Chronic myeloid leukemia presenting as compartment syndrome with acute loss of upper limb function

Hematological malignancies rarely present with spontaneous haematomas (Lakhotia et al., 2015 [1]). Although cutaneous and mucous membrane bleeds do occur in chronic myeloid leukemia (CML) due to quantitative or qualitative platelet abnormalities, deep soft tissue bleeds are rare (Lakhotia et al., 2015 [1]). We report the case of a 49 year old man presenting with an acute hematoma of the left biceps brachii causing compartment syndrome of his left upper limb leading to flaccid paralysis. He underwent surgical evacuation of the hematoma and investigations revealed that he had CML with leukemic infiltration in the biceps brachii.

The Impact of Hemodialysis and Liver Cirrhosis on the Plasma Concentrations of Tyrosine Kinase Inhibitors in a Patient with Chronic Myeloid Leukemia

We recently treated a chronic myeloid leukemia (CML) patient with liver and renal dysfunction, who was undergoing hemodialysis (HD). He was treated with 50 mg dasatinib (DAS) once daily just before HD. The maximum plasma concentration of DAS was 227 ng/mL on a non-HD day and 46.9 ng/mL on a HD day. He was subsequently treated with 200 mg bosutinib (BOS) once daily. The plasma concentration of BOS changed from 74.5 ng/mL before HD to 58.8 ng/mL after HD. Our results indicate that close monitoring of the plasma tyrosine kinase inhibitor concentrations should be considered in CML patients with organ impairment.

Internet-assisted cognitive behavioral intervention for targeted therapy-related fatigue in chronic myeloid leukemia: Results from a pilot randomized trial

BACKGROUND

Fatigue is a common and disabling side effect of targeted therapies such as tyrosine kinase inhibitors (TKIs) used to treat chronic myeloid leukemia (CML). The goal of the current study was to conduct a pilot randomized trial of the first cognitive behavioral intervention developed for fatigue due to targeted therapy.

METHODS

Patients with CML treated with a TKI who were reporting moderate to severe fatigue were recruited and randomized 2:1 to cognitive behavioral therapy for targeted therapy-related fatigue (CBT-TTF) delivered via FaceTime for the iPad or to a waitlist control (WLC) group. The outcomes were acceptability, feasibility, and preliminary efficacy for fatigue (Functional Assessment of Chronic Illness Therapy-Fatigue; primary outcome) and quality of life (Functional Assessment of Cancer Therapy-General; secondary outcome). Participants were assessed before randomization and after treatment (ie, approximately 18 weeks later).

RESULTS

A total of 44 patients (mean age, 55 years; 48% female) were assigned to CBT-TTF (n = 29) or WLC (n = 15). The study participation rate was 59%. Among the patients assigned to CBT-TTF, 79% completed the intervention. Intent-to-treat analyses indicated that patients assigned to CBT-TTF demonstrated greater improvements in fatigue (d = 1.06; P < .001) and overall quality of life (d = 1.15; P = .005) than those assigned to WLC. More patients randomized to CBT-TTF than WLC demonstrated clinically significant improvements in fatigue (85% vs 29%) and quality of life (88% vs 54%; P values ≤ .016).

CONCLUSIONS

CBT-TTF displays preliminary efficacy in improving fatigue and quality of life among fatigued patients with CML treated with TKIs. The findings suggest that a larger randomized study is warranted.

Nuclear-cytoplasmic Shuttling in Chronic Myeloid Leukemia: Implications in Leukemia Maintenance and Therapy

Nuclear-cytoplasmic shuttling is a highly regulated and complex process, which involves both proteins and nucleic acids. Changes in cellular compartmentalization of various proteins, including oncogenes and tumor suppressors, affect cellular behavior, promoting or inhibiting proliferation, apoptosis and sensitivity to therapies. In this review, we will recapitulate the role of various shuttling components in Chronic Myeloid Leukemia and we will provide insights on the potential role of shuttling proteins as therapeutic targets.

[Philadelphia chromosome-negative myeloid neoplasms in patients with Philadelphia chromosome-positive chronic myeloid leukemia during tyrosine kinase inhibtor-therapy]

Objective: To compare the clinical features between the 2 cohorts developing myelodysplastic syndrome or acute myeIogenous Ieukemia in Philadelphia chromosome-negative cells (Ph(-) MDS/AML) and maintaining disease stable in the patients with Philadelphia chromosome-positive chronic myeloid Ieukemia (Ph(+) CML) who had clonal chromosomal abnormalities in Philadelphia chromosome-negative metaphases (CCA/Ph(-)) during tyrosine kinase inhibtor (TKI) - therapy. Methods: We retrospectively analyzed Ph(+) CML patients who developed CCA/Ph(-) during TKI-therapy from May 2001 to December 2017. Results: Data of CCA/Ph(-) 63 patients, including 7 progressing to Ph(-) MDS/AML and 56 remaining disease stable were collected. Compared with those with stable disease, patients with Ph(-)MDS/AML had lower hemoglobin (P=0.007) and platelet (P=0.006) counts, and higher proportion of peripheral blasts (P<0.001) when the first time CCA/Ph(-) was detected, and more mosonomy 7 abnormality (5/7, 71.4%) when MDS or AML was diagnosed; meanwhile, trisomy 8 (32/56, 57.1%) was more common in those with stable disease. Outcome of the patients with Ph(-) MDS/AML were poor. However, most of those with CCA/Ph(-) and stable disease had optimal response on TKI-therapy. Conclusions: A few patients with Ph(+) CML developed CCA/Ph(-) during TKI-therapy, most of them had stable disease, but very few patients developed Ph(-) MDS/AML with more common occurrence of monosomy 7 or unknown cytopenia. Our data suggested the significance of monitoring of peripheral blood smear, bone marrow morphology and cytogenetic analysis once monosomy 7 or unknown cytopenia occurred.

