Epidemiology of childhood acute myeloid leukemia

The Clinical Profile of Newly Diagnosed Acute Myeloid Leukemia at a Tertiary Care Center in South India: A Cross-Sectional Study

Background and objective Acute myeloid leukemia (AML) is a heterogeneous and aggressive blood malignancy prevalent among both children and adults, accounting for a significant proportion of acute leukemia cases worldwide. Our study aimed to shed light on the demographic and clinical profile and risk stratification of newly diagnosed AML cases at a tertiary care government hospital in South India. Methods We conducted a cross-sectional study involving 221 patients with AML in the Department of Clinical Hematology, Rajiv Gandhi Government General Hospital and Madras Medical College, Chennai, Tamil Nadu from January 2020 to December 2022. All data were collected from the hospital database of patients' medical records. A thorough analysis of clinical history, comorbidities, laboratories, risk stratification, and chemotherapy regimen was performed. The patients included in the study were newly diagnosed cases of AML over the age of 13 years, and we excluded all the relapsed cases. Results The highest proportion of patients were in the age group of 41-50 years (22.2%), and there was a significant male predominance (55.7%) in the cohort. Occupationwise, 31% of the study population were farmers, followed by housewives (16.3%). While no identifiable risk factors for AML were found in 191 cases (86.4%), 4.1% had undergone previous chemotherapy, and 3.6% had myelodysplastic syndrome (MDS). Hyperuricemia was noted in 50 cases (22.6%) while 8.6% had tumor lysis syndrome (TLS). About 53.8% of cases fell in the intermediate risk category of AML. Standard induction chemotherapy was administered in 87.3% of cases of AML. Conclusions Gaining awareness and knowledge about the regional demographic data and clinical presentation of AML will aid in the early detection, prompt referral, and initiation of treatment, thereby further improving patient outcomes in the era of targeted therapy and hematopoietic stem cell transplantation.

Exposure to persistent organic pollutants in newborn dried blood spots and childhood acute myeloid leukemia

Acute myeloid leukemia (AML) is a rare malignancy representing 15-20% of all leukemia diagnoses among children. Maternal exposure to persistent organic pollutants is suggestive of increased risk for childhood AML based on existing evidence. We aimed to evaluate the relationship between persistent organic pollutants and childhood AML using newborn dried bloodspots (DBS) from the Michigan BioTrust for Health. We obtained data on AML cases diagnosed prior to 15 years of age (n = 130) and controls (n = 130) matched to cases on week of birth from the Michigan Department of Health and Human Services. We quantified levels of dichlorodiphenyldichloroethylene (p,p'-DDE), hexachlorobenzene (HCB), and polybrominated diphenyl ether congener 47 (BDE-47) in newborn DBS. We also evaluated other organochlorine pesticides, polychlorinated biphenyls, polybrominated biphenyl congener 153, and polybrominated diphenyl ethers, though these were not further evaluated as >60% of observations were above the limit of detection for these chemicals. To evaluate the association between each chemical and AML, we used multivariable conditional logistic regression. In our multivariable model of HCB adjusted for month of birth, maternal age at delivery, and area poverty, we observed no association with AML (Odds Ratio [OR] per interquartile range increase: 1.17, 95% CI: 0.80, 1.69). For p,p'-DDE, ORs were significantly lower for those exposed to the highest tertile of p,'p-DDE (≥0.29 pg/mL, OR: 0.32, 95% CI: 0.11, 0.95) compared to the first tertile (<0.09 pg/mL). We observed no statistically significant associations between HCB and BDE-47 and AML. We observed a reduced odds of exposure to p,'p-DDE and an increased, though imprecise, odds of exposure to HCB among AML cases compared to controls. Future studies would benefit from a larger sample of AML patients and pooling newborn DBS across multiple states to allow for additional variability in exposures and evaluation of AML subtypes, which may have differing etiology.

Addressing a Pre-Clinical Pipeline Gap: Development of the Pediatric Acute Myeloid Leukemia Patient-Derived Xenograft Program at Texas Children's Hospital at Baylor College of Medicine

The survival rate of pediatric acute myeloid leukemia (pAML) is currently around 60%. While survival has slowly increased over the past few decades, the development of novel agents likely to further improve survival for this heterogeneous patient population has been limited by gaps in the pAML pre-clinical pipeline. One of the major hurdles in evaluating new agents for pAML is the lack of pAML patient-derived xenograft (PDX) models. Unlike solid tumors and other types of leukemias, AML is notoriously hard to establish in mouse models, likely due in part to the need for specific human microenvironment elements. Our laboratory at TCH/BCM addressed this gap by establishing a systematic PDX workflow, leveraging advanced immunodeficient hosts and capitalizing on our high volume of pAML patients and close coordination between labs and clinical sections. Patients treated at TCH are offered the chance to participate in specimen banking protocols that allow blood and bone marrow collection as well as the collection of relevant clinical data. All patients who consent and have samples available are trialed for PDX development. In addition, samples from the Children's Oncology Group (COG) are also trialed for PDX generation. Serially transplanting PDX models are validated using short tandem repeat (STR) and characterized using both targeted DNA/RNA next generation sequencing and RNAseq. As of March 2023, this systematic approach has resulted in 26 serially transplanting models. Models have been shared with requesting labs to facilitate external pAML pre-clinical studies. Available PDX models can be located through the BCM PDX Portal. We expect our growing PDX resource to make a significant contribution to expediting the testing of promising novel therapeutics for pAML.

Treatment outcome and prognostic factors in relapsed pediatric acute myeloid leukemia

Background

Despite improved outcomes for pediatric patients with acute myeloid leukemia (AML), the prognosis for relapse remains poor. This study aimed to examine the clinical factors associated with prognosis in relapsed pediatric AML.

Methods

We conducted a chart review of pediatric patients with AML who experienced their first relapse and received treatment at our institution between 2008 and 2019. Risk stratification at diagnosis was performed according to the definition suggested by the ongoing AML 2012 study in Korea, and the clinical factors associated with prognosis were analyzed.

Results

A total of 27 pediatric patients with relapsed AML were identified. The 5-year overall survival (OS) and event-free survival (EFS) rates were 32.9% and 32.9%, respectively. A duration ≥12 months from diagnosis to relapse had a favorable impact on survival outcomes (5-yr OS, 64.0% vs. 15.7%; P=0.007). Patients who achieved complete remission (CR) after 1 course of chemotherapy following relapse (N=15) had a 5-year OS rate of 59.3%, while none of the other patients survived (P＜0.0001). Additionally, the 5-year OS differed significantly based on the risk group at initial diagnosis (62.3% [favorable and intermediate prognosis groups, N=11] vs. 13.3% [poor prognosis group, N=15]; P=0.014).

Conclusion

Patients with a longer duration of CR before relapse, who achieved CR following 1 course of reinduction chemotherapy, and were in the favorable or intermediate prognosis group at diagnosis demonstrated better outcomes. These findings emphasize the importance of tailoring treatment strategies based on the expected prognosis at relapse in pediatric patients with AML.

