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Abstract. Selective erythroid aplasia occurred in two children receiving chemotherapy for acute lymphoblastic leukemia. The aplasia was reversible on cessation of therapy in one patient, and the other child remains transfusion-dependent on chemotherapy. Possible causes of pure red cell aplasia are discussed. Pediatrics, 59:895-898, 1977, ERYTHROID APLASIA, LYMPHOBLASTIC LEUKEMIA. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article "Treating childhood acute lymphoblastic leukemia without cranial irradiation," by C-H Pui and colleagues in the June 25, 2009 issue.

One of the most complex issues in cancer treatment is the unavoidable conflict between administering cytotoxic agents with variable tumor selectivity and the resulting dose-dependent short- and long-term damage to normal tissues. Further, there is great uncertainty as to whether late outcomes from prior treatment protocols are relevant to the anticipated late outcomes from current protocols. Virtually all recipients of anthracycline therapy should be considered to have some degree of cardiotoxicity. However, the severity of cardiotoxicity, not its presence, should determine what actions are appropriate. Currently, changes in ejection fraction and other imaging or serologic biomarkers (singly or in combination) during therapy have weak predictive value for chronic cardiomyopathy after the end of therapy, and their clinical utility requires further verification. Cardiotoxicity justifying individual dose modification during therapy requires evidence that it improves survival. The low prior probability of congestive heart failure during anthracycline therapy with the current monitoring protocols means that the ejection fraction has an unacceptably low predictive value. As a result, continued reliance on published recommendations for withholding chemotherapy based on asymptomatic changes in ejection fraction increases the risk of treatment failure more than it decreases the likelihood of irreversible cardiac injury. However, abnormalities in ventricular size and function after the end of therapy do predict chronic, progressive cardiomyopathy and justify longitudinal monitoring. Here, we discuss the cardiotoxicity of some of these chemotherapeutic agents and provide a framework for deciding when the evidence of cardiotoxicity is strong enough to justify a change in management. [ABSTRACT FROM AUTHOR]

Advances in treating childhood cancers over the past 40 years have more than doubled 5-year survival rates. More effective use of chemotherapeutic agents has been key to this success. However, the increase has come at a price: chronic conditions are significantly more prevalent in long-term survivors of childhood cancer than they are in the general population, and managing these survivors can be challenging. In patients receiving anthracyclines, cardiotoxicity is the leading cause of morbidity and mortality after relapse and second malignancies. More than 50% of patients exposed to anthracyclines exhibit some form of cardiac dysfunction within 20 years after completing chemotherapy, and about 5% develop heart failure. These conditions greatly reduce the quality of life of the individual and also consume substantial amounts of healthcare resources. Dexrazoxane has been used to reduce anthracycline-related cardiotoxicity in children with cancer, but in 2011, the European Medicines Agency determined, on what it acknowledged were limited data, that dexrazoxane was contraindicated in children. Here, we review the evidence for the clinical effects of dexrazoxane in children. Studies published since 2011 have confirmed the efficacy of dexrazoxane in preventing or reducing anthracycline-related cardiotoxicity in children with cancer, and no new evidence of increased risks for recurrence of primary or second malignancies, or reductions in antitumor efficacy has been reported. As a result, we believe that dexrazoxane should be available to children with high-risk cancers to reduce the risk of cardiotoxicity associated with high-dose anthracycline treatment. [ABSTRACT FROM AUTHOR]

With growing numbers of childhood cancer survivors, it becomes increasingly important to understand the long-term toxicities associated with cure from malignancy. Many survivors were exposed to cardiotoxic chemotherapeutic agents at young ages. Indeed, cardiotoxicity is a leading cause of treatment-related morbidity and mortality in survivors of childhood cancer, and anthracycline exposure is a leading cause of these late cardiac effects. Nonetheless, anthracyclines remain critical agents in treating many pediatric cancers. Strategies to prevent anthracycline-associated cardiotoxicity include limiting lifetime cumulative anthracycline doses and adding cardioprotectant agents, such as dexrazoxane, to anthracycline-based regimens. However, attempts to reduce the cardiotoxicity of anthracyclines must also consider their effect on anti-cancer efficacy as well as new potential toxicities. In survivors of childhood acute lymphoblastic leukemia, the data suggest that including dexrazoxane in anthracycline-based regimens can prevent heart damage, does not reduce anti-leukemic efficacy, and can be safely administered. The controversies associated with dexrazoxane exemplify the challenges of changing therapy in cancers with a relatively good chance of event-free survival in efforts to prevent long-term sequelae. Studies of very-long-term survivor cohorts will continue to inform current practices. Continued efforts are needed to minimize cardiotoxic exposures during cancer treatment, to deliver safe and effective cardioprotectant measures when cardiotoxic agents cannot be avoided, to identify patients at greatest risk of serious cardiac toxicity, and to educate providers in the optimal care of survivors. [ABSTRACT FROM AUTHOR]

Tremendous strides have been made in improving the outcomes of haematological malignancies ( HM) over the last three decades, but adolescents and young adult ( AYA) patients have not benefitted equally compared to younger and older patients. Excellent outcomes in Hodgkin lymphoma have allowed tailoring of highly effective regimens that limit the incidence of late effects. Early successes in paediatric acute lymphoblastic leukaemia set the stage for a series of studies in young adults utilizing a paediatric-type treatment strategy. These studies have determined that AYAs benefit from paediatric-type chemotherapy regimens. Despite the increased incidence of acute myeloid leukaemia and non-Hodgkin lymphoma in the AYA age group, optimal strategies for these patients have not been systematically pursued. There is renewed interest in improving HM outcomes in AYA patients and this will rely on the development of clinical trials that specifically target these patients. Understanding and addressing the unique psychosocial challenges of this population will be critical in supporting this endeavor. [ABSTRACT FROM AUTHOR]

