Rituximab-combined anthracycline-free chemotherapy in newly diagnosed paediatric and adolescent patients with non-high-risk aggressive mature B cell lymphoma: protocol for a single-arm, open-label, multicentre, phase II study (the Japan Children's Cancer Group Multicentre Trial, JPLSG B-NHL-20).

INTRODUCTION: Children and adolescents with mature B cell non-Hodgkin lymphoma (B-NHL) are treated with short-intensive chemotherapy. The burden of short-term and long-term toxicity is highly relative to its high cure rate in good-risk patients. Although the addition of rituximab to standard lymphome Malin B (LMB) chemotherapy markedly prolongs event-free survival and overall survival in high-risk patients, the benefit of rituximab in good-risk patients remains to be elucidated. This clinical trial will examine whether the addition of rituximab eliminates anthracyclines in good-risk patients without compromising treatment outcomes. METHODS AND ANALYSIS: We will perform a single-arm, open-label, multicentre phase II study. Low-risk (stage I - completely resected, stage II abdominal) and intermediate-risk (stages I and II - incompletely resected; stage II - resected, other than abdominal; stage III with LDH <2× upper limit of normal) patients with newly diagnosed B-NHL are eligible. Low-risk patients receive two courses of R-COM1P (rituximab, cyclophosphamide, vincristine, methotrexate, prednisolone and intrathecal methotrexate with hydrocortisone), and intermediate-risk patients receive COP (cyclophosphamide, vincristine, prednisolone and intrathecal methotrexate with hydrocortisone) followed by two courses each of R-COM3P and R-CYM (rituximab, cytarabine, methotrexate and intrathecal methotrexate with hydrocortisone). The primary endpoint is a 3-year event-free survival rate in paediatric patients (<18 years) with intermediate-risk disease. 100 patients (10 low-risk and 90 intermediate-risk) will enrol within a 4-year enrolment period and the follow-up period will be 3 years. 108 institutions are participating as of 1 January 2024 (64 university hospitals, 29 general hospitals, 12 children's hospitals and three cancer centres). ETHICS AND DISSEMINATION: This research was approved by the Certified Review Board at NHO Nagoya Medical Center (Nagoya, Japan) on 21 September 2021. Written informed consent is obtained from all patients and/or their guardians. The results of this study will be disseminated through peer-reviewed publications and conference presentations. STUDY REGISTRATION: Japan Registry of Clinical Trials, jRCTs041210104.

Rituximab with standard LMB chemotherapy in pediatric high-risk mature B-cell non-Hodgkin lymphoma: A report from the JPLSG B-NHL14 trial.

BACKGROUND: The benefit of adding rituximab to standard lymphomes malins B (LMB) chemotherapy for children with high-risk mature B-cell non-Hodgkin lymphoma (B-NHL) has previously been demonstrated in an international randomized phase III trial, to which the Japanese Pediatric Leukemia/Lymphoma Study Group could not participate. METHODS: To evaluate the efficacy and safety of rituximab in combination with LMB chemotherapy in Japanese patients, we conducted a single-arm multicenter trial. RESULTS: In this study, 45 patients were enrolled between April 2016 and September 2018. A total of 33 (73.3%), 5 (11.1%), and 6 (13.3%) patients had Burkitt lymphoma/leukemia, diffuse large B-cell lymphoma, and aggressive mature B-NHL, not otherwise specified, respectively. Ten (22.2%) and 21 (46.7%) patients had central nervous system disease and leukemic disease, respectively. The median follow-up period was 47.5 months. Three-year event-free survival and overall survival were 97.7% (95% confidence interval, 84.9-99.7) and 100%, respectively. The only event was relapse, which occurred in a patient with diffuse large B-cell lymphoma. Seven patients (15.6%) developed Grade 4 or higher non-hematologic adverse events. Febrile neutropenia was the most frequent Grade 3 or higher adverse event after the pre-phase treatment, with a frequency of 54.5%. CONCLUSION: The efficacy and safety of rituximab in combination with LMB chemotherapy in children with high-risk mature B-NHL was observed in Japan.

