[131-I-meta-iodo-benzyl-guanidine therapy in childhood neuroblastoma.] / Gyermekkori neuroblastoma kezelésében alkalmazott 131-I-meta-jodo-benzil-guanidin terápia.

Neuroblastoma, representing one-tenth of childhood malignancies, is a clinically and prognostically heterogeneous disease. Survival in cases with poor prognosis has recently been significantly improved by rapidly evolving multimodal therapy. Our 4-year-old patient presented with bitemporal swelling and the diagnostic workup confirmed stage IV neuroblastoma (bone marrow and multiple bone metastases). While the tumor responded well to the initial treatment, it relapsed during post-consolidation therapy. As part of the salvage therapy for this high-risk disease with poor prognosis, 131-I-meta-iodo-benzyl-guanidine treatment was performed for the first time in our country, in a case of pediatric neuroblastoma. Neuroendocrine tissue cells express a norepinephrine transporter capable of uptaking the catecholamine analog meta-iodo-benzyl-guanidine. This mechanism makes it an adequate molecule for the imaging (123-I-meta-iodo-benzyl-guanidine) and target therapy (131-I-meta-iodo-benzyl-guanidine) of neuroendocrine tumors, including neuroblastoma. Treatment with 131-I-meta-iodo-benzyl-guanidine requires specific personnel and infrastructural equipment, particularly in pediatric cases. Careful organization and cooperation between nuclear medicine specialists and collaborating clinicians (pediatric oncologists and adult internists if necessary) are essential. Meta-iodo-benzyl-guanidine therapy, already routinely used abroad, has been considered as part of salvage therapy for recurrent neuroblastoma until now, but ongoing clinical trials suggest that it may become part of the first-line treatment soon. As the indications broaden, it is necessary to make it available for more and more children in our country. Orv Hetil. 2023; 164(39): 1550-1555.

PersonALL: a genetic scoring guide for personalized risk assessment in pediatric B-cell precursor acute lymphoblastic leukemia.

BACKGROUND: Recurrent genetic lesions provide basis for risk assessment in pediatric acute lymphoblastic leukemia (ALL). However, current prognostic classifiers rely on a limited number of predefined sets of alterations. METHODS: Disease-relevant copy number aberrations (CNAs) were screened genome-wide in 260 children with B-cell precursor ALL. Results were integrated with cytogenetic data to improve risk assessment. RESULTS: CNAs were detected in 93.8% (n = 244) of the patients. First, cytogenetic profiles were combined with IKZF1 status (IKZF1normal, IKZF1del and IKZF1plus) and three prognostic subgroups were distinguished with significantly different 5-year event-free survival (EFS) rates, IKAROS-low (n = 215): 86.3%, IKAROS-medium (n = 27): 57.4% and IKAROS-high (n = 18): 37.5%. Second, contribution of genetic aberrations to the clinical outcome was assessed and an aberration-specific score was assigned to each prognostically relevant alteration. By aggregating the scores of aberrations emerging in individual patients, personalized cumulative values were calculated and used for defining four prognostic subgroups with distinct clinical outcomes. Two favorable subgroups included 60% of patients (n = 157) with a 5-year EFS of 96.3% (excellent risk, n = 105) and 87.2% (good risk, n = 52), respectively; while 40% of patients (n = 103) showed high (n = 74) or ultra-poor (n = 29) risk profile (5-year EFS: 67.4% and 39.0%, respectively). CONCLUSIONS: PersonALL, our conceptually novel prognostic classifier considers all combinations of co-segregating genetic alterations, providing a highly personalized patient stratification.

Next-Generation Sequencing-Based Genomic Profiling of Children with Acute Myeloid Leukemia.

Pediatric acute myeloid leukemia (AML) represents a major cause of childhood leukemic mortality, with only a limited number of studies investigating the molecular landscape of the disease. Here, we present an integrative analysis of cytogenetic and molecular profiles of 75 patients with pediatric AML from a multicentric, real-world patient cohort treated according to AML Berlin-Frankfurt-Münster protocols. Targeted next-generation sequencing of 54 genes revealed 17 genes that were recurrently mutated in >5% of patients. Considerable differences were observed in the mutational profiles compared with previous studies, as BCORL1, CUX1, KDM6A, PHF6, and STAG2 mutations were detected at a higher frequency than previously reported, whereas KIT, NRAS, and KRAS were less frequently mutated. Our study identified novel recurrent mutations at diagnosis in the BCORL1 gene in 9% of the patients. Tumor suppressor gene (PHF6, TP53, and WT1) mutations were found to be associated with induction failure and shorter event-free survival, suggesting important roles of these alterations in resistance to therapy and disease progression. Comparison of the mutational landscape at diagnosis and relapse revealed an enrichment of mutations in tumor suppressor genes (16.2% versus 44.4%) and transcription factors (35.1% versus 55.6%) at relapse. Our findings shed further light on the heterogeneity of pediatric AML and identify previously unappreciated alterations that may lead to improved molecular characterization and risk stratification of pediatric AML.

