-versus-host disease developed in 37 patients (67.3%), and was grade IV in 6 of them. Chronic graft-versus-host disease developed in 17 patients (30.9%). Relapse occurred in only 2 patients (3.6%) till date. The leukaemia-free survival is 64.3% in the peripheral stem cell group, whereas it is 41.5% in the bone marrow recipient group. CONCLUSION: Allogeneic BMT appears to result in eradication of CML and ensure disease-free survival in about half the patients. However, efforts should be made to prevent graft-versus-host disease and minimize early mortality.

c-Abl, a conserved nonreceptor tyrosine kinase, integrates genotoxic stress responses, acting as a transducer of both pro- and antiapoptotic effector pathways. Nuclear c-Abl seems to interact with the p53 homolog p73 to elicit apoptosis. Although several observations suggest that cytoplasmic localization of c-Abl is required for antiapoptotic function, the signals that mediate its antiapoptotic effect are largely unknown. Here we show that worms carrying an abl-1 deletion allele, abl-1(ok171), are specifically hypersensitive to radiation-induced apoptosis in the Caenorhabditis elegans germ line. Our findings delineate an apoptotic pathway antagonized by ABL-1, which requires sequentially the cell cycle checkpoint genes clk-2, hus-1 and mrt-2; the C. elegans p53 homolog, cep-1; and the genes encoding the components of the conserved apoptotic machinery, ced-3, ced-9 and egl-1. ABL-1 does not antagonize germline apoptosis induced by the DNA-alkylating agent ethylnitrosourea. Furthermore, worms treated with the c-Abl inhibitor STI-571 (Gleevec; used in human cancer therapy), two newly synthesized STI-571 variants or PD166326 had a phenotype similar to that generated by abl-1(ok171). These studies indicate that ABL-1 distinguishes proapoptotic signals triggered by two different DNA-damaging agents and suggest that C. elegans might provide tissue models for development of anticancer drugs.

Juvenile myelomonocytic leukemia (JMML) is a rare clonal myeloproliferative disease of early childhood. To determine the diagnostic features, appropriate treatment, and overall patient survival pertaining to JMML for children, the authors reviewed the clinical data of 16 children with JMML admitted to the National Taiwan University Hospital between 1978 and 2001. Median age at diagnosis was 2.5 years. Fever was the most common symptom at diagnosis. At initial presentation, the mean white blood count and absolute monocyte count were 30 x 10(9)/L and 4.5 x 10(9)/L, respectively. Cytogenetic analysis was performed in 14 patients, and 2 patients (14%) had monosomy 7. Another patient, with normal karyotype at diagnosis, had deletion of 7q22 at the follow-up chromosome study. Forty-seven chronic myeloid leukemia (CML) patients were also diagnosed and followed at the same hospital during the same interval period. The age, leukocyte counts, platelet counts, basophil counts, monocyte percentages on peripheral blood smears, and median survival rate showed significant differences between JMML and CML patients (P < 0.05). The median survival was 10 months and the probability of 10-month survival was 0.38 by Kaplan-Meier analysis for 12 of the 16 JMML patients who did not receive hematopoietic stem cell transplantation (HSCT). Among three patients receiving HSCT, one patient relapsed 9 months after the first HSCT and was treated successfully by a second HSCT from the same sibling donor.

We describe unusual cytogenetic findings in a 33-year-old male with blastic phase of Philadelphia chromosome (Ph)-positive chronic myeloid leukemia. In addition to the t(9;22)(q34;q11), which was detected in all metaphases, a t(11;19)(q23;p13.3) was also identified as an evolutional change in all 20 metaphases. Fluorescence in situ hybridization (FISH) analysis showed that fusion signals of the ABL/BCR probes were found in 95% of blastic cells. Southern blotting and FISH analysis also revealed involvement of the MLL gene on 11q23. Clinical course was aggressive and the patient responded poorly to therapy. These findings suggest an association between Ph and 11q23 with poor prognosis, and that t(11;19)(q23;p13.3) was the essential pathogenic factor in our case.

Since its introduction 5 years ago, imatinib mesylate has shown remarkable efficacy in treating patients with chronic myeloid leukaemia. Here we shall review the clinical results seen with imatinib at all stages of the disease, current views on the best way to monitor patients’ responses and potential ways of predicting response to treatment. We shall also briefly cover the reasons why quiescent stem cells pose a theoretical threat to successful treatment.

The graft-versus-leukemia (GVL) effect, mediated by donor T cells, has revolutionized the treatment of leukemia. However, effective GVL remains difficult to separate from graft-versus-host disease (GVHD), and many neoplasms are GVL resistant. Murine studies aimed at solving these problems have been limited by the use of leukemia cell lines with limited homology to human leukemias and by the absence of loss-of-function leukemia variants. To address these concerns, we developed a GVL model against murine chronic-phase chronic myelogenous leukemia (mCP-CML) induced with retrovirus expressing the bcr-abl fusion cDNA, the defining genetic abnormality of chronic-phase CML (CP-CML). By generating mCP-CML in gene-deficient mice, we have studied GVL T-cell effector mechanisms. mCP-CML expression of Fas or tumor necrosis factor (TNF) receptors is not required for CD8-mediated GVL. Strikingly, maximal CD4-mediated GVL requires cognate interactions between CD4 cells and mCP-CML cells as major histocompatibility complex-negative (MHC II(-/-)) mCP-CML is relatively GVL resistant. Nevertheless, a minority of CD4 recipients cleared MHC II(-/-) mCP-CML; thus, CD4 cells can also kill indirectly. CD4 GVL did not require target Fas expression. These results suggest that CPCML’s GVL sensitivity may in part be explained by the minimal requirements for T-cell killing, and GVL-resistance may be related to MHC II expression.

Allogeneic bone marrow transplantation (alloBMT) is the only curative therapy for chronic myelogenous leukemia (CML). This success is explained by the delivery of high doses of antineoplastic agents followed by the rescue of marrow function and the induction of graft-versus-leukemia reaction mediated by allogeneic lymphocytes against host tumor cells. This reaction can also be induced by donor lymphocyte infusion (DLI) producing remission in most patients with CML who relapse after alloBMT. The immunological mechanisms involved in DLI therapy are poorly understood. We studied five CML patients in the chronic phase, who received DLI after relapsing from an HLA-identical BMT. Using flow cytometry we evaluated cellular activation and apoptosis, NK cytotoxicity, lymphocytes producing cytokines (IL-2, IL-4 and IFN-gamma), and unstimulated (in vivo) lymphocyte proliferation. In three CML patients who achieved hematological and/or cytogenetic remission after DLI we observed an increase of the percent of activation markers on T and NK cells (CD3/DR, CD3/CD25 and CD56/DR), of lymphocytes producing IL-2 and IFN-gamma, of NK activity, and of in vivo lymphocyte proliferation. These changes were not observed consistently in two of the five patients who did not achieve complete remission with DLI. The percent of apoptotic markers (Fas, FasL and Bcl-2) on lymphocytes and CD34-positive cells did not change after DLI throughout the different study periods. Taken together, these preliminary results suggest that the therapeutic effect of DLI in the chronic phase of CML is mediated by classic cytotoxic and proliferative events involving T and NK cells but not by the Fas pathway of apoptosis.