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Effective treatment of pediatric acute leukemia is dependent on accurate genomic classification, typically derived from a combination of multiple time-consuming and costly techniques such as flow cytometry, fluorescence in situ hybridization (FISH), karyotype analysis, targeted PCR, and microarrays (Arber et al., 2016; Iacobucci & Mullighan, 2017; Narayanan & Weinberg, 2020). We investigated the feasibility of a comprehensive single-assay classification approach using long-read sequencing, with real-time genome target enrichment, to classify chromosomal abnormalities and structural variants characteristic of acute leukemia. We performed whole genome sequencing on DNA from diagnostic peripheral blood or bone marrow for 54 pediatric acute leukemia cases with diverse genomic subtypes. We demonstrated the characterization of known, clinically relevant karyotype abnormalities and structural variants concordant with standard-of-care clinical testing. Subtype-defining genomic alterations were identified in all cases following a maximum of forty-eight hours of sequencing. In 18 cases, we performed real-time analysis - concurrent with sequencing - and identified the driving alteration in as little as fifteen minutes (for karyotype) or up to six hours (for complex structural variants). Whole genome nanopore sequencing with adaptive sampling has the potential to provide detailed genomic classification of acute leukemia specimens with reduced cost and turnaround time compared to the current standard of care., Competing Interests: Competing Interests: JG and JRW have received compensation for travel to speak at Oxford Nanopore Technologies events. The remaining authors declare no conflicts of interest.

Approximately 80% of pediatric tumors occur in low- and middle-income countries (LMIC), where diagnostic tools essential for treatment decisions are often unavailable or incomplete. Development of cost-effective molecular diagnostics will help bridge the cancer diagnostic gap and ultimately improve pediatric cancer outcomes in LMIC settings. We investigated the feasibility of using nanopore whole transcriptome sequencing on formalin-fixed paraffin embedded (FFPE)-derived RNA and a composite machine learning model for pediatric solid tumor diagnosis. Transcriptome cDNA sequencing was performed on a heterogenous set of 221 FFPE and 32 fresh frozen pediatric solid tumor and lymphoma specimens on Oxford Nanopore Technologies' sequencing platforms. A composite machine learning model was then used to classify transcriptional profiles into clinically actionable tumor types and subtypes. In total, 95.6% and 89.7% of pediatric solid tumors and lymphoma specimens were correctly classified, respectively. 71.5% of pediatric solid tumors had prediction probabilities > 0.8 and were classified with 100% accuracy. Similarly, for lymphomas, 72.4% of samples that had prediction probabilities > 0.6 were classified with 97.6% accuracy. Additionally, FOXO1 fusion status was predicted accurately for 97.4% of rhabdomyosarcomas and MYCN amplification was predicted with 88% accuracy in neuroblastoma. Whole transcriptome sequencing from FFPE-derived pediatric solid tumor and lymphoma samples has the potential to provide clinical classification of both tissue lineage and core genomic classification. Further expansion, refinement, and validation of this approach is necessary to explore whether this technology could be part of the solution of addressing the diagnostic limitations in LMIC., (© 2024. The Author(s).)

