Management of hyperleukocytosis in pediatric acute myeloid leukemia using immediate chemotherapy without leukapheresis: results from the NOPHO-DBH AML 2012 protocol.

Hyperleukocytosis in pediatric acute myeloid leukemia (AML) is associated with severe complications and an inferior outcome. We report results on patients with hyperleukocytosis included in the NOPHO-DBH AML 2012 study. We recommended immediate initiation of full-dose chemotherapy (etoposide monotherapy for 5 days as part of the first course), avoiding leukapheresis and prephase chemotherapy. Of 714 patients included in the NOPHO-DBH AML 2012 study, 122 (17.1%) had hyperleukocytosis, and 111 were treated according to the recommendations with etoposide upfront without preceding leukapheresis or prephase chemotherapy. The first dose was applied the same day as the AML diagnosis or the day after in 94%. Etoposide was administered via peripheral veins in 37% of patients without major complications. After initiation of etoposide the white blood cell counts on days 2-5 were 69%, 36%, 17% and 8%, respectively, of the pre-treatment level. On day 3, 81% of patients had a white blood cell count <100 x109/L. Five-year event-free and overall survival rates for all patients with hyperleukocytosis were 52.9% (95% confidence interval [95% CI]: 44.4-63.0) and 74.1% (95% CI: 66.4-82.6), compared to 64.9% (95% CI: 60.9-69.1) and 78.9% (95% CI: 75.4-82.4) for patients without hyperleukocytosis (P<0.001 for event-free survival, P=0.1 overall survival). Six-week early mortality was 4.1% for all patients with hyperleukocytosis (2.7% for the 111 patients treated with etoposide upfront). We conclude that management of hyperleukocytosis in pediatric AML with immediate etoposide monotherapy without leukapheresis or prephase chemotherapy is feasible, safe and effective. The reduction in white blood cell count during the first days is comparable to the reported results of leukapheresis, and outcomes seem at least equivalent to therapies including leukapheresis. Based on our results, we advocate abandoning leukapheresis for hyperleukocytosis in pediatric AML. Instead, it is crucial to start induction chemotherapy as early as possible.

Mitoxantrone Versus Liposomal Daunorubicin in Induction of Pediatric AML With Risk Stratification Based on Flow Cytometry Measurement of Residual Disease.

PURPOSE: Measurable residual disease (MRD) by using flow cytometry after induction therapy is strongly prognostic in pediatric AML, and hematopoietic stem-cell transplant (hSCT) may counteract a poor response. We designed a phase III study with intensified response-guided induction and MRD-based risk stratification and treated poor induction response with hSCT. The efficacy of liposomal daunorubicin (DNX) in induction was compared with mitoxantrone. METHODS: The study planned to randomly assign 300 patients, but the production of DNX ceased in 2017. One hundred ninety-four patients were randomly assigned to mitoxantrone or experimental DNX in induction 1. Ninety-three non-randomly assigned patients served as an observation cohort. Primary end point was fraction of patients with MRD <0.1% on day 22 after induction 1. Patients with MRD ≥15% after induction 1 or ≥0.1% after induction 2 or FLT3-ITD with NPM1 wildtype were stratified to high-risk therapy, including hSCT. RESULTS: Outcome for all 287 children was good with 5-year event-free survival (EFS5y) 66.7% (CI, 61.4 to 72.4) and 5-year overall survival (OS5y) 79.6% (CI, 75.0 to 84.4). Overall, 75% were stratified to standard-risk and 19% to high-risk. There was no difference in the proportion of patients with MRD <0.1% on day 22 after induction 1 (34% mitoxantrone, etoposide, araC [MEC], 30% DNX, P = .65), but the proportion increased to 61% for MEC versus 47% for DNX (P = .061) at the last evaluation before induction 2. EFS5y was significantly lower, 56.6% (CI, 46.7 to 66.5) versus 71.9% (CI, 63.0 to 80.9), and cumulative incidence of relapse (CIR) was higher, 35.1% (CI, 25.7 to 44.7) versus 18.8% (CI, 11.6 to 27.2) for DNX. The inferior outcome for DNX was only in standard-risk patients with EFS5y 55.3% (CI, 45.1 to 67.7) versus 79.9% (CI, 71.1 to 89.9), CIR 39.5% (CI, 28.4 to 50.3) versus 18.7% (CI, 10.5 to 28.7), and OS5y 76.2% (CI, 67.2 to 86.4) versus 88.6% (CI, 81.4 to 96.3). As-treated analyses, including the observation cohort, supported these results. For all high-risk patients, 85% received hSCT, and EFS5y was 77.7 (CI, 67.3 to 89.7) and OS5y was 83.0 (CI, 73.5 to 93.8). CONCLUSION: The intensification of induction therapy with risk stratification on the basis of response to induction and hSCT for high-risk patients led to improved outcomes. Mitoxantrone had a superior anti-leukemic effect than liposomal daunorubicin.