Genome-wide assessment of genetic risk loci for childhood acute lymphoblastic leukemia in Japanese patients.

Not available.

[Clinical characteristics and outcomes of childhood B-ALL with ZNF384 and MEF2D rearrangements].

B-cell precursor acute lymphoblastic leukemia (BCP-ALL) has many subtypes with diverse clinical and biological features and outcomes. Next generation sequencing has revealed several novel subtypes, including the ZNF384 and MEF2D rearrangements. The clinical characteristics and outcomes of the largest series of BCP-ALL cases with ZNF384 and MEF2D rearrangements in an international collaborative study are described here. Patients with ZNF384 rearrangements appear to express various leukemic phenotypes, including BCP-ALL (with or without abnormal expression of myeloid markers) and B/myeloid mixed phenotype acute leukemia. We provide strong evidence that among BCP-ALL patients with a ZNF384 fusion, the partner gene is associated with demographic features and influences the outcome; particularly the EP300-ZNF384 fusion is associated with a low risk of relapse. MEF2D rearrangements have been primarily described in children and young adults with BCP-ALL. Previous research has suggested that patients with MEF2D-BCL9 fusion have a high risk of relapse. Despite having the MEF2D-HNRNPUL1 fusion gene, the prognosis was favorable. Improved diagnostic genomic testing will enable future prospective studies to clarify the clinical significance of the ZNF384 and MEF2D rearrangements in childhood and young adult BCP-ALL.

TP53 and RB1 alterations characterize poor prognostic subgroups in pediatric acute myeloid leukemia.

Pediatric acute myeloid leukemia (AML) is a poor prognostic subtype of pediatric leukemia. However, the detailed characteristics of many genetic abnormalities are yet to be established in this disease. Although TP53 and RB1 are established as representative tumor suppressor genes in various cancers, alterations of these two genes, especially RB1, have not been characterized in pediatric AML. We performed next-generation sequencing in 328 pediatric AML patients from the Japanese AML-05 trial to ascertain TP53 and RB1 alterations, and their prognostic implications. We identified seven patients with TP53 alterations (2.1%) and six patients with RB1 alterations (1.8%). These alterations were found in only patients without RUNX1::RUNX1T1, CBFB::MYH11, or KMT2A rearrangements. TP53 and RB1 were frequently co-deleted with their neighboring genes PRPF8 and ELF1, respectively. Patients with TP53 alterations had significantly lower 5-year overall survival (OS; 14.3% vs. 71.4%, p < 0.001) and lower 5-year event-free survival (EFS; 0% vs. 56.3%, p < 0.001); similarly, patients with RB1 had significantly lower 5-year OS (0% vs. 71.8%, p < 0.001) and lower 5-year EFS (0% vs. 56.0%, p < 0.001) when compared to patients without these alterations. In gene expression analyses, oxidative phosphorylation, glycolysis, and protein secretion were upregulated in patients with TP53 and/or RB1 alterations. Additionally, Kaplan-Meier analysis revealed that high expressions of SLC2A5, KCNAB2, and CD300LF were related to poor OS of non-core-binding factor AML patients (p < 0.001, p = 0.001, and p = 0.021, respectively). This study will contribute to the development of risk-stratified therapy and precision medicine in pediatric AML.

UBTF-internal tandem duplication as a novel poor prognostic factor in pediatric acute myeloid leukemia.