Economic value of regular monitoring of response to treatment among US patients with chronic myeloid leukemia based on an economic model

BACKGROUND

Regular molecular monitoring with reverse-transcription quantitative PCR (RT-qPCR) analysis of BCR-ABL1 transcripts is associated with reduced disease progression among patients with chronic myeloid leukemia (CML). Molecular monitoring assists in the timely detection of primary or secondary resistance to tyrosine kinase inhibitor (TKI) therapy and is a recommended practice by the National Comprehensive Cancer Network guidelines. An economic model was developed to estimate the potential impact of CML monitoring vs lack of monitoring on patient healthcare costs.

METHODS

An Excel-based decision-analytic economic model was developed from a US payer perspective. The model was used to estimate the expected healthcare cost differences between regular molecular monitoring of CML patients and lack of monitoring. CML progression rates among patients with vs without monitoring, the annual cost of CML progression, the average number of monitoring tests per year, and the average cost per RT-qPCR monitoring test were incorporated into the model. Univariate and multivariable sensitivity analyses were conducted.

RESULTS

Based on estimates in published literature, disease progression to the accelerated/blast phase occurs among 0.35% of patients with monitoring and 5.12% of patients without monitoring, and the annual cost of CML progression is $136,308 per patient year. The analysis found that total healthcare costs, including the costs associated with CML progression and RT-qPCR monitoring tests (three tests per year), were $1,142 for patients with monitoring and $6,982 for patients without monitoring (difference = $5,840). In a hypothetical cohort of 100 patients with CML, achieving a 100% monitoring rate was associated with a total cost-savings of $584,005 compared to a 0% monitoring rate. This cost-savings remained consistent under both univariate and multivariable sensitivity analyses.

CONCLUSION

Regular CML monitoring was associated with improved outcomes among CML patients and, consequently, reduced healthcare costs.

Chronic Myeloid Leukemia-the Promise of Tyrosine Kinase Inhibitor Discontinuation

Some believe that tyrosine kinase inhibitor (TKI) therapy is as close to perfect as it gets in oncologic therapy. Patients diagnosed with chronic myeloid leukemia (CML) are treated with a daily oral therapy, through which most achieve remission. TKI therapy is not associated with classic chemotherapy side effects, and most patients are able to resume their normal activities of daily living. Moreover, recent data has demonstrated that CML does not affect the life expectancy of patients whose disease is well controlled with a TKI. However, TKI therapy is actually not that perfect. Patients need to stay on therapy forever. They have to remember to take their medications daily. TKIs are expensive, and the financial burden to patient and society cannot be overstated. Most patients' health-related quality of life is affected; common side effects include fatigue, muscle cramps, pain, edema, skin problems, and gastrointestinal symptoms. In addition, concerns about long-term side effects remain. Recently several studies have shown the feasibility and safety of discontinuation in a select group of patients. Herein, we will review the currently available data on stopping TKIs in CML.

Reactive oxygen species in BCR-ABL1-expressing cells - relevance to chronic myeloid leukemia

Chronic myeloid leukemia (CML) results from the t(9;22) reciprocal chromosomal translocation producing the BCR-ABL1 gene, conferring growth and proliferation advantages in the CML cells. CML progresses from chronic, often syndrome-free, to blast phase, fatal if not treated. Although the involvement of BCR-ABL1 in some signaling pathways is considered as the cause of CML, the mechanisms resulting in its progression are not completely known. However, BCR-ABL1 stimulates the production of reactive oxygen species (ROS), which levels increase with CML progression and induce BCR-ABL1 self-mutagenesis. Introducing imatinib and other tyrosine kinase inhibitors (TKIs) to CML therapy radically improved its outcome, but TKIs-resistance became an emerging problem. TKI resistance can be associated with even higher ROS production than in TKI-sensitive cells. Therefore, ROS-induced self-mutagenesis of BCR-ABL1 can be crucial for CML progression and TKI resistance and in this way should be taken into account in therapeutic strategies. As a continuous production of ROS by BCR-ABL1 would lead to its self-destruction and death of CML cells, there must be mechanisms controlling this phenomenon. These can be dependent on DNA repair, which is modulated by BCR-ABL1 and can be different in CML stem and progenitor cells. Altogether, the mechanisms of the involvement of BCR-ABL1 in ROS signaling can be engaged in CML progression and TKI-resistance and warrant further study.

Biophysical differences between chronic myelogenous leukemic quiescent and proliferating stem/progenitor cells

The treatment of chronic myeloid leukemia (CML), a clonal myeloproliferative disorder has improved recently, but most patients have not yet been cured. Some patients develop resistance to the available tyrosine kinase treatments. Persistence of residual quiescent CML stem cells (LSCs) that later resume proliferation is another common cause of recurrence or relapse of CML. Eradication of quiescent LSCs is a promising approach to prevent recurrence of CML. Here we report on new biophysical differences between quiescent and proliferating CD34+ LSCs, and speculate how this information could be of use to eradicate quiescent LSCs. Using AFM measurements on cells collected from four untreated CML patients, substantial differences are observed between quiescent and proliferating cells in the elastic modulus, pericellular brush length and its grafting density at the single cell level. The higher pericellular brush densities of quiescent LSCs are common for all samples. The significance of these observations is discussed.

Combination of White Blood Cell Count at Presentation With Molecular Response at 3 Months Better Predicts Deep Molecular Responses to Imatinib in Newly Diagnosed Chronic-Phase Chronic Myeloid Leukemia Patients

