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On the basis of the data suggesting that adolescents and young adult patients with acute lymphoblastic leukemia (ALL) have improved outcomes when treated on pediatric protocols, we assessed the feasibility of treating adult patients aged 18-50 years with ALL with the DFCI Pediatric ALL Consortium regimen utilizing a 30-week course of pharmacokinetically dose-adjusted E. coli L-asparaginase during consolidation. Between 2002 and 2008, 92 eligible patients aged 18-50 years were enrolled at 13 participating centers. Seventy-eight patients (85%) achieved a complete remission (CR) after 1 month of intensive induction therapy. With a median follow-up of 4.5 years, the 4-year disease-free survival (DFS) for the patients achieving a CR was 69% (95% confidence interval (CI) 56-78%) and the 4-year overall survival (OS) for all eligible patients was 67% (95% CI 56-76%). The 4-year DFS for the 64 patients who achieved a CR and were Philadelphia chromosome negative (Ph-) was 71% (95% CI 58-81%), and for all 74 Ph- patients the 4-year OS was 70% (95% CI 58-79%). We conclude that a pediatric-like treatment strategy for young adults with de novo ALL is feasible, associated with tolerable toxicity, and results in improved outcomes compared with historical regimens in young adult patients with ALL.

Background: Vincristine (VCR) is a standard component in the treatment of childhood acute lymphoblastic leukemia (ALL). VCR cytotoxicity is primarily due to its ability to disrupt the formation of microtubules of the mitotic spindle. Patients & methods: Seventeen polymorphisms in regulatory and coding regions of genes controlling VCR targets (TUBB1, MAP4, ACTG1 and CAPG) or potentially influencing VCR levels (ABCB1 and CYP3A5) were investigated for an association with peripheral neuropathy and outcome in childhood ALL patients. Results: High-grade neurotoxicity was more frequent in carriers of the A allele of synonymous (Ala310) G to A (rs1135989) variation in the ACTG1 gene. Substitution (rs4728709) in the promoter of the ABCB1 gene had a protective effect against lower grade neurotoxicity and C to A variation (rs3770102) located 17 nucleotides upstream from the transcription start site had a protective effect against high-grade neurotoxicity. Patients with the ABCB1 3435TT genotype had lower event-free survival; the association with event-free survival was not supported by the analysis in the replication patient set. Conclusion: The polymorphisms in the ACTG1, CAPG and ABCB1 genes may modulate VCR-related neurotoxicity, whereas the risk of relapse seems not to be affected by the genes of the VCR pathway. Original submitted 19 June 2013; Revision submitted 31 March 2014

Background: Despite outstanding cure rates of pediatric acute lymphoblastic leukemia (ALL), Blacks and Hispanics have inferior survival than Whites. We recently reported that among 794 children from DFCI ALL Consortium Protocol 05-001 trial, Hispanic patients had significantly lower rates of fracture and osteonecrosis, but higher risk of relapse and death compared with non-Hispanic Whites (PMID: 29090520). Studies from other groups have reported inferior ALL outcomes in children with Native American ancestry, however the association between genetic ancestry and skeletal toxicities has not been explored. We examined whether genetic inheritance could provide an explanation for the reduced incidence of skeletal toxicities in Hispanic patients in DFCI 05-001. Methods: A total of 576 DNA samples extracted from bone marrow samples or blood samples obtained during remission, including 2% blind duplicates, were genotyped using the Illumina OmniExpress Beadchip array. After data QC and cleaning, 449 ALL patients were retained in the final analysis. Estimates of global genetic ancestry were derived from STRUCTURE program, which was used to re-classify individuals with discordant clinical race/ethnicity as reported by study site, and to assign individuals with unknown race/ethnicity information to an ethnic group when possible. Regression model for the subdistribution hazard of the cumulative incidence function was used to relate clinical race/ethnicity, genetically reclassified race/ethnicity, and genetic ancestry respectively with risk of fracture and osteonecrosis, with death and recurrence as competing risk factors while controlling for age, gender and baseline clinical factors. Cox proportional regression models were used to test race/ethnicity and ancestry with overall survival (OS) and event-free survival (EFS). Results: Among the 449 patients analyzed, average age was 6.7 years; 26% of patients were ≥10 years and 44% were female. The demographic and clinical characteristics of patients with genotype data were similar to those of the overall cohort, although the proportion of Hispanics was slightly lower in the genotyped sub-cohort (17% vs. 21%), whereas the rates of fracture and osteonecrosis were higher (fracture: 25% vs. 18%; osteonecrosis: 10% vs. 8%). Based on clinical race/ethnicity, 66% of patients were non-Hispanic White, 17% were Hispanic, 5% were non-Hispanic Black, 3% were Asian, and 10% were reported as Other. Genetic ancestry analyses revealed that non-Hispanic White patients had a median of 96% European ancestry, non-Hispanic Black patients had a median of 76% African ancestry, and Asian patients had a median of 58% Asian ancestry. The genetic make-up of Hispanic patients in the 05-001 cohort was more admixed, with 23% Native American and 17% African ancestry, higher than the national average (18% and 6%, respectively). After genetic reassignment, racial/ethnic groups were as follows: 68% non-Hispanic White, 17% Hispanic, 9% non-Hispanic Black, 6% Asian, and 1% unassigned. In analysis of genetically reassigned race/ethnicity with skeletal toxicities, Hispanic and Black patients had significantly lower risk of fracture compared with white patients (Hispanic: subdistribution hazard ratio [SHR]=0.42, 95% confidence interval [CI]=0.22, 0.81; Black: HR=0.28, 95%CI=0.10, 0.75). These groups also had significantly less osteonecrosis (Hispanic: SHR=0.24, 95%CI=0.08, 0.78; Black: SHR=0.12, 95%CI=0.02, 0.93). Similar results were observed when using clinical race/ethnicity. Further analyses revealed that African genetic ancestry, but not Native American ancestry was associated with lower risk of fracture and osteonecrosis in a dose-dependent manner (Table 1). In analysis of death and recurrence, those with higher proportion of Native American ancestry had significantly higher risk of death/recurrence after adjustment (OS: hazard ratio [HR]=4.00, 95%CI=1.45, 11.02; EFS: HR=2.07, 95%CI=1.13, 3.79). Analysis of single variants and polygenic risk scores with skeletal toxicities and survival outcomes is ongoing. Conclusion: Hispanic children and adolescents from the DFCI 05-001 cohort, had highly heterogenous genetic ancestral make-up. Among Hispanic patients, the observed lower risk of skeletal toxicities might be driven by African ancestry, whereas poorer survival observed might be driven by Native American ancestry. Disclosures Silverman: Servier: Consultancy, Research Funding; Takeda: Consultancy.