Extensive endothelial cell proliferation and marked neovascularization are the most pronounced microenvironmental changes consistently observed in the bone marrow (BM) of patients with acute lymphoblastic leukemia (ALL). It is not known whether ALL cells induce this phenotype and whether they receive critical signals from the tumor-associated BM endothelium. Here, we show that leukemia cells actively stimulate BM endothelium, promote de novo angiogenesis, and induce neovascularization in the leukemic BM. Soluble factors, present in the leukemic BM microenvironment, promote the proliferation, migration, and morphogenesis of BM endothelial cells, which are critical processes in tumor angiogenesis. We also show in vitro that leukemia cells display directional motion towards assembled BM endothelium and following adherence exhibit cell polarization, pseudopodia, and ultrastructural features that suggest the existence of leukemia-endothelium cross-talk. Finally, we show that BM endothelium promotes leukemia cell survival through a mechanism mediated through the anti-apoptotic molecule bcl-2. These studies indicate that ALL cells actively recruit BM endothelium and mediate the leukemia-associated neovascularization observed in ALL. Therefore, disruption of interactions between leukemia cells and BM endothelium may constitute a valid therapeutic strategy. [Copyright &y& Elsevier]

Background: NUT midline carcinoma is a rare and aggressive genetically characterized subtype of squamous cell carcinoma frequently arising from the head and neck. The characteristics and optimal management of head and neck NUT midline carcinoma (HNNMC) are unclear.Methods: A retrospective review of all known cases of HNNMC in the International NUT Midline Carcinoma Registry as of December 31, 2014, was performed. Forty-eight consecutive patients were treated from 1993 to 2014, and clinicopathologic variables and outcomes for 40 patients were available for analyses; they composed the largest HNNMC cohort studied to date. Overall survival (OS) and progression-free survival (PFS) according to patient characteristics and treatment were analyzed.Results: This study identified a 5-fold increase in the diagnosis of HNNMC from 2011 to 2014. The median age was 21.9 years (range, 0.1-81.7 years); the male and female proportions were 40% and 60%, respectively; and 86% had bromodomain containing 4-nuclear protein in testis (BRD4-NUT) fusion. The initial treatment was initial surgery with or without adjuvant chemoradiation or adjuvant radiation (56%), initial radiation with or without chemotherapy (15%), or initial chemotherapy with or without surgery or radiation (28%). The median PFS was 6.6 months (range, 4.7-8.4 months). The median OS was 9.7 months (range, 6.6-15.6 months). The 2-year PFS rate was 26% (95% confidence interval [CI], 13%-40%). The 2-year OS rate was 30% (95% CI, 16%-46%). Initial surgery with or without postoperative chemoradiation or radiation (P = .04) and complete resection with negative margins (P = .01) were significant predictors of improved OS even after adjustments for age, tumor size, and neck lymphadenopathy. Initial radiation or chemotherapy and the NUT translocation type were not associated with outcomes.Conclusions: HNNMC portends a poor prognosis. Aggressive initial surgical resection with or without postoperative chemoradiation or radiation is associated with significantly enhanced survival. Chemotherapy or radiation alone is often inadequate. Cancer 2016;122:3632-40. © 2016 American Cancer Society. [ABSTRACT FROM AUTHOR]

Background: Impaired cardiac function in doxorubicin-treated childhood cancer survivors is partly mediated by the disruption of mitochondrial energy production. Doxorubicin intercalates into mitochondrial DNA (mtDNA) and disrupts genes encoding for polypeptides that make adenosine triphosphate.Methods: This cross-sectional study examined mtDNA copy numbers per cell and oxidative phosphorylation (OXPHOS) in peripheral blood mononuclear cells (PBMCs) in 64 childhood survivors of high-risk acute lymphoblastic leukemia (ALL) who had been treated on Dana-Farber Cancer Institute childhood ALL protocols and had received doxorubicin alone (42%) or doxorubicin with the cardioprotectant dexrazoxane (58%). The number of mtDNA copies per cell and the OXPHOS enzyme activity of nicotinamide adenine dinucleotide dehydrogenase (complex I [CI]) and cytochrome c oxidase (complex IV [CIV]) were measured with quantitative real-time polymerase chain reaction immunoassays and thin-layer chromatography, respectively.Results: At a median follow-up of 7.8 years after treatment, the median number of mtDNA copies per cell for patients treated with doxorubicin alone (1106.3) was significantly higher than the median number for those who had also received dexrazoxane (310.5; P = .001). No significant differences were detected between the groups for CI or CIV activity.Conclusions: Doxorubicin-treated survivors had an increased number of PBMC mtDNA copies per cell, and concomitant use of dexrazoxane was associated with a lower number of mtDNA copies per cell. Because of a possible compensatory increase in mtDNA copies per cell to maintain mitochondrial function in the setting of mitochondrial dysfunction, overall OXPHOS activity was not different between the groups. The long-term sustainability of this compensatory response in these survivors at risk for cardiac dysfunction over their lifespan is concerning. [ABSTRACT FROM AUTHOR]