There were no pediatric oncology centers in southwest Ethiopia prior to 2016. This study aims to describe presenting diagnoses and initial outcomes at Jimma University Medical Center (JUMC), the first pediatric oncology unit (POU) in southwest Ethiopia, provide initial insights into regional pediatric cancer epidemiology, illustrate the rapid growth of pediatric cancer services, and highlight ongoing challenges. We used a retrospective descriptive approach to assess the epidemiologic pattern and initial treatment outcomes of pediatric cancer at JUMC POU from August 2016 through December 2022. During the study period, 749 children were diagnosed with cancer at JUMC. The mean age was 7.2 years (20 days-18 years). Acute lymphoblastic leukemia was the most common diagnosis (16.4%), followed by non-Hodgkin lymphoma (12.4%), Wilms tumor (11.1%), soft tissue sarcoma (8.8%), Hodgkin lymphoma (8.4%), and retinoblastoma (8.3%). Brain tumors accounted for only 2.7% of the diagnoses. Of the 703 patients that were not referred elsewhere, 42% of the patients abandoned treatment, 29% died, 17% completed treatment, and 7% remained on treatment at the time of this assessment. The findings emphasize the growth in the diagnosis and treatment of children with cancer in the southwest region of Ethiopia. The data suggests a different epidemiologic profile of childhood cancer cases diagnosed at the JUMC POU compared to high-income countries and neighbouring countries in Africa. Treatment abandonment remains a barrier to care. Ongoing areas of focus include establishment of a hospital-based cancer registry, reduction of treatment abandonment, improvement of diagnostic capacity, and increased access to advanced supportive care., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Hordofa et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Background: The impact and downstream effects of the chemotherapy supply chain in Ethiopia are not well understood. The purpose of this study was to identify perceived gaps in supply chain and characterize their impact on patient care., Methods: A concurrent mixed-method study was conducted at a large academic cancer center in Ethiopia. In-depth interviews (IDIs) and surveys were completed in collaboration with external stakeholders with knowledge about chemotherapy supply chain in Ethiopia. Thematic coding was used for qualitative analysis of IDI and descriptive statistics were used to summarize quantitative survey data., Results: Six stakeholders participated in the IDIs and seven completed surveys. IDIs revealed that most chemotherapeutic agents are purchased by the Ethiopian Pharmaceutical Supply Agency (EPSA) and are distributed to cancer treatment centers. A free-market purchasing option also exists, but for chemotherapy obtained outside of government-subsidized channels, the potential for substandard or falsified chemotherapy was a concern. Participants expressed confidence that the correct treatment was administered to patients, but viewpoints on reliability and consistency of medication supply were variable. Quantitative data from the survey showed that participants were not confident that medications are prepared safely and correctly. Improper storage and manipulation of high-risk medications remain a significant risk to staff., Conclusions: This study provides insight from a healthcare staff perspective on how gaps in the chemotherapy supply chain process impact patient care in a low-income country. Inventory management, disruptions in supply chain, and product integrity were perceived as the largest gaps in the current chemotherapy supply chain structure., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background: The stark disparity in survival for children with cancer across the world has inspired a global call to expand chemotherapy access in low and middle income countries. Among the numerous barriers to success, a paucity of reliable information regarding chemotherapy pricing hinders the ability of governments and other key stakeholders to make informed budget decisions or negotiate lower medication prices. The aim of this study was to generate comparative price information on both individual chemotherapy agents and comprehensive treatment regimens for common childhood cancers using real-world data., Methods: Chemotherapy agents were selected based on their inclusion in the World Health Organization (WHO) Essential Medicines List for Children (EMLc) and their use in frontline regimens for the tracer cancer types prioritized by the WHO's Global Initiative for Childhood Cancer (GICC). Sources included IQVIA MIDAS data, obtained under license from IQVIA, and publicly available data from Management Sciences for Health (MSH). Data on chemotherapy prices and purchase volumes spanning 2012-2019 were aggregated according to WHO region and World Bank (WB) income classification. Cumulative chemotherapy prices for treatment regimens were compared across WB income classification., Findings: Data representing an estimated 1.1 billion doses of chemotherapy were obtained for 97 countries: 43 high income countries (HICs), 28 upper middle income countries (UMICs), and 26 low and lower middle income countries (LLMICs). Median drug prices in HICs were 0.9-20.4 times those of UMICs and 0.9-15.5 times those of LMICs. Regimen prices were generally higher for HICs, hematologic malignancies, non-adapted protocols, and higher risk stratification or stage, albeit with notable exceptions., Interpretation: This study represents the largest price analysis to date of chemotherapy agents used globally in childhood cancer therapy. The findings of this study form a basis for future cost-effectiveness analysis in pediatric cancer and should inform efforts of governments and stakeholders to negotiate drug prices and develop pooled purchasing strategies., Funding: NB received funding support from the American Lebanese Syrian Associated Charities and Cancer Center Support grant (CA21765) from the National Cancer Institute through the National Institutes of Health. TA received funding through the University of North Carolina Oncology K12 (K12CA120780) and the University Cancer Research Fund from the UNC Lineberger Comprehensive Cancer Center., Competing Interests: TA received support from NIH (K12CA120780 and R21CA259926), the 10.13039/100007602University Cancer Research Fund, Lineberger Comprehensive Cancer Center Fund from Lineberger Comprehensive Cancer Center, and 10.13039/100007737St. Jude Children's Research Hospital for grand rounds honoraria. NB received support from National Cancer Institute, American Lebanese Syrian Associated Charities (ALSAC), St. Jude Children’s Research Hospital NCI Comprehensive Cancer Center, and Memorial Sloan Kettering for grand rounds honoraria. SO received grant funding from Merck., (© 2023 The Author(s).)

6-mercaptopurine is a mainstay of acute lymphoblastic leukemia treatment. It has a narrow therapeutic window, dictated by its metabolite, thioguanine and 6-methylmercaptopurine. Skin manifestations usually consist of mild facial rash or hypersensitivity exanthems. We report a child who developed a painful acral rash and mucositis while undergoing maintenance therapy for B-cell acute lymphoblastic leukemia without infectious or known drug etiology. Thiopurine metabolites were skewed toward 6-methylmercaptopurine. Two weeks after allopurinol was added and 6-mercaptopurine (6-MP) dose adjusted, the cutaneous manifestations and other constitutional symptoms resolved. We posit that the rash was because of 6-MP toxicity related to skewed metabolism, adding to the growing list of toxicity related to altered 6-MP metabolism., Competing Interests: The authors declare no conflict of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Purpose: Most cases of pediatric acute leukemia occur in low- and middle-income countries, where health centers lack the tools required for accurate diagnosis and disease classification. Recent research shows the robustness of using unbiased short-read RNA sequencing to classify genomic subtypes of acute leukemia. Compared with short-read sequencing, nanopore sequencing has low capital and consumable costs, making it suitable for use in locations with limited health infrastructure., Materials and Methods: We show the feasibility of nanopore mRNA sequencing on 134 cryopreserved acute leukemia specimens (26 acute myeloid leukemia [AML], 73 B-lineage acute lymphoblastic leukemia [B-ALL], 34 T-lineage acute lymphoblastic leukemia, and one acute undifferentiated leukemia). Using multiple library preparation approaches, we generated long-read transcripts for each sample. We developed a novel composite classification approach to predict acute leukemia lineage and major B-ALL and AML molecular subtypes directly from gene expression profiles., Results: We demonstrate accurate classification of acute leukemia samples into AML, B-ALL, or T-lineage acute lymphoblastic leukemia (96.2% of cases are classifiable with a probability of > 0.8, with 100% accuracy) and further classification into clinically actionable genomic subtypes using shallow RNA nanopore sequencing, with 96.2% accuracy for major AML subtypes and 94.1% accuracy for major B-lineage acute lymphoblastic leukemia subtypes., Conclusion: Transcriptional profiling of acute leukemia samples using nanopore technology for diagnostic classification is feasible and accurate, which has the potential to improve the accuracy of cancer diagnosis in low-resource settings., Competing Interests: Mahler RevsineEmployment: Epic SystemsTravel, Accommodations, Expenses: Epic Systems Mark R. LitzowConsulting or Advisory Role: Omeros, Jazz PharmaceuticalsResearch Funding: Amgen, Astellas Pharma, Actinium Pharmaceuticals, Pluristem Therapeutics, AbbVie/Genentech, Tolero Pharmaceuticals, AbbVieOther Relationship: BioSight Yuri FedoriwHonoraria: Alexion Pharmaceuticals Kathryn G. RobertsStock and Other Ownership Interests: Amgen Charles G. MullighanStock and Other Ownership Interests: AmgenHonoraria: Amgen, IlluminaConsulting or Advisory Role: IlluminaSpeakers' Bureau: Amgen, PfizerResearch Funding: Loxo, Pfizer, AbbViePatents, Royalties, Other Intellectual Property: Inventor on a pending patent application related to gene expression signatures for detection of underlying Philadelphia chromosome–like events and therapeutic targeting in leukemia (PCT/US2012/069228), WO 2021/022076 A1. This Patent Highlight shows representative PROTAC compounds bound to JAK2, where ruxolitinib and baricitinib bind to the human JAK2 JH1. Furthermore, representative data illustrate protein degradation, cytotoxicity, and effect of the JAKSTAT signaling pathway of the PROTAC compounds in MHHCALL-4 cellsTravel, Accommodations, Expenses: Amgen, IlluminaNo other potential conflicts of interest were reported.