10006 Background: DFCI ALL Consortium Protocol 11-001 assessed the efficacy and toxicity of Calaspargase pegol (SC-PEG), a novel pegylated asparaginase (ASP) formulation with longer half-life, compared with standard pegaspargase (SS-PEG). Methods: Patients (pts) aged 1-21 years with newly diagnosed acute lymphoblastic leukemia (ALL) or lymphoblastic lymphoma (LL) were eligible. At study entry, pts were randomly assigned to receive either intravenous SS-PEG or SC-PEG, 2500 IU/m2/dose. Pts received 1 dose during the first treatment month. Beginning week 7, SS-PEG was administered every 2 weeks for 15 doses, SC-PEG every 3 weeks for 10 doses (30 weeks). Serum asparaginase activity (SAA) (considered therapeutic at ≥ 0.1 IU/mL) was assessed 4, 11, 18, and 25 days after the induction dose and before each post-induction dose. End-induction minimal residual disease (MRD) was assessed in ALL pts by IGH/TCR PCR. Results: Between 2012-2015, 239 eligible pts enrolled (230 ALL, 9 LL); 120 assigned to SS-PEG, 119 to SC-PEG. After dose 1, SAA remained ≥ 0.1 IU/mL in ≥ 95% of pts on both arms through day 18. Median SAA was higher (0.319 IU/mL vs 0.056 IU/mL) and more pts had therapeutic SAA (88% vs 17%, p˂0.001) with SC-PEG vs SS-PEG 25 days after dose 1. Post-induction, median nadir SAA (NSAA) were similar ( > 1.0 IU/mL) for both arms. There was no difference in rates of ASP-allergy, pancreatitis, thrombosis, hyperbilirubinemia, osteonecrosis, or infection. Of 230 evaluable pts, 99% of SS-PEG and 95% of SC-PEG pts achieved complete remission (p = 0.12). For B ALL pts, there was no difference in frequency of high end-induction MRD (10.3% SS-PEG, 9.5% SC-PEG, p = 1.0). With 4-year median follow-up, 4-year event-free survival (EFS) (90% confidence interval) for SS-PEG was 90.2% (84.3, 93.9), 87.7% (81.5, 91.9) for SC-PEG (p = 0.78); overall survival (OS) was 95.6% (91.0, 97.9) for SS-PEG, 94.8% (90.0, 97.3) for SC-PEG (p = 0.74). Conclusions: Every 3-week SC-PEG had similar EFS, OS, safety profile, and NSAA compared with every 2-week SS-PEG. The high NSAA observed for both preparations suggest dosing strategies can be further optimized. These data informed FDA approval of SC-PEG for pediatric pts. Clinical trial information: NCT01574274.

Treatment resistance in T-cell acute lymphoblastic leukemia (T-ALL) is associated with phosphatase and tensin homolog (PTEN) deletions and resultant phosphatidylinositol 3'-kinase (PI3K)-AKT pathway activation, as well as MYC overexpression, and these pathways repress mitochondrial apoptosis in established T-lymphoblasts through poorly defined mechanisms. Normal T-cell progenitors are hypersensitive to mitochondrial apoptosis, a phenotype that is dependent on the expression of proapoptotic BIM. In a conditional zebrafish model, MYC downregulation induced BIM expression in T-lymphoblasts, an effect that was blunted by expression of constitutively active AKT. In human T-ALL cell lines and treatment-resistant patient samples, treatment with MYC or PI3K-AKT pathway inhibitors each induced BIM upregulation and apoptosis, indicating that BIM is repressed downstream of MYC and PI3K-AKT in high-risk T-ALL. Restoring BIM function in human T-ALL cells using a stapled peptide mimetic of the BIM BH3 domain had therapeutic activity, indicating that BIM repression is required for T-ALL viability. In the zebrafish model, where MYC downregulation induces T-ALL regression via mitochondrial apoptosis, T-ALL persisted despite MYC downregulation in 10% of bim wild-type zebrafish, 18% of bim heterozygotes and in 33% of bim homozygous mutants (P=0.017). We conclude that downregulation of BIM represents a key survival signal downstream of oncogenic MYC and PI3K-AKT signaling in treatment-resistant T-ALL.

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

Background Dexamethasone is more efficacious than prednisone in the treatment of acute lymphoblastic leukemia (ALL), but has also been associated with greater toxicity. We compared neuropsychological outcomes for patients treated on DFCI ALL Consortium Protocol 00-01, which included a randomized comparison of the two steroid preparations during post-induction therapy in children and adolescents with ALL. Procedure Between 2000 and 2005, 408 children with standard-risk or high-risk ALL treated on Dana-Farber Cancer Institute Consortium Protocol 00-01 were randomly assigned to prednisone or dexamethasone administered as 5-day pulses every 3 weeks for 2 years, beginning at week 7 of treatment. Blinded neuropsychological testing was completed for 170 randomized patients (prednisone, N = 76; dexamethasone, N = 94), all of whom were in continuous complete remission after completion of therapy. Results Outcomes were comparable for most variables, although patients on the dexamethasone arm performed more poorly on a measure of fluid reasoning (P = 0.02). They also tended to be more likely to be enrolled in special education (dexamethasone, 33% vs. prednisone, 20%, P = 0.09). Conclusions Dexamethasone has well documented benefit in treatment of ALL. Although formal testing provided little indication of increased risk for neurotoxicity relative to prednisone, the somewhat greater utilization of special education services by patients treated with dexamethasone merits further investigation. Pediatr Blood Cancer 2013;60:1785–1791. © 2013 Wiley Periodicals, Inc.

In pediatric patients with acute lymphoblastic leukemia, adherence to oral chemotherapy relies largely on a parent's comprehension of the drug's indication and administration guidelines. We assessed how pediatric oncology providers educate families about oral chemotherapy. We conducted a cross-sectional survey of 68 physicians and nurses from 9 institutions in the Dana-Farber Cancer Institute Acute Lymphoblastic Leukemia Consortium. The inter-individual approach to patient education is variable and may consist of handouts, treatment calendars, and discussions. The extent of teaching often varies depending on a provider's subjective assessment of a family's needs. Twenty-five percent of providers suggested standardizing patient teaching. When developing educational models, care teams should consider approaches that (a) objectively identify families in need of extensive teaching, (b) designate allotted teaching time by nursing staff during clinic visits, and (c) maintain the variation and dynamism that informs a successful provider-patient relationship.

Over 90% of drugs with preclinical activity fail in human trials, largely due to insufficient efficacy. We hypothesized that adequately powered trials of patient-derived xenografts (PDX) in mice could efficiently define therapeutic activity across heterogeneous tumors. To address this hypothesis, we established a large, publically available repository of well-characterized leukemia and lymphoma PDXs that undergo orthotopic engraftment called the Public Repository of Xenografts (PRoXe; www.proxe.org). PRoXe includes all de-identified information relevant to the primary specimens and the PDXs derived from them. Using this repository, we demonstrate that large studies of acute leukemia PDXs that mimic human randomized clinical trials can characterize drug efficacy and generate transcriptional, functional and proteomic biomarkers in both treatment-naïve and relapsed/refractory disease.

Background Radiation and chemotherapy targeted to the central nervous system can cause cognitive impairment, including impaired memory. These memory impairments may be referable to damage to hippocampal structures resulting from central nervous system (CNS) treatment.