The prognosis of pediatric acute myeloid leukemia (AML) has improved via stratification therapy. However, relapse or death occurs in 30%-40% of cases. Novel genetic factors for pediatric AML need to be elucidated to improve prognosis. We detected recurrent internal tandem duplication in upstream binding transcription factor (UBTF-ITD) in 1.2% (6/503) of Japanese pediatric patients with de novo AML. No UBTF-ITD was detected in 175 adult patients with AML or in 65 cell lines that included 15 AML, 39 acute lymphoblastic leukemia, five chronic myeloid leukemia, and six neuroblastoma cell lines. All UBTF-ITDs were found in exon 13 and shared a duplicated region. UBTF-ITD was more frequently detected in patients with trisomy 8, FLT3-ITD, WT1 mutation, and/or high PRDM16 expression (trisomy 8, 3/6; FLT3-ITD, 5/6; WT1 mutation, 2/6; and high PRDM16 expression, 6/6). Gene expression patterns of patients with UBTF-ITD were similar to those of patients with NUP98::NSD1 or FUS::ERG. Survival analysis of the AML-05 cohort revealed that patients with UBTF-ITD had worse outcomes than those without UBTF-ITD (3-year event-free survival, 20% vs. 55%; 3-year overall survival, 40% vs. 74%). Moreover, among the 27 patients with trisomy 8, all three patients with UBTF -ITD had a poor prognosis resulting in early events (relapse or non-complete remission) within 1 year. Our findings suggest that UBTF-ITD may be a novel and significant prognostic factor for pediatric patients with AML.

Threshold theorem in isolated quantum dynamics with stochastic control errors.

We investigate the effect of stochastic control errors in the time-dependent Hamiltonian on isolated quantum dynamics. The control errors are formulated as time-dependent stochastic noise in the Schrödinger equation. For a class of stochastic control errors, we establish a threshold theorem that provides a sufficient condition to obtain the target state, which should be determined in noiseless isolated quantum dynamics, as a relation between the number of measurements and noise strength. The theorem guarantees that if the sum of the noise strengths is less than the inverse of computational time, the target state can be obtained through a constant-order number of measurements. If the opposite is true, the number of measurements to guarantee obtaining the target state increases exponentially with computational time. Our threshold theorem can be applied to any isolated quantum dynamics such as quantum annealing and adiabatic quantum computation. This article is part of the theme issue 'Quantum annealing and computation: challenges and perspectives'.

A phase III clinical trial evaluating efficacy and safety of minimal residual disease-based risk stratification for children with acute myeloid leukemia, incorporating a randomized study of gemtuzumab ozogamicin in combination with post-induction chemotherapy for non-low-risk patients (JPLSG-AML-20).

The purpose of this study is to establish a treatment with appropriate intensity for children (<16 years old at diagnosis) with de novo acute myeloid leukemia (excluding acute promyelocytic leukemia and myeloid leukemia associated with Down syndrome) according to a risk stratification based on recurrent leukemic cytogenetic abnormalities and flow-cytometric minimal residual disease at end of initial induction chemotherapy and to validate the safety and efficacy of gemtuzumab ozogamicin (GO)-combined post-induction chemotherapy for the non-low-risk (non-LR) patients. The primary endpoint of this phase III study is three-year disease-free survival rate, which will be compared between the GO and non-GO arms of the non-LR (intermediate-risk and high-risk [HR]) patients. All HR patients will be allocated to allogeneic hematopoietic stem cell transplantation in first remission. This trial has been registered at the Japan Registry of Clinical Trials (jRCTs041210015).

Genome-wide DNA methylation analysis in pediatric acute myeloid leukemia.

We investigated genome-wide DNA methylation patterns in 64 pediatric patients with acute myeloid leukemia (AML). Based on unsupervised clustering with the 567 most variably methylated cytosine guanine dinucleotide (CpG) sites, patients were categorized into 4 clusters associated with genetic alterations. Clusters 1 and 3 were characterized by the presence of known favorable prognostic factors, such as RUNX1-RUNX1T1 fusion and KMT2A rearrangement with low MECOM expression, and biallelic CEBPA mutations (all 8 patients), respectively. Clusters 2 and 4 comprised patients exhibiting molecular features associated with adverse outcomes, namely internal tandem duplication of FLT3 (FLT3-ITD), partial tandem duplication of KMT2A, and high PRDM16 expression. Depending on the methylation values of the 1243 CpG sites that were significantly different between FLT3-ITD+ and FLT3-ITD- AML, patients were categorized into 3 clusters: A, B, and C. The STAT5-binding motif was most frequently found close to the 1243 CpG sites. All 8 patients with FLT3-ITD in cluster A harbored high PRDM16 expression and experienced adverse events, whereas only 1 of 7 patients with FLT3-ITD in the other clusters experienced adverse events. PRDM16 expression levels were also related to DNA methylation patterns, which were drastically changed at the cutoff value of PRDM16/ABL1 = 0.10. The assay for transposase-accessible chromatin sequencing of AMLs supported enhanced chromatin accessibility around genomic regions, such as HOXB cluster genes, SCHIP1, and PRDM16, which were associated with DNA methylation changes in AMLs with FLT3-ITD and high PRDM16 expression. Our results suggest that DNA methylation levels at specific CpG sites are useful to support genetic alterations and gene expression patterns of patients with pediatric AML.