Rare hematologic malignancies display evidence of both myeloid and lymphoid differentiation. Here, we describe such a novel bilineal event discovered in an adult woman with B-lymphoblastic leukemia (BLL). At the time of BLL diagnosis, the patient had a normal karyotype and a bulk sequencing panel identified pathogenic variants in BCOR, EZH2, RUNX1, and U2AF1, a genotype more typical of myeloid neoplasia. Additionally, the patient was noted to have 3-year history of cytopenias, and morphologic dyspoiesis was noted on post-treatment samples, raising the possibility of an antecedent hematologic disorder. To investigate the clonal architecture of her disease, we performed targeted sequencing on fractionated samples enriched for either B-lymphoblasts or circulating granulocytes. These studies revealed a truncal founder mutation in the spliceosome gene U2AF1 in both fractions, while distinct secondary mutations were present only in B-lymphoblasts (BCOR, NRAS) or myeloid cells (ASXL1, EZH2, RUNX1). These results indicate that both processes evolved from a common U2AF1-mutated precursor, which then acquired additional mutations during a process of divergent evolution and bilineal differentiation. Our findings highlight an atypical mechanism of BLL leukemogenesis and demonstrate the potential utility of fractionated sequencing in the characterization of acute leukemia., (© 2021 by The American Society of Hematology. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved.)

Overexpression of Exportin-1 ( XPO1 ), a key regulator of nuclear-to-cytoplasmic transport, is associated with inferior patient outcomes across a range of adult malignancies. Targeting XPO1 with selinexor has demonstrated promising results in clinical trials, leading to FDA approval of its use for multiple relapsed/refractory cancers. However, XPO1 biology and selinexor sensitivity in childhood cancer is only recently being explored. In this review, we will focus on the differential biology of childhood and adult cancers as it relates to XPO1 and key cargo proteins. We will further explore the current state of pre-clinical and clinical development of XPO1 inhibitors in childhood cancers. Finally, we will outline potentially promising future therapeutic strategies for, as well as potential challenges to, integrating XPO1 inhibition to improve outcomes for children with cancer.

In Ethiopia, cancer accounts for about 5.8% of total national mortality, with an estimated annual incidence of cancer of approximately 60,960 cases and an annual mortality of over 44,000 persons. This is likely an underestimation. Survival rates for pediatric malignancies are likewise suboptimal although exact figures are unknown since a national cancer registry is unavailable. The World Health Organization (WHO) provides recommendations for the creation of cancer registries to track such data. Here we describe our pharmacist-led, pre-implementation assessment of introducing an enhanced national pediatric cancer registry in Ethiopia. Our assessment project had three specific aims around which the methods were designed: 1) characterization of the current spreadsheet-based tool across participating sites, including which variables were being collected, how these variables compared to standards set by the WHO, and a description of how the data were entered and its completeness; 2) assessment of the perceptions of an enhanced registry from hospital staff; and 3) evaluation of workflow gaps regarding documentation. The hospital staff and leadership have generally positive perceptions of an enhanced pediatric cancer registry, which were further improved by our interactions. The workflow assessment revealed several gaps, which were addressed systematically using a three-phase implementation science approach. The assessment also demonstrated that the existing spreadsheet-based tool was missing WHO-recommended variables and had inconsistent completion due to the workflow gaps. A pediatric oncology summary sheet will be implemented in upcoming trips in patient charts to better summarize the patients' journey starting from diagnosis. This document will be used by the data clerks in an enhanced-spreadsheet to have a more complete data set.