The objective was to quantify the health-related quality of life (HRQL) of children treated for acute lymphoblastic leukemia (ALL) and identify specific disabilities for remediation.Two types of subjects were included: ALL patients 5 plus years old in a multi-center clinical trial and general population control groups. Patients were assessed during all four major phases of active treatment and approximately 2 years after treatment. Health status and HRQL were measured using HEALTH UTILITIES INDEX® (HUI®) Mark 2 (HUI2) and Mark 3 (HUI3). HRQL scores were used to calculate quality-adjusted life years (QALYs). Excess disability rates identified attributes for remediation.HUI assessments (n = 749) were collected during the five phases. Mean HRQL increased from induction through the post-treatment phase (P0.001). There were no significant demographic or treatment effects on HRQL, except for type of asparaginase during continuation therapy (P = 0.005 for HUI2 and P = 0.007 for HUI3). Differences in mean HRQL scores between patients and controls were important (P0.001) during the active treatment phases but not during the post-treatment phase. Relative to controls, patients lost approximately 0.2 QALYs during active treatment. Disability was evident in mobility/ambulation, emotion, self-care and pain, and declined over time.Patients with ALL experienced important but declining deficits in HRQL during active treatment phases: Equivalent to losing approximately 2 months of life in perfect health. HRQL within the 2-years post-treatment phase was similar to controls. The policy challenge is to develop new treatment protocols producing fewer disabilities in mobility/ambulation, emotion, self-care, and pain without compromising survival.

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/m 2 /dose, cumulative dose 300mg/m 2 ) preceded by dexrazoxane (300mg/m 2 /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.

The optimal management of asparaginase-associated thrombotic complications is not well-defined. We report the features, management and outcome of paediatric (ages 0-18years) and adult (18-50years) 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 >30years 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.

The tendency of mitochondria to undergo or resist BCL2-controlled apoptosis (so-called mitochondrial priming) is a powerful predictor of response to cytotoxic chemotherapy. Fully exploiting this finding will require unraveling the molecular genetics underlying phenotypic variability in mitochondrial priming. We analyzed pre-treatment T-ALL clinical specimens from a cohort of 47 patients (enriched for treatment failure, but with sufficient controls) treated on the COG AALL0434 or DFCI 05001 clinical trials using BH3 profiling analysis to assess mitochondrial apoptotic priming. We found that there was a strong association between resistance to mitochondrial apoptosis and a poor response to induction chemotherapy (P = 0.008). Furthermore, mitochondrial apoptosis resistance predicted significantly inferior event-free survival (65% vs. 91% at 5 years; P = 0.0376). To define the molecular determinants of this mitochondrial apoptosis resistance, we performed targeted exon sequencing and array CGH copy number analysis. This revealed that loss-of-function mutations in the polycomb repressive complex 2 (PRC2) core subunits (EZH2, EED or SUZ12) were associated with mitochondrial apoptosis resistance (P = 0.007) in clinical specimens. PRC2 is a chromatin modifying complex best known for its role in transcriptional repression, which functions as a tumor suppressor in T-ALL, but whether PRC2 regulates mitochondrial apoptosis is unknown. Using shRNA knockdown in human T-ALL cells, we found that depletion of PRC2 subunits in T-ALL cells induced mitochondrial apoptosis resistance, as assessed by BH3 profiling analysis (P < 0.001). PRC2 inactivation also induced resistance to chemotherapy-induced apoptosis (P < 0.0001), and increased T-ALL fitness following treatment with the antileukemic drug vincristine (P = 0.0001). Apoptosis resistance upon inactivation of EZH2 (a PRC2 catalytic subunit) was reversed by transduction of wild-type EZH2, but not by an EZH2 point mutant with impaired methyltransferase activity, indicating that this effect is mediated by the enzymatic activity of PRC2. In normal mouse thymocytes, heterozygous deletion of the PRC2 subunits Ezh2 or Eed was sufficient to induce apoptosis resistance in non-transformed double-negative T-cell progenitors (P < 0.010), indicating that apoptosis resistance can arise prior to oncogenic transformation. The best-known regulators of mitochondrial apoptosis are BCL2-family genes, but RNA-seq analysis of shRNA knockdown of the PRC2 subunits in a T-ALL cell line revealed that PRC2 did not regulate expression of any of the known BCL2 family members. Instead, PRC2 loss led to upregulation of TRAP1, a mitochondrially localized chaperone of the HSP90 family. TRAP1 upregulation was necessary for induction of apoptosis resistance following PRC2 inactivation, because shRNA knockdown of TRAP1 in the human CCRF-CEM cell line completely blocked induction of apoptosis resistance following PRC2 inactivation (P < 0.0001). Moreover, pharmacologic TRAP1 inhibition synergized with the antileukemic drugs dexamethasone and doxorubicin (combination index = 0.37 and 0.42, respectively). To define how PRC2 regulates TRAP1, we performed ChIP-seq analysis, which revealed that TRAP1 regulation by PRC2 is indirect. Combined ChIP-seq and RNA-seq analysis revealed a number of direct targets of PRC2, all of which were tested for their ability to upregulate TRAP1 and induce apoptosis resistance. This showed that the LIM domain transcription factor CRIP2 is a direct target of PRC2 that is necessary and sufficient for regulation of TRAP1, and for induction of apoptosis resistance downstream of PRC2 inactivation. To confirm the relevance of our findings, we used the EZH2 inhibitor GSK126 to inhibit enzymatic activity of PRC2, which revealed that EZH2 normally represses CRIP2 and TRAP1 expression in primary patient-derived xenografts. Finally, we found that increased TRAP1 expression correlates with treatment failure in T-ALL clinical specimens (P = 0.028). Taken together, our findings support a model in which loss of PRC2 induces transcriptional upregulation of its direct target CRIP2, which subsequently activates expression of TRAP1, leading to resistance to chemotherapy-induced mitochondrial apoptosis. Disclosures Aries: Pfizer: Employment. Teachey:Amgen: Consultancy; La Roche: Consultancy. Letai:AstraZeneca: Consultancy, Other: Lab research report; AbbVie: Consultancy, Other: Lab research report; Flash Therapeutics: Equity Ownership; Novartis: Consultancy, Other: Lab research report; Vivid Biosciences: Equity Ownership.