Cardiotoxicity related to doxorubicin chemotherapy is a major late effect in childhood cancer survivors. Serum cardiac troponin concentrations (cTnT) can be elevated during doxorubicin therapy but the cellular associations with this myocardial injury are not well understood. We evaluate a novel nanotechnology-based biomarker discovery approach on a pilot set of serial serum samples from 11 children with acute lymphoblastic leukemia receiving doxorubicin therapy to determine if a proteomic signature of myocardial injury could be identified. This nanoparticle-based biomarker capture technology was utilized to analyze 40 serial serum samples from these children, 3 of whom seroconverted, 2 from cTnT-negative to cTnT-positive and 1 from cTnT-positive to cTnT-negative. High-resolution mass spectrometry analysis of the captured material identified 13 differentially expressed candidate proteins, whose spectral count values reflected changes in cTnT concentrations, which were verified in the serum samples from the 3 consistently cTnT-negative and 5 consistently cTnT-positive children. Of the 13 candidate proteins, 5 were significantly elevated (p < 0.1) in the independent validation set of cTnT-positive samples (serum amyloid A, cardiac muscle actin proprotein, a gamma globulin, HIV-enhancer-element binding protein, and C-reactive protein). These results demonstrate the potential for novel nanoparticle-capture biomarker discovery workflow to be applied to the doxorubicin cardiotoxicity-based setting. The identified candidate biomarkers require further validation in larger cohorts to evaluate clinical impact. Significance Identification of new biomarkers for early detection of chemotherapy-induced cardiotoxicity is of critical importance so that administration of cardioprotectants can be utilized before substantial heart damage has occurred. We developed and utilized a unique biomarker workflow based on a novel nanotechnology method in order to demonstrate the potential for such an approach to uncover low abundance markers that could be useful in a clinical setting once extensively validated. [ABSTRACT FROM AUTHOR]

Treatment advances have increased survival in children with cancer, but subclinical, progressive, irreversible, and sometimes fatal treatment-related cardiovascular effects may appear years later. Cardio-oncologists have identified promising preventive and treatment strategies. Dexrazoxane provides longterm cardioprotection from doxorubicin-associated cardiotoxicity without compromising the efficacy of anticancer treatment. Continuous infusion of doxorubicin is as effective as bolus administration in leukemia treatment, but no evidence has indicated that it provides long-term cardioprotection; continuous infusions should be eliminated from pediatric cancer treatment. Angiotensin-Converting enzyme inhibitors can delay the progression of subclinical and clinical cardiotoxicity. All survivors, regardless of whether they were treated with anthracyclines or radiation, should be monitored for systemic inflammation and the risk of premature cardiovascular disease. Echocardiography screening must be supplemented with screening for biomarkers of cardiotoxicity and perhaps by identification of genetic susceptibilities to cardiovascular diseases; optimal strategies need to be identified. The health burden related to cancer treatment will increase as this population expands and ages. [ABSTRACT FROM AUTHOR]

Activating mutations of the interleukin-7 receptor ( IL7R) occur in approximately 10% of patients with T cell acute lymphoblastic leukaemia (T- ALL). Most mutations generate a cysteine at the transmembrane domain leading to receptor homodimerization through disulfide bond formation and ligand-independent activation of STAT5. We hypothesized that the reducing agent N-acetylcysteine ( NAC), a well-tolerated drug used widely in clinical practice to treat acetaminophen overdose, would reduce disulfide bond formation, and inhibit mutant IL7R-mediated oncogenic signalling. We found that treatment with NAC disrupted IL7R homodimerization in IL7R-mutant DND-41 cells as assessed by non-reducing Western blot, as well as in a luciferase complementation assay. NAC led to STAT5 dephosphorylation and cell apoptosis at clinically achievable concentrations in DND-41 cells, and Ba/F3 cells transformed by an IL7R-mutant construct containing a cysteine insertion. The apoptotic effects of NAC could be rescued in part by a constitutively active allele of STAT5. Despite using doses lower than those tolerated in humans, NAC treatment significantly inhibited the progression of human DND-41 cells engrafted in immunodeficient mice. Thus, targeting leukaemogenic IL7R homodimerization with NAC offers a potentially effective and feasible therapeutic strategy that warrants testing in patients with T- ALL. [ABSTRACT FROM AUTHOR]

In certain human cancers, the expression of critical oncogenes is driven from large regulatory elements, called super-enhancers, that recruit much of the cell's transcriptional apparatus and are defined by extensive acetylation of histone H3 lysine 27 (H3K27ac). In a subset of T-cell acute lymphoblastic leukemia (T-ALL) cases, we found that heterozygous somatic mutations are acquired that introduce binding motifs for the MYB transcription factor in a precise noncoding site, which creates a super-enhancer upstream of the TAL1 oncogene. MYB binds to this new site and recruits its H3K27 acetylase-binding partner CBP, as well as core components of a major leukemogenic transcriptional complex that contains RUNX1, GATA-3, and TAL1 itself. Additionally, most endogenous super-enhancers found in T-ALL cells are occupied by MYB and CBP, which suggests a general role for MYB in super-enhancer initiation. Thus, this study identifies a genetic mechanism responsible for the generation of oncogenic super-enhancers in malignant cells. [ABSTRACT FROM AUTHOR]

Cardio-oncology is a relatively new discipline that focuses on the cardiovascular sequelae of anti-tumour drugs. As any other young adolescent discipline, cardio-oncology struggles to define its scientific boundaries and to identify best standards of care for cancer patients or survivors at risk of cardiovascular events. The International Colloquium on Cardio-Oncology was held in Rome, Italy, 12-14 March 2014, with the aim of illuminating controversial issues and unmet needs in modern cardio-oncology. This colloquium embraced contributions from different kind of disciplines (oncology and cardiology but also paediatrics, geriatrics, genetics, and translational research); in fact, cardio-oncology goes way beyond the merging of cardiology with oncology. Moreover, the colloquium programme did not review cardiovascular toxicity from one drug or the other, rather it looked at patients as we see them in their fight against cancer and eventually returning to everyday life. This represents the melting pot in which anti-cancer therapies, genetic backgrounds, and risk factors conspire in producing cardiovascular sequelae, and this calls for screening programmes and well-designed platforms of collaboration between one key professional figure and another. The International Colloquium on Cardio-Oncology was promoted by the Menarini International Foundation and co-chaired by Giorgio Minotti (Rome), Joseph R Carver (Philadelphia, Pennsylvania, United States), and Steven E Lipshultz (Detroit, Michigan, United States). The programme was split into five sessions of broad investigational and clinical relevance (what is cardiotoxicity?, cardiotoxicity in children, adolescents, and young adults, cardiotoxicity in adults, cardiotoxicity in special populations, and the future of cardio-oncology). Here, the colloquium chairs and all the session chairs briefly summarised what was said at the colloquium. Topics and controversies were reported on behalf of all members of the working group of the International Colloquium on Cardio-Oncology. [ABSTRACT FROM AUTHOR]