Genetic features of B-cell lymphoblastic lymphoma with TCF3-PBX1.

BACKGROUND: Lymphoblastic lymphoma (LBL) and acute lymphoblastic leukemia (ALL) are categorized as the same entity under precursor lymphoid neoplasms in the World Health Organization classification. However, compared to B-cell ALL, the molecular genetic makeup of B-cell LBL remains to be understood, mainly due to its rarity. We performed whole exome sequencing (WES) on seven patients with TCF3-PBX1-positive B-cell LBL. METHODS: WES was performed using DNA extracted from tumor specimens and paired blood samples at remission for six patients, and tumor-only analysis was performed for one patient whose remission sample was not available. For one patient, a relapsed sample was also analyzed. RESULTS: KMT2D variants and 6q LOH were found as recurrent alterations. Somatic variants of KMT2D were identified in three of the seven patients. Of note, the two patients with heterozygous nonsense variant of KMT2D were at stage III, without bone marrow infiltration. 6q LOH was also identified in two others, out of the seven patients. The common 6q deleted region of the two patients ranged from 6q12 to 6q16.3. Both patients had bone marrow infiltration. Analysis of recurrent case also revealed that the relapsed clone might be derived from a minor clone of the bone marrow at diagnosis. CONCLUSION: In this study, through WES for seven patients with TCF3-PBX1-positive B-LBL, we identified KMT2D mutations and 6q LOH as recurrent alterations. In order to elucidate the relationship between these recurrent alterations and disease specificity or outcomes, further studies comparing with TCF3-PBX1-positive B-ALL are required.

Clinical significance of RAS pathway alterations in pediatric acute myeloid leukemia.

RAS pathway alterations have been implicated in the pathogenesis of various hematological malignancies. However, their clinical relevance in pediatric acute myeloid leukemia (AML) is not well characterized. We analyzed the frequency, clinical significance, and prognostic relevance of RAS pathway alterations in 328 pediatric patients with de novo AML. RAS pathway alterations were detected in 80 (24.4%) of 328 patients: NF1 (n=7, 2.1%), PTPN11 (n=15, 4.6%), CBL (n=6, 1.8%), NRAS (n=44, 13.4%), KRAS (n=12, 3.7%). Most of these alterations in the RAS pathway were mutually exclusive also together with other aberrations of signal transduction pathways such as FLT3-ITD (P=0.001) and KIT mutation (P=0.004). NF1 alterations were frequently detected in patients with complex karyotype (P=0.031) and were found to be independent predictors of poor overall survival (OS) in multivariate analysis (P=0.007). At least four of seven patients with NF1 alterations had biallelic inactivation. NRAS mutations were frequently observed in patients with CBFB-MYH11 and were independent predictors of favorable outcomes in multivariate analysis (OS, P=0.023; event-free survival [EFS], P=0.037). Patients with PTPN11 mutations more frequently received stem cell transplantation (P=0.035) and showed poor EFS than patients without PTPN11 mutations (P=0.013). Detailed analysis of RAS pathway alterations may enable a more accurate prognostic stratification of pediatric AML and may provide novel therapeutic molecular targets related to this signal transduction pathway.

NUDT15 variants confer high incidence of second malignancies in children with acute lymphoblastic leukemia.