Corrigendum: Cancer data quality and harmonization in Europe: The experience of the BENCHISTA Project - International Benchmarking of Childhood Cancer Survival by Stage.

[This corrects the article DOI: 10.3389/fonc.2023.1232451.].

Cancer data quality and harmonization in Europe: the experience of the BENCHISTA Project - international benchmarking of childhood cancer survival by stage.

Introduction: Variation in stage at diagnosis of childhood cancers (CC) may explain differences in survival rates observed across geographical regions. The BENCHISTA project aims to understand these differences and to encourage the application of the Toronto Staging Guidelines (TG) by Population-Based Cancer Registries (PBCRs) to the most common solid paediatric cancers. Methods: PBCRs within and outside Europe were invited to participate and identify all cases of Neuroblastoma, Wilms Tumour, Medulloblastoma, Ewing Sarcoma, Rhabdomyosarcoma and Osteosarcoma diagnosed in a consecutive three-year period (2014-2017) and apply TG at diagnosis. Other non-stage prognostic factors, treatment, progression/recurrence, and cause of death information were collected as optional variables. A minimum of three-year follow-up was required. To standardise TG application by PBCRs, on-line workshops led by six tumour-specific clinical experts were held. To understand the role of data availability and quality, a survey focused on data collection/sharing processes and a quality assurance exercise were generated. To support data harmonization and query resolution a dedicated email and a question-and-answers bank were created. Results: 67 PBCRs from 28 countries participated and provided a maximally de-personalized, patient-level dataset. For 26 PBCRs, data format and ethical approval obtained by the two sponsoring institutions (UCL and INT) was sufficient for data sharing. 41 participating PBCRs required a Data Transfer Agreement (DTA) to comply with data protection regulations. Due to heterogeneity found in legal aspects, 18 months were spent on finalizing the DTA. The data collection survey was answered by 68 respondents from 63 PBCRs; 44% of them confirmed the ability to re-consult a clinician in cases where stage ascertainment was difficult/uncertain. Of the total participating PBCRs, 75% completed the staging quality assurance exercise, with a median correct answer proportion of 92% [range: 70% (rhabdomyosarcoma) to 100% (Wilms tumour)]. Conclusion: Differences in interpretation and processes required to harmonize general data protection regulations across countries were encountered causing delays in data transfer. Despite challenges, the BENCHISTA Project has established a large collaboration between PBCRs and clinicians to collect detailed and standardised TG at a population-level enhancing the understanding of the reasons for variation in overall survival rates for CC, stimulate research and improve national/regional child health plans.

Characteristics and outcome of primary resistant disease in paediatric acute myeloid leukaemia.

A significant proportion of events in paediatric acute myeloid leukaemia (AML) are caused by resistant disease (RD). We investigated clinical and biological characteristics in 66 patients with RD from 1013 children with AML registered and treated according to the NOPHO-AML 93, NOPHO-AML 2004, DB AML-01 and NOPHO-DBH AML 2012 protocols. Risk factors for RD were age10 years or older and a white-blood-cell count (WBC) of 100 × 109 /L or more at diagnosis. The five-year overall survival (OS) was 38% (95% confidence interval [CI]: 28%-52%). Of the 63 children that received salvage therapy with chemotherapy, 59% (N = 37) achieved complete remission (CR) with OS 57% (95% CI: 42%-75%) compared to 12% (95% CI: 4%-35%) for children that did not achieve CR. Giving more than two salvage chemotherapy courses did not increase CR rates. OS for all 43 patients receiving allogeneic haematopoietic stem cell transplantation (HSCT) was 49% (95% CI: 36%-66%). Those achieving CR and proceeding to HSCT had an OS of 56% (95% CI: 41%-77%, N = 30). This study showed that almost 40% of children with primary resistant AML can be cured with salvage therapy followed by HSCT. Children that did not achieve CR after two salvage courses with chemotherapy did not benefit from additional chemotherapy.