Although prognosis has improved for children with T-cell acute lymphoblastic leukemia (T-ALL), 20% to 30% of patients undergo induction failure (IF) or relapse. Leukemia-initiating cells (LICs) are hypothesized to be resistant to chemotherapy and to mediate relapse. We and others have shown that Notch1 directly regulates c-Myc, a known regulator of quiescence in stem and progenitor populations, leading us to examine whether c-Myc inhibition results in efficient targeting of T-ALL-initiating cells. We demonstrate that c-Myc suppression by small hairpin RNA or pharmacologic approaches prevents leukemia initiation in mice by eliminating LIC activity. Consistent with its anti-LIC activity in mice, treatment with the BET bromodomain BRD4 inhibitor JQ1 reduces C-MYC expression and inhibits the growth of relapsed and IF pediatric T-ALL samples in vitro. These findings demonstrate a critical role for c-Myc in LIC maintenance and provide evidence that MYC inhibition may be an effective therapy for relapsed/IFT-ALL patients. [ABSTRACT FROM AUTHOR]

A scientific statement from the American Heart Association on long-term cardiovascular toxicity in children, adolescents and young adults receiving cancer therapy is presented. It describes cardiovascular changes induced by chemotherapeutic agents, including paclitaxel and thalidomide. It also cites challenges in developing targeted therapies for decreasing lifelong cardiovascular risk in cancer survivors.

BACKGROUND Doxorubicin is associated with progressive cardiac dysfunction, possibly through the formation of doxorubicin-iron complexes leading to free-radical injury. The authors determined the frequency of hemochromatosis (HFE) gene mutations associated with hereditary hemochromatosis and their relationship with doxorubicin-associated cardiotoxicity in survivors of childhood high-risk acute lymphoblastic leukemia. METHODS Peripheral blood was tested for 2 common HFE allelic variants: C282Y and H63D. Serum cardiac troponin-T (cTnT) and N-terminal pro-brain natriuretic peptide (NT-proBNP), which are biomarkers of cardiac injury and cardiomyopathy, respectively, were assayed during therapy. Left ventricular (LV) structure and function were assessed with echocardiography. RESULTS A total of 184 patients had DNA results for at least 1 variant, and 167 had DNA results for both: 24% carried H63D and 10% carried C282Y. Heterozygous C282Y genotype was associated with multiple elevations in cTnT concentrations ( P = .039), but not NT-proBNP. At a median of 2.2 years (range, 1.0 years-3.6 years) after diagnosis, the mean Z-scores for LV fractional shortening (−0.71 [standard error (SE), 0.25]; P = .008), mass (−0.84 [SE, 0.17]; P < .001), and end-systolic (−4.36 [SE, 0.26], P < .001) and end-diastolic (−0.68 [SE, 0.25]; P = .01) posterior wall thickness were found to be abnormal in children with either allele (n = 32). Noncarriers (n = 63) also were found to have below-normal LV mass (−0.45 [SE, 0.15]; P = .006) and end-systolic posterior wall thickness (−4.06 [SE, 0.17]; P < .001). Later follow-up demonstrated similar results. CONCLUSIONS Doxorubicin-associated myocardial injury was associated with C282Y HFE carriers. Although LV mass and wall thickness were found to be abnormally low overall, they were even lower in HFE carriers, who also had reduced LV function. Screening newly diagnosed cancer patients for HFE mutations may identify those at risk for doxorubicin-induced cardiotoxicity. Cancer 2013;119:3555-3562.. © 2013 American Cancer Society. [ABSTRACT FROM AUTHOR]

BACKGROUND AND OBJECTIVES: Doxorubicin, effective against many malignancies, is limited by cardiotoxicity. Continuous-infusion doxorubicin, compared with bolus-infusion, reduces early cardiotoxicity in adults. Its effectiveness in reducing late cardiotoxicity in children remains uncertain. We determined continuous-infusion doxorubicin cardioprotective efficacy in long-term survivors of childhood acute lymphoblastic leukemia (ALL). METHODS: The Dana-Farber Cancer Institute ALL Consortium Protocol 91-01 enrolled pediatric patients between 1991 and 1995. Newly diagnosed high-risk patients were randomly assigned to receive a total of 360 mg/m2 of doxorubicin in 30 mg/m2 doses every 3 weeks, by either continuous (over 48 hours) or bolus-infusion (within 15 minutes). Echocardiograms at baseline, during, and after doxorubicin therapy were blindly remeasured centrally. Primary outcomes were late left ventricular (LV) structure and function. RESULTS: A total of 102 children were randomized to each treatment group. We analyzed 484 serial echocardiograms from 92 patients (n = 49 continuous; n = 43 bolus) with ≥1 echocardiogram ≥3 years after assignment. Both groups had similar demographics and normal baseline LV characteristics. Cardiac follow-up after randomization (median, 8 years) showed changes from baseline within the randomized groups (depressed systolic function, systolic dilation, reduced wall thickness, and reduced mass) at 3, 6, and 8 years; there were no statistically significant differences between randomized groups. Ten-year ALL event- free survival rates did not differ between the 2 groups (continuous- infusion, 83% versus bolus-infusion, 78%; P = .24). CONCLUSIONS: In survivors of childhood high-risk ALL, continuous- infusion doxorubicin, compared with bolus-infusion, provided no long- term cardioprotection or improvement in ALL event-free survival, hence provided no benefit over bolus-infusion. [ABSTRACT FROM AUTHOR]