Combining venetoclax, a selective BCL2 inhibitor, with low-dose navitoclax, a BCL-X L /BCL2 inhibitor, may allow targeting of both BCL2 and BCL-X L without dose-limiting thrombocytopenia associated with navitoclax monotherapy. The safety and preliminary efficacy of venetoclax with low-dose navitoclax and chemotherapy was assessed in this phase I dose-escalation study (NCT03181126) in pediatric and adult patients with relapsed/refractory (R/R) acute lymphoblastic leukemia or lymphoblastic lymphoma. Forty-seven patients received treatment. A recommended phase II dose of 50 mg navitoclax for adults and 25 mg for patients <45 kg with 400 mg adult-equivalent venetoclax was identified. Delayed hematopoietic recovery was the primary safety finding. The complete remission rate was 60%, including responses in patients who had previously received hematopoietic cell transplantation or immunotherapy. Thirteen patients (28%) proceeded to transplantation or CAR T-cell therapy on study. Venetoclax with navitoclax and chemotherapy was well tolerated and had promising efficacy in this heavily pretreated patient population. SIGNIFICANCE: In this phase I study, venetoclax with low-dose navitoclax and chemotherapy was well tolerated and had promising efficacy in patients with relapsed/refractory acute lymphoblastic leukemia or lymphoblastic lymphoma. Responses were observed in patients across histologic and genomic subtypes and in those who failed available therapies including stem cell transplant. See related commentary by Larkin and Byrd, p. 1324 . This article is highlighted in the In This Issue feature, p. 1307 ., (©2021 American Association for Cancer Research.)

Purpose of Review: Mixed phenotype acute leukemia (MPAL) is a rare subtype of acute leukemia with features of both acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). The review examines current definitions and controversies in classification of MPAL, new insights into genomic drivers and pathogenesis, recent evidence to support treatment recommendations, and opportunities for future research., Recent Findings: Recent collaborative efforts have made progress in understanding the genomic landscape and optimal therapy for MPAL. The preponderance of retrospective data supports beginning therapy with ALL directed regimens. Differences in prognosis for adult and children with MPAL have led to divergent approaches for therapy intensity, including use of stem cell transplantation consolidation. MPAL remains a challenging leukemia to understand, research, and treat due to low incidence, shifting and subjective approaches to classification, and innate biological heterogeneity. Ongoing research hopes to surmount these obstacles through prospective studies within large cooperative groups to provide new insight into targetable biology and further refine optimal therapy.

Blinatumomab, a bispecific antibody that directs CD3+ T cells to CD19+ tumor cells, shows variable efficacy in B-progenitor acute lymphoblastic leukemia (B-ALL). To determine tumor-intrinsic and -extrinsic determinants of response, we studied 44 adults with relapsed or refractory B-ALL (including 2 minimal residual disease positive) treated with blinatumomab using bulk tumor and single-cell sequencing. The overall response rate in patients with hematological disease was 55%, with a high response rate in those with CRLF2-rearranged Philadelphia chromosome-like ALL (12 [75%] of 16). Pretreatment samples of responders exhibited a tumor-intrinsic transcriptomic signature of heightened immune response. Multiple mechanisms resulted in loss of CD19 expression, including CD19 mutations, CD19-mutant allele-specific expression, low CD19 RNA expression, and mutations in CD19 signaling complex member CD81. Patients with low hypodiploid ALL were prone to CD19- relapse resulting from aneuploidy-mediated loss of the nonmutated CD19 allele. Increased expression of a CD19 isoform with intraexonic splicing of exon 2, CD19 ex2part, at baseline or during therapy was associated with treatment failure. These analyses demonstrate both tumor-intrinsic and -extrinsic factors influence blinatumomab response. We show that CD19 mutations are commonly detected in CD19- relapse during blinatumomab treatment. Identification of the CD19 ex2part splice variant represents a new biomarker predictive of blinatumomab therapy failure., (© 2021 by The American Society of Hematology.)

Purpose: A considerable barrier to global pediatric oncology efforts has been the scarcity and even absence of trained professionals in many low- and middle-income countries, where the majority of children with cancer reside. In 2013, no dedicated pediatric hematology-oncology (PHO) programs existed in Ethiopia despite the estimated annual incidence of 6000-12000 cases. The Aslan Project initiative was established to fill this gap in order to improve pediatric cancer care in Ethiopia. A major objective was to increase subspecialty PHO-trained physicians who were committed to practicing locally and empowered to lead programmatic development., Methods: We designed and implemented a PHO training curriculum to provide a robust educational and clinical experience within the existing resource-constrained environment in Ethiopia. Education relied on visiting PHO faculty, a training attachment abroad, and extraordinary initiative from trainees., Results: Four physicians have completed comprehensive PHO subspecialty training based primarily in Ethiopia, and all have remained local. Former fellows are now leading two PHO centers in Ethiopia with a combined capacity of 64 inpatient beds and over 800 new diagnoses per year; an additional former fellow is developing a pediatric cancer program in Nairobi, Kenya. Two fellows currently are in training. Program leadership, teaching, and advocacy are being transitioned to these physicians., Conclusions: Despite myriad challenges, a subspecialty PHO training program was successfully implemented in a low-income country. PHO training in Ethiopia is approaching sustainability through human resource development, and is accelerating the growth of dedicated PHO services where none existed 7 years ago., (© 2020 Wiley Periodicals LLC.)