SUMMARY The authors measured the cognitive function and physical growth of 51 children who had been treated for acute lymphoblastic leukemia with chemotherapy, cranial irradiation and intrathecal methotrexate, and who had remained disease-free for five to 12 years. A comparison group of 15 children treated for Wilms' tumor was also studied. Cognitive impairment and growth retardation were greater among the leukemia group. Of potentially greater significance, however, was the finding that female sex was the pre-eminent risk factor for central nervous system toxicity resulting from treatment. Cognitive impairment, short stature and excessive weight were all more prevalent among females than males. Approximately half the children were microcephalic, but there was no sex difference. Age at evaluation and diagnosis, as well as socio-economic status, were differentially related to outcomes for the two sexes. The authors believe the sex differences were indicative of a fundamental interaction between postnatal neural development and other biological processes. RESUME Les effets secondaires tardifs de traitement du systeme nerveux central durant les leucemies aigues lymphoblastiques son lies au sexe Les auteurs ont apprecie la fonction cognitive et la croissance physique de 51 enfants traites pour leucemie aigues lymphoblastiques par chimiotherapie, irradiation cranienne et methotrexate intra-rachidien, et demeures sans recidive pendant cinq a 12 ans. Un groupe de comparaison de 15 enfants traites pour tumeur de Wilm a aussi ete etudie. L'alteration cognitive et le retard de croissance etaient plus marques dans le groupe leucemique. Mais de signification potentielle plus grande etait le fait que le sexe feminin etait un facteur de risque predominant de toxicite du traitement pour le systeme nerveux central. L'alteration cognitive, la petite taille et l'obesite predominaient chez les filles par rapport aux garcons. A peu pres la moite des enfants etaient microcephales, sans difference en fonction du sexe. L'âge d'evaluation et de diagnostic, aussi bien que le statut socio-economique, etaient differentiellement lies au devenir pour les deux sexes. Les auteurs pensent que les differences liees au sexe indiquent une interaction fondamentale entre le developpement neuroloqique post-natal et d'autres facteurs biologiques. ZUSAMMENFASSUNG Spatfolgen der ZNS-Behandlung bei akuter lymphoblastischer Leukamie im Kindesalter sind geschlechtsgebunden Die Autoren haben bei 51 Kindern, die wegen einer akuten Lymphoblastenleukamie mit Chemotherapie, ZNS-Bestrahlung und intrathekalen Methotrexatinjektionen behandelt worden und funf bis 12 Jahre rezidivfrei geblieben waren, die cognitive Funktion und das Korperwachstum gemessen. Auserdem wurde eine Gruppe von 15 Kindern, die wegen eines Wilms Tumors behandelt worden waren, zum Vergleich untersucht. Storungen der cognitiven Funktion und Wachstumsverzogerungen waren in der Leukamiegruppe starker. Die grosere Signifikanz kommt wahrscheinlich aber dem Befund zu, das das weibliche Geschlecht der wichtigste Risikofaktor fur die ZNS-Toxizitat der Behandlung ist. Cognitive Storungen, Kleinwuchs und Ubergewicht waren bei Madchen ausgepragter als bei Jungen. Etwa die Halfte der Kinder war mikrocephal, jedoch fand sich dabei kein Geschlechtsunterschied. Untersuchungs- und Diagnosealter, sowie sozio-okonomischer Status waren unterschiedlich zu den Outcomes fur die beiden Geschlechter korreliert. Die Autoren glauben, das die Geschlechtsunterschiede auf fundamentale Interaktionen zwischen postnataler neuraler Entwicklung und anderen biologischen Faktoren hinweist. RESUMEN Los efectos tardios en el sistema nervioso central del tratamiento seguido en ninos con leucemia linfoblastica esta en dependencia con el sexo Los autores midieron la funcon cognitiva y el crecimiento fisico de 51 ninos que habian sido tratados por una leucemia linfoblastica aguda con quimioterapicos, irradiacion craneana y metotrexato intratecal y que habian permanecido libres de la enfermedad durante cinco a 12 anos. Tambien se estudio un grupo comparativo de 15 ninos tratados por un tumor de Wilms. La alteracion cognitiva y el retraso en el crecimiento era mayor en el grupo leucemico. Sin embargo loque tenia un mayor significado potencial era el que el sexo femenino era el factor de riesgo preeminente de una alteracion neurologica como resultado del tratamiento. La alteracion cognitiva, la baja estatura y el peso excesivo eran mas prevalentes entre las hembras que entre los varones. Aproximadamente la mitad de los varones eran microcefalicos, pero no habia diferencia entre los sexos. La edad en el momento de la evaluacion y diagnostico, asi como la situacion socioeconmica estaban diferencialmente relacionados con el curso seguido para ambos sexos. Los autores creen que las diferencias sexuales eran indicativas de una interaccion fundamental entre el desarrollo neuronal posnatal y otros procesos biologicos.

6085Background: NUT midline carcinoma (NMC) is a rare subtype of squamous cancer defined by rearrangement of the NUT gene. Due to its rarity and under-diagnosis, there are no existing models to cla...

Background We sought to determine the feasibility of co-administering everolimus with a four-drug reinduction in children and adolescents with acute lymphoblastic leukemia (ALL) experiencing a first marrow relapse. Procedure This phase I study tested everolimus with vincristine, prednisone, pegaspargase and doxorubicin in patients with marrow relapse occurring >18 months after first complete remission (CR). The primary aim was to identify the maximum tolerated dose of everolimus. Three dose levels (DLs) were tested during dose escalation (2, 3, and 5 mg/m2 /day). Additional patients were enrolled at the 3- and 5 mg/m2 /day DLs to further evaluate toxicity (dose expansion). Results Thirteen patients enrolled during dose escalation and nine during dose expansion. During dose escalation, one dose-limiting toxicity occurred (grade 4 hyperbilirubinemia) in six evaluable patients at DL3 (5 mg/m2 /day). The most common grade ≥3 adverse events were febrile neutropenia, infections, transaminitis, hyperbilirubinemia, and hypophosphatemia. Two of the 12 patients treated at DL3 developed Rothia mucilaginosa meningitis. Nineteen patients (86%) achieved a second CR (CR2). Of those, 13 (68%) had a low end-reinduction minimal residual disease (MRD) level (≤10-3 by polymerase chain reaction-based assay). The CR2 rate for patients with B-cell ALL treated at DL3 (n = 12) was 92%; 82% of these patients had low MRD. Conclusions Everolimus combined with four-drug reinduction chemotherapy was generally well tolerated and associated with favorable rates of CR2 and low end-reinduction MRD. The recommended phase 2 dose of everolimus given in combination with a four-drug reinduction is 5 mg/m2 /day. This promising combination should be further evaluated in a larger patient cohort.

Cardiac signaling proteins regulate the intrinsic cardioprotective and repair response to doxorubicin cardiotoxicity. We estimated the relationship between these proteins, serum biomarkers of cardiac status and imaging in doxorubicin-treated children with ALL. Concentrations of the proteins

The Dana-Farber Cancer Institute (DFCI) acute lymphoblastic leukemia (ALL) Consortium has been conducting multi-institutional clinical trials in childhood ALL since 1981. The treatment backbone has included 20-30 consecutive weeks of asparaginase during intensification and frequent vincristine/corticosteroid pulses during the continuation phase. Between 1985 and 2000, 1457 children aged 0-18 years were treated on four consecutive protocols: 85-01 (1985-1987), 87-01 (1987-1991), 91-01 (1991-1955) and 95-01 (1996-2000). The 10-year event-free survival (EFS)+/-s.e. by protocol was 77.9+/-2.8% (85-01), 74.2+/-2.3% (87-01), 80.8+/-2.1% (91-01) and 80.5+/-1.8% (95-01). Approximately 82% of patients treated in the 1980s and 88% treated in the 1990s were long-term survivors. Both EFS and overall survival (OS) rates were significantly higher for patients treated in the 1990s compared with the 1980s (P=0.05 and 0.01, respectively). On the two protocols conducted in the 1990s, EFS was 79-85% for T-cell ALL patients and 75-78% for adolescents (age 10-18 years). Results of randomized studies revealed that dexrazoxane prevented acute cardiac injury without adversely affecting EFS or OS in high-risk (HR) patients, and frequently dosed intrathecal chemotherapy was an effective substitute for cranial radiation in standard-risk (SR) patients. Current studies continue to focus on improving efficacy while minimizing acute and late toxicities.