Hypodiploidy has unfavorable impact on survival in pediatric acute myeloid leukemia: an I-BFM Study Group collaboration.

Hypodiploidy, defined as modal numbers (MNs) 45 or lower, has not been independently investigated in pediatric acute myeloid leukemia (AML) but is a well-described high-risk factor in pediatric acute lymphoblastic leukemia. We aimed to characterize and study the prognostic impact of hypodiploidy in pediatric AML. In this retrospective cohort study, we included children below 18 years of age with de novo AML and a hypodiploid karyotype diagnosed from 2000 to 2015 in 14 childhood AML groups from the International Berlin-Frankfurt-Münster (I-BFM) framework. Exclusion criteria comprised constitutional hypodiploidy, monosomy 7, composite karyotype, and t(8;21) with concurring sex chromosome loss. Hypodiploidy occurred in 81 patients (1.3%) with MNs, 45 (n = 66); 44 (n = 10) and 43 (n = 5). The most frequently lost chromosomes were chromosome 9 and sex chromosomes. Five-year event-free survival (EFS) and overall survival (OS) were 34% and 52%, respectively, for the hypodiploid cohort. Children with MN≤44 (n = 15) had inferior EFS (21%) and OS (33%) compared with children with MN = 45 (n = 66; EFS, 37%; OS, 56%). Adjusted hazard ratios (HRs) were 4.9 (P = .001) and 6.1 (P = .003). Monosomal karyotype or monosomy 9 had particular poor OS (43% and 15%, respectively). Allogeneic stem cell transplantation (SCT) in first complete remission (CR1) (n = 18) did not mitigate the unfavorable outcome of hypodiploidy (adjusted HR for OS was 1.5; P = .42). We identified pediatric hypodiploid AML as a rare subgroup with an inferior prognosis even in the patients treated with SCT in CR1.

Proteogenomic analysis of acute myeloid leukemia associates relapsed disease with reprogrammed energy metabolism both in adults and children.

Despite improvement of current treatment strategies and novel targeted drugs, relapse and treatment resistance largely determine the outcome for acute myeloid leukemia (AML) patients. To identify the underlying molecular characteristics, numerous studies have been aimed to decipher the genomic- and transcriptomic landscape of AML. Nevertheless, further molecular changes allowing malignant cells to escape treatment remain to be elucidated. Mass spectrometry is a powerful tool enabling detailed insights into proteomic changes that could explain AML relapse and resistance. Here, we investigated AML samples from 47 adult and 22 pediatric patients at serial time-points during disease progression using mass spectrometry-based in-depth proteomics. We show that the proteomic profile at relapse is enriched for mitochondrial ribosomal proteins and subunits of the respiratory chain complex, indicative of reprogrammed energy metabolism from diagnosis to relapse. Further, higher levels of granzymes and lower levels of the anti-inflammatory protein CR1/CD35 suggest an inflammatory signature promoting disease progression. Finally, through a proteogenomic approach, we detected novel peptides, which present a promising repertoire in the search for biomarkers and tumor-specific druggable targets. Altogether, this study highlights the importance of proteomic studies in holistic approaches to improve treatment and survival of AML patients.

Supportive care in pediatric acute myeloid leukemia:Expert-based recommendations of the NOPHO-DB-SHIP consortium.

INTRODUCTION: Pediatric acute myeloid leukemia (AML) is the second most common type of pediatric leukemia. Patients with AML are at high risk for several complications such as infections, typhlitis, and acute and long-term cardiotoxicity. Despite this knowledge, there are no definite supportive care guidelines as to what the best approach is to manage or prevent these complications. AREA COVERED: The NOPHO-DB-SHIP (Nordic-Dutch-Belgian-Spain-Hong-Kong-Israel-Portugal) consortium, in preparation for a new trial in pediatric AML patients, had dedicated meetings for supportive care. In this review, the authors discuss the available data and outline recommendations for the management of children and adolescents with AML with an emphasis on hyperleukocytosis, tumor lysis syndrome, coagulation abnormalities and bleeding, infection, typhlitis, malnutrition, cardiotoxicity, and fertility preservation. EXPERT OPINION: Improved supportive care has significantly contributed to increased cure rates. Recommendations on supportive care are an essential part of treatment for this highly susceptible population and will further improve their outcome.

Abdominal Complications During Treatment for Pediatric Acute Myeloid Leukemia.