Therapeutic targeting in pediatric acute myeloid leukemia with aberrant HOX/MEIS1 expression

Despite advances in the clinical management of childhood acute myeloid leukemia (AML) during the last decades, outcome remains fatal in approximately one third of patients. Primary chemoresistance, relapse and acute and long-term toxicities to conventional myelosuppressive therapies still constitute significant challenges and emphasize the unmet need for effective targeted therapies. Years of scientific efforts have translated into extensive insights on the heterogeneous spectrum of genetics and oncogenic signaling pathways of AML and identified a subset of patients characterized by upregulation of HOXA and HOXB homeobox genes and myeloid ecotropic virus insertion site 1 (MEIS1). Aberrant HOXA/MEIS1 expression is associated with genotypes such as rearrangements in Histone-lysine N-methyltransferase 2A (KMT2A-r), nucleoporin 98 (NUP98-r) and mutated nucleophosmin (NPM1c) that are found in approximately one third of children with AML. AML with upregulated HOXA/MEIS1 shares a number of molecular vulnerabilities amenable to recently developed molecules targeting the assembly of protein complexes or transcriptional regulators. The interaction between the nuclear scaffold protein menin and KMT2A has gained particular interest and constitutes a molecular dependency for maintenance of the HOXA/MEIS1 transcription program. Menin inhibitors disrupt the menin-KMT2A complex in preclinical models of KMT2A-r, NUP98-r and NPM1c acute leukemias and its occupancy at target genes leading to leukemic cell differentiation and apoptosis. Early-phase clinical trials are either ongoing or in development and preliminary data suggests tolerable toxicities and encouraging efficacy of menin inhibitors in adults with relapsed or refractory KMT2A-r and NPM1c AML. The Pediatric Acute Leukemia/European Pediatric Acute Leukemia (PedAL/EUPAL) project is focused to advance and coordinate informative clinical trials with new agents and constitute an ideal framework for testing of menin inhibitors in pediatric study populations. Menin inhibitors in combination with standard chemotherapy or other targeting agents may enhance anti-leukemic effects and constitute rational treatment strategies for select genotypes of childhood AML, and provide enhanced safety to avoid differentiation syndrome. In this review, we discuss the pathophysiological mechanisms in KMT2A-r, NUP98-r and NPM1c AML, emerging molecules targeting the HOXA/MEIS1 transcription program with menin inhibitors as the most prominent examples and future therapeutic implications of these agents in childhood AML.

Environmental Risk Factors for Pediatric Acute Leukemia: Methodology and Early Findings

Background

Acute leukemia is the most common type of malignancy in children, and no major environmental risk factors have been identified relating to its pathogenesis. This study has been conducted with the aim for identifying risk factors associated with this disease.

Methods

This study was conducted in 2016-2020 among children aged <15 years residing in Isfahan Province, Iran. Children with newly diagnosed Acute lymphoblastic leukemia, including Acute myeloid leukemia (ALL and AML) were considered a case group. The control group was selected among children hospitalized in orthopedic and surgery wards in the same region. Demographic data, parental occupational exposures and educational level, maternal obstetric history, type of feeding during infancy and parental smoking habits, exposure to pesticides, and hydrocarbons besides dietary habits (using a food frequency questionnaire) were evaluated.

Results

Overall, 497 children (195 cases and 302 controls) completed the survey. In the initial analysis, there was no significant difference between case and control groups about type of milk feeding (P = 0.34) or parental age (P = 0.56); however, an association between mothers' education and increased risk for ALL was observed (P = 0.02).

Conclusions

The results of this study can be helpful in better understanding the environmental risk factors involved in the incidence of acute leukemia. Future publications based on the analysis of the database created in the present study can lead to recognizing these factors. In addition, evaluating the effect of these factors on treatment outcomes is an important step in reducing the burden of the disease.

Genomic alterations in a cohort of pediatric acute myeloid leukemia patients at two cancer centers in Colombia

Few studies identifying genomic aspects in pediatric acute myeloid leukemia patients in Latin American countries have been reported. The aim of this study was to identify genomic alterations, clinical characteristics and outcomes in a cohort of pediatric AML patients. This descriptive observational cohort study included patients with confirmed de novo acute myeloid leukemia up to 18 years of age. Cytogenetics and conventional FISH analysis, next-generation sequencing and PCR testing were performed. The correlation of genomic data with treatment response and outcomes were analyzed. Of the 51 patients analyzed, 67.4% had a cytogenetic abnormality and 74.5% had a genetic variant. FLT3 variants (ITD or TKD D835) were found in 27.4%, followed by NRAS (21.6%), KRAS (13.7%) and WT1 and KIT (11.8%). Patients were stratified by risk (66.6% high-risk) after the end of induction. FLT3-ITD was associated with relapse (OR 11.25; CI 1.89-66.72, p 0.006) and NRAS with death during induction (OR 16.71; CI 1.51-184.59, p 0.022). Our study highlights the importance of rapid incorporation of genetic testing in pediatric AML in Colombia, as it directly affects treatment decisions and outcomes. Incorporation of targeted therapies with conventional chemotherapy is an increasingly urgent need in pediatric patients.

Distinct noncoding RNAs and RNA binding proteins associated with high-risk pediatric and adult acute myeloid leukemias detected by regulatory network analysis

BACKGROUND

Acute myeloid leukemia (AML) is a heterogeneous disease in both children and adults. Although it is well-known that adult and pediatric AMLs are genetically distinct diseases, the driver genes for high-risk pediatric and adult AMLs are still not fully understood. Particularly, the interactions between RNA binding proteins (RBPs) and noncoding RNAs (ncRNAs) for high-risk AMLs have not been explored.

AIM

To identify RBPs and noncoding RNAs (ncRNAs) that are the master regulators of high-risk AML.

METHODS

In this manuscript, we identify over 400 upregulated genes in high-risk adult and pediatric AMLs respectively with the expression profiles of TCGA and TARGET cohorts. There are less than 5% genes commonly upregulated in both cohorts, highlighting the genetic differences in adult and childhood AMLs. A novel distance correlation test is proposed for gene regulatory network construction. We build RBP-based regulatory networks with upregulated genes in high-risk adult and pediatric AMLs, separately.

RESULTS

We discover that three RBPs, three snoRNAs, and two circRNAs function together and regulate over 100 upregulated RNA targets in adult AML, whereas two RBPs are associated with 17 long noncoding RNAs (lncRNAs), and all together regulate over 90 upregulated RNA targets in pediatric AML. Of which, two RBPs, MLLT3 and RBPMS, and their circRNA targets, PTK2 and NRIP1, are associated with the overall survival (OS) in adult AML (p ≤ 0.01), whereas two different RBPs, MSI2 and DNMT3B, and 13 (out of 17) associated lncRNAs are prognostically significant in pediatric AML.

CONCLUSIONS

Both RBPs and ncRNAs are known to be the major regulators of transcriptional processes. The RBP-ncRNA pairs identified from the regulatory networks will allow better understanding of molecular mechanisms underlying high-risk adult and pediatric AMLs, and assist in the development of novel RBPs and ncRNAs based therapeutic strategies.

Persistently high incidence rates of childhood acute leukemias from 2010 to 2017 in Mexico City: A population study from the MIGICCL

Introduction

Over the years, the Hispanic population living in the United States has consistently shown high incidence rates of childhood acute leukemias (AL). Similarly, high AL incidence was previously observed in Mexico City (MC). Here, we estimated the AL incidence rates among children under 15 years of age in MC during the period 2010-2017.

Methods

The Mexican Interinstitutional Group for the Identification of the Causes of Childhood Leukemia conducted a study gathering clinical and epidemiological information regarding children newly diagnosed with AL at public health institutions of MC. Crude age incidence rates (cAIR) were obtained. Age-standardized incidence rates worldwide (ASIRw) and by municipalities (ASIRm) were calculated by the direct and indirect methods, respectively. These were reported per million population <15 years of age; stratified by age group, sex, AL subtypes, immunophenotype and gene rearrangements.

Results

A total of 903 AL cases were registered. The ASIRw was 63.3 (cases per million) for AL, 53.1 for acute lymphoblastic leukemia (ALL), and 9.4 for acute myeloblastic leukemia. The highest cAIR for AL was observed in the age group between 1 and 4 years (male: 102.34 and female: 82.73). By immunophenotype, the ASIRw was 47.3 for B-cell and 3.7 for T-cell. The incidence did not show any significant trends during the study period. The ASIRm for ALL were 68.6, 66.6 and 62.8 at Iztacalco, Venustiano Carranza and Benito Juárez, respectively, whereas, other municipalities exhibited null values mainly for AML.

Conclusion

The ASIRw for childhood AL in MC is among the highest reported worldwide. We observed spatial heterogeneity of rates by municipalities. The elevated AL incidence observed in Mexican children may be explained by a combination of genetic background and exposure to environmental risk factors.