Assessment of the results and hematological side effects of 3D conformal and IMRT/ARC therapies delivered during craniospinal irradiation of childhood tumors with a follow-up period of five years.

BACKGROUND: Craniospinal irradiation (CSI) of childhood tumors with the RapidArc technique is a new method of treatment. Our objective was to compare the acute hematological toxicity pattern during 3D conformal radiotherapy with the application of the novel technique. METHODS: Data from patients treated between 2007 and 2014 were collected, and seven patients were identified in both treatment groups. After establishing a general linear model, acute blood toxicity results were obtained using SPSS software. Furthermore, the exposure dose of the organs at risk was compared. Patients were followed for a minimum of 5 years, and progression-free survival and overall survival data were assessed. RESULTS: After assessment of the laboratory parameters in the two groups, it may be concluded that no significant differences were detected in terms of the mean dose exposures of the normal tissues or the acute hematological side effects during the IMRT/ARC and 3D conformal treatments. Laboratory parameters decreased significantly compared to the baseline values during the treatment weeks. Nevertheless, no significant differences were detected between the two groups. No remarkable differences were confirmed between the two groups regarding the five-year progression-free survival or overall survival, and no signs of serious organ toxicity due to irradiation were observed during the follow-up period in either of the groups. CONCLUSION: The RapidArc technique can be used safely even in the treatment of childhood tumors, as the extent of the exposure dose in normal tissues and the amount of acute hematological side effects are not higher with this technique.

Late mortality in survivors of childhood cancer in Hungary.

The Hungarian Pediatric Oncology Network provides centralized treatment and population-based registration for cases of childhood cancer since 1973. We collected and analized data on late mortality, secondary malignancies and cardiac diseases in survivors (> 5 years) of childhood cancer to evaluate long-term risks. We extracted all solid tumour cases (3,650 followed up for 5-39.3 years, diagnosis: 1973-2008) from the database of the Hungarian Childhood Cancer Registry and checked against the Population Registry. Among the 301 patients who died after 5 years (8.2%) the most common causes of death were progression of primary cancer (52.5%), secondary malignancies (16%) and cardiovascular diseases (8%). Late mortality rates (SMR, total: 35,006 pyrs) showed highly elevated risk of death (SMR: 10.7 95% CI 9-12.4) for the second 5 years of follow up and moderately elevated risk for 10-year survivors (SMR: 3.5 95% CI 3-4.1). Marked differences were detected in the pattern of causes of death between diagnostic groups of primary cancer; with highest risks beyond 10 years for CNS tumours, Hodgkin disease, osteosarcoma and advanced stage neuroblastoma. The longstanding mortality risk for 5-year survivors underlines the need for tailored long-term follow-up and monitoring of late consequences according to the context of different primary diseases of childhood cancer.

Comprehensive profiling of disease-relevant copy number aberrations for advanced clinical diagnostics of pediatric acute lymphoblastic leukemia.

Acute lymphoblastic leukemia is the most common pediatric cancer characterized by a heterogeneous genomic landscape with copy number aberrations occurring at various stages of pathogenesis, disease progression, and treatment resistance. In this study, disease-relevant copy number aberrations were profiled in bone marrow samples of 91 children with B- or T-cell precursor acute lymphoblastic leukemia using digital multiplex ligation-dependent probe amplification (digitalMLPATM). Whole chromosome gains and losses, subchromosomal copy number aberrations, as well as unbalanced alterations conferring intrachromosomal gene fusions were simultaneously identified with results available within 36 hours. Aberrations were observed in 96% of diagnostic patient samples, and increased numbers of copy number aberrations were detected at the time of relapse as compared with diagnosis. Comparative scrutiny of 24 matching diagnostic and relapse samples from 11 patients revealed three different patterns of clonal relationships with (i) one patient displaying identical copy number aberration profiles at diagnosis and relapse, (ii) six patients showing clonal evolution with all lesions detected at diagnosis being present at relapse, and (iii) four patients displaying conserved as well as lost or gained copy number aberrations at the time of relapse, suggestive of the presence of a common ancestral cell compartment giving rise to clinically manifest leukemia at different time points during the disease course. A newly introduced risk classifier combining cytogenetic data with digitalMLPATM-based copy number aberration profiles allowed for the determination of four genetic subgroups of B-cell precursor acute lymphoblastic leukemia with distinct event-free survival rates. DigitalMLPATM provides fast, robust, and highly optimized copy number aberration profiling for the genomic characterization of acute lymphoblastic leukemia samples, facilitates the decipherment of the clonal origin of relapse and provides highly relevant information for clinical prognosis assessment.