The aim of this study was to evaluate the impact of white blood cell (WBC) counts at presentation on the achievement of deep molecular response.A total of 362 newly diagnosed chronic-phase chronic myeloid leukemia patients (CML-CP) receiving 400 mg/day imatinib were serially monitored for a median of 36 months (range 6-115).Patients showing an optimal response at 3, 6, and 12 months as defined by the 2013 European LeukemiaNet recommendations had significantly lower WBC counts at presentation than those showing nonoptimal responses (all P < 0.0001). Among the cutoff values with a similar Youden index, 150 × 10E9/L (abbreviated WBC > 150) was selected to identify the greatest amount of patients with the potential to achieve a sustained molecular response of 4.5 (MR4.5). Regardless of whether the Sokal risk score was included, the BCR-ABL value at 3 months, WBC counts at presentation, hemoglobin levels, and sex were the common independent predictors for an MR4.5, with the former 2 presenting the highest hazard risk. Low Sokal risk scores did not independently predict the achievement of an MR4.5. Patients with concurrent WBC > 150 and BCR-ABL(IS) ≤ 10% had a similar incidence of 4-year MR4.5 compared with patients with concurrent WBC ≤ 150 and BCR-ABL(IS) > 10% and concurrent WBC > 150 and BCR-ABL(IS) > 10% (13.5% vs 13.2% vs 8.8%, P = 0.47), and all of these values were significantly lower than the values for patients with concurrent WBC ≤ 150 and BCR-ABL(IS) ≤ 10% (55.0%, all P < 0.0001). Patients with concurrent WBC ≤ 150 and BCR-ABL(IS) ≤ 10% had better 4-year event-free survival rates, progression-free survival rates, and overall survival rates compared with patients with WBC > 150 or BCR-ABL(IS) > 10%. The combination of WBC count at presentation and BCR-ABL(IS) at 3 months provides improved predictions of deep molecular response in imatinib-treated CML-CP patients. Therefore, the WBC count at presentation might be used to differentiate patients at the beginning of imatinib treatment.

Functional studies of miR-130a on the inhibitory pathways of apoptosis in patients with chronic myeloid leukemia

The p53 mutation in chronic myeloid leukemia (CML) led to decreased overall survival and therapy resistance which was also closely correlated with the downstream proto-oncogenes BCL-2, TCL-1 and MCL-1. We in this study aimed to investigate the function of miR130a in p53 tumor suppressor signaling pathway. We performed microRNA (miRNA) expression profile analysis in CML cancer stem cells of 38 cases and extracted total RNA from peripheral blood of 143 cases. Standard curves of U6 and miRNA were made from 10-fold serial dilutions of the cDNA, which were quantified using real-time quantitative PCR with SYBR Green by ABI 7300. The p53 mutations and BCR/ABL mutation status analysis in CML patients were detected by PCR and direct sequencing. Candidate targets of miR130a of putative relevance in CML pathogenesis were analyzed by bioinformatics approach. We then used dual-luciferase activity assay to verify the target genes of miR130a and used western blot analysis to elucidate the mechanism of miR130a on modulating drug resistance. The levels of miR-130a expression in CML were significantly lower in poor prognostic subgroups, defined by prognostic factors including mutated BCR/ABL status, p53 and ATM deletions and p53 mutations. Furthermore, underexpression of miR-130a was significantly associated with shorter overall survival and treatment-free survival in CML patients. We demonstrated that miR130a function as tumor suppressors by inhibiting multiple anti-apoptosis proteins, including BCL-2, MCL-1 and XIAP. This was a direct effect because miR130a negatively regulated expression of a BCL-2/MCL-1/XIAP 3'untranslated region-based reporter construct. Transfection of miR130a mimics into CML cells from 30 patients without p53 aberrations led to significant increases in apoptosis compared with transfection with the miRNA control. Besides, enforced expression of miR130a had no significant drug-sensitization effect in CML cells from p53-attenuated patients. MiR-130a may have an important role in the pathogenesis of CML and may be useful for assessing prognosis in patients with CML. Moreover, miR130a may provide a possible therapeutic avenue and a sensitive indicator of the activity of the p53 in CML.

Diagnosis and Treatment of Chronic Myeloid Leukemia in 2015

Few neoplastic diseases have undergone a transformation in a relatively short period like chronic myeloid leukemia (CML) has in the last few years. In 1960, CML was the first cancer in which a unique chromosomal abnormality was identified and a pathophysiologic correlation suggested. Landmark work followed, recognizing the underlying translocation between chromosomes 9 and 22 that gave rise to this abnormality and, shortly afterward, the specific genes involved and the pathophysiologic implications of this novel rearrangement. Fast forward a few years and this knowledge has given us the most remarkable example of a specific therapy that targets the dysregulated kinase activity represented by this molecular change. The broad use of tyrosine kinase inhibitors has resulted in an improvement in the overall survival to the point where the life expectancy of patients today is nearly equal to that of the general population. Still, there are challenges and unanswered questions that define the reasons why the progress still escapes many patients, and the details that separate patients from ultimate cure. In this article, we review our current understanding of CML in 2015, present recommendations for optimal management, and discuss the unanswered questions and what could be done to answer them in the near future.

[Effect of cryptotanshinone on imatinib sensitivity and P-glycoprotein expression of chronic myeloid leukemia cells]

Cryptotanshinone (CPT), a lipid soluble active compound in Salvia miltiorrhiza, has a significant inhibitory effect on multiple malignant tumors, e. g. chronic myeloid leukemia (CML) cells and can effectively enhance imatinib's chemotherapeutic effect. However, its functional molecular mechanism remained unclear. In this experiment, the authors conducted a systematic study on the effect of CPT on the imatinib sensitivity and P-glycoprotein (P-gp) expression in CML cells by using CML cells K562 and imatinib persister K562-R. The MTT assays were performed to determine CPT's impact on the inhibitory effect of imatinib. Annexin V-FITC/PI staining analysis was used to detect the changes in the cell apoptosis rate. The active changes in apoptosis regulatory proteins Caspase-3, Caspase-9 and PARP were determined by Western blot. After the cells were pretreated with the gradient concentration of CPT, the expression of P-gp was analyzed by Western blot and flow cytometry. The changes in intracellular concentrations of imatinib were determined by HPLC analysis. The results indicated that the pretreatment with CPT significantly increased the proliferation inhibiting and apoptosis inducing effects of imatinib on K562 and K562-R cells as well as the degradation product expression of pro-apoptotic proteins Caspase-3, Caspase-9 and PARP, with a significant difference with the control group (P < 0.01). However, CPT showed no impact on the P-gp expression in CML cells and the intracellular concentrations of imatinib. In summary, the findings suggested that CPT enhanced the sensitivity of CML cells to imatinib. Its mechanism is not dependent on the inhibition in P-gp expression and the increase in intracellular drug concentration.