Background: Novel therapies are urgently needed for pediatric patients with relapsed acute myeloid leukemia (AML)., Methods: To determine whether the histone deacetylase inhibitor panobinostat could be safely given in combination with intensive chemotherapy, a phase 1 trial was performed in which 17 pediatric patients with relapsed or refractory AML received panobinostat (10, 15, or 20 mg/m 2 ) before and in combination with fludarabine and cytarabine., Results: All dose levels were tolerated, with no dose-limiting toxicities observed at any dose level. Pharmacokinetic studies demonstrated that exposure to panobinostat was proportional to the dose given, with no associations between pharmacokinetic parameters and age, weight, or body surface area. Among the 9 patients who had sufficient (>2%) circulating blasts on which histone acetylation studies could be performed, 7 demonstrated at least 1.5-fold increases in acetylation. Although no patients had a decrease in circulating blasts after single-agent panobinostat, 8 of the 17 patients (47%), including 5 of the 6 patients treated at dose level 3, achieved complete remission. Among the 8 complete responders, 6 (75%) attained negative minimal residual disease status., Conclusions: Panobinostat can be safely administered with chemotherapy and results in increased blast histone acetylation. This suggests that it should be further studied in AML., (© 2020 American Cancer Society.)

Background: Outcomes for children with relapsed or refractory acute myeloid leukaemia remain poor. The BCL-2 inhibitor, venetoclax, has shown promising activity in combination with hypomethylating agents and low-dose cytarabine in older adults for whom chemotherapy is not suitable with newly diagnosed acute myeloid leukaemia. We aimed to determine the safety and explore the activity of venetoclax in combination with standard and high-dose chemotherapy in paediatric patients with relapsed or refractory acute myeloid leukaemia., Methods: We did a phase 1, dose-escalation study at three research hospitals in the USA. Eligible patients were aged 2-22 years with relapsed or refractory acute myeloid leukaemia or acute leukaemia of ambiguous lineage with adequate organ function and performance status. During dose escalation, participants received venetoclax orally once per day in continuous 28-day cycles at either 240 mg/m 2 or 360 mg/m 2 , in combination with cytarabine received intravenously every 12 h at either 100 mg/m 2 for 20 doses or 1000 mg/m 2 for eight doses, with or without intravenous idarubicin (12 mg/m 2 ) as a single dose, using a rolling-6 accrual strategy. The primary endpoint was the recommended phase 2 dose of venetoclax plus chemotherapy and the secondary endpoint was the proportion of patients treated at the recommended phase 2 dose who achieved complete remission or complete remission with incomplete haematological recovery. Analyses were done on patients who received combination therapy. The study is registered with ClinicalTrials.gov (NCT03194932) and is now enrolling to address secondary and exploratory objectives., Findings: Between July 1, 2017, and July 2, 2019, 38 patients were enrolled (aged 3-22 years; median 10 [IQR 7-13]), 36 of whom received combination therapy with dose escalation, with a median follow-up of 7·1 months (IQR 5·1-11·2). The recommended phase 2 dose of venetoclax was found to be 360 mg/m 2 (maximum 600 mg) combined with cytarabine (1000 mg/m 2 per dose for eight doses), with or without idarubicin (12 mg/m 2 as a single dose). Overall responses were observed in 24 (69%) of the 35 patients who were evaluable after cycle 1. Among the 20 patients treated at the recommended phase 2 dose, 14 (70%, 95% CI 46-88) showed complete response with or without complete haematological recovery, and two (10%) showed partial response. The most common grade 3-4 adverse events were febrile neutropenia (22 [66%]), bloodstream infections (six [16%]), and invasive fungal infections (six [16%]). Treatment-related death occurred in one patient due to colitis and sepsis., Interpretation: The safety and activity of venetoclax plus chemotherapy in paediatric patients with heavily relapsed and refractory acute myeloid leukaemia suggests that this combination should be tested in newly diagnosed paediatric patients with high-risk acute myeloid leukaemia., Funding: US National Institutes of Health, American Lebanese Syrian Associated Charities, AbbVie, and Gateway for Cancer Research., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Background: Optimal chemotherapy for treating mixed-phenotype acute leukemia (MPAL) and the role of hematopoietic stem cell transplantation (HSCT) remain uncertain. Major limitations in interpreting available data are MPAL's rarity and the use of definitions other than the currently widely accepted criteria: the World Health Organization 2016 (WHO2016) classification., Methods: To assess the relative efficacy of chemotherapy types for treating pediatric MPAL, the Children's Oncology Group (COG) Acute Leukemia of Ambiguous Lineage Task Force assembled a retrospective cohort of centrally reviewed WHO2016 MPAL cases selected from banking studies for acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). Patients were not treated in COG trials; treatment and outcome data were captured separately. The findings were then integrated with the available, mixed literature to develop a prospective trial in pediatric MPAL., Results: The central review confirmed that 54 of 70 cases fulfilled WHO2016 criteria for MPAL. ALL induction regimens achieved remission in 72% of the cases (28 of 39), whereas AML regimens achieved remission in 69% (9 of 13). The 5-year event-free survival (EFS) and overall survival (OS) rates for the entire cohort were 72% ± 8% and 77% ± 7%, respectively. EFS and OS were 75% ± 13% and 84% ± 11%, respectively, for those receiving ALL chemotherapy alone without HSCT (n = 21)., Conclusions: The results of the COG MPAL cohort and a literature review suggest that ALL chemotherapy without HSCT may be the preferred initial therapy. A prospective trial within the COG is proposed to investigate this approach; AML chemotherapy and/or HSCT will be reserved for those with treatment failure as assessed by minimal residual disease. Embedded biology studies will provide further insight into MPAL genomics., (© 2019 American Cancer Society.)