Hemophagocytic Lymphohistiocytosis in the Setting of Therapy-Induced Acute Myeloid Leukemia: An Autopsy Report

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening hyper-inflammatory disorder that occurs due to immunologic dysregulation. HLH can be primary (hereditary) or secondary to infections, autoimmune diseases, immune deficiencies, metabolic diseases, drugs, or malignancies. Lymphoid neoplasms mostly accompany malignancy-associated HLH. We present a case of a 12-year-old boy with a history of precursor B lymphoblastic leukemia (B-ALL), who subsequently developed chemotherapy-induced acute myeloid leukemia (t-AML). The patient was admitted for febrile neutropenia and initial laboratory tests revealed hemophagocytic lymphohistiocytosis (HLH). The hospital course was complicated by multiple infections and septic shock. The patient received several broad-spectrum antimicrobials, dexamethasone, as well as a pericardial drain to drain the hemorrhagic pericardial effusion. Despite intervention, the patient expired, and an autopsy was performed. We provide a synopsis of the main autopsy findings.

Ferroptosis-related gene signature predicts the clinical outcome in pediatric acute myeloid leukemia patients and refines the 2017 ELN classification system

Background: The prognostic roles of ferroptosis-related mRNAs (FG) and lncRNAs (FL) in pediatric acute myeloid leukemia (P-AML) patients remain unclear.

Methods: RNA-seq and clinical data of P-AML patients were downloaded from the TARGET project. Cox and LASSO regression analyses were performed to identify FG, FL, and FGL (combination of FG and FL) prognostic models, and their performances were compared. Tumor microenvironment, functional enrichment, mutation landscape, and anticancer drug sensitivity were analyzed.

Results: An FGL model of 22 ferroptosis-related signatures was identified as an independent parameter, and it showed performance better than FG, FL, and four additional public prognostic models. The FGL model divided patients in the discovery cohort (N = 145), validation cohort (N = 111), combination cohort (N = 256), and intermediate-risk group (N = 103) defined by the 2017 European LeukemiaNet (ELN) classification system into two groups with distinct survival. The high-risk group was enriched in apoptosis, hypoxia, TNFA signaling via NFKB, reactive oxygen species pathway, oxidative phosphorylation, and p53 pathway and associated with low immunity, while patients in the low-risk group may benefit from anti-TIM3 antibodies. In addition, patients within the FGL high-risk group might benefit from treatment using SB505124_1194 and JAK_8517_1739.

Conclusion: Our established FGL model may refine and provide a reference for clinical prognosis judgment and immunotherapies for P-AML patients.

Cancer incidence in indigenous populations of Western Amazon, Brazil

OBJECTIVES

This study aims to estimate a population-based cancer incidence among indigenous populations in the State of Acre, Brazilian Western Amazon, to provide knowledge about cancer epidemiological profiles contributing to healthcare policies and service planning. Although cancer epidemiology in Brazil is well described through incidence and mortality estimate in the general population, cancer estimates among indigenous peoples are still unknown.

DESIGN

This is a descriptive study of cancer incidence among the indigenous population (2000-2012) in the State of Acre, Brazil. The sources used were population-based cancer registries of Goiânia, hospital-based cancer registry of Acre, São Paulo, and Porto Velho; Special Indigenous Health Districts databases of Acre, Goiânia, and São Paulo; Mortality Information System, and Rio Branco's public and private laboratories' reports. Standardized Incidence Ratio (SIR) was calculated using cancer incidence rates of Goiânia as reference.

RESULTS

From 137 cancer cases, 51.8% occurred in women and 32.1% in people aged 70 + . Among men, the most frequent cancer sites were stomach (25.8%), liver (15.1%), colorectal (7.6%), leukemia (7.6%), and prostate (6.1%). Among women, the most frequent were cervical (50.7%), stomach (8.5%), leukemia (5.6%), liver (4.3%), and breast (4.3%). Among men, there was an excess of cancer cases for stomach (SIR=1.75; 95%CI:1.67-1.83), liver (SIR=1.77; 95%CI:1.66-1.88), and leukemia (SIR=1.64; 95%CI:1.49-1.78). In women, an excess of cancer cases was observed for cervical (SIR=4.49; 95%CI:4.34-4.64) and liver (SIR=2.11; 95%CI:1.88-2.34). A lower cancer incidence for prostate (SIR=0.06; 95%CI:0.05-0.07) and female breast (SIR=0.12; 95%CI:0.11-0.14) was observed.

CONCLUSIONS

Cervical, stomach, and liver cancers corresponded to 52% of the cases and were highly incident among the Brazilian indigenous population of Western Amazon compared to non-indigenous counterparts. Despite the low frequency of breast and prostate cancer, the fact they were present among indigenous peoples suggests a complex epidemiological transition framework in these populations.

Studying the potential of upregulated PTGS2 and VEGF-C besides hyper-methylation of PTGS2 promoter as biomarkers of Acute myeloid leukemia

Hereby, we aimed to investigate the expression of prostaglandin-endoperoxide synthase 2 (PTGS2) and Vascular Endothelial Factor-C (VEGF-C) besides the methylation of PTGS2 in AML patients. VEGF-C and PTGS2 expression analysis were evaluated in newly diagnosed AML patients and healthy controls by quantitative Reverse Transcriptase PCR method. Also, PTGS2 methylation status was evaluated by Methylation-Sensitive High-Resolution Melting Curve Analysis (MS-HRM). While 34% of patients were female, the mean age of the patients was 43.41 ± 17.60 years suffering mostly from M4 (48.21%) type of AML. Although methylation level between patients and controls was not significantly different, none of the normal controls showed methylation in the PTGS2 promoter. PTGS2 and VEGF-C levels were elevated in AML cases and correlated with WBC, Platelet, and Hemoglobin levels. The survival of patients with overexpressed VEGF-C and PTGS2 was poorer than others. It can be concluded that PTGS2 and especially VEGF-C expression but not PTGS2 methylation can be considered as diagnostic biomarkers for AML.

High-Risk Acute Myeloid Leukemia: A Pediatric Prospective

Pediatric acute myeloid leukemia is a clonal disorder characterized by malignant transformation of the hematopoietic stem cell. The incidence and the outcome remain inferior when compared to pediatric ALL, although prognosis has improved in the last decades, with 80% overall survival rate reported in some studies. The standard therapeutic approach is a combined cytarabine and anthracycline-based regimen followed by consolidation with allogeneic stem cell transplantation (allo-SCT) for high-risk AML and allo-SCT for non-high-risk patients only in second complete remission after relapse. In the last decade, several drugs have been used in clinical trials to improve outcomes in pediatric AML treatment.

2-Hydroxyglutarate in Acute Myeloid Leukemia: A Journey from Pathogenesis to Therapies

The oncometabolite 2-hydroxyglutarate (2-HG) plays a key role in differentiation blockade and metabolic reprogramming of cancer cells. Approximatively 20–30% of acute myeloid leukemia (AML) cases carry mutations in the isocitrate dehydrogenase (IDH) enzymes, leading to a reduction in the Krebs cycle intermediate α-ketoglutarate (α-KG) to 2-HG. Relapse and chemoresistance of AML blasts following initial good response to standard therapy account for the very poor outcome of this pathology, which represents a great challenge for hematologists. The decrease of 2-HG levels through pharmacological inhibition of mutated IDH enzymes induces the differentiation of AML blasts and sensitizes leukemic cells to several anticancer drugs. In this review, we provide an overview of the main genetic mutations in AML, with a focus on IDH mutants and the role of 2-HG in AML pathogenesis. Moreover, we discuss the impact of high levels of 2-HG on the response of AML cells to antileukemic therapies and recent evidence for highly efficient combinations of mutant IDH inhibitors with other drugs for the management of relapsed/refractory (R/R) AML.