[CHRONIC MYELOID LEUKEMIA IN A YOUNG MALE PRESENTING WITH BILATERAL CALF PAIN DUE TO LEUKOSTASIS]

Chronic myeloid Leukemia (CML) is a chronic myeloproliferative disorder, caused by the unregulated proliferation of granulocytes at different stages of development and maturation. Leukostasis is one of the complications of CML, causing partial or total occlusion of microvasculature with a variety of clinical manifestations, mostly ophthalmic, neurologic or respiratory. Recently, we encountered a 21-year old soldier, who complained of severe bilateral calf pain which began a few months earlier during training. He underwent complete ambulatory orthopedic evaluation which was unrevealing, and finally presented to the hospital casualty department where CML was diagnosed on the basis of an elevated WBC count and morphologic findings. Bilateral retinal hemorrhages due to leukostasis were noticed at fundoscopy. The calf pain resolved completely after leukapheresis and initial cytoreductive therapy and was in retrospect attributed to peripheral leukostasis. To the best of our knowledge this is the first report of CML presenting with bilateral calf pain due to Leukocytosis and possible leukostasis. This case report highlights the importance of differential diagnosis in cases of calf pain and the awareness of this rare manifestation of CML.

Natural course and biology of CML

Chronic myeloid leukaemia (CML) is a myeloproliferative disorder arising in the haemopoietic stem cell (HSC) compartment. This disease is characterised by a reciprocal t(9;22) chromosomal translocation, resulting in the formation of the Philadelphia (Ph) chromosome containing the BCR-ABL1 gene. As such, diagnosis and monitoring of disease involves detection of BCR-ABL1. It is the BCR-ABL1 protein, in particular its constitutively active tyrosine kinase activity, that forges the pathogenesis of CML. This aberrant kinase signalling activates downstream targets that reprogram the cell to cause uncontrolled proliferation and results in myeloid hyperplasia and 'indolent' symptoms of chronic phase (CP) CML. Without successful intervention, the disease will progress into blast crisis (BC), resembling an acute leukaemia. This advanced disease stage takes on an aggressive phenotype and is almost always fatal. The cell biology of CML is also centred on BCR-ABL1. The presence of BCR-ABL1 can explain virtually all the cellular features of the leukaemia (enhanced cell growth, inhibition of apoptosis, altered cell adhesion, growth factor independence, impaired genomic surveillance and differentiation). This article provides an overview of the clinical and cell biology of CML, and highlights key findings and unanswered questions essential for understanding this disease.

[Bone marrow microenvironment in chronic myeloid leukemia: implications for disease physiopathology and response to treatment]

Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm related to the presence of the BCR-ABL1 fusion gene, linked to t (9;22) (q34;q11). It is originated from an abnormal hematopoietic stem cell, which is characterized as its normal counterparts by long-term self-renewal and multi-lineage differentiation. Both leukemic and quiescent normal hematopoietic stem cells preferentially reside in the osteoblastic niche. Mesenchymal stromal cells (MSC) are located near them, playing a critical role in their regulation. Currently, with tyrosine kinase inhibitor (TKI) therapy, long term clinical responses are achieved in most CML cases. However, late treatment failures may be observed related to the persistence of leukemic stem cells. The interactions between the leukemic stem cell and the microenvironment may be responsible in part for these events. We review the interactions between the leukemic stem cell and BM stroma and its potential clinical and therapeutic implications.

Two consecutive twin and a singleton pregnancy in a patient with chronic myeloid leukemia

Consecutive multiple pregnancies with Chronic myeloid leukemia is a rare event and little is known about its prevalence and management with or without chemotherapy. We present a case of three consecutive pregnancies in a woman with CML, two of which were multiple pregnancies.

Data and implication based comparison of two chronic myeloid leukemia models

Chronic myeloid leukemia, a disorder of hematopoietic stem cells, is currently treated using targeted molecular therapy with imatinib. We compare two models that describe the treatment of CML, a multi-scale model (Model 1) and a simple cell competition model (Model 2). Both models describe the competition of leukemic and normal cells, however Model 1 also describes the dynamics of BCR-ABL, the oncogene targeted by imatinib, at the sub-cellular level. Using clinical data, we analyze the differences in estimated parameters between the models and the capacity for each model to predict drug resistance. We found that while both models fit the data well, Model 1 is more biologically relevant. The estimated parameter ranges for Model 2 are unrealistic, whereas the parameter ranges for Model 1 are close to values found in literature. We also found that Model 1 predicts long-term drug resistance from patient data, which is exhibited by both an increase in the proportion of leukemic cells as well as an increase in BCR-ABL/ABL Model 2, however, is not able to predict resistance and accurately model the clinical data. These results suggest that including sub-cellular mechanisms in a mathematical model of CML can increase the accuracy of parameter estimation and may help to predict long-term drug resistance.

The role of oxidant injury in the pathophysiology of human thalassemias

The anemia in beta-thalassemia major is caused by a combination of hemolysis and ineffective erythropoiesis, with the latter being more important. Studies of the underlying cause of the hemolysis have indicated that oxidant injury to circulating red blood cells (RBCs) was of critical importance, with evidence of oxidant damage to RBC membrane proteins 4.1 and band 3. Therefore, it seemed reasonable that oxidant damage to thalassemic erythroid precursors would cause their accelerated apoptosis and ineffective erythropoiesis. However, direct analysis showed that the apoptotic programs turned on in thalassemics were not those triggered by oxidative damage but were dependent on activation of FAS/FAS-Ligand interaction. Thus, destruction of thalassemic erythroid precursors may involve different mechanisms from those that cause RBC hemolysis.