Purpose: Dihydrofolate reductase (DHFR) is the major target of methotrexate, a key component in childhood acute lymphoblastic leukemia (ALL) treatment. We recently reported an association of DHFR promoter polymorphisms with ALL outcome. Lower event-free survival correlated with haplotype *1, defined by A317 and C1610 alleles. Haplotype *1 was also associated higher DHFR expression. Experimental Design: Here, we analyzed adjacent 400-bp region participating in DHFR regulation as both a major promoter and a noncoding minor transcript. Results: Six polymorphisms were identified, of which five were single nucleotide polymorphisms and one was length polymorphism composed of variable number of 9-bp elements and 9-bp insertion/deletion. Haplotype analysis including all promoter polymorphisms revealed diversification of haplotype *1 into five subtypes (*1a-*1e). DNA variations of major promoter/noncoding transcript region and haplotype *1 subtypes were subsequently analyzed for the association with ALL outcome. Lower event-free survival was associated with an A allele of G308A polymorphism (P = 0.02) and with *1b haplotype (P = 0.01). This association was particularly striking in high-risk patients (P = 0.001) and was subsequently confirmed in independent patient cohort (P = 0.02). Haplotype *1b was the only haplotype *1 subtype associated with higher mRNA levels. Conclusions: The study provides a new insight into DHFR regulatory variations predisposing to an event in ALL patients. (Clin Cancer Res 2009;15(22):69318)

Background Escherichia coli asparaginase is an important component of treatment for childhood acute lymphoblastic leukemia (ALL); however, hypersensitivity develops in up to 30% of patients. We assessed the nadir enzyme activity and tolerability of Erwinia asparaginase, an alternative preparation, in E. coli asparaginase-allergic patients. Patients and Methods Between 2000 and 2002, 215 children with newly diagnosed ALL were enrolled on Dana-Farber Cancer Institute ALL Consortium Protocol 00-01 and were to receive 30 weekly doses of intramuscular E. coli asparaginase. If E. coli asparaginase allergy developed, patients were switched to twice-weekly intramuscular Erwinia asparaginase (25,000 IU/m2). Nadir serum asparaginase activity (NSAA) was measured every 3 weeks. Results Forty-two patients (20%) developed E. coli asparaginase allergy and switched to Erwinia. Of 38 patients with evaluable samples, 34 (89%) Erwinia-treated patients had at least one therapeutic NSAA (≥0.1 IU/ml). The median NSAA was 0.247 IU/ml 3 days and 0.077 IU/ml 4 days after an Erwinia dose. Associated toxicities included allergy in 14 (33%) and pancreatitis in 3 patients (7%). At a median follow-up of 5.4 years, event-free survival (±standard error) of the 42 patients who switched to Erwinia was 86 ± 5% compared with 81 ± 3% for the 170 patients without E. coli asparaginase allergy (P = 0.55). Conclusions Twice-weekly Erwinia asparaginase was well tolerated and achieved a therapeutically effective NSAA in most E. coli asparaginase-allergic patients. Development of E. coli allergy and subsequent treatment with twice-weekly Erwinia did not adversely impact event-free survival. Erwinia asparaginase should be considered for E. coli asparaginase-allergic patients. Pediatr Blood Cancer 2010;54:199–205. © 2009 Wiley-Liss, Inc.

Background Asparaginase, an agent used in the treatment of acute lymphoblastic leukemia (ALL), is associated with the development of pancreatitis. The clinical course and long-term outcome of patients experiencing this complication has not been extensively detailed.

Survivors of childhood acute lymphoblastic leukemia (ALL) are at risk for late effects of cancer therapy. Five-year ALL survivors (< 21 years at diagnosis; n = 5760 eligible, 4151 participants), diagnosed from 1970 to 1986 were compared with the general population and a sibling cohort (n = 3899). Cumulative mortality of 5760 5-year survivors was 13% at 25 years from diagnosis. Recurrent ALL (n = 483) and second neoplasms (SNs; n = 89) were the major causes of death. Among 185 survivors, 199 SNs occurred, 53% in the CNS. Survivors reported more multiple chronic medical conditions (CMCs; odds ratio [OR], 2.8; 95% CI, 2.4-3.2) and severe or life-threatening CMCs (OR, 3.6; 95% CI, 3.0-4.5) than siblings. Cumulative incidence of severe CMCs, including death, 25 years from diagnosis was 21.3% (95% CI, 18.2-24.4; 23.3% [95% CI, 19.4-27.2] and 13.4% [95% CI, 8.4-18.4] for irradiated and nonirradiated survivors, respectively). Survivors reported more adverse general and mental health, functional impairment, and activity limitations compared with siblings (P < .001). Rates of marriage, college graduation, employment, and health insurance were all lower compared with sibling controls (P < .001). Long-term survivors of childhood ALL exhibit excess mortality and morbidity. Survivors who received radiation therapy as part of their treatment or had a leukemia relapse are at greatest risk for adverse outcomes.

Cancer cells acquire disruptions in normal signal transduction pathways and homeostatic mechanisms that would trigger apoptosis in normal cells. These abnormalities include genomic instability, oncogene activation, and growth factor independent proliferation. Therefore, cancer cells likely require a block in apoptosis in order to survive. Overexpression of the antiapoptotic protein BCL-2 provides a block in apoptosis that is frequently observed in cancer cells. We have developed methods for the detection and analysis of BCL-2 dependence and here apply them to acute lymphoblastic leukemia (ALL). BH3 profiling, a mitochondrial assay that classifies blocks in the intrinsic apoptotic pathway, indicated a dependence on BCL-2 of both ALL cell lines and primary samples. This dependence predicted that BCL-2 would be complexed with select pro-death BH3 family proteins, a prediction confirmed by the isolation of BCL-2 complexes with BIM. Furthermore, the BH3 profiling and protein analysis predicted that ALL cell lines and primary cells would be sensitive to ABT-737 as a single agent. Finally, BH3 profiling and protein studies accurately predicted a relative degree of sensitivity to BCL-2 antagonism in cell lines. The ALL cells studied exhibit BCL-2 dependence, supporting clinical trials of BCL-2 antagonists in ALL as single agents or combination therapies.

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.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.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.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.

Purpose Survivors of childhood acute lymphoblastic leukemia (ALL) exhibit increased rates of neurocognitive deficits. This study was conducted to test whether interpatient variability in neurocognitive outcomes can be explained by polymorphisms in candidate genes conferring susceptibility to neurocognitive decline. Methods Neurocognitive testing was conducted in 350 pediatric leukemia survivors, treated on Dana-Farber Cancer Institute ALL Consortium Protocols 95-01 or 00-01. Genomic DNA was isolated from bone marrow collected at remission. Candidate polymorphisms were selected on the basis of prior literature, targeting genes related to drug metabolism, oxidative damage, altered neurotransmission, neuroinflammation, and folate physiology. Single nucleotide polymorphisms were detected using either a customized multiplexed Sequenom MassARRAY assay or polymerase chain reaction–based allelic discrimination assays. Multivariable logistic regression models were used to estimate the effects of genotype on neurocognitive outcomes, adjusted for the effects of demographic and treatment variables. False-discovery rate correction was made for multiple hypothesis testing, indicated as a Q value. Results Inferior cognitive or behavioral outcomes were associated with polymorphisms in three genes related to oxidative stress and/or neuroinflammation: NOS3 (IQ, Q = 0.008; Vocabulary Q = 0.011; Matrix Reasoning Q = 0.008), SLCO2A1 (IQ Q = 0.043; Digit Span Q = 0.006; Block Design Q = 0.076), and COMT (Behavioral Assessment System for Children-2 Attention Q = 0.080; and Hyperactivity Q = 0.084). Survivors homozygous for NOS3 894T, with at least one SLCO2A1 variant G allele or with at least one GSTP1 variant allele, had lower mean estimated IQ scores than those without these genotypes. Conclusion These data are consistent with the hypothesis that oxidative damage contributes to chemotherapy-associated neurocognitive decline among children with leukemia.