Infant Feeding Practices And Childhood Acute Leukemia: Findings From The Childhood Cancer & Leukemia International Consortium

Increasing evidence suggests that breastfeeding may protect from childhood acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). However, most studies have limited their analyses to any breastfeeding, and only a few data have examined exclusive breastfeeding, or other exposures such as formula milk. We performed pooled analyses and individual participant data meta-analyses of data from sixteen studies (N=17,189 controls; N=10,782 ALL and N=1,690 AML cases) from the Childhood Leukemia International Consortium (CLIC) to characterize the associations of breastfeeding duration with ALL and AML, as well as exclusive breastfeeding duration and age at introduction to formula with ALL. In unconditional multivariable logistic regression analyses of pooled data, we observed decreased odds of ALL among children breastfed 4-6 months (0.88, 95% CI 0.81-0.96) or 7-12 months (OR 0.85, 0.79-0.92). We observed a similar inverse association between breastfeeding ≥4 months and AML (0.82, 95% CI 0.71-0.95). Odds of ALL were reduced among children exclusively breastfed 4-6 months (OR 0.73, 95% CI 0.63-0.85) or 7-12 months (OR 0.70, 95% CI 0.53-0.92). Random effects meta-analyses produced similar estimates, and findings were unchanged in sensitivity analyses adjusted for race/ethnicity or mode of delivery, restricted to children diagnosed ≥1 year of age, or diagnosed with B-ALL. Our pooled analyses indicate that longer breastfeeding is associated with decreased odds of ALL and AML. Few risk factors for ALL and AML have been described, therefore our findings highlight the need to promote breastfeeding for leukemia prevention.

Increasing Complexity of Molecular Landscapes in Human Hematopoietic Stem and Progenitor Cells during Development and Aging

The past five decades have seen significant progress in our understanding of human hematopoiesis. This has in part been due to the unprecedented development of advanced technologies, which have allowed the identification and characterization of rare subsets of human hematopoietic stem and progenitor cells and their lineage trajectories from embryonic through to adult life. Additionally, surrogate in vitro and in vivo models, although not fully recapitulating human hematopoiesis, have spurred on these scientific advances. These approaches have heightened our knowledge of hematological disorders and diseases and have led to their improved diagnosis and therapies. Here, we review human hematopoiesis at each end of the age spectrum, during embryonic and fetal development and on aging, providing exemplars of recent progress in deciphering the increasingly complex cellular and molecular hematopoietic landscapes in health and disease. This review concludes by highlighting links between chronic inflammation and metabolic and epigenetic changes associated with aging and in the development of clonal hematopoiesis.

Donor memory-like NK cells persist and induce remissions in pediatric patients with relapsed AML after transplant

Pediatric and young adult (YA) patients with acute myeloid leukemia (AML) who relapse after allogeneic hematopoietic cell transplantation (HCT) have an extremely poor prognosis. Standard salvage chemotherapy and donor lymphocyte infusions (DLIs) have little curative potential. Previous studies showed that natural killer (NK) cells can be stimulated ex vivo with interleukin-12 (IL-12), -15, and -18 to generate memory-like (ML) NK cells with enhanced antileukemia responses. We treated 9 pediatric/YA patients with post-HCT relapsed AML with donor ML NK cells in a phase 1 trial. Patients received fludarabine, cytarabine, and filgrastim followed 2 weeks later by infusion of donor lymphocytes and ML NK cells from the original HCT donor. ML NK cells were successfully generated from haploidentical and matched-related and -unrelated donors. After infusion, donor-derived ML NK cells expanded and maintained an ML multidimensional mass cytometry phenotype for >3 months. Furthermore, ML NK cells exhibited persistent functional responses as evidenced by leukemia-triggered interferon-γ production. After DLI and ML NK cell adoptive transfer, 4 of 8 evaluable patients achieved complete remission at day 28. Two patients maintained a durable remission for >3 months, with 1 patient in remission for >2 years. No significant toxicity was experienced. This study demonstrates that, in a compatible post-HCT immune environment, donor ML NK cells robustly expand and persist with potent antileukemic activity in the absence of exogenous cytokines. ML NK cells in combination with DLI present a novel immunotherapy platform for AML that has relapsed after allogeneic HCT. This trial was registered at https://clinicaltrials.gov as #NCT03068819.

Blood Count Recovery Following Induction Therapy for Acute Myeloid Leukemia in Children Does Not Predict Survival

Simple Summary

International Working Group (IWG) and European LeukemiaNet (ELN) adult response definitions are currently used to evaluate the efficacy of new agents for childhood acute myeloid leukemia (AML); however, the criteria are not consistent with consensus definitions used in pediatric trials or the common practice of intensifying treatment prior to full hematopoietic recovery of ANC ≥ 1000 cells/μL and platelets ≥ 100 cells/μL. This retrospective analysis of the two most recent Phase 3 AML trials in the Children’s Oncology Group assesses the incidence, timing, and prognostic significance of count recovery following induction chemotherapy in children with AML. These data confirm that awaiting count recovery to meet adult criteria does not reflect standard practice in pediatric AML and IWG/ELN-defined CR does not have a significant impact on survival in children. Continuing to use adult IWG/ELN count recovery definitions limits childhood AML drug development by underestimating response, and therefore, updated response criteria are needed for pediatric AML patients.

Abstract

International Working Group (IWG) and European LeukemiaNet (ELN) response definitions are utilized to evaluate the efficacy of new agents for childhood acute myeloid leukemia (AML) for regulatory purposes. However, these criteria are not consistent with definitions used in pediatric AML trials or with standard pediatric practice to proceed with subsequent therapy cycles prior to IWG/ELN-defined count recovery. We retrospectively analyzed data from the two most recent Phase 3 pediatric AML clinical trials conducted by the Children’s Oncology Group (COG) to assess the incidence, timing, and prognostic significance of count recovery following induction chemotherapy. Of the patients with fewer than 5% bone marrow blasts at the end of first induction, 21.5% of patients proceeded to a second induction cycle prior to achieving ANC ≥ 500 cells/μL and platelets ≥ 50,000 cells/μL, both well below the IWG/ELN thresholds of ANC > 1000 cells/μL and platelets > 100,000 cells/μL. In these two sequential childhood AML Phase 3 trials, neither ANC nor platelet recovery predicted survival. Intensification of treatment through the initiation of subsequent therapy cycles prior to attainment of IWG/ELN-defined CR is common practice in clinical trials for children with AML, suggesting that updated response definitions are needed for pediatric AML.

Acute myeloid leukaemia presenting as proptosis in an infant

Paediatric patients with acute myeloid leukaemia (AML) often present with symptoms associated with the disruption of normal haematopoiesis and subsequent cellular deficiencies. Periosteal reactions are common in paediatric leukaemia, but typically manifest as a thin, laminated pattern along long bones. Aggressive periosteal reactions are much less frequently seen. Here, we report a case of paediatric AML initially presenting with proptosis and periorbital swelling caused by aggressive, sunburst periosteal reactions surrounding the sphenoid and zygomatic bones. This unique presentation emphasises the importance of considering leukaemic infiltration in the differential for sunburst periosteal reaction in paediatric patients.

A Role for the Bone Marrow Microenvironment in Drug Resistance of Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is a heterogeneous disease with a poor prognosis and remarkable resistance to chemotherapeutic agents. Understanding resistance mechanisms against currently available drugs helps to recognize the therapeutic obstacles. Various mechanisms of resistance to chemotherapy or targeted inhibitors have been described for AML cells, including a role for the bone marrow niche in both the initiation and persistence of the disease, and in drug resistance of the leukemic stem cell (LSC) population. The BM niche supports LSC survival through direct and indirect interactions among the stromal cells, hematopoietic stem/progenitor cells, and leukemic cells. Additionally, the BM niche mediates changes in metabolic and signal pathway activation due to the acquisition of new mutations or selection and expansion of a minor clone. This review briefly discusses the role of the BM microenvironment and metabolic pathways in resistance to therapy, as discovered through AML clinical studies or cell line and animal models.