Prospective histomorphometric and DXA evaluation of bone remodeling in imatinib-treated CML patients: evidence for site-specific skeletal effects

CONTEXT

Imatinib is a tyrosine kinase inhibitor that has been successfully used to treat Philadelphia chromosome-positive chronic myeloid leukemia (CML) and Kit(+) gastrointestinal stromal tumors. We have previously shown that imatinib therapy is associated with an increase in trabecular bone volume.

OBJECTIVE

In the present study, we performed a prospective analysis of bone indices in imatinib-treated CML patients to determine the mechanism responsible for this altered bone remodeling. DESIGN, PATIENTS, AND INTERVENTION: This study assessed the effects of high-dose (600 mg/d) imatinib on bone parameters in newly diagnosed chronic-phase Philadelphia chromosome-positive CML patients (n = 11) enrolled in the TIDEL II study. At baseline and after 6, 12, and 24 months of treatment, serum markers of bone remodeling were quantitated, dual-energy x-ray absorptiometry analysis of bone mineral density (BMD) was carried out, and a bone biopsy was collected for histological and micro-computed tomography analysis.

RESULTS

Our studies show that the increase in trabecular bone volume and trabecular thickness after imatinib treatment was associated with a significant decrease in osteoclast numbers, accompanied by a significant decrease in serum levels of a marker of osteoclast activity. In contrast, osteoblast numbers were not altered by up to 24 months of imatinib treatment. Notably, we also found that imatinib caused a site-specific decrease in BMD at the femoral neck.

CONCLUSIONS

These data suggest that imatinib therapy dysregulates bone remodeling, causing a generalized decrease in osteoclast number and activity that is not counterbalanced by a decrease in osteoblast activity, leading to increased trabecular bone volume. Further long-term investigations are required to determine the causes and consequences of the site-specific decrease in BMD at the femoral neck.

Monitoring and switching patterns of patients with chronic myeloid leukemia treated with imatinib in community settings: a chart review analysis

OBJECTIVES

Monitoring treatment response is an integral part of chronic myeloid leukemia (CML) treatment. The guidelines recommend regular monitoring using standard methods (e.g., real-time quantitative polymerase chain reaction based on the international scale for molecular response) and treatment adjustment when failure is detected among patients treated with imatinib. The objective of this study was to assess the real-world monitoring and therapy adjustment in this patient population in the US.

METHODS

Twenty-nine physicians from community practices across the US participated in an online chart review. Adult patients with chronic phase CML who initiated imatinib as first-line therapy during 2006-2010 were selected. Information was collected up to 36 months after imatinib initiation, including response monitoring, response status, and therapy adjustment upon treatment failure.

RESULTS

The study included 297 eligible patients. By 18 months, 47% of patients had received cytogenetic response assessment continuously as recommended by the guidelines. The corresponding proportion was 39% for continuous molecular response assessment. Among patients who experienced treatment failure by 18 months, only 14%-38% of patients switched to a second-generation tyrosine kinase inhibitor as recommended by the National Comprehensive Cancer Network and the European Leukemia Net guidelines.

LIMITATIONS

Major limitations included limited generalizability and the inability to accurately assess molecular response due to the variations in testing methods during the study period.

CONCLUSIONS

Based on the guidelines, the rates of treatment monitoring and switching upon failure were low, demonstrating the need for improvement in CML care in community settings in the US.

The 2011 Gordon Wilson Lecture: overcoming resistance to targeted cancer drugs

During the past decade, molecularly targeted drugs have had a transformative impact on the treatment of several cancer types. Although the clinical benefits of these drugs are impressive, their effects are generally short-lived due to the acquisition of resistance. Unlike most cytotoxic agents, for which resistance mechanisms have remained obscure despite decades of clinical use, an understanding of the molecular basis of resistance to most targeted agents has emerged quickly. This rapid progress has been possible due to advances in molecular technologies that allow genome-wide profiling of patient samples. One important and consistent theme is that resistance is almost invariably associated with restoration of the signaling pathway inhibited by the targeted agent. Here I review examples from three diseases--chronic myeloid leukemia, prostate cancer, and lung cancer--that illustrate these points and reveal how insights into resistance mechanisms can rapidly accelerate the development of second-generation targeted therapies or combination regimens to improve patient outcome.

[Analysis of relationship between bcr-abl transcription level detected by real-time quantitative polymerase chain reaction and clinical status of CML patients]

This study was aimed to investigate the bcr-abl transcription level and its relationship with the clinical status of patients so as to provide some bases for predicting patient status according to absolute value of bcr-abl transcript. The bcr-abl/abl values (%) of bone marrow samples from 30 newly diagnosed CML patients at the baseline bcr-abl/abl value obtained in CML patients with bcr-abl positive were defined, then 161 bone marrow samples from 82 patients were detected at virions time points, and the bcr-abl/abl value of each sample was compared with baseline value and its relationship with clinical status of patient at same time point was investigated. The results showed that bcr-abl/abl values (%) of 30 patients showed positive skew distribution and a large variation with mean 13.5631 (1.0206 - 98.3159) and mathematical mean of 21.1491 (95% CI: 12.3532 - 29.9450). For strict standard, the baseline value of bcr-abl/abl (%) was set as 1, the lower limit of these values. In the detected results of 161 samples, there were 33 samples' values above the baseline value, in which resistance/relapse/progression (R/R/P) 13 (39.4%, 13/33), no remission (NR) 17 (51.5%, 17/33) and complete hematologic remission (CHR) 3 (9.1%, 3/33) were observed. the values of 26 samples decreased by 0 - 1 order of magnitude (0.1 < or = bcr-abl/abl % < 1), in which R/R/P 6 (23.1%, 6/26), NR 7 (26.9%, 7/26), CHR 7 (26.9%, 7/26) and cytogenetic remission (CyR) 6 (23.1%, 6/26) were observed, the values of 19 samples decreased by 1 - 2 order of magnitude (0.01 < or = bcr-abl/abl % < 0.1), in which NR 2 (10.5%, 2/19), CHR 3 (15.8%, 3/19) and CyR 14 (73.7%, 14/19) were determined. 7 samples decreased by 2 - 3 order of magnitude (0.001 < or = bcr-abl/abl % < 0.01) in which major CyR (MCyR) 2 (28.6%, 2/7) and complete CyR (CCyR) 5 (71.4%, 5/7) were determined, the values of 76 samples decreased by 3 or more order of magnitude (bcr-abl/abl % < 0.001), and all these were CCyR. In conclusion, the using decrease degree of one time point-detected value compared to the baseline could well assess the patient clinical status. The bcr-abl/abl % < 0.01 can reliably reflect CyR obtained by patients at the time point, and bcr-abl/abl % < 0.001 can reflect CCyR obtained by patients. However, exact judgments of patient status relies on dynamic and serial monitoring.

