Pediatric acute myeloid leukemia is a rare and heterogeneous disease in relation to morphology, immunophenotyping, germline and somatic cytogenetic and genetic abnormalities. Over recent decades, ...outcomes have greatly improved, although survival rates remain around 70% and the relapse rate is high, at around 30%. Cytogenetics is an important factor for diagnosis and indication of prognosis. The main cytogenetic abnormalities are referenced in the current WHO classification of acute myeloid leukemia, where there is an indication for risk-adapted therapy. The aim of this article is to provide an updated review of cytogenetics in pediatric AML, describing well-known WHO entities, as well as new subgroups and germline mutations with therapeutic implications. We describe the main chromosomal abnormalities, their frequency according to age and AML subtypes, and their prognostic relevance within current therapeutic protocols. We focus on de novo AML and on cytogenetic diagnosis, including the practical difficulties encountered, based on the most recent hematological and cytogenetic recommendations.
Variants in ETV6, which encodes a transcription repressor of the E26 transformation-specific family, have recently been reported to be responsible for inherited thrombocytopenia and hematologic ...malignancy. We sequenced the DNA from cases with unexplained dominant thrombocytopenia and identified six likely pathogenic variants in ETV6, of which five are novel. We observed low repressive activity of all tested ETV6 variants, and variants located in the E26 transformation-specific binding domain (encoding p.A377T, p.Y401N) led to reduced binding to corepressors. We also observed a large expansion of megakaryocyte colony-forming units derived from variant carriers and reduced proplatelet formation with abnormal cytoskeletal organization. The defect in proplatelet formation was also observed in control CD34
cell-derived megakaryocytes transduced with lentiviral particles encoding mutant ETV6. Reduced expression levels of key regulators of the actin cytoskeleton CDC42 and RHOA were measured. Moreover, changes in the actin structures are typically accompanied by a rounder platelet shape with a highly heterogeneous size, decreased platelet arachidonic response, and spreading and retarded clot retraction in ETV6 deficient platelets. Elevated numbers of circulating CD34
cells were found in p.P214L and p.Y401N carriers, and two patients from different families suffered from refractory anemia with excess blasts, while one patient from a third family was successfully treated for acute myeloid leukemia. Overall, our study provides novel insights into the role of ETV6 as a driver of cytoskeletal regulatory gene expression during platelet production, and the impact of variants resulting in platelets with altered size, shape and function and potentially also in changes in circulating progenitor levels.
Cardiovascular conditions are serious long-term complications of childhood acute leukemia. However, few studies have investigated the risk of metabolic syndrome, a known predictor of cardiovascular ...disease, in patients treated without hematopoietic stem cell transplantation. We describe the overall and age-specific prevalence, and the risk factors for metabolic syndrome and its components in the L.E.A. (Leucémie de l'Enfant et de l'Adolescent) French cohort of childhood acute leukemia survivors treated without hematopoietic stem cell transplantation. The study included 650 adult patients (mean age at evaluation: 24.2 years; mean follow-up after leukemia diagnosis: 16.0 years). The prevalence of metabolic syndrome was 6.9% (95% CI 5.1-9.2). The age-specific cumulative prevalence at 20, 25, 30 and 35 years of age was 1.3%, 6.1%, 10.8% and 22.4%, respectively. The prevalence of decreased high-density lipoprotein cholesterol, increased triglycerides, increased fasting glucose, increased blood pressure and increased abdominal circumference was 26.8%, 11.7%, 5.8%, 36.7% and 16.7%, respectively. Risk factors significantly associated with metabolic syndrome in the multivariate analysis were male sex (OR 2.64; 95% CI 1.32-5.29), age at last evaluation (OR 1.10; 95% CI 1.04-1.17) and body mass index at diagnosis (OR 1.15; 95% CI 1.01-1.32). The cumulative steroid dose was not a significant risk factor. Irradiated and non-irradiated patients exhibited different patterns of metabolic abnormalities, with more frequent abdominal obesity in irradiated patients and more frequent hypertension in non-irradiated patients. Survivors of childhood acute leukemia are at risk of metabolic syndrome, even when treated without hematopoietic stem cell transplantation or central nervous system irradiation. A preventive approach with regular screening for cardiovascular risk factors is recommended. clinicaltrials.gov identifier:01756599.