The Fetal-to-Adult Hematopoietic Stem Cell Transition and its Role in Childhood Hematopoietic Malignancies

As with most organ systems that undergo continuous generation and maturation during the transition from fetal to adult life, the hematopoietic and immune systems also experience dynamic changes. Such changes lead to many unique features in blood cell function and immune responses in early childhood. The blood cells and immune cells in neonates are a mixture of fetal and adult origin due to the co-existence of both fetal and adult types of hematopoietic stem cells (HSCs) and progenitor cells (HPCs). Fetal blood and immune cells gradually diminish during maturation of the infant and are almost completely replaced by adult types of cells by 3 to 4 weeks after birth in mice. Such features in early childhood are associated with unique features of hematopoietic and immune diseases, such as leukemia, at these developmental stages. Therefore, understanding the cellular and molecular mechanisms by which hematopoietic and immune changes occur throughout ontogeny will provide useful information for the study and treatment of pediatric blood and immune diseases. In this review, we summarize the most recent studies on hematopoietic initiation during early embryonic development, the expansion of both fetal and adult types of HSCs and HPCs in the fetal liver and fetal bone marrow stages, and the shift from fetal to adult hematopoiesis/immunity during neonatal/infant development. We also discuss the contributions of fetal types of HSCs/HPCs to childhood leukemias.

Effects of Lifestyle and Environmental Factors on the Risk of Acute Myeloid Leukemia: Result of a Hospital-based Case-Control Study

Background: Acute myeloid leukemia (AML) is a common malignancy in adults. A vast variety of environmental and lifestyle factors play a role in AML incidence. This study aimed to assess the factors related to AML.

Study design: A case-control study.

Methods: This case-control study was performed on 137 AML cases during 2018-2021 at Beheshti Hospital in Hamadan, Iran, and 137 gender/age-matched controls. A questionnaire including 12 items was used to obtain information about lifestyle and environmental factors. A univariate and multiple variate logistic regression was used to estimate the odds ratios (OR), and a 95% confidence interval (CI) was used to investigate the relationship between the studied variables and the incidence of AML.

Results: Based on findings, 62 (45.3%) out of the 137 leukemic cases were male and 75 (4.7%) were females. A statistically significant increased risk for AML was found with regard to prior usage of cytotoxic agents (OR: 8.00, 95% CI: 1.01, 63.9, P=0.050), family history of malignancies (OR: 3.62, 95% CI: 1.65, 7.92, P=0.001), exposure to electrical power (OR: 3.22, 95% CI: 1.52, 6.81, P=0.002), and history of mental diseases (OR: 8.50, 95% CI: 3.64, 19.80, P=0.001). It was found that the AML incidence had no association with age, gender, radiation therapy, cigarette smoking, prior chemotherapy, congenital disorders, exposure to chemical agents, history of infectious mononucleosis, exercise, and blood transfusion (P>0.05).

Conclusion: The current results suggested that cytotoxic agents, family history of malignancy, mental disorders, and exposure to electrical power could play a role in AML incidence.

Etiology of Acute Leukemia: A Review

Simple Summary

Acute leukemias are some of the most common cancers affecting all age groups. Despite a significant improvement made in the treatment of acute leukemias, their cause remains unknown. A number of genetic and environmental factors for the development of acute leukemias have been proposed, but none have been proven. Undoubtedly, genetics have a major role in the development of these diseases. The effects of a variety of environmental factors, occupations and hobbies have been explored. A recent “two-hit” theory” for the development of acute lymphoblastic leukemia has been proposed. This combines genetic factors and exposure to infections for the development of this disease. Several genetic factors are suggested. Most recently, for the infection portion, exposure to a virus containing Aspergillus Flavus has been proposed. This review summarizes what is currently known about the factors that are proposed for the development of acute leukemias.

Abstract

Acute leukemias constitute some of the most common malignant disorders. Despite significant progress made in the treatment of these disorders, their etiology remains unknown. A large and diverse group of genetic and environmental variables have been proposed. The role of a variety of factors, including pre-existing and acquired genetic mutations, exposure to radiation and various chemicals during preconception, pregnancy and throughout life, have been explored. The effects of inherited genetic variations and disorders, pre-existing diseases, infectious agents, hobbies, occupations, prior treatments, and a host of other factors have been proposed, but none is universally applicable to all cases. Variation in the incidence and prognosis based on the age, sex, race, type of the disease, geographic area of residence and other factors are intriguing but remain unexplained. Advances in genomic profiling, including genome-wide gene expression, DNA copy number and single nucleotide polymorphism (SNP) genotype, may shed some light on the role of genetics in these disparities. Separate two-hit hypotheses for the development of acute myeloblastic and lymphoblastic leukemia have been proposed. The latter combines genetics and infection factors resulting in leukemogenesis. A number of pre- and post-natal environmental conditions and exposure to infections, including a mycovirus infected Aspergillus flavus, have been suggested. The exact nature, timing, sequence of the events and mechanisms resulting in the occurrence of leukemia requires further investigations. This review summarizes some of the above factors in acute lymphoblastic and myeloblastic leukemias and the direction for future research on the etiology of these disorders.

Untargeted metabolomics of newborn dried blood spots reveals sex-specific associations with pediatric acute myeloid leukemia

The etiology of pediatric acute myeloid leukemia (AML) is largely unknown, but evidence for mutations in utero and long latency periods suggests that environmental factors play a role. Therefore, we used untargeted metabolomics of archived newborn dried blood spots (DBS) to investigate neonatal exposures as potential causal risk factors for AML. Untargeted metabolomics profiling was performed on DBS punches from 48 pediatric patients with AML and 46 healthy controls as part of the California Childhood Leukemia Study (CCLS). Because sex disparities are suggested by differences in AML incidence rates, metabolite features associated with AML were identified in analyses stratified by sex. There was no overlap between the 16 predictors of AML in females and 15 predictors in males, suggesting that neonatal metabolomic profiles of pediatric AML risk are sex-specific. In females, four predictors of AML were putatively annotated as ceramides, a class of metabolites that has been linked with cancer cell proliferation. In females, two metabolite predictors of AML were strongly correlated with breastfeeding duration, indicating a possible biological link between this putative protective risk factor and childhood leukemia. In males, a heterogeneous metabolite profile of AML predictors was observed. Replication with larger participant numbers is required to validate findings.

The Prenatal Origin of Childhood Leukemia: Potential Applications for Epidemiology and Newborn Screening

Childhood leukemias are heterogeneous diseases with widely differing incident rates worldwide. As circulating tumors, childhood acute leukemias are uniquely accessible, and their natural history has been described in greater detail than for solid tumors. For several decades, it has been apparent that most cases of childhood acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML) initiate in utero. Circumstantial evidence in support of this contention includes the young age of onset and high rate of concordance among identical twins. "Backtracking" of leukemic somatic mutations, particularly gene translocations, to cord blood and dried blood spots collected during the perinatal period has provided molecular proof of prenatal leukemogenesis. Detection of a patient's leukemia translocation in easily accessible birth samples, such as dried blood spots, is straightforward with the knowledge of their idiosyncratic breakpoints. However, to translate these findings into population-based screening and leukemia prevention requires novel methods able to detect translocations at all possible breakpoints when present in a low frequency of cells. Several studies have attempted to screen for leukemic translocations, mainly the common ETV6-RUNX1 translocation, in cord blood samples from healthy children. Most studies have reported finding translocations in healthy children, but estimates of prevalence have varied widely and greatly exceed the incidence of leukemia, leading to concerns that technical artifact or contamination produced an artificially inflated estimate of translocation prevalence at birth. New generation techniques that capture the presence of these translocations at birth have the potential to vastly increase our understanding of the epidemiology of acute leukemias. For instance, if leukemic translocations are present at birth in a far higher proportion of children than eventually develop acute leukemia, what are the exposures and somatic molecular events that lead to disease? And could children with translocations present at birth be targeted for prevention of disease? These questions must be answered before large-scale newborn screening for leukemia can occur as a public health initiative. Here, we review the literature regarding backtracking of acute leukemias and the prevalence of leukemic translocations at birth. We further suggest an agenda for epidemiologic research using new tools for population screening of leukemic translocations.

Birth characteristics and childhood leukemia in Switzerland: a register-based case-control study

Purpose

Initial genetic alterations in the development of childhood leukemia occur in utero or before conception; both genetic and environmental factors are suspected to play a role. We aimed to investigate the associations between childhood leukemia and perinatal characteristics including birth order, birth interval to older siblings, parental age, birth weight, and multiple birth.