[Chronic myeloid leukemia in the 21st century: biology and treatment]

Chronic Myeloid Leukaemia (CML) is a clonal disease, originated at the level of Hematopoietic Stem Cells (HSC) and characterized by the presence of the Philadelphia (Ph) chromosome and its oncogenic product p210(BcrAbl). Such a protein has been shown to be essential for malignant transformation, since it is capable of altering cell adhesion, proliferation and apoptosis. Historically, CML has been treated by using different approaches: arsenic (in the early days), a variety of chemical agents (busulfan, hydroxyurea, cytarabine), cytokines (IFN-alpha, IFNalpha-PEG), hematopoietic cell transplant (HCT), and more recently drugs generated by design (imatinib, nilotinib, dasatinib). All these molecules exert specific effects on HSC and lead to a variety of clinical and biological responses. In this article, we present an overview about hematopoiesis in CML and its implications in the treatment of this disease.

[Angiogenesis in different clinical phases of chronic myeloid leukemia]

Angiogensis plays the crucial role in growth and dissemination of neoplastic diseases, both for solid tumors and hematopoietic malignancies. Development of the abundant neoplastic vasculature results from an imbalance between pro- and antiangiogenic regulatory mechanisms. The investigation was focused on expression of the main regulatory angiogeneic factors in different phases of chronic myeloid leukemia (CML) and on influence of leukemic cells on the human umbilical vein endothelial cells proliferation. The groups of 29 patients with CML and of 14 healthy controls were enrolled to the study. The expression of vascular endothelial growth factor (VEGF), basic fibroblast growth factor, interleukin-8, angiopoetin-1, platelet factor-4, extracellular matrix metalloproteinases (MMP) -2 and -9 as well as tissue inhibitors of metalloproteinases was determined in peripheral blood and bone marrow mononuclear cells with the use of quantitative real-time PCR method and additionally the concentration of VEGF with the flow cytofluorometry. We evaluated the phosphorylation of endothelial mitogen activated protein kinase in human umbilical vein endothelial cells after incubation in CML cells conditioned media, applying Western blot technique. We determined an influence of the leukemic cells on the endothelial cells proliferation with the colorimetric metabolic MTT test. We showed, that in peripheral blood and bone marrow mononuclear cells in CML patients most of the studied factors were increased at the time of CML diagnosis and became lower in remission. In newly diagnosed CML patients an expression of VEGF, MMP-2 and MMP-9 was particularly elevated. In remission, the levels of VEGF and metalloproteinases, specifically MMP-9, were decreased. If failed to achieve remission, the patients presented the elevated expression of most of the investigated angiogenic factors. In the acceleration or blast crisis phase angiopoetin, VEGF and MMP-2 levels were particularly high. We noticed the markedly enhanced human umbilical vein endothelium proliferation after an incubation in CML cells conditioned media, both in the test of mitogen activated protein kinase phosphorylation in endothelial cells and in the metabolic test for the proliferation intensity of endothelium. The differences of an angiogeneic potential found between clinical phases of CML, and the ability of leukemic cells to stimulate endothelial proliferation, point at the significance of neovascularisation in CML pathogenesis. Further studies are necessary to delineate the possibility of the use of angiogenic inhibitors in the treatment of this malignancy.

Primary myelodysplastic syndrome in Jordan: a single-centre experience

OBJECTIVE

Study of the disease patterns and clinical evaluation of myelodysplastic syndrome (MDS).

SUBJECTS AND METHODS

A retrospective analysis was carried out on 85 patients, with MDS who were followed up over a period of 23 years at Jordan University Hospital, Amman, Jordan. Cases were analyzed according to the French, American and British Classification.

RESULTS

Of the 85 patients, 42 (49.4%) were females and 43 (50%) males; mean age was 59 +/- 19 years (range 18-88). Most subtypes found in patients were refractory anemia (RA) in 27 (31.8%) and RA with excess blasts (RAEB) in 28 (32.9%). Adverse prognostic indicators were RAEB subtype and requirement for blood transfusion.

CONCLUSION

Our findings showed that MDSs appeared at a younger age and tended to be of the aggressive subtype. Chronic myelomonocytic leukemia subtype seemed to appear dominantly in men.

Secondary pulmonary alveolar proteinosis in a patient with chronic myeloid leukemia in the accelerated phase

Pulmonary alveolar proteinosis (PAP) is a rare respiratory disease the character of which is accumulation of protein consisting of surfactant in alveolar spaces. PAP sometimes complicates with hematological malignancies, especially myeloid leukemia. As one of the cause of PAP, impairment of alveolar macrophage is considered. We experienced a case of PAP with chronic myeloid leukemia (CML). 41 years old woman having CML for nine years developed PAP, and was treated by bronchoalveolar lavage and imatinib. She died of respiratory failure in the end, but BAL fluid had been becoming gradually crystalline after induction of imatinib. We consider that we should try to treat to improve respiratory status not only PAP but also hematological disease.