Acute myeloid leukemia (AML) accounts for 15% to 20% of childhood leukemias. Because of high-intensive therapy, up to 5% of patients suffer from treatment-related mortality (TRM). Abdominal complications are frequent, however, literature on this subject is sparse. We aimed to characterize severe abdominal pain (AP) and hyperbilirubinemia experienced by pediatric AML patients treated according to the Nordic Society of Pediatric Hematology and Oncology (NOPHO)-AML 2004 protocol (n=313). Patients were censored at hematopoietic stem cell transplantation and relapse. Toxicity information was collected prospectively. Additional information was requested retrospectively from the treating centers. Sixteen episodes of hyperbilirubinemia and 107 episodes of AP were reported. The treating centers deemed infection (30%) and typhlitis (18%) as the most frequent causes of AP. Six patients developed appendicitis (2%). Patients experiencing concurrent AP and sepsis had a high risk of TRM (36%, n=4). Eighty percent of episodes with hyperbilirubinemia fulfilled the European Society for Bone and Marrow Transplantation criteria for sinusoidal obstruction syndrome. In conclusion, abdominal complications were frequent with infection considered the predominate cause. Most patients with hyperbilirubinemia fulfilled the criteria for sinusoidal obstruction syndrome. AML treatment might be associated with appendicitis. Patients suffering from concurrent AP and sepsis had a high risk of TRM indicating that high awareness of abdominal complications is essential to reduce mortality, especially during sepsis.

Transcriptomic analysis reveals proinflammatory signatures associated with acute myeloid leukemia progression.

Numerous studies have been performed over the last decade to exploit the complexity of genomic and transcriptomic lesions driving the initiation of acute myeloid leukemia (AML). These studies have helped improve risk classification and treatment options. Detailed molecular characterization of longitudinal AML samples is sparse, however; meanwhile, relapse and therapy resistance represent the main challenges in AML care. To this end, we performed transcriptome-wide RNA sequencing of longitudinal diagnosis, relapse, and/or primary resistant samples from 47 adult and 23 pediatric AML patients with known mutational background. Gene expression analysis revealed the association of short event-free survival with overexpression of GLI2 and IL1R1, as well as downregulation of ST18. Moreover, CR1 downregulation and DPEP1 upregulation were associated with AML relapse both in adults and children. Finally, machine learning-based and network-based analysis identified overexpressed CD6 and downregulated INSR as highly copredictive genes depicting important relapse-associated characteristics among adult patients with AML. Our findings highlight the importance of a tumor-promoting inflammatory environment in leukemia progression, as indicated by several of the herein identified differentially expressed genes. Together, this knowledge provides the foundation for novel personalized drug targets and has the potential to maximize the benefit of current treatments to improve cure rates in AML.

DNA Methylation Signatures Predict Cytogenetic Subtype and Outcome in Pediatric Acute Myeloid Leukemia (AML).

Pediatric acute myeloid leukemia (AML) is a heterogeneous disease composed of clinically relevant subtypes defined by recurrent cytogenetic aberrations. The majority of the aberrations used in risk grouping for treatment decisions are extensively studied, but still a large proportion of pediatric AML patients remain cytogenetically undefined and would therefore benefit from additional molecular investigation. As aberrant epigenetic regulation has been widely observed during leukemogenesis, we hypothesized that DNA methylation signatures could be used to predict molecular subtypes and identify signatures with prognostic impact in AML. To study genome-wide DNA methylation, we analyzed 123 diagnostic and 19 relapse AML samples on Illumina 450k DNA methylation arrays. We designed and validated DNA methylation-based classifiers for AML cytogenetic subtype, resulting in an overall test accuracy of 91%. Furthermore, we identified methylation signatures associated with outcome in t(8;21)/RUNX1-RUNX1T1, normal karyotype, and MLL/KMT2A-rearranged subgroups (p < 0.01). Overall, these results further underscore the clinical value of DNA methylation analysis in AML.

Therapeutic implications of improved molecular diagnostics for rare CNS embryonal tumor entities: results of an international, retrospective study.