The prevalence of the metabolic syndrome among adults from the French LEA childhood acute leukemia survivors' cohort was prospectively evaluated considering the type of anti-leukemic treatment ...received, and compared with that of controls. The metabolic profile of these patients was compared with that of controls. A total of 3203 patients from a French volunteer cohort were age- and sex-matched 3:1 to 1025 leukemia survivors (in both cohorts, mean age: 24.4 years; females: 51%). Metabolic syndrome was defined according to the National Cholesterol Education Program's Adult Treatment Panel III criteria. Metabolic syndrome was found in 10.3% of patients (mean follow-up duration: 16.3±0.2 years) and 4.5% of controls, (OR=2.49;
<0.001). Patients transplanted with total body irradiation presented the highest risk (OR=6.26;
<0.001); the other treatment groups also showed a higher risk than controls, including patients treated with chemotherapy only. Odd Ratios were 1.68 (
=0.005) after chemotherapy only, 2.32 (
=0.002) after chemotherapy and cranial irradiation, and 2.18 (
=0.057) in patients transplanted without irradiation. Total body irradiation recipients with metabolic syndrome displayed a unique profile compared with controls: smaller waist circumference (91
99.6 cm;
=0.01), and increased triglyceride levels (3.99
1.5 mmol/L;
<0.001), fasting glucose levels (6.2
5.6 mmol/L;
=0.049), and systolic blood pressure (137.9
132.8 mmHg;
=0.005). By contrast, cranial irradiation recipients with metabolic syndrome had a larger waist circumference (109
99.6 cm;
=0.007) than controls. Regardless of the anti-leukemic treatment, metabolic syndrome risk was higher among childhood leukemia survivors. Its presentation differed depending on the treatment type, thus suggesting a divergent pathophysiology. This study is registered at
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Glanzmann thrombasthenia (GT) is a genetic bleeding disorder characterised by severely reduced/absent platelet aggregation in response to multiple physiological agonists. The severity of bleeding in ...GT varies markedly, as does the emergency situations and complications encountered in patients. A number of emergency situations may occur in the context of GT, including spontaneous or provoked bleeding, such as surgery or childbirth. While general management principles apply in each of these settings, specific considerations are essential for the management of GT to avoid escalating minor bleeding events. These recommendations have been developed from a literature review and consensus from experts of the French Network for Inherited Platelet Disorders, the French Society of Emergency Medicine, representatives of patients' associations, and Orphanet to aid decision making and optimise clinical care by non-GT expert health professionals who encounter emergency situations in patients with GT.
to evaluate the safety and efficacy of a physical activity program (PAP) in children and adolescents with cancer.
children and adolescents with cancer were randomly assigned in a 1:1 ratio to the ...six-month PAP (intervention group) or to the control group. The first evaluation was performed at the end of the PAP (T0 + 6 mo). At T0 + 6 mo, both groups received the six-month PAP with a second evaluation at T0 + 12 mo. The primary outcome was the evolution of exercise capacity measured using the six-minute walk test (6 MWT) at T0 + 6 mo. Secondary outcomes included PAP safety and changes in other physical functions, self-esteem, and quality-of-life parameters.
The trial involved 80 children and adolescents (age range 5.0-18.4 years), of whom 41 were assigned to the interventional group and 39 to the control group. Underlying malignancies were leukemia (39%) and a broad range of solid tumors (61%). No adverse events occurred. At T0 + 6 mo, the evolution of the 6 MWT distance (±SEM) was improved in the intervention group vs. the control group (86 ± 12 m vs. 32 ± 6 m,
< 0.001). Several other physical parameters were significantly improved in the intervention group. Global self-esteem and parent-reported quality-of-life were significantly increased in the intervention group. Analysis at T0 + 12 mo showed persistence of the benefits in the intervention group on exercise capacity evolution (115 ± 18 m vs. 49 ± 11 m,
= 0.004) and on most physical and QoL parameters.
In children and adolescents with cancer, a physical activity program is safe, improves exercise capacity, and may have physical and psychological benefits.
Congenital macrothrombocytopenia is a family of rare diseases, of which a significant fraction remains to be genetically characterized. To analyze cases of unexplained thrombocytopenia, 27 ...individuals from a patient cohort of the Bleeding and Thrombosis Exploration Center of the University Hospital of Marseille were recruited for a high-throughput gene sequencing study. This strategy led to the identification of two novel
variants (c.1010G>A and c.1033A>G) responsible for macrothrombocytopenia. The
variant carriers' platelets exhibited a defect in aggregation induced by low-dose adenosine diphosphate (ADP), collagen and thrombin receptor-activating peptide (TRAP), a defect in adenosine triphosphate (ATP) secretion, a reduced mepacrine uptake and release and a reduced CD63 expression upon TRAP stimulation. Precise ultrastructural analysis of platelet content was performed using transmission electron microscopy and focused ion beam scanning electron microscopy. Remarkably, dense granules were nearly absent in the carriers' platelets, presumably due to a biogenesis defect. Additionally, 25-29% of the platelets displayed giant α-granules, while a smaller proportion displayed vacuoles (7-9%) and autophagosome-like structures (0-3%).
study of megakaryocytes derived from circulating CD34
cells of the carriers revealed a maturation defect and reduced proplatelet formation potential. The study of the
variants revealed a significant reduction in protein nuclear accumulation and transcriptional activity properties. Intraplatelet flow cytometry efficiently detected the biomarker MYH10 in
variant carriers. Overall, this study provides new insights into the phenotype, pathophysiology and diagnosis of
variant-associated thrombocytopenia.
The population of survivors of childhood leukemia who reach adulthood is growing due to improved therapy. However, survivors are at risk of long-term complications. Comprehensive follow-up programs ...play a key role in childhood leukemia survivor care. The major determinant of long-term complications is the therapeutic burden accumulated over time. Relapse chemotherapy, central nervous system irradiation, hematopoietic stem cell transplantation, and total body irradiation are associated with greater risk of long-term complications. Other parameters include clinical characteristics such as age and sex as well as environmental, genetic, and socioeconomic factors, which can help stratify the risk of long-term complications and organize follow-up program. Early diagnosis improves the management of several late complications such as anthracycline-related cardiomyopathy, secondary cancers, metabolic syndrome, development defects, and infertility. Total body irradiation is the treatment associated with worse long-term toxicity profile with a wide range of complications. Patients treated with chemotherapy alone are at a lower risk of long-term complications, although the optimal long-term follow-up remains unclear. Novel immunotherapies and targeted therapy are generally associated with a better short-term safety profile but still require careful long-term toxicity monitoring. Advances in understanding genetic susceptibility to long-term complications could enable tailored therapeutic strategies for leukemia treatment and optimized follow-up programs.
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