Rho-signaling pathways in chronic myelogenous leukemia

Chronic myelogenous leukemia (CML) is a hematological malignancy that is characteristic by as expansion of myeloid cells and their premature release into the circulation. The molecular cause of CML is the fusion oncoprotein Bcr-Abl whose constitutive tyrosine-kinase (TK) activity maintains enhanced signaling through multiple signal transduction pathways and confers proliferative and survival advantage to CML cells. These effects can be largely suppressed by TK inhibitor Imatinib mesylate, currently the leading drug in CML treatment. However, Bcr-Abl contains also additional functional domains, in particular a DBL homology (DH) domain with guanine-exchange function (GEF) which can activate small GTPases of Rho family and a Src-homology3 (SH3) domain which recruits other proteins with GEF activity. Bcr-Abl affects among others the RhoA/ROCK/LIM/cofilin pathway that regulates the actin cytoskeleton assembly and thereby the cellular adhesion and migration. This review deals in detail with the known points of interference between Bcr-Abl and Rho kinase pathways and with the effects of Imatinib mesylate on Rho signaling and cell adhesion to the extracellular matrix (ECM) components. The potential protein targets related to Bcr-Abl non-kinase activity are discussed.

Chronic myeloid leukaemia at the University Hospital of the West Indies: a 17-year review

OBJECTIVE

To determine the presenting features and evolution of patients diagnosed with chronic myeloid leukaemia between 1983 and 1999 at the University Hospital of the West Indies.

METHODS

Forty-one records were retrospectively analyzed for the patients' demographics, reasons for referral, clinical features, laboratory investigations and the time to blast transformation and death.

RESULTS

Seventy-one per cent were males and 29% were females. The male to female ratio was 2.4:1. The median age at presentation was 37 years (range 14-81 years). Seventy-eight per cent of the patients presented in the chronic phase. Weight loss and splenomegaly were the most frequent presenting features being seen in 54 and 83 per cent respectively. The median survival was 36 months.

CONCLUSION

In this study, the clinical features and evolution were comparable to existing data. Improved accrual and routine Philadelphia chromosome testing would provide a more accurate reflection of the status of CML in our population.

Therapy options in imatinib failures

Chronic myelogenous leukemia (CML) is defined by the presence of the constitutively active tyrosine kinase breakpoint cluster region/Abelson (Bcr-Abl), which activates numerous signal transduction pathways leading to uncontrolled cell proliferation. The development of the Bcr-Abl-targeted imatinib represents a paradigm shift in the treatment of CML, because treatment with imatinib resulted in significantly better patient outcome, response rates, and overall survival compared with previous standards. Despite this advance, not all patients benefit from imatinib because of resistance and intolerance. Resistance to imatinib can develop from a number of mechanisms that can be defined as Bcr-Abl-dependent (e.g., most commonly resulting from point mutations in the Abl kinase domain) and Bcr-Abl-independent mechanisms (including the constitutive activation of downstream signaling molecules, e.g., Src family kinases), which could result in the activation of the pathway regardless of Bcr-Abl inhibition. Clearly, new treatment approaches are required for patients resistant to or intolerant of imatinib, which can be dose escalated in patients who demonstrate resistance. This does not result in long-term responses. Hematopoietic stem cell transplantation is limited by the availability of matched donors and the potential for morbidity. Dasatinib, a dual Bcr-Abl/Src kinase inhibitor, has shown efficacy against all imatinib-resistant Bcr-Abl mutations except for T315I. A large trial program showed that dasatinib is effective in patients previously exposed to imatinib and has a manageable safety profile in all phases of CML and Philadelphia chromosome-positive acute lymphoblastic leukemia, resulting in its approval. Nilotinib, an analogue of imatinib, also has demonstrated activity in a similar patient population. These agents and less clinically advanced strategies are discussed in this review.

Neurological complications of chronic myeloid leukaemia: any cure?

OBJECTIVE

To attempt to explain the non-reversal, contrary to the widely held view, of the neurological deficits complicating chronic myeloid leukaemia.

METHOD

Using patients' case folders and haematological malignancy register all cases of chronic myeloid leukaemia seen in Jos University Teaching Hospital between July 1995 and June 2005 were retrospectively studied. All the available literature on the subject was also reviewed.

RESULTS

Thirty-three cases of chronic myeloid leukaemia were seen within the study period. Five (15.15%) of them had one or more sensori-neural defects. Of the five, two (40%) patients presented with bilateral hearing impairment, each beginning with the left ear; one (20%) presented with left ear hearing loss; one (20%) came with severe left ear tinnitus; one (20%) presented with complete bilateral hearing and bilateral visual losses. Fundoscopy showed leukaemic deposits on the retina. Other causes of blindness and deafness, e.g. trauma and foreign body in the ear respectively, were excluded.

CONCLUSION

While the complications due to hyperleucocytosis-induced stasis recover following the conventional treatment, those due to other pathogenetic mechanisms such as leukaemic deposits do not return to their pre-morbid states following disease control despite the use of the currently available treatment protocols. For future research, more still needs to be done to elicit other uncommon pathogenetic mechanisms underlying these complications with a view to finding specific treatment measures for worrisome chronic myeloid leukaemia-related sensori-neural deficits.

Rho GTPases and regulation of hematopoietic stem cell localization

Bone marrow engraftment in the context of hematopoietic stem cell and progenitor (HSC/P) transplantation is based on the ability of intravenously administered cells to lodge in the medullary cavity and be retained in the appropriate marrow space, a process referred to as homing. It is likely that homing is a multistep process, encompassing a sequence of highly regulated events that mimic the migration of leukocytes to inflammatory sites. In leukocyte biology, this process includes an initial phase of tethering and rolling of cells to the endothelium via E- and P-selectins, firm adhesion to the vessel wall via integrins that appear to be activated in an "inside-out" fashion, transendothelial migration, and chemotaxis through the extracellular matrix (ECM) to the inflammatory nidus. For HSC/P, the cells appear to migrate to the endosteal space of the bone marrow. A second phase of engraftment involves the subsequent interaction of specific HSC/P surface receptors, such as alpha(4)beta(1) integrin receptors with vascular cell-cell adhesion molecule-1 and fibronectin in the ECM, and interactions with growth factors that are soluble, membrane, or matrix bound. We have utilized knockout and conditional knockout mouse lines generated by gene targeting to study the role of Rac1 and Rac2 in blood cell development and function. We have determined that Rac is activated via stimulation of CXCR4 by SDF-1, by adhesion via beta(1) integrins, and via stimulation of c-kit by the stem cell factor-all of which involved in stem cell engraftment. Thus Rac proteins are key molecular switches of HSC/P engraftment and marrow retention. We have defined Rac proteins as key regulators of HSC/P cell function and delineated key unique and overlapping functions of these two highly related GTPases in a variety of primary hematopoietic cell lineages in vitro and in vivo. Further, we have begun to define the mechanisms by which each GTPase leads to specific functions in these cells. These studies have led to important new understanding of stem cell bone marrow retention and trafficking in the peripheral circulation and to the development of a novel small molecule inhibitor that can modulate stem cell functions, including adhesion, mobilization, and proliferation. This chapter describes the biochemical footprint of stem cell engraftment and marrow retention related to Rho GTPases. In addition, it reviews abnormalities of Rho GTPases implicated in human immunohematopoietic diseases and in leukemia/lymphoma.