BACKGROUND: Only few data are available on treatment-associated behavior of distinct rare CNS embryonal tumor entities previously treated as "CNS-primitive neuroectodermal tumors" (CNS-PNET). Respective data on specific entities, including CNS neuroblastoma, FOXR2 activated (CNS NB-FOXR2), and embryonal tumors with multilayered rosettes (ETMR) are needed for development of differentiated treatment strategies. METHODS: Within this retrospective, international study, tumor samples of clinically well-annotated patients with the original diagnosis of CNS-PNET were analyzed using DNA methylation arrays (n = 307). Additional cases (n = 66) with DNA methylation pattern of CNS NB-FOXR2 were included irrespective of initial histological diagnosis. Pooled clinical data (n = 292) were descriptively analyzed. RESULTS: DNA methylation profiling of "CNS-PNET" classified 58 (19%) cases as ETMR, 57 (19%) as high-grade glioma (HGG), 36 (12%) as CNS NB-FOXR2, and 89(29%) cases were classified into 18 other entities. Sixty-seven (22%) cases did not show DNA methylation patterns similar to established CNS tumor reference classes. Best treatment results were achieved for CNS NB-FOXR2 patients (5-year PFS: 63% ± 7%, OS: 85% ± 5%, n = 63), with 35/42 progression-free survivors after upfront craniospinal irradiation (CSI) and chemotherapy. The worst outcome was seen for ETMR and HGG patients with 5-year PFS of 18% ± 6% and 22% ± 7%, and 5-year OS of 24% ± 6% and 25% ± 7%, respectively. CONCLUSION: The historically reported poor outcome of CNS-PNET patients becomes highly variable when tumors are molecularly classified based on DNA methylation profiling. Patients with CNS NB-FOXR2 responded well to current treatments and a standard-risk CSI-based regimen may be prospectively evaluated. The poor outcome of ETMR across applied treatment strategies substantiates the necessity for evaluation of novel treatments.

Genomic characterization of relapsed acute myeloid leukemia reveals novel putative therapeutic targets.

Relapse is the leading cause of death of adult and pediatric patients with acute myeloid leukemia (AML). Numerous studies have helped to elucidate the complex mutational landscape at diagnosis of AML, leading to improved risk stratification and new therapeutic options. However, multi-whole-genome studies of adult and pediatric AML at relapse are necessary for further advances. To this end, we performed whole-genome and whole-exome sequencing analyses of longitudinal diagnosis, relapse, and/or primary resistant specimens from 48 adult and 25 pediatric patients with AML. We identified mutations recurrently gained at relapse in ARID1A and CSF1R, both of which represent potentially actionable therapeutic alternatives. Further, we report specific differences in the mutational spectrum between adult vs pediatric relapsed AML, with MGA and H3F3A p.Lys28Met mutations recurrently found at relapse in adults, whereas internal tandem duplications in UBTF were identified solely in children. Finally, our study revealed recurrent mutations in IKZF1, KANSL1, and NIPBL at relapse. All of the mentioned genes have either never been reported at diagnosis in de novo AML or have been reported at low frequency, suggesting important roles for these alterations predominantly in disease progression and/or resistance to therapy. Our findings shed further light on the complexity of relapsed AML and identified previously unappreciated alterations that may lead to improved outcomes through personalized medicine.

Therapy-induced Deletion in 11q23 Leading to Fusion of KMT2A With ARHGEF12 and Development of B Lineage Acute Lymphoplastic Leukemia in a Child Treated for Acute Myeloid Leukemia Caused by t(9;11)(p21;q23)/KMT2A-MLLT3.

BACKGROUND/AIM: Fusion of histone-lysine N-methyltransferase 2A gene (KMT2A) with the Rho guanine nucleotide exchange factor 12 gene (ARHGEF12), both located in 11q23, was reported in some leukemic patients. We report a KMT2A-ARHGEF12 fusion occurring during treatment of a pediatric acute myeloid leukemia (AML) with topoisomerase II inhibitors leading to a secondary acute lymphoblastic leukemia (ALL). MATERIALS AND METHODS: Multiple genetic analyses were performed on bone marrow cells of a girl initially diagnosed with AML. RESULTS: At the time of diagnosis with AML, the t(9;11)(p21;q23)/KMT2A-MLLT3 genetic abnormality was found. After chemotherapy resulting in AML clinical remission, a 2 Mb deletion in 11q23 was found generating a KMT2A-ARHGEF12 fusion gene. When the patient later developed B lineage ALL, a t(14;19)(q32;q13), loss of one chromosome 9, and KMT2A-ARHGEF12 were detected. CONCLUSION: The patient sequentially developed AML and ALL with three leukemia-specific genomic abnormalities in her bone marrow cells, two of which were KMT2A-rearrangements.