Cytotoxic chemotherapy targets elements common to all nucleated human cells, such as DNA and microtubules, yet it selectively kills tumor cells. Here we show that clinical response to these drugs correlates with, and may be partially governed by, the pretreatment proximity of tumor cell mitochondria to the apoptotic threshold, a property called mitochondrial priming. We used BH3 profiling to measure priming in tumor cells from patients with multiple myeloma, acute myelogenous and lymphoblastic leukemia, and ovarian cancer. This assay measures mitochondrial response to peptides derived from proapoptotic BH3 domains of proteins critical for death signaling to mitochondria. Patients with highly primed cancers exhibited superior clinical response to chemotherapy. In contrast, chemoresistant cancers and normal tissues were poorly primed. Manipulation of mitochondrial priming might enhance the efficacy of cytotoxic agents. [ABSTRACT FROM AUTHOR]

Asparaginase is a standard and critical component in the therapy of childhood acute lymphoblastic leukemia. Asparagine synthetase (ASNS) and the basic region leucine zipper activating transcription factor 5 (ATF5) and arginosuccinate synthase 1 (ASS1) have been shown to mediate the antileukemic effect of asparaginase and to display variable expression between leukemia cells that are resistant and sensitive to treatment. Fourteen polymorphisms in the regulatory and coding regions of these genes were investigated for an association with acute lymphoblastic leukemia outcome. Lower event-free survival (EFS) was associated with ATF5 T1562C, tandem-repeat ASNS polymorphism, derived haplotype, and ASS1 G1343T and G34T substitutions (P ≥ .03). Associations were limited to patients who received Escherichia coli asparaginase. Variations that sustained correction for multiple testing (ATF5 T1562C, P = .005; ASNS tandem-repeat and related haplotype, P ≥ .01) were subsequently analyzed in the replication cohort. The E coli-dependent association of the ATF5 T1562 allele with reduced EFS was confirmed (P = .01). A gene-reporter assay showed that the haplotype tagged by T1562 had higher promoter activity (P ≥ .01). The remaining regulatory polymorphisms also appeared to affect ATF5 function; 2 additional high-activity haplotypes were identified (P ≥ .02) and were further corroborated by quantitative mRNA analysis in lymphoblastoid cell lines. The ATF5-regulated increase in ASNS expression in response to more efficacious E coli-induced asparagine depletion may explain our observed results. [ABSTRACT FROM AUTHOR]

The BCL11B transcription factor is required for normal T-cell development, and has recently been implicated in the pathogenesis of T-cell acute lymphoblastic leukemia (T-ALL) induced by TLX overexpression or Atm deficiency. To comprehensively assess the contribution of BCL11B inactivation to human T-ALL, we performed DNA copy number and sequencing analyses of T-ALL diagnostic specimens, revealing monoallelic BCL11B deletions or missense mutations in 9% (n = 10 of 117) of cases. Structural homology modeling revealed that several of the BCL11B mutations disrupted the structure of zinc finger domains required for this transcription factor to bind DNA. BCL11B haploinsufficiency occurred across each of the major molecular subtypes of T-ALL, including early T-cell precursor, HOXA-positive, LEF1-inactivated, and TAL1-positive subtypes, which have differentiation arrest at diverse stages of thymocyte development. Our findings provide compelling evidence that BCL11B is a haploinsufficient tumor suppressor that collaborates with all major T-ALL oncogenic lesions in human thymocyte transformation. [ABSTRACT FROM AUTHOR]

Abstract: Background: Dexrazoxane reduces the risk of anthracycline-related cardiotoxicity. In a study of children with Hodgkin lymphoma, the addition of dexrazoxane may have been associated with a higher risk for developing second malignant neoplasms (SMNs) including acute myelogenous leukaemia (AML) and myelodysplastic syndrome (MDS). We determined the incidence of SMNs in children and adolescents with acute lymphoblastic leukaemia (ALL) who were treated with dexrazoxane. Methods: Between 1996 and 2010, the Dana-Faber Cancer Institute ALL Consortium conducted three consecutive multicentre trials for children with newly diagnosed ALL. In the first (1996–2000), high risk patients were randomly assigned to receive doxorubicin (30mg/m2/dose, cumulative dose 300mg/m2) preceded by dexrazoxane (300mg/m2/dose, 10 doses), or the same dose of doxorubicin without dexrazoxane, during induction and intensification phases. In subsequent trials (2000–2005 and 2005–2010), all high risk and very high risk patients received doxorubicin preceded by dexrazoxane. Cases of SMNs were collected prospectively and were pooled for analysis. The frequency and 5-year cumulative incidence (CI) of SMNs were determined for patients who had received dexrazoxane. Findings: Among 553 patients treated with dexrazoxane (1996–2000, N =101; 2000–2005, N =196; and 2005–2010, N =256), the number of SMNs observed by protocol was 0 (median follow-up 9.6years), 0 (median follow-up 5.2years), and 1 (median follow-up 2.1years). The only SMN was a case of AML, which developed in a patient with MLL-rearranged ALL 2.14years after initial diagnosis. The overall 5-year CI of SMNs for all 553 patients was 0.24±0.24%. Interpretation: In a large population of children with high risk ALL who received dexrazoxane as a cardioprotectant drug, the occurrence of secondary AML was a rare event. [Copyright &y& Elsevier]

Despite exhibiting oncogenic events, patient's leukemia cells are responsive and dependent on signals from their malignant bone marrow (BM) microenvironment, which modulate their survival, cell cycle progression, trafficking and resistance to chemotherapy. Identification of the signaling pathways mediating this leukemia/microenvironment interplay is critical for the development of novel molecular targeted therapies. We observed that primary leukemia B-cell precursors aberrantly express receptors of the BAFF-system, BAFF-R, BCMA, and TACI. These receptors are functional as their ligation triggers activation of NF-kB, MAPK/JNK, and Akt signaling. Leukemia cells express surface BAFF and APRIL ligands, and soluble BAFF is significantly higher in leukemia patients in comparison to age-matched controls. Interestingly, leukemia cells also express surface APRIL, which seems to be encoded by APRIL-d, a novel isoform that lacks the furin convertase domain. Importantly, we observed BM microenvironmental cells express the ligands BAFF and APRIL, including surface and secreted BAFF by BM endothelial cells. Functional studies showed that signals through BAFF-system receptors impact the survival and basal proliferation of leukemia B-cell precursors, and support the involvement of both homotypic and heterotypic mechanisms. This study shows an unforeseen role for the BAFF-system in the biology of precursor B-cell leukemia, and suggests that the target disruption of BAFF signals may constitute a valid strategy for the treatment of this cancer. [ABSTRACT FROM AUTHOR]