Anthracyclines are efficient chemotherapy agents. However, their use is limited by anthracycline-induced cardiotoxicity (CT). We investigated the influence of polymorphisms in doxorubicin metabolic and functional pathways on late-onset CT as estimated by echocardiography in 251 childhood acute lymphoblastic leukemia (cALL) patients. Association analyses revealed a modulating effect of two variants: A-1629 T in ABCC5, an ATP-binding cassette transporter, and G894T in the NOS3 endothelial nitric oxide synthase gene. Individuals with the ABCC5 TT-1629 genotype had an average of 8-12% reduction of ejection (EF) and shortening fractions (SF; EF: P

SummaryDrug 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.

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.

MLL rearranged acute lymphoblastic leukemia (MLL) is an aggressive type of acute lymphoblastic leukemia (ALL), diagnosed predominantly in infants (1 years of age). Since current chemotherapy fails in50% of patients with MLL, new therapeutic strategies are desperately needed. For this, understanding the biological features characterizing MLL is necessary. Analysis of gene expression profiles revealed that the expression of the tumor suppressor gene FHIT is reduced in children with MLL rearranged ALL as compared to ALL patients carrying germ line MLL. This finding was confirmed by quantitative real-time PCR. In 100% of the infant MLL cases tested, methylation of the FHIT 5'CpG region was observed, resulting in strongly reduced mRNA and protein expression. In contrast, FHIT methylation in infant and non-infant ALL patients carrying germ line MLL was found in only approximately 60% (Por =0.004). FHIT expression was restored upon exposing leukemic cells to the demethylating agent decitabine, which induced apoptosis. Likewise and more specifically, leukemic cell death was induced by transfecting MLL rearranged leukemic cells with expression vectors encoding wild-type FHIT, confirming tumor suppressor activity of this gene. These observations imply that suppression of FHIT may be required for the development of MLL, and provide new insights into leukemogenesis and therapeutic possibilities for MLL.

Despite profound T-cell immunodeficiency, most patients treated with chemotherapy do not succumb to infection. The basis for residual protective immunity in lymphopenic patients is not known. We prospectively measured T-cell numbers, thymopoiesis, and T-cell memory in 73 children undergoing a 2-year chemotherapy regimen for acute lymphoblastic leukemia (ALL) and compared them to an age-matched cohort of 805 healthy children. Most patients had profound defects in CD4 and CD8 T-cell numbers at diagnosis that did not recover during the 2 years of therapy. Thymic output and the fraction of naive T cells were significantly lower than in healthy controls. However, the remaining T-cell compartment was enriched for antigen-experienced, memory T cells defined both by phenotype and by function. This relative sparing of T-cell memory may, in part, account for the maintenance of protective immunity in lymphopenic patients treated for ALL. Moreover, because the memory T-cell compartment is least affected by ALL and its treatment, strategies to induce immunity to pathogens or tumor antigens in cancer patients may be most successful if they seek to expand pre-existing memory T cells. (Blood. 2005; 106:1749-1754)

Purpose Cross-sectional studies show that cardiac abnormalities are common in long-term survivors of doxorubicin-treated childhood malignancies. Longitudinal data, however, are rare. Methods Serial echocardiograms (N = 499) were obtained from 115 doxorubicin-treated long-term survivors of childhood acute lymphoblastic leukemia (median age at diagnosis, 4.8 years; median follow-up after completion of doxorubicin, 11.8 years). Results were expressed as z scores to indicate the number of standard deviations (SDs) above (+) or below (−) the normal predicted value. Median individual and cumulative doxorubicin doses were 30 mg/m2 per dose and 352 mg/m2, respectively. Results Left ventricular fractional shortening was significantly reduced after doxorubicin therapy, and the reduction was related to cumulative dose. z scores for fractional shortening transiently improved before falling to −2.76 more than 12 years after diagnosis. Reduced fractional shortening was related to impaired contractility and increasing afterload, consequences of a progressive reduction of ventricular mass, and wall thickness relative to body-surface area. Left ventricular contractility fell significantly over time and was depressed at last follow-up in patients receiving more than 300 mg/m2 of doxorubicin. Systolic and diastolic blood pressures were below normal more than 9 years after diagnosis. Even patients receiving lower cumulative doxorubicin doses experienced reduced mass and dimension. Fractional shortening and dimension at the end of therapy predicted these parameters 11.8 years later. Conclusion Cardiac abnormalities were persistent and progressive after doxorubicin therapy. Inadequate ventricular mass with chronic afterload excess was associated with progressive contractile deficit and possibly reduced cardiac output and restrictive cardiomyopathy. The deficits were worst after highest cumulative doses of doxorubicin, but appeared even after low doses.

PurposeMembers of a family with hereditary gastrointestinal stromal tumors (GISTs) and a germline KIT oncogene mutation were evaluated for other potential syndrome manifestations. A tumor from the proband was analyzed to compare features with sporadic GISTs.Patients and MethodsMembers of a kindred in which six relatives in four consecutive generations comprised an autosomal dominant pattern of documented GISTs and cutaneous lesions underwent physical examination, imaging studies, and germline KIT analysis. A recurrent GIST from the proband was studied using microarray, karyotypic, immunohistochemical, and immunoblotting techniques.ResultsIn addition to evidence of multiple GISTs, lentigines, malignant melanoma, and an angioleiomyoma were identified in relatives. A previously reported gain-of-function missense mutation in KIT exon 11 (T → C) that results in a V559A substitution within the juxtamembrane domain was identified in three family members. The proband's recurrent gastric GIST had a 44,XY−14,−22 karyotype and immunohistochemical evidence of strong diffuse cytoplasmic KIT expression without expression of actin, desmin, or S-100. Immunoblotting showed strong expression of phosphorylated KIT and downstream signaling intermediates (AKT and MAPK) at levels comparable with those reported in sporadic GISTs. cDNA array profiling demonstrated clustering with sporadic GISTs, and expression of GIST markers comparable to sporadic GISTs.ConclusionThese studies provide the first evidence that gene expression and mechanisms of cytogenetic progression and cell signaling are indistinguishable in familial and sporadic GISTs. Current investigations of molecularly targeted therapies in GIST patients provide opportunities to increase the understanding of features of the hereditary syndrome, and risk factors and molecular pathways of the neoplastic phenotypes.

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.

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.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).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, P0.001) and extremely elevated troponin T levels (32 percent vs. 10 percent, P0.001). 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).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.

