Search Results (585)

Background: Chromosomal rearrangements involving lysine methyltransferase 2A (KMT2A) define a genetically distinct subset of acute myeloid leukemia (AML) in 10% of cases in adult patients; the frequency of KMT2A-r is higher in pediatric AML. Translocations involving the KMT2A locus at chromosome 11q23 result in the formation of a chimeric oncogene partner, where the N-terminal part of KMT2A is fused to a variety of translocation partners. The leukemogenic activity of KMT2A-fusion partners is related to their capacity to hyperactivate the expression of HOX-A and MEIS1 target genes, which stimulate the proliferation of hematopoietic stem cells. The oncogenic activity of KMT2A fusion proteins requires the binding with Menin, and this interaction can be targeted pharmacologically by small molecules acting as potent and selective Menin inhibitors. Methods: A search of the literature showed a marked development of experimental studies exploring the molecular pathogenesis of AML with KMT2A-r and of clinical studies evaluating new induction intensive treatments and the development of a targeted therapy based on Menin inhibitors. Results and Conclusions: In the present review article, we summarize our current understanding of the biology of KMT2A-r in AML development and the recent consistent progress made in the treatment of KMT2A-r AML through new chemotherapy regimens and targeted therapy using Menin inhibitors. However, the prognosis of older KMT2A-r AML patients remains poor and could be improved by drug combination studies including Menin inhibitors. Many encouraging observations derived from ongoing clinical trials with Menin inhibitors need to be confirmed through randomized clinical trials. Full article

Background/Objectives: Immunocompromised children undergoing chemotherapy or allogeneic hematopoietic stem cell transplantation (HSCT) for hematologic disorders face a high risk of serious, life-threatening infections caused by multidrug-resistant (MDR) bacteria. Cefiderocol is a novel siderophore cephalosporin, indicated for use in adult patients with MDR Gram-negative infections. Clinical data in immunocompromised children are limited. To report a multicenter real-life experience from the Infection Working Group of the Italian Pediatric Hematology and Oncology Association (IWG-AIEOP) on the use of cefiderocol in treating pediatric onco-hematologic patients with severe, high-risk infections. Methods: Multicenter retrospective collection of infectious episodes treated with cefiderocol, from January 2021 to December 2024, in patients 18 years or younger, after treatment for malignancies or undergoing HSCT in the AIEOP network, part of a prospective, observational study on the etiology and outcome of febrile episodes among 24 AIEOP centers (code NCT06419426). Results: Fifteen episodes of MDR, life-threatening Gram-negative infections treated with cefiderocol in 13 pediatric onco-hematologic patients were collected. There were eight males and five females, mainly affected by acute leukemia (six lymphoblastic and four myeloid, three other hematologic malignancies). The median age was 11.1 years (range 1–17.4 years), and the median weight was 37.8 kg (range 8–65). Bloodstream infection occurred in 10 of 15 episodes. Pseudomonas aeruginosa, Klebsiella pneumoniae, and Stenotrophomonas maltophilia were isolated in 11, 3, and 1 episodes, respectively. Notably, 11 of 15 isolated pathogens carried a metallo-beta-lactamase (MBL) gene (Verona integron-encoded, VIM, n = 10; New Delhi, NDM, n = 1). All patients achieved infection resolution and were alive and infection-free 90 days after infection onset. Conclusions: Cefiderocol was well tolerated and showed encouraging, favorable clinical outcomes, without serious adverse effects. Full article

Background: Acute lymphoblastic leukemia (ALL) requires intensive induction, but implementation of pediatric-inspired regimens in low- and middle-income countries is constrained by diagnostic gaps, procurement instability, and limited supportive-care capacity. We evaluated the feasibility, safety, and affordability of a pragmatically adapted pediatric-inspired induction regimen for adults with Philadelphia chromosome-negative Ph(−) ALL in a Pakistani tertiary hospital. Methods: In this prospective single-center cohort study at the Pakistan Institute of Medical Sciences (December 2024–June 2025), consecutive adults aged 18–50 years with newly diagnosed Ph(−)ALL received an adapted pediatric-inspired induction regimen. The primary outcome was complete remission (CR) after induction, with or without extended induction. Secondary outcomes were early mortality, treatment abandonment, grade 3–4 toxicities, and service delivery feasibility indicators. Affordability was assessed against household income. Results: Among 200 adults (mean age 30.3 ± 8.8 years; 65.5% male), 39.5% presented with WBC ≥ 30 × 10⁹/L and 88.0% with platelets < 50 × 10³/µL. CR was achieved in 83.0% of patients. Early mortality was 2.0%, and treatment abandonment was 1.5%. Grade 3–4 toxicities included febrile neutropenia (15.0%) and sepsis (7.5%). The Day-30 evaluability was high (96.5%). Observed out-of-pocket diagnostic costs were USD 119, whereas a guideline-complete diagnostic package would cost USD 929, equivalent to 3–6 months of income for households in the poorest quintile. Conclusions: This adapted pediatric-inspired induction regimen was operationally deliverable in a resource-restricted hospital and produced favorable induction-phase outcomes. Limited diagnostic capacity and a lack of financial protection for testing remain barriers to risk-adapted care. Expanding subsidies for essential diagnostics and stabilizing the procurement of critical agents may yield the greatest implementation gains. Full article

