variants underlying pediatric low-hypodiploidy B-cell acute lymphoblastic leukemia demonstrate diverse origins and may persist as a hematopoietic clone in remission.

Pediatric low-hypodiploidy B-cell acute lymphoblastic leukemia (LH-ALL) with variants has been proposed to be considered a manifestation of Li-Fraumeni syndrome (LFS). However, our study demonstrates that of the majority the pathogenic variants in the TP53 gene are somatic (70.5%), and only 12.

Pediatric therapy-related hematologic neoplasms show enrichment for rearrangement and lymphoblastic phenotype.

In children, therapy-related hematologic neoplasms (t-HN) are uncommon. Many are driven by genetic events independent of clonal hematopoiesis. We sought to understand the clinical and genetic factors of pediatric t-HN in a large independent cohort.

Rapid but nondurable response of a exon 15 double-mutated spindle cell sarcoma to a combination of BRAF and MEK inhibitors.

Introduction: BRAF V600E substitution predicts sensitivity of a cancer to BRAF inhibitor therapy. The mutation is rarely found in soft-tissue sarcomas. Here we describe a case of undifferentiated spindle cell sarcoma showing primary insensitivity to standard chemotherapy and pronounced but non-sustained response to BRAF/MEK inhibitors at recurrence.

Midline Low-Grade Gliomas of Early Childhood: Focus on Targeted Therapies.

Purpose: Midline low-grade gliomas (mLGGs) of early childhood have a poorer prognosis compared with tumors of other localizations and in older patients. LGGs are associated with aberrant activation of RAS-RAF-MEK pathway, and pharmacological inhibition of the pathway has therapeutic promise. The aim of this study was clinical and molecular characterization of infantile mLGGs, with emphasis on the efficacy of targeted kinase inhibition.

Immunophenotypic but Not Genetic Changes Reclassify the Majority of Relapsed/Refractory Pediatric Cases of Early T-Cell Precursor Acute Lymphoblastic Leukemia.

Early T-cell precursor acute lymphoblastic leukemia (ETP-ALL) develops from very early cells with the potential for both T-cell and myeloid differentiation. The ambiguous nature of leukemic blasts in ETP-ALL may lead to immunophenotypic alterations at relapse. Here, we address immunophenotypic alterations and related classification issues, as well as genetic features of relapsed pediatric ETP-ALL.

Blinatumomab as postremission therapy replaces consolidation and substantial parts of maintenance chemotherapy and results in stable MRD negativity in children with newly diagnosed B-lineage ALL.

The bispecific T cell-binding antibody blinatumomab (CD19/CD3) is widely and successfully used for the treatment of children with relapsed or refractory B-cell precursor acute lymphoblastic leukemia (BCP-ALL). Here, we report the efficacy of a single course of blinatumomab instead of consolidation chemotherapy to eliminate minimal residual disease (MRD) and maintain stable MRD-negativity in children with primary BCP-ALL.Between February 2020 and November 2022, 177 children with non-high-risk BCP-ALL were enrolled in the ALL-MB 2019 pilot study (NCT04723342).

Dissecting thrombus-directed chemotaxis and random movement in neutrophil near-thrombus motion in flow chambers.

Background: Thromboinflammation is caused by mutual activation of platelets and neutrophils. The site of thromboinflammation is determined by chemoattracting agents release by endothelium, immune cells, and platelets. Impaired neutrophil chemotaxis contributes to the pathogenesis of Shwachman-Diamond syndrome (SDS).

Combined therapy with IL-1 and JAK inhibitors in a patient with the gene mutation and a complex inflammatory phenotype.

A patient presented with overlapping clinical and laboratory features of 2 rare autoinflammatory diseases, NLRP1-associated autoinflammation with arthritis and dyskeratosis and familial multiple self-healing palmoplantar carcinoma. Her severe inflammatory attack was treated with the IL-1 receptor-α inhibitor anakinra along with the Janus kinase inhibitor ruxolitinib. Three years into the treatment, the patient's inflammatory symptoms are completely in remission.

Flow cytometric minimal residual disease measurement accounting for cytogenetics in children with non-high-risk acute lymphoblastic leukemia treated according to the ALL-MB 2008 protocol.

Background: Quantitative measurement of minimal residual disease (MRD) is the "gold standard" for estimating the response to therapy in childhood B-cell precursor acute lymphoblastic leukemia (BCP-ALL). Nevertheless, the speed of the MRD response differs for different cytogenetic subgroups. Here we present results of MRD measurement in children with BCP-ALL, in terms of genetic subgroups with relation to clinically defined risk groups.

Laboratory characterization of the pediatric B/T subtype of mixed-phenotype acute leukemia: Report of a case series.

Objectives: Mixed-phenotype acute leukemia (MPAL) is a rare disease associated with difficulties in the correct lineage assignment of leukemic cells. One of the least common subtypes within this category is characterized by the simultaneous presence of B- and T-lineage-defining antigens. Each case of suspected B/T MPAL should be considered in light of all available laboratory and clinical data to avoid misdiagnosis.

Flow cytometry for comprehensive assessment of platelet functional activity in response to ADP stimulation.

Objectives: Flow cytometry with adenosine diphosphate (ADP) allows to characterize molecular changes of platelet function caused by this physiologically important activation, but the methodology has not been thoroughly investigated, standardized and characterized yet. We analyzed the influence of several major variables and chose optimal conditions for platelet function assessment.