Acute erythroid leukemia (AEL) is a high-risk leukemia of poorly understood genetic basis, with controversy regarding diagnosis in the spectrum of myelodysplasia and myeloid leukemia. We compared genomic features of 159 childhood and adult AEL cases with non-AEL myeloid disorders and defined five age-related subgroups with distinct transcriptional profiles: adult, TP53 mutated; NPM1 mutated; KMT2A mutated/rearranged; adult, DDX41 mutated; and pediatric, NUP98 rearranged. Genomic features influenced outcome, with NPM1 mutations and HOXB9 overexpression being associated with a favorable prognosis and TP53, FLT3 or RB1 alterations associated with poor survival. Targetable signaling mutations were present in 45% of cases and included recurrent mutations of ALK and NTRK1, the latter of which drives erythroid leukemogenesis sensitive to TRK inhibition. This genomic landscape of AEL provides the framework for accurate diagnosis and risk stratification of this disease, and the rationale for testing targeted therapies in this high-risk leukemia.

Although generally curable with intensive chemotherapy in resource-rich settings, Burkitt lymphoma (BL) remains a deadly disease in older patients and in sub-Saharan Africa. Epstein-Barr virus (EBV) positivity is a feature in more than 90% of cases in malaria-endemic regions, and up to 30% elsewhere. However, the molecular features of BL have not been comprehensively evaluated when taking into account tumor EBV status or geographic origin. Through an integrative analysis of whole-genome and transcriptome data, we show a striking genome-wide increase in aberrant somatic hypermutation in EBV-positive tumors, supporting a link between EBV and activation-induced cytidine deaminase (AICDA) activity. In addition to identifying novel candidate BL genes such as SIN3A , USP7 , and CHD8 , we demonstrate that EBV-positive tumors had significantly fewer driver mutations, especially among genes with roles in apoptosis. We also found immunoglobulin variable region genes that were disproportionally used to encode clonal B-cell receptors (BCRs) in the tumors. These include IGHV4-34, known to produce autoreactive antibodies, and IGKV3-20, a feature described in other B-cell malignancies but not yet in BL. Our results suggest that tumor EBV status defines a specific BL phenotype irrespective of geographic origin, with particular molecular properties and distinct pathogenic mechanisms. The novel mutation patterns identified here imply rational use of DNA-damaging chemotherapy in some patients with BL and targeted agents such as the CDK4/6 inhibitor palbociclib in others, whereas the importance of BCR signaling in BL strengthens the potential benefit of inhibitors for PI3K, Syk, and Src family kinases among these patients., (© 2019 by The American Society of Hematology.)

Mixed phenotype acute leukaemia (MPAL) is a high-risk subtype of leukaemia with myeloid and lymphoid features, limited genetic characterization, and a lack of consensus regarding appropriate therapy. Here we show that the two principal subtypes of MPAL, T/myeloid (T/M) and B/myeloid (B/M), are genetically distinct. Rearrangement of ZNF384 is common in B/M MPAL, and biallelic WT1 alterations are common in T/M MPAL, which shares genomic features with early T-cell precursor acute lymphoblastic leukaemia. We show that the intratumoral immunophenotypic heterogeneity characteristic of MPAL is independent of somatic genetic variation, that founding lesions arise in primitive haematopoietic progenitors, and that individual phenotypic subpopulations can reconstitute the immunophenotypic diversity in vivo. These findings indicate that the cell of origin and founding lesions, rather than an accumulation of distinct genomic alterations, prime tumour cells for lineage promiscuity. Moreover, these findings position MPAL in the spectrum of immature leukaemias and provide a genetically informed framework for future clinical trials of potential treatments for MPAL.

Despite attempts to improve the definitions of ambiguous lineage leukemia (ALAL) during the last 2 decades, general therapy recommendations are missing. Herein, we report a large cohort of children with ALAL and propose a treatment strategy. A retrospective multinational study (International Berlin-Frankfurt-Münster Study of Leukemias of Ambiguous Lineage [iBFM-AMBI2012]) of 233 cases of pediatric ALAL patients is presented. Survival statistics were used to compare the prognosis of subsets and types of treatment. Five-year event-free survival (EFS) of patients with acute lymphoblastic leukemia (ALL)-type primary therapy (80% ± 4%) was superior to that of children who received acute myeloid leukemia (AML)-type or combined-type treatment (36% ± 7.2% and 50% ± 12%, respectively). When ALL- or AML-specific gene fusions were excluded, 5-year EFS of CD19 + leukemia was 83% ± 5.3% on ALL-type primary treatment compared with 0% ± 0% and 28% ± 14% on AML-type and combined-type primary treatment, respectively. Superiority of ALL-type treatment was documented in single-population mixed phenotype ALAL (using World Health Organization and/or European Group for Immunophenotyping of Leukemia definitions) and bilineal ALAL. Treatment with ALL-type protocols is recommended for the majority of pediatric patients with ALAL, including cases with CD19 + ALAL. AML-type treatment is preferred in a minority of ALAL cases with CD19 - and no other lymphoid features. No overall benefit of transplantation was documented, and it could be introduced in some patients with a poor response to treatment. As no clear indicator was found for a change in treatment type, this is to be considered only in cases with ≥5% blasts after remission induction. The results provide a basis for a prospective trial., (© 2018 by The American Society of Hematology.)