Methods

We identified cases diagnosed between 1981 and 2015 and born in Switzerland between 1969 and 2015 from the Swiss Childhood Cancer Registry and randomly sampled five controls per case from national birth records matched on date of birth, sex, and municipality of residence at birth. We used conditional logistic regression to investigate associations between perinatal characteristics and leukemia at ages 0–15 and 0–4 years, and the subtypes acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML).

Results

The study included 1,403 cases of leukemia. We observed increased risks associated with high birth weight (adjusted OR 1.37, 95% CI 1.12–1.69) and multiple birth (1.89, 1.24–2.86). These associations were similar for ALL and stronger for leukemia at ages 0–4 years. For AML, we observed an increased risk for higher birth order (3.08, 0.43–22.03 for fourth or later born children). We found no associations with other perinatal characteristics.

Conclusion

This register-based case–control study adds to the existing evidence of a positive association between high birth weight and risk of childhood leukemia. Furthermore, it suggests children from multiple births are at an increased risk of leukemia.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10552-021-01423-3.

TPEN exerts selective anti-leukemic efficacy in ex vivo drug-resistant childhood acute leukemia

Despite some advances in the treatment of acute lymphoblastic (ALL) and myeloid leukemia (AML) in recent years, there is still a prominent percentage of pediatric patients with a reduced overall prognosis. Therefore, other therapeutic approaches are needed to treat those patients. In the present study, we report that the metal chelator TPEN affected ΔΨ_m and DNA content in isolated CD34⁺ refractory cells from bone marrow ALL (n = 7; B-cell, n = 4; T-cell, n = 3) and AML (n = 3) pediatric patients. Furthermore, TPEN induced oxidation of hydrogen peroxide (H₂O₂) sensor protein DJ-1, induced up-regulation of BH3-only pro-apoptotic protein PUMA, transcription factor p53 and activated the executor protease CASPASE-3 as apoptosis markers, and reduced the reactivity of the cellular proliferating marker Ki-67 in all acute leukemic groups, and reduced the phosphorylation of c-ABL protein signal in an AML case. Remarkably, bone marrow cells from non-leukemic patients' cells (n = 2) displayed neither loss of ΔΨ_m nor loss of DNA content when exposed to TPEN. We conclude that TPEN selectively induces apoptosis in acute leukemic cells via reactive oxygen species (ROS) signaling mechanism. Understanding the pathways of TPEN-induced cell death may provide insight into more effective therapeutic ROS-inducing anticancer agents.

Acute monocytic leukemia presenting as generalized lymphadenopathy and skin rash in a toddler: highlighting the clinicopathologic mimics

Acute myeloid leukemia (AML) is the fifth most common malignancy in children. Extramedullary involvement in acute myeloid leukemia is rare and can be seen in soft tissues, central nervous system, skin and lymphoreticular organs. The clinical presentations can often be non-specific and hence, the diagnosis can be very challenging, especially in cases without a prior hematologic diagnosis. We report a case of pediatric acute monocytic leukemia presenting with generalized lymphadenopathy and cutaneous rash. Fine-needle aspiration was performed from the lymph nodes and a cytologic diagnosis of infiltration by a lymphoreticular malignancy was suggested. Peripheral blood, bone marrow and cerebrospinal fluid involvement were noted subsequently. Flow cytometry on the bone marrow aspirate confirmed a diagnosis of acute monocytic leukemia. The index case besides highlighting an uncommon presentation of acute monocytic leukemia in a toddler, also emphasizes the need to consider acute monocytic leukemia as a cytomorphologic differential in such presentations.

Role of microRNA dysregulation in childhood acute leukemias: Diagnostics, monitoring and therapeutics: A comprehensive review

MicroRNAs (miRNAs) are short noncoding RNAs that regulate the expression of genes by sequence-specific binding to mRNA to either promote or block its translation; they can also act as tumor suppressors (e.g., let-7b, miR-29a, miR-99, mir-100, miR-155, and miR-181) and/or oncogenes (e.g., miR-29a, miR-125b, miR-143-p3, mir-155, miR-181, miR-183, miR-196b, and miR-223) in childhood acute leukemia (AL). Differentially expressed miRNAs are important factors associated with the initiation and progression of AL. As shown in many studies, they can be used as noninvasive diagnostic and prognostic biomarkers, which are useful in monitoring early stages of AL development or during therapy (e.g., miR-125b, miR-146b, miR-181c, and miR-4786), accurate classification of different cellular or molecular AL subgroups (e.g., let-7b, miR-98, miR-100, miR-128b, and miR-223), and identification and development of new therapeutic agents (e.g., mir-10, miR-125b, miR-203, miR-210, miR-335). Specific miRNA patterns have also been described for commonly used AL therapy drugs (e.g., miR-125b and miR-223 for doxorubicin, miR-335 and miR-1208 for prednisolone, and miR-203 for imatinib), uncovering miRNAs that are associated with treatment response. In the current review, the role of miRNAs in the development, progression, and therapy monitoring of pediatric ALs will be presented and discussed.

TRIM31 promotes acute myeloid leukemia progression and sensitivity to daunorubicin through the Wnt/β-catenin signaling

Tripartite motif (TRIM) 31 is a member of TRIM family and exerts oncogenic role in the progression and drug resistance of several cancers. However, little is known about the relevance of TRIM31 in acute myeloid leukemia (AML). Herein, we investigated the role of TRIM31 in AML. We examined the expression levels of TRIM31 in the blood samples from 34 patients with AML and 34 healthy volunteers using qRT-PCR. The mRNA levels of TRIM31 in human bone marrow stromal cells (HS-5) and five AML cell lines were also detected. Loss/gain-of-function assays were performed to assess the role of TRIM31 in AML cells proliferation, apoptosis and sensitivity to daunorubicin. The expression levels of pro-caspase 3, cleaved caspase 3, Wnt3a, β-catenin, cyclin D1 and c-Myc were measured using Western blot. TRIM31 expression levels were significantly up-regulated in AML patients and cell lines. Knockdown of TRIM31 suppressed cell proliferation and promoted apoptosis in AML-5 and U937 cells. The IC50 of daunorubicin was significantly decreased in TRIM31 siRNA (si-TRIM31) transfected cells. Oppositely, induced cell proliferation and decreased cell apoptosis were observed in pcDNA-3.1-TRIM31 transfected cells. Furthermore, knockdown of TRIM31 suppressed the activation of Wnt/β-catenin pathway in AML cells. Activation of Wnt/β-catenin pathway by LiCl abolished the effects of si-TRIM31 on cell proliferation, apoptosis and sensitivity to daunorubicin in AML cells. In conclusion, the results indicated that TRIM31 promoted leukemogenesis and chemoresistance to daunorubicin in AML. The oncogenic role of TRIM31 in AML was mediated by the Wnt/β-catenin pathway. Thus, TRIM31 might serve as a therapeutic target for the AML treatment.

Cancer Stem Cells in the Development of Novel Therapeutics for Refractory Pediatric Leukemia

Although treatment strategies for pediatric leukemia have improved overall survival rates in the recent past, relapse rates in certain subgroups such as infant leukemia remain unacceptably high. Despite undergoing extensive chemotherapy designed to target the rapidly proliferating leukemia cells, many of these children experience relapse. In refractory leukemia, the existence of cell populations with stemness characteristics, termed leukemia stem cells (LSCs), which remain quiescent and subsequently replenish the blast population, has been described. A significant body of evidence exists, derived largely from xenograft models of adult acute myeloid leukemia, to support the idea that LSCs may play a fundamental role in refractory disease. In addition, clinical studies have also linked LSCs with increased minimal residual disease, higher relapse rate, and decreased survival rates in these patients. Recently, a number of reports have addressed effective ways to utilize new-generation genomic sequencing and transcriptomic analyses to identify targeted therapeutic agents aimed at LSCs, while sparing normal hematopoietic stem cells. These data underscore the value of timely translation of knowledge from adult studies to the unique molecular and physiological characteristics seen in pediatric leukemia. We aim to summarize this article in the rapidly expanding field of stem cell biology in hematopoietic malignancies, focusing particularly on relevant preclinical models and novel targeted therapeutics, and their applicability to childhood leukemia.