The optimal management of asparaginase-associated thrombotic complications is not well-defined. We report the features, management and outcome of paediatric (ages 0-18 years) and adult (18-50 years) patients with acute lymphoblastic leukaemia (ALL) with asparaginase-related venous thromboembolic events (VTE) treated at Dana-Farber Cancer Institute on clinical trials for newly diagnosed ALL between 1991-2008. Of 548 patients, 43 (8%) had VTE, including 27/501 (5%) paediatric and 16/47 (34%) adult patients. Sinus venous thrombosis occurred in 1·6% of patients. Age was the only significant predictor of VTE, with those aged >30 years at very high risk (VTE rate 42%). 74% of patients received low molecular weight heparin after VTE. Complications of anticoagulation included epistaxis (9%), bruising (2%) and, in two adult patients, major bleeding. Thirty patients (70%) ultimately received at least 85% of the intended doses of asparaginase. 33% of patients experienced recurrent VTE (paediatric 17% vs. adults 47%, P = 0·07). The 48-month event-free survival for patients with VTE was 85 ± 6% compared with 88 ± 2% for those without VTE ( P = 0·36). This study confirms that, after VTE, asparaginase can be restarted with closely monitored anticoagulation after imaging demonstrates clot stabilization or improvement. With this management strategy, a history of VTE does not appear to adversely impact prognosis. [ABSTRACT FROM AUTHOR]

Summary: Background: Doxorubicin chemotherapy is associated with cardiomyopathy. Dexrazoxane reduces cardiac damage during treatment with doxorubicin in children with acute lymphoblastic leukaemia (ALL). We aimed to establish the long-term effect of dexrazoxane on the subclinical state of cardiac health in survivors of childhood high-risk ALL 5 years after completion of doxorubicin treatment. Methods: Between January, 1996, and September, 2000, children with high-risk ALL were enrolled from nine centres in the USA, Canada, and Puerto Rico. Patients were assigned by block randomisation to receive ten doses of 30 mg/m2 doxorubicin alone or the same dose of doxorubicin preceded by 300 mg/m2 dexrazoxane. Treatment assignment was obtained through a telephone call to a centralised registrar to conceal allocation. Investigators were masked to treatment assignment but treating physicians and patients were not; however, investigators, physicians, and patients were masked to study serum cardiac troponin-T concentrations and echocardiographic measurements. The primary endpoints were late left ventricular structure and function abnormalities as assessed by echocardiography; analyses were done including all patients with data available after treatment completion. This trial has been completed and is registered with ClinicalTrials.gov, number NCT00165087. Findings: 100 children were assigned to doxorubicin (66 analysed) and 105 to doxorubicin plus dexrazoxane (68 analysed). 5 years after the completion of doxorubicin chemotherapy, mean left ventricular fractional shortening and end-systolic dimension Z scores were significantly worse than normal for children who received doxorubicin alone (left ventricular fractional shortening: −0·82, 95% CI −1·31 to −0·33; end-systolic dimension: 0·57, 0·21–0·93) but not for those who also received dexrazoxane (−0·41, −0·88 to 0·06; 0·15, −0·20 to 0·51). The protective effect of dexrazoxane, relative to doxorubicin alone, on left ventricular wall thickness (difference between groups: 0·47, 0·46–0·48) and thickness-to-dimension ratio (0·66, 0·64–0·68) were the only statistically significant characteristics at 5 years. Subgroup analysis showed dexrazoxane protection (p=0·04) for left ventricular fractional shortening at 5 years in girls (1·17, 0·24–2·11), but not in boys (−0·10, −0·87 to 0·68). Similarly, subgroup analysis showed dexrazoxane protection (p=0·046) for the left ventricular thickness-to-dimension ratio at 5 years in girls (1·15, 0·44–1·85), but not in boys (0·19, −0·42 to 0·81). With a median follow-up for recurrence and death of 8·7 years (range 1·3–12·1), event-free survival was 77% (95% CI 67–84) for children in the doxorubicin-alone group, and 76% (67–84) for children in the doxorubicin plus dexrazoxane group (p=0·99). Interpretation: Dexrazoxane provides long-term cardioprotection without compromising oncological efficacy in doxorubicin-treated children with high-risk ALL. Dexrazoxane exerts greater long-term cardioprotective effects in girls than in boys. Funding: US National Institutes of Health, Children''s Cardiomyopathy Foundation, University of Miami Women''s Cancer Association, Lance Armstrong Foundation, Roche Diagnostics, Pfizer, and Novartis. [Copyright &y& Elsevier]

Summary: Drug resistance remains a major obstacle to successful cancer treatment. A database of drug-associated gene expression profiles was screened for molecules whose profile overlapped with a gene expression signature of glucocorticoid (GC) sensitivity/resistance in acute lymphoblastic leukemia (ALL) cells. The screen indicated that the mTOR inhibitor rapamycin profile matched the signature of GC sensitivity. We tested the hypothesis that rapamycin would induce GC sensitivity in lymphoid malignancy cells and found that it sensitized to GC-induced apoptosis via modulation of antiapoptotic MCL1. These data indicate that MCL1 is an important regulator of GC-induced apoptosis and that the combination of rapamycin and glucocorticoids has potential utility in lymphoid malignancies. Furthermore, this approach represents a strategy for identification of promising combination therapies for cancer. [Copyright &y& Elsevier]