Background: Outcomes for children with acute myeloid leukemia (AML) have improved over the past 20 years even though the medications used for induction therapy have not changed., Methods: This study analyzed data from patients with AML who were enrolled in successive protocols (AML97 and AML02) to determine the contributors to the improved outcomes of the latter clinical trial., Results: There were significant improvements in 5-year overall survival (48.9% vs 71.2%; P < .0001) and event-free survival (43.5% vs 61.8%; P = .002) from AML97 to AML02. The 5-year cumulative incidence of early death (ED)/treatment-related mortality (TRM) was reduced for patients treated in AML02 (18.5% vs 7.9%; P = .007). Although the overall incidence of refractory disease (6.5% vs 5.6%; P = .736) and relapse (29.3% vs 21.0%; P = .12) did not differ between the 2 studies, patients with low-risk AML who were treated in AML02 had a reduced incidence of relapse (27.3% vs 8.8%; P = .036)., Conclusions: The improved outcomes of the AML02 trial resulted from improved disease control for low-risk patients and overall decreased ED/TRM. These results emphasize the importance of supportive-care measures throughout chemotherapy courses and hematopoietic cell transplantation and the value of treatment intensity for patients with low-risk AML while underscoring the need for novel therapy, rather than increased therapy intensity, for children with high-risk AML. Cancer 2017;123:3791-3798. © 2017 American Cancer Society., (© 2017 American Cancer Society.)

Purpose To characterize the toxicity, pharmacokinetics, and pharmacodynamics of selinexor, a selective inhibitor of nuclear export, when combined with fludarabine and cytarabine, in children with relapsed or refractory leukemia. Patients and Methods Eighteen patients with relapsed or refractory acute leukemia were enrolled in the SELHEM (Selinexor With Fludarabine and Cytarabine for Treatment of Refractory or Relapsed Leukemia or Myelodysplastic Syndrome) clinical trial (NCT02212561). Selinexor, initially at 30 mg/m 2 per dose, was given orally on days 1, 3, 8, 10, 22, and 24 and was escalated according to a rolling-six design. Fludarabine 30 mg/m 2 and cytarabine 2 g/m 2 were administered on days 15 to 19. Pharmacokinetic and pharmacodynamic studies were performed on days 1 and 22. Response evaluations were performed on day 15 and at the completion of course 1. Results Among the 17 patients who were evaluable for toxicity, three were treated at 30 mg/m 2 , three at 40 mg/m 2 , six at 55 mg/m 2 , and five at 70 mg/m 2 . The most common grade 3 nonhematologic toxicity was asymptomatic hyponatremia. Two patients who were treated at 70 mg/m 2 experienced reversible cerebellar toxicity, thereby defining the dose-limiting toxicity. Pharmacokinetic parameters demonstrated that plasma exposure was dose proportional. Fifteen of 16 patients demonstrated at least a twofold increase of XPO1 mRNA, indicating inhibition of the XPO1 protein. In this group of heavily pretreated, relapsed, and refractory patients, seven of 15 evaluable patients (47%) achieved complete response or complete response with incomplete count recovery. Conclusion Selinexor, in combination with fludarabine and cytarabine, is tolerable at doses up to 55 mg/m 2 in pediatric patients with relapsed or refractory leukemia. All patients who received selinexor at ≥ 40 mg/m 2 demonstrated XPO1 target inhibition. Response rates are promising and will be further explored in a phase II trial.

Constitutional mismatch repair deficiency (CMMRD) is a cancer predisposition syndrome associated with a high risk of developing early-onset malignancies of the blood, brain, and intestinal tract. We present the case of a patient with T-lymphoblastic lymphoma at the age of 3 years, followed by Burkitt lymphoma 10 years later. This patient also exhibited numerous nonmalignant findings including café au lait spots, lipomas, bilateral renal nodules, a nonossifying fibroma, multiple colonic adenomas, and a rapidly enlarging pilomatrixoma. The spectrum of malignant and nonmalignant neoplasms in this patient highlights the remarkable diversity, and early onset, of lesions seen in children with CMMRD., (© 2016 Wiley Periodicals, Inc.)

Hoxa2 gene is a primary player in regulation of craniofacial programs of head development in vertebrates. Here we investigate the evolution of a Hoxa2 neural crest enhancer identified originally in mouse by comparing and contrasting the fugu hoxa2a and hoxa2b genes with their orthologous teleost and mammalian sequences. Using sequence analyses in combination with transgenic regulatory assays in zebrafish and mouse embryos we demonstrate subfunctionalization of regulatory activity for expression in hindbrain segments and neural crest cells between these two fugu co-orthologs. hoxa2a regulatory sequences have retained the ability to mediate expression in neural crest cells while those of hoxa2b include cis-elements that direct expression in rhombomeres. Functional dissection of the neural crest regulatory potential of the fugu hoxa2a and hoxa2b genes identify the previously unknown cis-element NC5, which is implicated in generating the differential activity of the enhancers from these genes. The NC5 region plays a similar role in the ability of this enhancer to mediate reporter expression in mice, suggesting it is a conserved component involved in control of neural crest expression of Hoxa2 in vertebrate craniofacial development., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Unlabelled: Otolaryngologic problems are common in the 22q11.2 deletion syndrome (DS) population. Structural anomalies and retrognathia may predispose these patients to obstructive sleep apnea (OSA). The current association of OSA in this population is not defined., Objective: (1) Define the frequency of OSA in 22q11.2 DS patients referred for polysomnography (PSG). (2) Determine if OSA is present before and/or after surgery to correct velopharyngeal insufficiency (VPI). (3) Determine effect of prior adenotonsillectomy on OSA following VPI surgery., Methods: Retrospective review of children treated from 2006 to 2013 in a tertiary care setting identified by ICD-9 758.32 (velocardiofacial syndrome) and 279.11 (DiGeorge syndrome). Surgical history and PSG data were abstracted from the identified records., Results: We identified 323 patients with 22q11.2 DS; 57 (18%) were screened at any point in care using PSG and 15 patients had PSG at multiple time points in care. In most cases, indication for PSG was sleep disordered breathing or pre-operative planning. Overall, 33 patients met criteria for OSA on PSG, accounting for 10.2% of our study population; however, the percentage of patients with OSA was significantly higher within the group of 57 patients (58%) who were screened with PSG. Twenty-one of the screened patients (54%) had PSG prior to any pharyngeal surgery and had mild to severe OSA (obstructive apnea/hypopnea index (AHI): median 5.1/h, range 1.9-25.6). Eighteen patients had PSG after adenotonsillectomy; 8 of these patients (44%) had mild to moderate OSA (median AHI 2.95/h, range 1.9-5.4). Seventeen patients had PSG after VPI surgery (palatopharyngeal flap (PPF) n=16, sphincteroplasty n=1). Nine of these patients (53%) had mild to severe OSA (median AHI 3/h, range 1.9-15). Patients who underwent adenotonsillectomy prior to VPI surgery had similar prevalence of OSA (50%, n=12) than those who did not (OSA: 60%, n=5, p=0.70). Most children had mild OSA., Conclusion: Prevalence of OSA in this population of 22q11.2 DS patients is higher than expected in the general population. OSA risk is highest after VPI surgery, and may be decreased by adenotonsillectomy. Providers should have awareness of increased prevalence of OSA in patients with 22q11.2 DS. Close monitoring for OSA is warranted given the likelihood of subsequent surgical intervention that can worsen OSA., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