Immunoglobulin (Ig) and T-cell receptor (TCR) gene rearrangements provide clonal markers useful for diagnosis and measurement of minimal residual disease (MRD) in acute lymphoblastic leukemia (ALL). We analyzed the sequences of Ig and TCR gene rearrangements obtained at presentation and relapse in 41 children with ALL to study clonal stability, which has important implications for monitoring MRD, during the course of the disease. In 42%, all original Ig and/or TCR sequences were conserved. In 24%, one original sequence was preserved but the other lost, and in 14% the original sequences were conserved with new sequences identified at relapse. In 20% only new sequences were found at relapse. Using primers designed from the novel relapse sequences, the relapse clone could be identified as subdominant clones in the diagnostic sample in 8 of 14 patients. Alteration of these clonal gene rearrangements is a common feature in childhood ALL. MRD detection should include multiple gene targets to minimize false-negative samples or include also multicolor flow cytometry. In some cases the leukemic progenitor cell might arise earlier in lineage before DHJH recombination but retain the capacity to further differentiate into cells capable of altering the pattern of Ig and/or TCR rearrangements. (Blood. 2003;102:4520-4526)

Rearrangements of the MLL locus, located on human chromosome 11q23, are frequent in both infant and therapy-related leukemias. Gene expression analysis of MLL-rearranged B-precursor acute lymphoblastic leukemias (MLL B-ALLs) has identified these cases as a unique subtype of leukemia, characterized by the expression of genes associated with both lymphoid and myeloid hematopoietic lineages. Here we show that MLL fusions also generate a distinct genetic subtype of T-lineage ALL (MLL T-ALL), in which leukemic cells are characterized by an early arrest in thymocyte differentiation, with suggestive evidence of commitment to the γδ lineage. Interestingly, multiple genes linked to cell proliferation (eg, PCNA, MYC, CDK2, and POLA) were down-regulated in MLL-fusion samples, relative to those transformed by other T-ALL oncogenes (P < .000 001, Fisher exact test). Overall, MLL T-ALL cases consistently demonstrated increased levels of expression of a subset of major HOX genes—HOXA9, HOXA10, and HOXC6—and the MEIS1 HOX coregulator (P < .008, one-sided Wilcoxon test), a pattern of gene expression that was reiterated in MLL B-ALLs. However, expression of myeloid lineage genes, previously reported in MLL B-ALLs, was not identified in T-lineage cases with this abnormality, suggesting that myeloid gene dysregulation is dispensable in leukemic transformation mediated by MLL fusion proteins. Our findings implicate dysregulation of HOX gene family members as a dominant mechanism of leukemic transformation induced by chimeric MLL oncogenes. (Blood. 2003;102:262-268)

The development of effective therapy for children with acute lymphoblastic leukemia is one of the great successes of clinical hematology andoncology. Fifty years ago, childhood acute lymphoblastic leukemia was universally fatal, but current long-term event-free survival rates are nearly 80%. Despite this improved outcome, there are still many challenges facing investigators today. In some recent clinical trials, the outcome of "high-risk" patients has approached that of "lower risk" patients, suggesting that currently applied clinical factors, such as age and presenting leukocyte count, no longer identify the 20% of newly diagnosed patients who ultimately will relapse. Additionally, therapy remains nonspecific, toxic, and sometimes lethal. As more children with acute lymphoblastic leukemia survive into adolescence and adulthood, there is a need to address the late sequelae of current therapy and to develop more leukemia-specific treatments. Promising avenues of research, which may identify biologically distinctive subsets of acute lymphoblastic leukemia and potential targets for novel therapies, include studies of minimal residual disease, lymphoblast genetics (including genetic profiling studies), and host-related pharmacogenomics.

To assess the clinical heterogeneity among patients with acute lymphoblastic leukemia (ALL) and various 11q23 abnormalities, we analyzed data on 497 infants, children and young adults treated between 1983 and 1995 by 11 cooperative groups and single institutions. The substantial sample size allowed separate analyses according to age younger or older than 12 months for the various cytogenetic subsets. Infants with t(4;11) ALL had an especially dismal prognosis when their disease was characterized by a poor early response to prednisone (P=0.0005 for overall comparison; 5-year event-free survival (EFS), 0 vs 23+/-+/-12% s.e. for those with good response), or age less than 3 months (P=0.0003, 5-year EFS, 5+/-+/-5% vs 23.4+/-+/-4% for those over 3 months). A poor prednisone response also appeared to confer a worse outcome for older children with t(4;11) ALL. Hematopoietic stem cell transplantation failed to improve outcome in either age group. Among patients with t(11;19) ALL, those with a T-lineage immunophenotype, who were all over 1 year of age, had a better outcome than patients over 1 year of age with B-lineage ALL (overall comparison, P=0.065; 5-year EFS, 88+/-+/-13 vs 46+/-14%). In the heterogeneous subgroup with del(11)(q23), National Cancer Institute-Rome risk criteria based on age and leukocyte count had prognostic significance (P=0.04 for overall comparison; 5-year EFS, 64+/-+/-8% (high risk) vs 83+/-+/-6% (standard risk)). This study illustrates the marked clinical heterogeneity among and within subgroups of infants or older children with ALL and specific 11q23 abnormalities, and identifies patients at particularly high risk of failure who may benefit from innovative therapy.

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.

BACKGROUND Pediatric patients receiving induction chemotherapy for newly diagnosed acute lymphoblastic leukemia (ALL) are at high risk of developing life-threatening infections. We investigated whether uniform antibacterial guidelines, including mandatory antibacterial prophylaxis in afebrile patients during induction, decreases the incidence of microbiologically documented bacteremia. METHODS Between 2012 and 2015, 230 patients with newly diagnosed ALL (aged 1-21) were enrolled on Dana-Farber Cancer Institute ALL Consortium Protocol 11-001 (DFCI 11-001). Induction therapy, regardless of risk group, included vincristine, prednisone, doxorubicin, methotrexate, and PEG-asparaginase. Afebrile patients received fluoroquinolone prophylaxis at the initiation of induction and those presenting with fever received broad-spectrum antibiotics; antibiotics were continued until blood count recovery. Rates of documented bacteremias and fungal infections on DFCI 11-001 were compared to those on the predecessor protocol (DFCI 05-001), which included the same induction phase without antibiotic prophylaxis guidelines. RESULTS Sixty-six (28.7%) patients received fluoroquinolone prophylaxis, the remaining patients received broad-spectrum antibiotics. Twenty-four (36.4%) patients on prophylaxis developed fever and seven (10.6%) developed bacteremia. The overall rate of infection during induction on DFCI 11-001 was lower than on DFCl 05-001 (14.3% vs. 26.3%, P

Although L-asparaginase (ASP) is associated with several toxicities, its myelosuppressive effect has not been well characterized. On DFCI ALL Consortium Protocol 05-01 for children with newly diagnosed acute lymphoblastic leukemia, the Consolidation phase and the initial portion of the Continuation phase were identical for standard risk patients, except ASP was given only during Consolidation. Comparing the two treatment phases revealed that low blood counts during Consolidation with ASP resulted in more dosage reductions of 6-mercaptopurine and methotrexate. The myelosuppressive effect of ASP should be considered when designing treatment regimens to avoid excessive toxicity and dose reductions of other critical chemotherapy agents.