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.

Comparing the epidemiology, clinical characteristics and prognostic factors of acute myeloid leukemia with and without acute promyelocytic leukemia

Acute promyelocytic leukemia (APL) is a particularly aggressive subtype of acute myeloid leukemia (AML), with high rates of early death. It is important to examine how epidemiological characteristics, clinical and treatment factors, cytogenetic and genetic data affect survival and differ between APL and non-APL AML patients. We analyzed population data from the New York State Cancer Registry to characterize AML including APL incidence rates by demographics. APL incidence rates were higher among Hispanics than non-Hispanics [incidence rate ratio = 1.22; 95% confidence interval (CI) = 1.02-1.43]; and among foreign-born than USA-born persons. APL incidence rates increased more rapidly through 1995-2014 than non-APL AML; and its frequency increased faster among foreign-born persons. In a hospital cohort of 390 AML patients, the risk of death was significantly higher among APL patients with FLT3-internal tandem duplications than those without [hazard ratio (HR) = 11.74; 95% CI = 1.03-134.5]; and among APL patients with secondary versus de novo disease (HR = 17.32; 95% CI = 1.56-192.1). Among non-APL AML patients, risk of death was significantly associated with prior chemotherapy with antitubulin agents after adjusting for age, gender and ethnicity (adjusted HR = 3.30; 95% CI = 1.49-7.32); and separately with older age, unfavorable cytogenetics and complex karyotype. This study highlights FLT3-internal tandem duplications as a prognostic factor in APL and proposes consideration of prior antitubulin therapy as a prognostic factor in non-APL AML.

LukS-PV induces apoptosis in acute myeloid leukemia cells mediated by C5a receptor

LukS‐PV is one of the two components of Panton‐Valentine leucocidin (PVL). Our previous study showed that LukS‐PV can induce apoptosis in human acute myeloid leukemia (AML) THP‐1 and HL‐60 cells. C5aR (C5a receptor) is the receptor for PVL, but whether C5aR plays a key role in LukS‐PV induced apoptosis is unclear. The aim of this study was to establish whether C5aR plays a physiological role in apoptosis of leukemia cells induced by LukS‐PV. We investigated the role of C5aR in leukemia cell apoptosis induced by LukS‐PV by pretreatment of THP‐1 and HL‐60 cells with C5aR antagonist and transfection to knockdown C5aR in THP‐1 cells or overexpress C5aR in Jurkat cells before treatment with LukS‐PV. Cell apoptosis was analyzed by staining with Annexin V/propidium iodide or Annexin V‐PE/7‐AAD. Mitochondrial membrane potential (MMP) was determined using JC‐1 dye. The expression of apoptosis‐associated genes and proteins was identified by qRT‐polymerase chain reaction and Western blotting analysis, respectively. As the C5aR antagonist concentration increased, the rate of apoptosis induced by LukS‐PV decreased, the MMP increased, and expression of pro‐apoptotic Bax and Bak genes and proteins was downregulated while that of anti‐apoptotic Bcl‐2 and Bcl‐x genes and proteins was upregulated. Knockdown of C5aR also decreased LukS‐PV–induced THP‐1 cell apoptosis. LukS‐PV did not induce apoptosis of Jurkat cells, which have no endogenous C5aR expression; however, LukS‐PV did induce apoptosis in Jurkat cells after overexpression of C5aR. Correspondingly, the MMP decreased and Bax and Bak were upregulated while Bcl‐2 and Bcl‐x were downregulated. LukS‐PV can induce apoptosis in AML cells by targeting C5aR. C5aR may be a potential therapeutic target for AML and LukS‐PV is a candidate targeted drug for the treatment of AML.

Parental age and the risk of childhood acute myeloid leukemia: results from the Childhood Leukemia International Consortium

BACKGROUND

Parental age has been associated with several childhood cancers, albeit the evidence is still inconsistent.

AIM

To examine the associations of parental age at birth with acute myeloid leukemia (AML) among children aged 0-14 years using individual-level data from the Childhood Leukemia International Consortium (CLIC) and non-CLIC studies.

MATERIAL/METHODS

We analyzed data of 3182 incident AML cases and 8377 controls from 17 studies [seven registry-based case-control (RCC) studies and ten questionnaire-based case-control (QCC) studies]. AML risk in association with parental age was calculated using multiple logistic regression, meta-analyses, and pooled-effect estimates. Models were stratified by age at diagnosis (infants <1 year-old vs. children 1-14 years-old) and by study design, using five-year parental age increments and controlling for sex, ethnicity, birthweight, prematurity, multiple gestation, birth order, maternal smoking and education, age at diagnosis (cases aged 1-14 years), and recruitment time period.

RESULTS

Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) derived from RCC, but not from the QCC, studies showed a higher AML risk for infants of mothers ≥40-year-old (OR = 6.87; 95% CI: 2.12-22.25). There were no associations observed between any other maternal or paternal age group and AML risk for children older than one year.

CONCLUSIONS

An increased risk of infant AML with advanced maternal age was found using data from RCC, but not from QCC studies; no parental age-AML associations were observed for older children.

Advances in hematopoietic cell transplant for the treatment of hematologic malignancies

PURPOSE OF REVIEW

Incorporation of minimal residual disease (MRD) testing in acute lymphoblastic leukemia (ALL) and acute myeloblastic leukemia (AML) has transformed the landscape of hematopoietic cell transplantation (HCT). Pre-HCT MRD has allowed prognostication of HCT outcomes for high-risk leukemia patients, whereas the detection of post-HCT MRD has allowed for interventions to decrease relapse.

RECENT FINDINGS

In this review, we emphasize studies from the past two decades that highlight the critical role of MRD in HCT in pediatric ALL and AML. Advances in MRD detection methodology, using next-generation sequencing, have improved the sensitivity of MRD testing allowing for more accurate predictions of HCT outcomes for patients with relapsed and refractory ALL and AML. In addition, novel pre-HCT therapies, especially immunotherapy in ALL, have dramatically increased the number of patients who achieve MRD-negative remissions pre-HCT, resulting in improved HCT outcomes. Post-HCT MRD remains a challenge and new therapeutic interventions are needed to reduce post-HCT relapse.

SUMMARY

As immunotherapy increases pre-HCT MRD-negative remissions, and next-generation sequencing-MRD is incorporated to improve the sensitivity of MRD detection, future clinical studies will investigate less toxic HCT approaches to reduce long-term sequelae and to identify which patients may benefit most from early post-HCT intervention to reduce relapse.

Complete Remission of a Refractory Acute Myeloid Leukemia with Myelodysplastic- and Monosomy 7-Related Changes after a Combined Conditioning Regimen of Plerixafor, Cytarabine and Melphalan in a 4-Year-Old Boy: A Case Report and Review of Literature

Acute myeloid leukemia with myelodysplastic changes and monosomy 7 is a rare form of pediatric leukemia associated with very poor disease-free survival. The refractoriness of the disease is due to the protection offered by the bone marrow niche, making leukemic stem cells impervious to whatever chemotherapy or myeloablative regimen is chosen. Using a mobilizing agent for haematopoietic stem cells, Plerixafor, could sensitise leukemic cells to the myeloablative therapy. This approach was not previously used in a pediatric population, and in adult populations, was used in combination with busulphan with no difference in overall survival. We describe the case of a 4-year-old boy affected by refractory acute myeloid leukemia with myelodysplastic changes and monosomy 7. The child had never achieved a remission. We proposed a combined time-scheduled scheme of therapy with plerixafor and melphalan. Combining pharmacokinetics of plerixafor with pharmacokinetics and rapid and elevated myeloablative potential of melphalan in high dosage (200 mg/m²), we succeeded in mobilizing more than 85% of stem blasts immediately before infusion of Melphalan. The count of residual blasts after 8 h from melphalan infusion was only 1.3 cells/μL. The child achieved an engraftment at day +32 with full donor chimerism. Sixteen months after haematopoietic stem cell transplantation (HSCT), he is well and in complete remission. Our case suggests that the use of plerixafor before a conditioning therapy with melphalan could induce remission in acute myeloid leukemia refractory to the usual conditioning therapy in pediatric patients. This work adds strength to the body of knowledge regarding the “personalized” conditioning regimen for high-risk leukemic patients.