Background: Sleepwalking is typically a benign and self-limited non-rapid eye movement parasomnia of childhood., Patient: We describe an unusual 15-year-old boy referred to our sleep center for new-onset sleepwalking., Results: An overnight polysomnogram was normal from a respiratory standpoint, but a concurrent extended electroencephalogram montage showed frequent epileptiform discharges from the right parietal-temporal region and two electroclinical seizures arising from the right-frontal-central-temporal region during sleep. Magnetic resonance imaging scan revealed a right parasagittal parietal region lesion consistent with a low-grade neoplasm, and surgical resection of the lesion demonstrated a right parietal dysembryoplastic neuroepithelial tumor. Complex partial seizures and sleepwalking remitted completely with anticonvulsant therapy following surgery., Conclusions: This patient highlights the differential diagnosis of nocturnal events appearing to be typical parasomnias, especially when they arise abruptly at an older age., (Copyright © 2013 Elsevier Inc. All rights reserved.)

The novel gene ashwin was isolated in a differential display screen for genes activated or up-regulated early in neural specification. ashwin is expressed maternally and zygotically, and it is up-regulated in the neural ectoderm after the midgastrula stage. It is expressed in the neural plate and later in the embryonic brain, eyes, and spinal cord. Overexpression of ashwin in whole embryos leads to anterior truncations and other defects. However, a second Organizer does not form, and the secondary axial structures may result from splitting of the Organizer, rather than axis duplication. Morpholino oligonucleotide-mediated reduction in ashwin expression leads to lethality or abnormalities in gastrulation, as well as significant apoptosis in midgastrula embryos. Apoptosis is also observed in midgastrula embryos overexpressing ashwin. Coexpression of ashwin with the bone morphogenetic protein-4 antagonist noggin has a synergistic effect on neural-specific gene expression in isolated animal cap ectoderm. Ashwin has no previously characterized domains, although two nuclear localization signals can be identified. Orthologues have been identified in the human, mouse, chicken, and pufferfish genomes. Our results suggest that ashwin regulates cell survival and anteroposterior patterning., ((c) 2006 Wiley-Liss, Inc.)

We have previously shown that mitogen-activated protein (MAP) kinase activity is required for neural specification in Xenopus. In mammalian cells, the BMP-4 effector Smad1 is inhibited by phosphorylation at MAP kinase sites (Kretzschmar et al., 1997). To test the hypothesis that MAP kinase inhibits the BMP-4/Smad1 pathway during early Xenopus development, we have generated a Smad1 mutant lacking the MAP kinase phosphorylation sites (M4A-Smad1) and compared the effects of wild-type (WT)- and M4A-Smad1 on axial pattern and neural specification in Xenopus embryos. Although overexpression of either WT- or M4A-Smad1 produced ventralized embryos, at each mRNA concentration, M4A-Smad1 had a greater ventralizing effect than WT-Smad1. Interestingly, overexpression of either form of Smad1 in ventral blastomeres disrupted posterior pattern and morphogenesis; again, more severe defects were produced by expression of M4A-Smad1 than by equal amounts of WT-Smad1. Ectodermal expression of M4A-Smad1 disrupted expression of the anterior neural gene otx2 in vivo and inhibited neural specification in response to endogenous signals in mesoderm-ectoderm recombinates. In contrast, overexpression of WT-Smad1 at identical levels had little effect on either neural specification or otx2 expression. Comparisons of protein levels following overexpression of either WT- or M4A-Smad1 indicate that WT-Smad1 may be slightly more stable than M4A-Smad1; thus, differences in stability cannot account for the increased effectiveness of M4A-Smad1. Our results demonstrate that mutations disrupting the MAPK phosphorylation sites act collectively as a gain-of-function mutation in Smad1 and that inhibitory phosphorylation of Smad1 may be a significant mechanism for the regulation of BMP-4/Smad1 signals during Xenopus development.