PURPOSE: A common late effect of doxorubicin therapy for childhood cancer is reduced left-ventricular (LV) wall thickness resulting in elevated LV afterload and depressed LV function. Many children are given angiotensin-converting enzyme inhibitors, which have been studied primarily in adults. We document the long-term effects of angiotensin-converting enzyme inhibitors in doxorubicin-treated survivors of childhood cancer. PATIENTS AND METHODS: In this retrospective study, we reviewed records of 18 children who had regular echocardiographic examinations during enalapril therapy (mean age at cancer diagnosis, 8 years; mean time between completion of doxorubicin therapy and start of enalapril, 7 years; median follow-up since the start of enalapril, 10 years). RESULTS: Over the first 6 years of enalapril therapy, there was progressive improvement toward normal values in LV dimension, afterload, fractional shortening, and mass, but all these parameters deteriorated between 6 and 10 years. LV wall thickness deteriorated throughout the study period, as did LV contractility and systolic blood pressure. Diastolic blood pressure fell slightly. By 6 years on enalapril, all six patients who had had congestive heart failure at the start of enalapril therapy had either died or undergone cardiac transplantation, compared with three of the 12 asymptomatic patients. CONCLUSION: In doxorubicin-treated long-term survivors of childhood cancer, enalapril-induced improvement in LV structure and function is transient. The primary defect, which is LV wall thinning, continues to deteriorate, and thus the short-term improvement was mostly related to lowered diastolic blood pressure.

PURPOSE: Acute doxorubicin-induced cardiotoxicity can be prevented in adults by continuous infusion of the drug, but mechanisms of cardiotoxicity are different in children. We compared cardiac outcomes in children receiving bolus or continuous infusion of doxorubicin. PATIENTS AND METHODS: In a randomized study, children with high-risk acute lymphoblastic leukemia received doxorubicin 360 mg/m2 in 30-mg/m2 doses every 3 weeks either by bolus (within 1 hour, n = 57) or by continuous infusion (over 48 hours, n = 64). Echocardiograms obtained before doxorubicin and at longest follow-up times were centrally remeasured, and z scores of cardiac measurements were calculated based on a healthy population. RESULTS: The groups were similar in age, sex distribution, doxorubicin dose, and duration of follow-up. Before treatment, measures of left ventricular (LV) structure and function did not reveal dilated cardiomyopathy and were not statistically different between bolus and continuous-infusion groups. The follow-up echocardiograms demonstrated no significant difference between the two groups for any cardiac characteristic, but both groups showed significant abnormalities of LV structure and function compared with normal and with baseline. For example, the mean LV fractional shortening fell by approximately two SD in both groups between the two echocardiograms. LV contractility was depressed in both groups (for bolus patients, median z score = −0.70 SD, P = .006; for continuous-infusion patients, median z score = −0.765, P = .005). Dilated cardiomyopathy and inadequate LV hypertrophy were noted in both groups. Clinical cardiac manifestations and event-free survival did not differ. CONCLUSION: Continuous doxorubicin infusion over 48 hours for childhood leukemia did not offer a cardioprotective advantage over bolus infusion. Both regimens were associated with progressive subclinical cardiotoxicity. Other cardioprotective strategies should be explored.

The tendency of mitochondria to undergo or resist BCL2-controlled apoptosis (so-called mitochondrial priming) is a powerful predictor of the outcome of cytotoxic chemotherapy for cancer. To fully exploit this finding, it will be important to understand the molecular genetic contexts responsible for the relative mitochondrial priming of chemotherapy-sensitive versus resistant cell populations. Here we report that mitochondrial apoptosis resistance in T-cell acute lymphoblastic leukemia (T-ALL) is mediated by inactivation of polycomb repressive complex 2 (PRC2) and consequent downstream upregulation of the TRAP1 gene, which encodes a mitochondrial chaperone protein of the HSP90 family. In clinical samples from 47 T-ALL patients, we found that loss-of-function mutations in any of three core components of PRC2 (EZH2, EED or SUZ12) were associated with resistance to mitochondrial apoptosis, as assessed by BH3 profiling (P = 0.015). In human T-ALL cells, PRC2 depletion induced resistance to mitochondrial apoptosis induction, as assessed by caspase 3/7 activation or annexin V/PI staining, in response to multiple antileukemic drugs with distinct mechanisms of action, including dexamethasone, doxorubicin, vincristine, and asparaginase (P < 0.01). In mouse immature T-cell progenitors, haploinsufficiency for the PRC2 components Ezh2 or Eed was sufficient to induce resistance to mitochondrial apoptosis, as assessed by BH3 profiling analysis (P ≤ 0.01). PRC2 is a histone-modifying complex whose activity is strongly associated with transcriptional repression. We found that PRC2 represses transcription of TRAP1, a nuclearly encoded, mitochondrially localized chaperone of the HSP90 family. Importantly, TRAP1 overexpression was necessary to induce resistance to chemotherapy-induced apoptosis downstream of PRC2 inactivation (P < 0.001), while pharmacologic inhibition of TRAP1 synergized with antileukemic drugs in PRC2-deficient leukemic cells. These findings demonstrate the importance of relative mitochondrial apoptotic priming as a prognostic factor in T-ALL, and implicate mitochondrial chaperone function as a molecular determinant of response to cancer chemotherapy, suggesting a rationale for targeted therapeutic intervention. This abstract is also being presented as Poster 07. Citation Format: Ingrid Aries, Triona Ni Chonghaile, Salmaan Karim, Sebastian Balbach, Melissa Burns, Gayle Pouliot, Stevenson Kristen, Donna Neuberg, Meenakshi Devidas, Loh Mignon, Stephen Hunger, Stuart Winter, David Teachey, Karen Rabin, Kimberly Dunsmore, Brent Wood, Lewis Silverman, Stephen Sallan, Peter Van Vlierberghe, Stuart H. Orkin, Anthony G. Letai, Alejandro Gutierrez. Polycomb repressive complex 2 inactivation induces primary chemotherapy resistance in T-ALL by upregulating the TRAP1 mitochondrial chaperone [abstract]. In: Proceedings of the Second AACR Conference on Hematologic Malignancies: Translating Discoveries to Novel Therapies; May 6-9, 2017; Boston, MA. Philadelphia (PA): AACR; Clin Cancer Res 2017;23(24_Suppl):Abstract nr PR14.

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.

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.

Relapsed paediatric acute lymphoblastic leukaemia (ALL) has high rates of treatment failure. Epigenetic regulators have been proposed as modulators of chemoresistance, here, we sequence genes encoding epigenetic regulators in matched diagnosis-remission-relapse ALL samples. We find significant enrichment of mutations in epigenetic regulators at relapse with recurrent somatic mutations in SETD2, CREBBP, MSH6, KDM6A and MLL2, mutations in signalling factors are not enriched. Somatic alterations in SETD2, including frameshift and nonsense mutations, are present at 12% in a large de novo ALL patient cohort. We conclude that the enrichment of mutations in epigenetic regulators at relapse is consistent with a role in mediating therapy resistance.