Neurological complications, particularly seizures, represent a significant and often under-recognized clinical challenge in pediatric hematologic malignancies. Distinguishing CNS leukemia-associated epilepsy from chemotherapy-induced neurotoxicity is critical for optimizing therapy but remains difficult due to overlapping clinical presentations. This review highlights the distinct molecular mechanisms underlying these two entities. CNS leukemia-associated seizures are primarily driven by blood–brain barrier (BBB) disruption following leukemic infiltration, which triggers a neuroinflammatory cascade involving pro-inflammatory cytokines such as IL-6 and TNF-α, and impairs glutamate homeostasis. In contrast, chemotherapy-induced seizures, particularly those associated with high-dose methotrexate, arise from disrupted folate metabolism, intracellular oxidative stress, and subsequent N-methyl-D-aspartate (NMDA) receptor-mediated excitotoxicity. We provide a comparative analysis of these pathways, integrating current evidence on pharmacogenomic susceptibility—including polymorphisms in methylenetetrahydrofolate reductase (MTHFR) and drug transporter genes—as well as epigenetic factors. By synthesizing these molecular insights, we propose a mechanistic framework for precise clinical differentiation, which may inform biomarker-driven diagnostic approaches and targeted neuroprotective strategies in this vulnerable population. Full article

Acute lymphoblastic leukemia (ALL) is the most common childhood malignancy, with most cases arising from B-cell precursors expressing the CD19 marker. CD19 negativity in B-lineage ALL (B-ALL) is very rare de novo and poses diagnostic and therapeutic challenges. Sometimes, de novo CD19-negative B-ALL is associated with hypercalcemia, which is a potentially life-threatening metabolic disorder in children, rarely occurring in cancers. Most often it is reported in solid tumors, and few cases are reported in pediatric acute leukemia. CD19-negative B-ALL relapse is also an increasing dramatic event, secondary to immunotherapy. We describe a ten-month-old infant presenting with hypercalcemia, anemia, and osteolytic bone lesions. Bone marrow analysis revealed CD10-positive and CD19-negative B-ALL. The patient achieved complete remission but later experienced two relapses and died of respiratory failure after a second allogeneic hematopoietic stem cell transplantation (HSCT). Only nine cases of de novo CD19-negative B-ALL have been reported so far. Many are associated with hypercalcemia and osteolytic lesions. However, here we highlight the clinical impact of the more common secondary form of CD19-negative B-ALL as a relapse of CD19-positive ALL, right after the administration of targeted immunotherapy. Full article