Chronic myeloid leukaemia

Chronic myeloid leukaemia (CML) was the first neoplastic disease for which knowledge of the genotype led to a rationally designed therapy. As a result of its well known pathophysiology, straightforward diagnosis, well established prognostic factors, and treatment for the cause of disease, CML has been studied to an extent that far exceeds that expected from its frequency, and serves as a model disease for other cancers. Imatinib, an inhibitor of BCR-ABL tyrosine kinase, has revolutionised treatment of this disease, and is now recommended as standard treatment for chronic-phase CML. Interferon alfa is an acceptable alternative treatment in the early chronic phase for patients who do not tolerate imatinib. If imatinib treatment fails, allogeneic stem-cell transplantation, a dose increase of imatinib, or new drugs are recommended. Up to 87% of patients achieve complete cytogenetic remission, therefore we provide guidance for monitoring disease status. Many trials of new drugs and combination therapies that include imatinib are underway.

Concise review: Telomere biology in normal and leukemic hematopoietic stem cells

The measurement of telomere length can give an insight into the replicative history of the cells in question. Much of the observed telomere loss occurs at the stem and progenitor cell level, even though these populations express the enzyme telomerase. Telomerase-transfected hematopoietic stem cells (HSC), although able to maintain telomere length, are still limited in terms of ability to undergo sequential transplantation, and other factors require to be addressed to achieve optimal levels of stem cell expansion. Unchecked telomere loss by HSC, meanwhile, would appear to play a significant role in the pathogenesis of bone marrow failure, as observed in the condition dyskeratosis congenita. This heterogeneous inherited condition appears to exhibit telomerase dysfunction as a common final pathogenic mechanism. Although less well-established for acquired marrow failure syndromes, mutations in key telomerase components have been described. The identification of the leukemic stem cell (LSC), along with the desire to target this population with anti-leukemia therapy, demands that telomerase biology be fully understood in this cell compartment. Future studies using primary selected LSC-rich samples are required. A better understanding of telomerase regulation in this population may allow effective targeting of the telomerase enzyme complex using small molecule inhibitors or additional novel approaches. Disclosure of potential conflicts of interest is found at the end of this article.

Modulating autophagy for therapeutic benefit

Autophagy is an ancient cell survival pathway that allows cells to recoup ATP and essential building blocks for biosynthesis when they are starved of nutrients or when they are exposed to hypoxia, which are hallmarks of the tumor microenvironment. This pathway involves the formation of double-membraned vesicles, coined autophagosomes, which envelop bulk cellular material and/or organelles and that subsequently fuse with lysosomes that degrade their cargo. Autophagy has been suggested to play important roles in chemoresistance of cancer to some therapeutic agents, which typically induce an apoptotic response. For example, the histone deacetylase inhibitor SAHA induces both apoptosis and autophagy, suggesting that agents that disrupt the autophagy pathway might augment its efficacy as a therapeutic agent. We tested this notion in a model of Imatinib-refractory chronic myelogenous leukemia (CML) and in imatinib-resistant primary CML cells from patients bearing mutations in Bcr-Abl, including the T315I mutation that causes resistance to currently utilized tyrosine kinase inhibitors and translates into a very poor clinical prognosis. Agents that disrupt autophagy were shown to synergize with SAHA in provoking apoptotic death of these refractory tumors. These findings support the use of agents that disrupt the autophagy pathway in settings of chemorefractory malignancies.

Important Therapeutic Targets in Chronic Myelogenous Leukemia

PURPOSE

Review the state-of-art knowledge of the biology and therapy of chronic myelogenous leukemia (CML).

EXPERIMENTAL DESIGN

A review of the literature was undertaken to summarize current information on the pathophysiology of CML and to update data of imatinib mesylate therapy, mechanisms of resistance, and in vitro and clinical data with the new tyrosine kinase inhibitors.

RESULTS

Imatinib, which targets the ABL kinase activity of BCR-ABL, has prolonged survival in CML. Despite the efficacy of imatinib, some patients in chronic phase and more in advanced phases of CML develop resistance, frequently as a result of BCR-ABL tyrosine kinase domain mutants that impair imatinib binding but retain enzymatic activity. New tyrosine kinase inhibitors inhibit BCR-ABL more potently than imatinib and maintain activity against an array of imatinib-resistant BCR-ABL mutants. The IC(50) values of nilotinib and dasatinib are at least 10- to 100-fold lower for BCR-ABL compared with imatinib. Phase I-II trials of nilotinib and dasatinib showed high activity in imatinib-resistant CML and Philadelphia chromosome-positive ALL. Dasatinib also inhibits members of the Src family of kinases (SFKs); nilotinib does not. Whether SFKs have a critical role in imatinib resistance or BCR-ABL-mediated oncogenesis is unresolved. Agents that target signals downstream of BCR-ABL (e.g. Ras/Raf and phosphatidylinositol 3-kinase) are under investigation.

CONCLUSIONS

Understanding the pathophysiology of CML and mechanisms of resistance has produced effective targeted strategies for imatinib-resistant CML.