Comparison of survival outcome between donor types or stem cell sources for childhood acute myeloid leukemia after allogenic hematopoietic stem cell transplantation: A multicenter retrospective study of Study Alliance of Yeungnam Pediatric Hematology-oncology

We compared transplant outcomes between donor types and stem cell sources for childhood acute myeloid leukemia (AML). The medical records of children with AML in the Yeungnam region of Korea from January 2000 to June 2017 were reviewed. In all, 76 children with AML (male-to-female ratio = 46:30) received allogenic hematopoietic stem cell transplantation (allo-HSCT). In total, 29 patients received HSCT from either a matched-related donor or a mismatched-related donor, 32 patients received an unrelated donor, and 15 patients received umbilical cord blood. In term of stem cell sources, bone marrow was used in 15 patients and peripheral blood in 46 patients. For all HSCT cases, the 5-year overall survival (OS) was 73.1% (95% CI: 62.7-83.5) and the 5-year event-free survival (EFS) was 66.1% (95% CI: 54.5-77.7). There was no statistical difference in 5-year OS according to the donor types or stem cell sources (P = .869 and P = .911). There was no statistical difference in 5-year EFS between donor types or stem cell sources (P = .526 and P = .478). For all HSCT cases, the 5-year relapse rate was 16.1% (95% CI: 7.3-24.9) and the 5-year non-relapse mortality (NRM) was 13.3% (95% CI: 5.1-21.5). There was no statistical difference in the 5-year relapse rate according to the donor types or stem cell sources (P = .971 and P = .965). There was no statistical difference in the 5-year NRM between donor types or stem cell sources (P = .461 and P = .470).

EPHX1 rs1051740 T>C (Tyr113His) is strongly associated with acute myeloid leukemia and KMT2A rearrangements in early age

Experimental and epidemiological data have shown that acute myeloid leukemia in early-age (i-AML) originates prenatally. The risk association between transplacental exposure to benzene metabolites and i-AML might be influenced by genetic susceptibility. In this study, we investigated the relationship between genetic polymorphisms in CYP2E1, EPHX1, MPO, NQO1, GSTM1 and GSTT1 genes, and i-AML risk. The study included 101 i-AMLs and 416 healthy controls. Genomic DNA from study subjects was purified from bone marrow or peripheral blood aspirates and genotyped for genetic polymorphisms by real-time PCR allelic discrimination, Sanger sequencing and multiplex PCR. Crude and adjusted odds ratios (OR, _adjOR, respectively) with 95% confidence intervals (95% CI) were assessed using unconditional logistic regression to estimate the magnitude of risk associations. EPHX1 rs1051740 T>C was associated with i-AML risk under the co-dominant (_adjOR 3.04, P = 0.003) and recessive (_adjOR 2.99, P = 0.002) models. In stratified analysis, EPHX1 rs1051740 was associated with increased risk for i-AML with KMT2A rearrangement (_adjOR 3.06, P = 0.045), i-AML with megakaryocytic differentiation (_adjOR 5.10, P = 0.008), and i-AML with type I mutation (_adjOR 2.02, P = 0.037). EPHX1 rs1051740-rs2234922 C-G haplotype was also associated with increased risk for i-AML (_adjOR 2.55, P = 0.043), and for i-AML with KMT2A rearrangement (_adjOR 3.23, P = 0.034). Since EPHX1 enzyme is essential in cellular defense against epoxides, the diminished enzymatic activity conferred by the variant allele C could explain the risk associations found for i-AML. In conclusion, EPHX1 rs1051740 plays an important role in i-AML's genetic susceptibility by modulating the carcinogenic effects of epoxide exposures in the bone marrow.

Profile of Skin pH in Leukaemia's Children with Chemotherapy Treatments at Haji Adam Malik General Hospital, Medan

BACKGROUND:

One of the treatments for leukaemia is chemotherapy. Side effects and toxicity of this treatment can be seen on the skin, adnexal, and mucous membranes. They might increase potential hydrogen (pH) value on the skin surface, therefore, disrupting epidermal barrier defences.

AIM:

To describe the pH of the skin in children with leukaemia who received chemotherapy.

SUBJECT AND METHOD:

This study was an observational descriptive, cross-sectional study, conducted from March until December 2016 with 32 children with leukaemia who treated at Haji Adam Malik General Hospital, Medan as subjects. Skin pH was measured by a pH meter.

RESULT:

We found mean skin pH in ALL (6.28 ± 0.58), CML (5.9 ± 0) and AML (6.5 ± 0.50). The mean skin pH after 1-5 weeks of chemotherapy was 6.13 ± 0.49, at 6-10 weeks (6.32 ± 0.51), and at 11-15 weeks (7.12 ± 0.36). The mean skin pH of patients with two drugs (5.98 ± 0.44), four drugs (6.28 ± 0.55), and six drugs (6.63 ± 0.56).

CONCLUSION:

The highest mean of skin pH were obtained in AML group, 11-15 weeks length of chemotherapy and group with six drugs regimen.

Gene Mutations as Emerging Biomarkers and Therapeutic Targets for Relapsed Acute Myeloid Leukemia

It is believed that there are key differences in the genomic profile between adult and childhood acute myeloid leukemia (AML). Relapse is the significant contributor of mortality in patients with AML and remains as the leading cause of cancer death among children, posing great challenges in the treatment of AML. The knowledge about the genomic lesions in childhood AML is still premature as most genomic events defined in children were derived from adult cohorts. However, the emerging technologies of next generation sequencing have narrowed the gap of knowledge in the biology of AML by the detection of gene mutations for each sub-type which have led to the improvement in terms of prognostication as well as the use of targeted therapies. In this review, we describe the recent understanding of the genomic landscape including the prevalence of mutation, prognostic impact, and targeted therapies that will provide an insight into the pathogenesis of AML relapse in both adult and childhood cases.

Acute myeloid leukaemia at an early age: Reviewing the interaction between pesticide exposure and KMT2A-rearrangement

Acute myeloid leukaemia (AML) in early childhood is characterised by a high frequency of recurrent genomic aberrations associated with distinct myeloid subtypes, clinical outcomes and pathogenesis. Genomic instability is the first step of pathogenic mechanism in early childhood AML. A sum of adverse events is necessary to the development of infant AML (i-AML), which includes latency of biochemical-molecular and cellular effects. Inherited genetic susceptibility associated with exposures to biotransformation substances can modulate the risk of DNA damage and it is a very important piece in the pathogenic puzzle. In this review, we have aimed to explore the chain of events in the time-points of the natural history of i-AML, which includes maternal exposures during pregnancy, the speculations about the formation of somatic mutations during foetal life and the secondary genomic aberrations associated with i-AML. The modulation of risk conferred by xenobiotic metabolism´s genes variants is the bottom line of the pathogenic process. Since we have conducted observational and molecular investigations in early childhood leukaemia, the data focused here is based on Brazilian findings with summarised results of our experience with epidemiological and molecular studies in early-age leukaemia.

Immunotherapy for acute myeloid leukemia (AML): a potent alternative therapy

The standard therapy of AML for many years has been chemotherapy with or without stem transplantation. However, there has not been any tangible improvement in this treatment beyond induction through chemotherapy and consolidation with allogeneic stem cell transplantation or chemotherapy. Residual AML cells which later cause relapse mostly persist even after rigorous standard therapy. It is imperative therefore to find an alternative therapy that can take care of the residual AML cells. With a better understanding of how the immune system works to destroy tumor cells and inhibit their growth, another therapeutic option immunotherapy has emerged to address the difficulties associated with the standard therapy. Identification of leukemia-associated antigens (LAA) and the fact that T and NK cells can be activated to exert cytotoxicity on AML cells have further introduced diverse immunotherapeutic development strategies. This review discusses the merits of current immunotherapeutic strategies such as the use of antibodies, adoptive T cells and alloreactive NK cell, and vaccination as against the standard therapy of AML.