Background/Objectives: To study the hypothesis that cognitive functions and learning skills are impaired in child/adolescent childhood cancer survivors (CCS). Secondary outcomes included psychosocial parameters and quality of life. Methods: This case–control study was conducted over four years (2017–2021) at the largest pediatric Aghia Sophia Children’s Hospital, in Greece. Eligible participants were children and adolescents in Greece. For CCS, ≥1 year should have elapsed from completion of cancer treatment. Assessments of neurocognitive function, learning and psychosocial skills and health-related quality of life (HRQoL) were performed with validated instruments (WISC-III, LAMDA software, Achenbach CBCL/6-18 and YSR, KIDSCREEN-52, respectively). Results: In total, 219 participants (47.49% males, mean age ± SD 11.72 ± 2.32 years), 70 CCS and 149 controls (matched for age, sex, family income), were included. Cases were CCS of acute lymphoblastic leukemia (n = 25)/brain tumors (n = 19)/lymphoma (n = 17)/nephroblastoma (n = 5)/Ewing sarcoma (n = 3)/rhabdomyosarcoma (n = 1). CCS had worse scores in full-scale Intelligence Quotient (FSIQ) (p = 0.004), verbal IQ (VIQ) (p = 0.005) and all its subscales, performance IQ (PIQ) (p = 0.021), and almost all learning parameters than controls. Attention, working memory, writing/visual–motor coordination, processing accuracy/speed, language acquisition/expression, all psychosocial scales, and HRQoL domains of mood and emotions, were negatively affected in CCS. Female CCS demonstrated lower FSIQ (p = 0.019) and VIQ (p = 0.014) than control females, whereas male CCS retained their total IQ unaffected. Among CCS, those with non-central nervous system (CNS) tumors, higher parental educational level or higher family income had significantly higher IQ than those with CNS tumors, lower parental educational level or lower family income, respectively. Conclusions: CCS in Greece carry a significant burden of cognitive and psychological morbidity. Cognitive/educational and psychosocial support to CCS is imperative. Full article

Background/Objectives: Acute pancreatitis (AP) is an uncommon but serious complication in children undergoing treatment for acute leukemia. We aimed to determine the prevalence of AP in pediatric patients with acute leukemia, identify its risk factors, and evaluate their impact on treatment outcomes and overall survival. Materials and Methods: We retrospectively reviewed the medical records of children with acute leukemia who developed acute abdominal pain suggestive of AP at Songklanagarind Hospital between 2004 and 2024. Demographic data, including leukemia subtypes, treatment protocols, and clinical outcomes, were compared between the patients with and without AP. Results: Of the 618 patients with leukemia, 70 children with abdominal pain were identified, and 17 were diagnosed with AP. The prevalence of AP was 2.8%. Most children with acute leukemia and AP had T-cell subtypes (50.0%) and received high- to very-high-risk treatment protocols (76.5%). Patients with AP experienced a shorter duration of abdominal pain before diagnosis and required imaging more frequently than the non-AP patients did (100% vs. 56.6%). They required a prolonged fasting period and greater intravenous fluid volume within 48 h. The overall mortality rate (all-cause during follow-up) was significantly higher in the AP group. Using high- to very-high-risk chemotherapy protocols was a risk factor for AP, and the accumulative L-asparaginase dose of ≥55,200 IU/m² could increase AP risk. Conclusions: AP is significantly associated with increased overall mortality in children with acute leukemia. Careful monitoring of L-asparaginase dosing may be required. Larger studies are needed to better identify the risk factors and preventive strategies. Full article

Central nervous system (CNS) evaluation for leukemic involvement is essential both at initial diagnosis and throughout relapse surveillance in childhood acute lymphoblastic leukemia (ALL). Accurate CNS risk classification is a cornerstone of individualized chemotherapy and has significantly advanced treatment strategies. However, detecting leukemic cells in the cerebrospinal fluid (CSF) is challenging, particularly when only a small number of cells are present. While cytomorphology remains a standard diagnostic method, it is limited by low sensitivity and interobserver variability, especially in low-cellularity or equivocal samples. Flow cytometry offers superior sensitivity and specificity and is increasingly recommended to confirm or clarify ambiguous findings. Current guidelines support the use of both cytomorphologic review and flow cytometry to maximize diagnostic accuracy. Evidence consistently demonstrates that any detectable CSF blasts—even in the setting of low WBC counts—are associated with increased risk of CNS relapse and poorer outcomes, underscoring the importance of risk-adapted CNS-directed therapy. Although the prognostic significance of isolated flow-only positivity remains under study, emerging data suggest that timely therapeutic intensification may mitigate adverse outcomes. Additional modalities, including advanced flow cytometry and molecular assays, may further refine CSF assessment in the future. This review summarizes current diagnostic approaches and highlights the need for standardized protocols for CSF evaluation in pediatric ALL. Full article