Infant acute lymphoblastic leukaemia (ALL) represents a rare but unique subset with poor prognosis. We analysed mixed-lineage leukaemia ( MLL) gene rearrangements and the sequences of complete and incomplete immunoglobulin heavy chain gene rearrangements ( IGH) in 14 infants (age ≤12 months at diagnosis) enrolled on Dana-Farber Cancer Institute ALL Consortium Protocol 95–01. The dynamics of the leukaemic clone were followed during the course of the disease by quantitative real-time polymerase chain reaction of IGH rearrangements. Sixteen sequences were obtained from 13 (93%) of these infants. There was marked over usage of the VH6.1 gene segment (64%) in infants compared with older children with ALL (8%), ( P < 0·001) and overusage of DH6 ( P = 0·004) and JH1 ( P = 0·004). Poor outcome was associated with MLL gene rearrangements rather than any specific VHDHJH gene usage patterns. Levels of minimal residual disease (MRD) at the end of induction appeared to be high in infants with ALL compared with older children, and although the number of infant cases studied was small, there were no differences in MRD levels after induction therapy in infant ALL with or without MLL gene rearrangements ( P = 0·41) and quantitative MRD assessment at the early time points may not be predictive of outcome. Novel treatment strategies are required to improve the outcome in this poor prognosis subset of children with ALL. [ABSTRACT FROM AUTHOR]

Objective. The objective was to assess the cardiac effects of growth hormone (GH) therapy. Anthracycline-treated childhood cancer survivors frequently have reduced left ventricular (LV) wall thickness and contractility, and GH therapy may affect these factors. Methods. We examined serial cardiac findings for anthracycline-treated childhood cancer survivors with several years of GH therapy and baseline cardiac z scores similar to those of a comparison group (86 similar cancer survivors without GH therapy). Results. LV contractility was decreased among GH- treated patients before, during, and after GH therapy (-1.08 SD below the age-adjusted population mean before therapy and -1.88 SD 4 years after therapy ceased, with each value depressed below normal). Contractility was higher in the control group than in the GH-treated group, with this difference being nearly significant. The GH-treated children had thinner LV walls before GH therapy (-1.38 SD). Wall thickness increased during GH therapy (from -1.38 SD to -1.09 SD after 3 years of GH therapy), but the effect was lost shortly after GH therapy ended and thickness diminished over time (-1.50 SD 1 year after therapy and -1.96 SD at 4 years). During GH therapy, the wall thickness for the GH-treated group was greater than that for the control group; however, by years after therapy, there was no difference between the GH-treated group and the control group. Conclusions. GH therapy among anthracycline- treated survivors of childhood cancer increased LV wall thickness, but the effect was lost after therapy was discontinued. The therapy did not affect the progressive LV dysfunction. [ABSTRACT FROM AUTHOR]

Objectives: We and others have shown that B cell precursor acute lymphoblastic leukemia cells (ALL) stimulated with CD40 ligand become efficient antigen-presenting cells (APC) capable of expanding autologous, tumor-specific T cells from patients. Translation of these preclinical findings to a novel treatment strategy required four separate issues to be determined: (1) if a CD40-ALL vaccine could be generated for clinical use; (2) whether clinical translation could be achieved; (3) whether the vaccination was safe; and (4) whether a window of time could be identified that would optimize the efficacy of vaccination. Patients and methods: Nine patients with relapsed/refractory ALL were enrolled in a phase I trial of vaccination with autologous CD40-ALL. Immunologic reconstitution was measured in a separate cohort of 23 patients with newly diagnosed ALL. Results: We successfully prepared autologous vaccines for all nine patients in the phase I trial. CD40-ALL were potent APC, capable of stimulating allogeneic and peptide-specific T cells in vitro. Two patients were vaccinated without adverse events. Five patients died or progressed before vaccination, suggesting that rapid disease progression limits vaccination in patients with relapse disease, thus limiting clinical translation. We therefore sought to identify a window of time for vaccination during which this approach might be feasible. To achieve this end, we evaluated immunological reconstitution in newly diagnosed patients with ALL patients. Despite recovery of myelopoiesis, most patients had profound defects in T, B, and natural killer (NK) cell numbers that failed to recover at any point during therapy. Conclusion: Autologous tumor vaccination at a time of ALL relapse is not feasible. Alternative strategies for immunotherapy of ALL may require ex vivo generation of antigen specific T cells and adoptive therapy. [Copyright &y& Elsevier]

We recently found that MLL-rearranged acute lymphoblastic leukemias (MLL) have a unique gene expression profile including high level expression of the receptor tyrosine kinase FLT3. We hypothesized that FLT3 might be a therapeutic target in MLL and found that 5 of 30 MLLs contain mutations in the activation loop of FLT3 that result in constitutive activation. Three are a newly described deletion of I836 and the others are D835 mutations. The recently described FLT3 inhibitor PKC412 proved cytotoxic to Ba/F3 cells dependent upon activated FLT3 containing either mutation. PKC412 is also differentially cytotoxic to leukemia cells with MLL translocations and FLT3 that is activated by either overexpression of the wild-type receptor or mutation. Finally, we developed a mouse model of MLL and used bioluminescent imaging to determine that PKC412 is active against MLL in vivo. [Copyright &y& Elsevier]

Acute lymphoblastic leukemias carrying a chromosomal translocation involving the mixed-lineage leukemia gene (MLL, ALL1, HRX) have a particularly poor prognosis. Here we show that they have a characteristic, highly distinct gene expression profile that is consistent with an early hematopoietic progenitor expressing select multilineage markers and individual HOX genes. Clustering algorithms reveal that lymphoblastic leukemias with MLL translocations can clearly be separated from conventional acute lymphoblastic and acute myelogenous leukemias. We propose that they constitute a distinct disease, denoted here as MLL, and show that the differences in gene expression are robust enough to classify leukemias correctly as MLL, acute lymphoblastic leukemia or acute myelogenous leukemia. Establishing that MLL is a unique entity is critical, as it mandates the examination of selectively expressed genes for urgently needed molecular targets. [ABSTRACT FROM AUTHOR]