TYRO3 Truncation Resulting From a t(10;15)(p11;q15) Chromosomal Translocation in Pediatric Acute Myeloid Leukemia.

BACKGROUND/AIM: Novel acquired chromosome aberrations in cancer may provide insights into pathogenetic mechanisms, be of diagnostic and/or prognostic significance and pave the way for new modes of therapeutic intervention. Here, we report a novel chromosome translocation and its molecular genetic consequences in a pediatric acute myeloid leukemia (AML) case. MATERIALS AND METHODS: Cytogenetic, RNA sequencing, and molecular analyses were performed on the bone marrow cells of a child with AML. RESULTS: The patient entered complete hematologic remission after treatment according to the NOPHO-AML 2004 protocol. A novel t(10;15)(p11;q15) translocation was found in leukemic cells at diagnosis resulting in a fusion of exon 13 of TYRO3 with a sequence from 10p11. The transcript codes for a putative TYRO3 protein lacking the tyrosine kinase domain. CONCLUSION: The t(10;15)(p11;q15) translocation in neoplastic bone marrow cells results in truncated TYRO3. Because the role of the truncated TYRO3 cannot be predicted functional studies are required.

Measurable residual disease assessment by qPCR in peripheral blood is an informative tool for disease surveillance in childhood acute myeloid leukaemia.

Serial assessments of measurable (or minimal) residual disease (MRD) by qPCR may identify nascent relapse in children with acute myeloid leukaemia (AML) and enable pre-emptive therapy. We investigated the kinetics and prognostic impact of recurrent fusion transcripts (RUNX1-RUNX1T1, CBFB-MYH11, KMT2A-MLLT3 or KMT2A-ELL) in 774 post-induction samples from bone marrow (BM, 347) and peripheral blood (PB, 427) from 75 children with AML. BM MRD persistence during consolidation did not increase the risk of relapse, and MRD at therapy completion did not correlate to outcome (HR = 0·64/MRD log reduction (CI: 0·32-1·26), P = 0·19). In contrast, 8/8 patients with detectable MRD in PB after first consolidation relapsed. Persistence (n = 4) and shifting from negative to positive (n = 10) in PB during follow-up predicted relapse in 14/14 patients. All 253 PB samples collected during follow-up from 36 patients in continuous complete remission were MRD negative. In core-binding factor AML, persistent low-level MRD positivity in BM during follow-up was frequent but an increment to above 5 × 10-4 heralded subsequent haematological relapse in 12/12 patients. We demonstrate that MRD monitoring in PB after induction therapy is highly informative and propose an MRD increment above 5 × 10-4 in PB and BM as a definition of molecular relapse since it always leads to haematological relapse.

Associations between pretherapeutic body mass index, outcome, and cytogenetic abnormalities in pediatric acute myeloid leukemia.

BACKGROUND: Associations between body mass index (BMI), outcome, and leukemia-related factors in children with acute myeloid leukemia (AML) remain unclear. We investigated associations between pretherapeutic BMI, cytogenetic abnormalities, and outcome in a large multinational cohort of children with AML. METHODS: We included patients, age 2-17 years, diagnosed with de novo AML from the five Nordic countries (2004-2016), Hong Kong (2007-2016), the Netherlands and Belgium (2010-2016), and Canada and USA (1995-2012). BMI standard deviations score for age and sex was calculated and categorized according to the World Health Organization. Cumulative incidence functions, Kaplan-Meier estimator, Cox regression, and logistic regression were used to investigate associations. RESULTS: In total, 867 patients were included. The median age was 10 years (range 2-17 years). At diagnosis, 32 (4%) were underweight, 632 (73%) were healthy weight, 127 (15%) were overweight, and 76 (9%) were obese. There was no difference in relapse risk, treatment-related mortality or overall mortality across BMI groups. The frequency of t(8;21) and inv(16) increased with increasing BMI. For obese patients, the sex, age, and country adjusted odds ratio of having t(8;21) or inv(16) were 1.9 (95% confidence interval (CI) 1.1-3.4) and 2.8 (95% CI 1.3-5.8), respectively, compared to healthy weight patients. CONCLUSIONS: This study did not confirm previous reports of associations between overweight and increased treatment-related or overall mortality in children. Obesity was associated with a higher frequency of t(8;21) and inv(16). AML cytogenetics appear to differ by BMI status.