Background/Objectives: Molecular subtyping of pediatric B-cell acute lymphoblastic leukemia (B-ALL) has improved patient outcomes through stratification and selection of targeted therapies. Despite extensive genomic and transcriptomic profiling of this cancer, few studies to date have characterized the proteomic landscape, although proteins are the direct targets of many therapeutic agents. Methods: In this study, we demonstrate the utility of multi-omic integration of global transcriptomic, proteomic, and phosphoproteomic profiles of samples from patients diagnosed with either of two B-ALL subtypes—Ph-like (BCR::ABL1-like) and ETV6::RUNX1. Through individual and multi-omic analysis, we recapitulate known transcriptomic findings and identify novel subtype-specific proteomic and phosphoproteomic biomarkers. Conclusions: Our findings suggest a previously undescribed role for calcium-dependent signaling processes in Ph-like B-ALL, which has the potential to serve as a novel avenue for targeted treatments. By integrating multiple -omics modalities, we identify not only features of interest but also begin to unravel the regulatory interactions driving subtype-specific mechanisms of leukemogenesis. This integrated analytic approach paves the way for enhanced precision medicine for precise subtyping and treatment selection for pediatric leukemia patients. Full article

Hematopoietic stem cell transplant (HSCT) is a curative therapy for acute lymphoblastic leukemia (ALL), but its success is limited by chronic graft-versus-host disease (cGvHD) and disease relapse. A central challenge is uncoupling the graft-versus-leukemia (GvL) effect from cGvHD. Early changes in the bone marrow microenvironment following HSCT may offer a predictive window into these divergent outcomes. We conducted a retrospective, single-center, exploratory study on 14 pediatric ALL HSCT patients. Applying single-cell antibody-sequencing (AbSeq) on archived bone marrow aspirates collected 60–100 days post-HSCT, we evaluated immune patterns associated with the development of cGvHD or ALL relapse after day 114. cGvHD after day 114 was associated with upregulation of the endoplasmic reticulum (ER) stress transcription factor XBP1 in transitional B cell and IgM memory B cell populations, a mincle^highPD1⁻ neutrophil population, and exhausted LAG3⁺ effector memory T cells (T_EM). ALL relapse after day 114 was associated with higher CD22, CD24, and ARG1 expression in M(IL-4)-like macrophages and exhausted TIGIT⁺ T_EM. Results from this exploratory study suggest that marrow immune signatures of B cell ER stress preceding later development of cGvHD and macrophage-mediated immune evasion preceding relapse may potentially be early biomarkers for separating GvL from cGvHD in ALL HSCT. Validation with larger cohorts is warranted. Full article

Background/Objectives: B-cell precursor acute lymphoblastic leukemia (B-ALL), the most common pediatric acute leukemia (AL), is frequently characterized by aberrant antigen expression, which aids diagnosis and prognosis. The myeloid antigen CD66c is notably frequent in B-ALL and has been proposed as a marker of disease aggressiveness and treatment response. Evaluating CD66c in Mexican pediatric patients may provide insights into disease biology. Methods: A cohort of 128 pediatric patients was referred to the Laboratory of Oncoimmunology and Cytomics of Childhood Cancer (OCL) at Instituto Mexicano del Seguro Social (IMSS) for immunophenotyping tests between March 2022 and November 2023. Additionally, control bone marrow (BM) samples were assessed. Aberrant antigen expression in hematopoietic populations and BM microenvironment stroma phenotyping were performed. Results: In total, 84.38% of B-ALL patients exhibited aberrant expression of ≥1 myeloid antigen. Among CD66c-positive patients, 13.79% had detectable measurable residual disease (MRD) during follow-up and 20.69% died. Mesenchymal stromal cells (MSCs) from patients with positive or low CD66c expression displayed inflammatory profiles. ProB leukemias with low CD66c expression were more likely to exhibit detectable MRD, increased mortality, and reduced survival. Conclusions: Low CD66c expression induces molecular stealth that could favor immune evasion and niche persistence, thereby increasing the risk of relapse and therapeutic failure. Full article

Background/Objectives: This pilot study aimed to evaluate the metabolic profiles in plasma and cerebrospinal fluid (CSF) of 14 patients with acute lymphoblastic leukemia (ALL) and plasma of a control group, using proton magnetic resonance spectroscopy (¹H NMR). Methods: Multivariate analysis, including orthogonal partial least-squares discriminant analysis (OPLS-DA), was used to analyze the metabolome composition. Results: Significant differences in plasma metabolic profiles were found between the ALL and control groups. We detected elevated levels of formate, citrate, and glycerophosphocholine (GPC), along with decreased concentrations of glutamine and myo-inositol. The OPLS-DA model showed stability, with R²Y = 69.7% and Q² = 45.15%. Additionally, we observed differences in chemical shifts for leucine, myo-inositol, alanine, phenylalanine, and valine between CSF and plasma in patients with ALL. Conclusions: Our findings suggest that metabolomic analysis with ¹H NMR is a promising tool for identifying potential molecular biomarkers and for deepening our understanding of metabolic reprogramming in pediatric ALL. The observed metabolic differences highlight the potential involvement of the central nervous system in the disease’s pathophysiology. Full article