Background: Late cardiotoxic effects of doxorubicin are increasingly a problem for patients who survive childhood cancer. Cardiotoxicity is often progressive, and some patients have disabling symptoms. Our objective was to identify risk factors for late cardiotoxicity. Methods: We examined echocardiograms from 120 children and adults who had received cumulative doses of 244 to 550 mg of doxorubicin per square meter of body-surface area for the treatment of acute lymphoblastic leukemia or osteogenic sarcoma in childhood, a mean of 8.1 years earlier. Measurements of blood pressure and left ventricular function, contractility (measured as the stress-velocity index), end-diastolic posterior-wall thickness, end-diastolic dimension, mass, and afterload (measured as end-systolic wall stress) were compared with sex-specific values from a cohort of 296 normal subjects. Results: All echocardiographic measurements were abnormal at follow-up a minimum of two years after the end of therapy, with more frequent and severe abnormalities in female patients. In a multivariate analysis, female sex and a higher cumulative dose of doxorubicin were associated with depressed contractility (P < or = 0.001), and there was an interaction between these two variables. Independent and significant associations were found between a higher rate of administration of doxorubicin and increased afterload (P < or = 0.001), left ventricular dilatation, and depressed left ventricular function; between a higher cumulative dose and depressed left ventricular function (P < or = 0.001); between a younger age at diagnosis and reduced left-ventricular-wall thickness and mass and increased afterload; and between a longer time since the completion of doxorubicin therapy and reduced left-ventricular-wall thickness and increased afterload (P < or = 0.001). Conclusions: Female sex and a higher rate of administration of doxorubicin were independent risk factors for cardiac abnormalities after treatment with doxorubicin for childhood cancer; the prevalence and severity of abnormalities increased with longer follow-up. [ABSTRACT FROM AUTHOR]

Objective: Rationally designed therapies aim at the specific disruption of critical signaling pathways activated by malignant transformation or signals from the tumor microenvironment. Because mammalian target of rapamycin (mTOR) is an important signal integrator and a key translational regulator, we evaluated its potential involvement in T-cell acute lymphoblastic leukemia (T-ALL) and whether mTOR blockade synergizes with chemotherapeutic agents or other signaling antagonists to inhibit primary leukemia T cells. Materials and Methods: mTOR signaling status was assessed using biochemical, immunostaining, and molecular regulation studies and functional assays performed to assess the impact of mTOR blockade on T-ALL proliferation, survival, and cell cycle. Results: We observed that mTOR signaling is highly activated in all T-ALL patients tested, with phosphorylation of its downstream substrates eIF4G and S6 ribosomal protein. mTOR activation was detected in vivo and was further increased in vitro by stimulation with interleukin-7, a potentially leukemogenic cytokine normally produced by the bone marrow microenvironment. In T-ALL cells, mTOR blockade was associated with accumulation of the cyclin-dependent kinase inhibitor p27kip1, which preferentially adopted a nuclear localization. Functional studies using rapamycin or CCI-779 showed a dominant inhibitory effect of mTOR blockade on interleukin-7−induced proliferation, survival, and cell-cycle progression of T-ALL cells. Furthermore, mTOR blockade markedly potentiated the antileukemia effects of dexamethasone and doxorubicin, and showed highly synergistic interactions in combination with specific inhibitors of phosphatidylinositol 3-kinase/Akt and Janus kinase 3 signaling. Conclusions: This study shows activation of mTOR signaling in primary T-ALL cells evolving in the leukemic bone marrow, and supports the inclusion of mTOR antagonists in current therapeutic regimens for this cancer. [ABSTRACT FROM AUTHOR]

Background: Doxorubicin chemotherapy is very effective in children with acute lymphoblastic leukemia (ALL) but also injures myocardial cells. Dexrazoxane, a free-radical scavenger, may protect the heart from doxorubicin-associated damage. Methods: To determine whether dexrazoxane decreases doxorubicin-associated injury of cardiomyocytes, we randomly assigned 101 children with ALL to receive doxorubicin alone (30 mg per square meter of body-surface area every three weeks for 10 doses) and 105 to receive dexrazoxane (300 mg per square meter) followed immediately by doxorubicin. Serial measurements of serum cardiac troponin T were obtained in 76 of 101 patients in the doxorubicin group and 82 of 105 patients in the group given dexrazoxane and doxorubicin. A total of 2377 serum samples (mean, 15.1 samples per patient) were obtained before, during, and after treatment with doxorubicin. Troponin T levels were evaluated in a blinded fashion to determine whether they were elevated (>0.01 ng per milliliter) — the primary end point — or extremely elevated (>0.025 ng per milliliter). Results: Elevations of troponin T occurred in 35 percent of the patients (55 of 158). Patients treated with doxorubicin alone were more likely than those who received dexrazoxane and doxorubicin to have elevated troponin T levels (50 percent vs. 21 percent, P<0.001) and extremely elevated troponin T levels (32 percent vs. 10 percent, P<0.001). The median follow-up was 2.7 years. The rate of event-free survival at 2.5 years was 83 percent in both groups (P=0.87 by the log-rank test). Conclusions: Dexrazoxane prevents or reduces cardiac injury, as reflected by elevations in troponin T, that is associated with the use of doxorubicin for childhood ALL without compromising the antileukemic efficacy of doxorubicin. Longer follow-up will be necessary to determine the influence of dexrazoxane on echocardiographic findings at four years and on event-free survival. N Engl J Med 2004;351:145-53. [ABSTRACT FROM AUTHOR]