[High hyperdiploid acute lymphoblastic leukemia is a highly curable subtype of childhood leukemia]. / A gyermekkori akut limfoblasztos leukémia kedvezõ prognosztikai alcsoportja: a magasan hiperdiploid leukémia.

Acute lymphoblastic leukemia (ALL) is the most frequent malignancy in children. In Hungary 60-70 new cases are diagnosed annually. The survival rate is 85-90% in developed countries with current treatment protocols. The most common genetic category of childhood ALL is the high hyperdiploid subtype (HHD) with chromosome numbers of 51 to 67. It accounts for approximately 25% of all cases. The prognosis is very good, though relapse occurs in ~15% of cases and there are data on the heterogeneity of this subgroup as well. In this paper we give an overview of the cytogenetic, clinical, epidemiological and prognostic features of this subgroup. We also demonstrate our interphase fluorescent in situ hybridization (iFISH) analysis performed retrospectively on 168 untreated bone marrow samples of precursor B pediatric ALL patients to reveal the numerical aberrations of chromosomes 4, 6, 10, 14, 17, 18, 21 and X, which are most frequently affected by gain in HHD ALL. Data from 48 high hyperdiploid patients indicated that high modal number (>55 chromosomes) and specific chromosomal gains (+4, +4/+6, +4/+17, +4/+18) exhibited significance in terms of beneficial overall survival.

Sequential and hierarchical chromosomal changes and chromosome instability are distinct features of high hyperdiploid pediatric acute lymphoblastic leukemia.

BACKGROUND: Pathogenesis of the non-random accumulation of extra chromosomes in the low and high hyperdiploid (HeL, HeH) pre-B pediatric acute lymphoblastic leukemia (B-pALL) is largely unknown, and has been clarified with respect only to tetrasomic chromosomes. We analyzed the hierarchy of changes in chromosome number and chromosomal instability, as well as clonal heterogeneity and evolution, in the untreated bone marrow cell samples from 214 B-pALL patients. PROCEDURE: Applying relocation, 2 × 4 color interphase fluorescence in situ hybridization was used to detect copy number alterations (CNAs) of the most commonly involved chromosomes, 4, 6, 10, 14, 17, 18, 21, and X. This approach allowed us to acquire a dataset correlated for all eight parameters. RESULTS: Based on chromosome number, an average of 6.9 and 10.2, whereas according to unique constellation 15.3 and 26.7 subclones could be identified in the HeL and HeH subgroups, respectively. Cluster analysis revealed the order of CNAs to chromosomes was highly conserved, and network analysis indicated changes in chromosome number were sequential for 80-90% of all numerical aberrations. Significant chromosome instability was revealed in both subgroups of leukemia. CONCLUSIONS: Data generated using this new approach indicate that chromosomal instability, which causes heterogeneity in the subclonal landscape, and the sequential changes to chromosome numbers, are both determining factors in the pathomechanism of the hyperdiploid B-pALL. These new observations could prompt research into the mitotic machinery of leukemic cells to identify new therapeutic targets for treating this disease.

A novel IL2RG mutation associated with maternal T lymphocyte engraftment in a patient with severe combined immunodeficiency.

Severe combined immunodeficiency (SCID) represents a genetically heterogeneous group of primary immunodeficiency disorders. Irrespective of the genetic defect, patients with SCID may be engrafted with transplacentally derived maternal T-lymphocytes that in a subset of cases may be responsive to phytohemagglutinin. Here, we present, from a genetic perspective, an SCID patient who not only harbored a novel mutation in the gene encoding the common gamma chain (gamma c) of the IL-2 receptor (IL2RG), but also carried reactive maternal T lymphocytes that produced a karyotype that was initially perplexing.