Background: Cardiorespiratory fitness is frequently impaired in survivors of pediatric acute lymphoblastic leukemia (ALL), limiting their functional performance. While aerobic exercise is recommended, evidence is needed to guide the prescription of specific training protocols in this population. Objective: This study sought to compare the efficacy of constant-load (CL-AEx) and graded aerobic exercise (G-AEx) protocols on cardiorespiratory fitness and functional capability in pediatric survivors of ALL. Methods: Seventy-two pediatric ALL survivors were allocated to CL-AEx, G-AEx, or a control group. Cardiopulmonary fitness [peak oxygen consumption (peak VO₂), peak minute ventilation (VE), ventilatory equivalent for oxygen (VE/VO₂), respiratory exchange ratio (RER), peak oxygen pulse (peak O₂P), maximum heart rate (max HR), and one-minute heart rate recovery (HHR₁)] and functional performance [six-minute walk test (6MWT), 4x10-m shuttle run test (4x10-mSRT), and timed up down stairs (TUDS)] were assessed at pre- and post-intervention. Results: The G-AEx group exhibited significantly enhanced cardiorespiratory and functional outcomes compared to both the CL-AEx and control groups (all p < 0.05). The G-AEx group demonstrated more pronounced improvements, showing significant increases in peak VO₂, VE, VE/VO₂, peak O₂P, and HHR1, alongside a more efficient RER. Functionally, the G-AEx intervention led to superior improvements in 6MWT distance, and significantly faster completion times in the 4x10-mSRT and TUDS, highlighting multi-domain functional gain. Conclusions: In pediatric survivors of ALL, G-AEx demonstrated superior improvements in cardiorespiratory fitness and functional performance compared to CL-AEx over 12 weeks. These findings suggest that G-AEx is an effective modality for addressing acute physical deconditioning in this population. Incorporating G-AEx into clinical rehabilitation may enhance immediate physiological and functional recovery during the survivorship phase. Full article

Background: Myeloid sarcoma (MS) is a malignant extramedullary tumor that occurs in patients with acute myeloid leukemia (AML), myelodysplastic syndrome (MDS), or chronic myeloid leukemia (CML). The standard first-line treatment for MS is intensive chemotherapy according to the AML protocol, regardless of bone marrow involvement. The role of allogeneic hematopoietic stem cell transplantation (alloHSCT) in the treatment of pediatric patients with MS requires further investigation. The aim of the study was to evaluate treatment outcomes for MS in pediatric patients with a focus on assessing the impact of allogeneic hematopoietic stem cell transplantation (alloHSCT) on treatment efficacy. Material and Methods: The study included 64 patients aged 0 to 19 years from 15 pediatric oncology centers in Poland who were diagnosed with MS between 1998 and 2024. An Excel database was created to collect data on clinical features and treatment methods and outcomes. Results: The probability of 5-year overall survival (pOS) for the entire cohort was 0.63 ± 0.07, while the 5-year event-free survival (pEFS) and 5-year relapse-free survival (pRFS) were 0.62 ± 0.07 and 0.72 ± 0.07, respectively. Treatment outcomes were compared between patients who underwent allogeneic hematopoietic stem cell transplantation (alloHSCT) in first complete remission (ICR) (n1 = 17/64; 27%) and those who did not receive alloHSCT (n2 = 47/64; 73%). In the alloHSCT group (n1), the estimated survival probabilities were pOS = 0.49 ± 0.13, pEFS = 0.44 ± 0.14, and pRFS = 0.40 ± 0.14. In the non-alloHSCT group (n2), these values were pOS = 0.68 ± 0.08, pEFS = 0.68 ± 0.08, and pRFS = 0.84 ± 0.06. The difference in pRFS between groups n1 and n2 was statistically significant (p = 0.0049). Extramedullary relapses were more frequently observed in patients who had undergone allogeneic hematopoietic stem cell transplantation (alloHSCT) (p = 0.0001). Conclusions: Allogeneic hematopoietic stem cell transplantation (alloHSCT) does not improve the outcome of patients with MS. Further research is needed to identify effective strategies for sustaining remission in patients with MS after alloHSCT. Full article