Methods: For activation, 2.

A Single Dose of PEG-Asparaginase at the Beginning of Induction Not Only Accelerates MRD Clearance but Also Improves Long-Term Outcome in Children with B-Lineage ALL.

Unlabelled: This report presents the results of the assessment of MRD response by multicolor flow cytometry (MFC) with regard to the randomized use of pegylated asparaginase (PEG). In this study, PEG was randomly administered at a dose of 1000 U/m on day 3 of induction therapy in children with B-lineage ALL.

Methods: Conventional induction therapy consisted of dexamethasone, vincristine, and daunorubicin.

Novel hemizygous variant leads to combined immunodeficiency with defective platelet calcium signaling and cell mobility.

Background: To date, fewer than 20 patients have been identified as having germline biallelic mutations in the coronin-1A gene () and its protein with clinical features of combined immunodeficiency characterized by T-cell lymphopenia ranging from the severe phenotype to the mild phenotype, recurrent infections, and lymphoproliferative disorders. However, the effects of CORO1A protein disruption on actin-dependent functions in primary cells have not been fully delineated.

Objective: We sought to characterize the underlying defects of actin-dependent cellular functions in a female patient with combined immunodeficiency caused by a novel missense variant in the gene in combination with a heterozygous microdeletion of chromosome 16p11.

Comparison of platelet proteomic profiles between children and adults reveals origins of functional differences.

Background: Platelets are blood cells responsible for the prevention of blood loss upon vessel wall disruption. It has been demonstrated that platelet functioning differs significantly between adult and pediatric donors. This study aimed to identify potential differences between the protein composition of platelets of pediatric, adolescent, and adult donors.

Unusual Presentation of -Associated Concomitant Hematological Neoplasm in a Child-Diagnostic and Treatment Struggle.

Simultaneous multilineage hematologic malignancies are uncommon and associated with poorer prognosis than single-lineage leukemia or lymphoma. Here, we describe a concomitant malignant neoplasm in a 4-year-old boy. The child presented with massive lymphoproliferative syndrome, nasal breathing difficulties, and snoring.

Case Report: Two clinical cases of Wilms tumor comorbid to gingival fibromatosis in young children with constitutionally mutated .

Introduction: Nephroblastoma (Wilms tumor (WT)) is an embryonal tumor accounting for >90% of pediatric renal cancers. About 10% of WTs harbor pathogenic germline mutations. The gene, classified as a putative tumor suppressor, is affected in 2% of WTs.

Platelet functional abnormalities in pediatric patients with kaposiform hemangioendothelioma/Kasabach-Merritt phenomenon.

Kaposiform hemangioendothelioma (KHE) is a rare vascular tumor of infancy that is commonly associated with a life-threatening thrombocytopenic condition, Kasabach-Merritt phenomenon (KMP). Platelet CLEC-2, tumor podoplanin interaction is considered the key mechanism of platelet clearance in these patients. Here, we aimed to assess platelet functionality in such patients.

Accelerated death of megakaryocytes from Wiskott-Aldrich syndrome patients.

Wiskott-Aldrich syndrome (WAS) is an X-linked recessive disorder caused by WAS gene mutations resulting in haematopoietic/immune cell defects. Recent studies report accelerated death of WAS platelets and lymphocytes. Data on megakaryocyte (MK) maturation, viability and their possible role in thrombocytopenia development in WAS are limited.

Vemurafenib combined with cladribine and cytarabine results in durable remission of pediatric BRAF V600E-positive LCH.

Langerhans cell histiocytosis (LCH) is a disorder with a variety of clinical signs. The most severe forms affect risk organs (RO). The established role of the BRAF V600E mutation in LCH led to a targeted approach.

Novel SLFN14 mutation associated with macrothrombocytopenia in a patient with severe haemorrhagic syndrome.

Background: Platelet-type bleeding disorder 20 (BDPLT20), as known as SLFN14-related thrombocytopenia, is a rare inherited thrombocytopenia (IT). Previously, only 5 heterozygous missense mutations in the SLFN14 gene have been reported.

Methods: A comprehensive clinical and laboratory examination of a 17-year-old female patient with macrothrombocytopenia and severe mucocutaneous bleeding was performed.

Recognizing Minor Leukemic Populations with Monocytic Features in Mixed-Phenotype Acute Leukemia by Flow Cell Sorting Followed by Cytogenetic and Molecular Studies: Report of Five Exemplary Cases.

Mixed-phenotype acute leukemia (MPAL), a rare and heterogeneous category of acute leukemia, is characterized by cross-lineage antigen expression. Leukemic blasts in MPAL can be represented either by one population with multiple markers of different lineages or by several single-lineage populations. In some cases, a major blast population may coexist with a smaller population that has minor immunophenotypic abnormalities and may be missed even by an experienced pathologist.

Molecular Heterogeneity of Pediatric AML with Atypical Promyelocytes Accumulation in Children-A Single Center Experience.

Acute promyelocytic leukemia (APL) pathogenesis is based on gene translocations, which are of high importance in the diagnosis of and proper therapy selection for APL. However, in some cases acute myeloid leukemia (AML) demonstrates APL-like morphological features such as atypical promyelocytes accumulation. This type of AML is characterized by the involvement of other family members or completely different genes.