The effect of genetic variation on second malignant neoplasms (SMNs) remains unclear. First, we identified the pathogenic germline variants in cancer-predisposing genes among 15 children with SMNs after childhood leukemia/lymphoma using whole-exome sequencing. Because the prevalence was low, we focused on the association between SMNs and NUDT15 in primary acute lymphoblastic leukemia (ALL) cases. NUDT15 is one of the 6-mercaptopurine (6-MP) metabolic genes, and its variants are common in East Asian individuals. The prevalence of NUDT15 hypomorphic variants was higher in patients with SMNs (n = 14; 42.9%) than in the general population in the gnomAD database (19.7%; P = .042). In the validation study with a cohort of 438 unselected patients with ALL, the cumulative incidence of SMNs was significantly higher among those with (3.0%; 95% confidence interval [CI], 0.6% to 9.4%) than among those without NUDT15 variants (0.3%; 95% CI, 0.0% to 1.5%; P = .045). The 6-MP dose administered to patients with ALL with a NUDT15 variant was higher than that given to those without SMNs (P = .045). The 6-MP-related mutational signature was observed in SMN specimens after 6-MP exposure. In cells exposed to 6-MP, a higher level of 6-MP induced DNA damage in NUDT15-knockdown induced pluripotent stem cells. Our study indicates that NUDT15 variants may confer a risk of SMNs after treatment with 6-MP in patients with ALL.

Clinicopathological features and prognostic significance of programmed death ligand 1 in pediatric ALK-positive anaplastic large cell lymphoma: results of the ALCL99 treatment in Japan.

Programmed cell death 1/programmed death ligand 1 (PD-1/PD-L1) blockade is a promising therapy for hematological malignancies. However, the association of PD-L1 expression with the clinicopathological features and prognosis in pediatric ALK-positive anaplastic large cell lymphoma (ALCL) remains unclear. Using PD-L1/ALK immunofluorescence double staining, we evaluated the PD-L1 expression on tumor cells/tumor-infiltrating immune cells (TIICs) and the quantity of TIICs in 54 children with ALK-positive ALCL treated with the ALCL99 protocol. The percentages of PD-L1-positive tumor cells were significantly lower in patients with skin/mediastinum involvement, clinical high-risk group, present minimal disseminated disease (MDD), and a low ALK-antibody titer. The percentages of PD-L1-positive TIICs were significantly higher in patients with absent MDD. The percentages of TIICs were significantly lower in patients with absent MDD and a common morphological pattern. We classified patients according to the PD-L1 expression on tumor cells (Tumor-PD-L1), PD-L1 expression on TIICs (TIIC-PD-L1), and quantity of TIICs (TIIC-quantity). The progression-free survival (PFS) did not differ between Tumor-PD-L1high and Tumor-PD-L1low ALCL; TIIC-PD-L1high and TIIC-PD-L1low ALCL; and TIIC-quantityhigh and TIIC-quantitylow ALCL. According to the combined parameters of Tumor-PD-L1 and TIIC-quantity, Tumor-PD-L1high/TIIC-quantityhigh ALCL had a worse 5-year PFS than other ALCL (50% versus 83%; P = .009). Tumor-PD-L1high/TIIC-quantityhigh ALCL remained a significant prognostic factor in multivariate analysis (P = .044). This is the first study to demonstrate that a high tumoral PD-L1 expression with a high quantity of TIICs was associated with a poor prognosis in pediatric ALK-positive ALCL. The tumor microenvironment of ALK-positive ALCL may be relevant to the clinicopathological features and prognosis.

Characteristics of genetic alterations of peripheral T-cell lymphoma in childhood including identification of novel fusion genes: the Japan Children's Cancer Group (JCCG).

Peripheral T-cell lymphoma (PTCL) is a group of heterogeneous non-Hodgkin lymphomas showing a mature T-cell or natural killer cell phenotype, but its molecular abnormalities in paediatric patients remain unclear. By employing next-generation sequencing and multiplex ligation-dependent probe amplification of tumour samples from 26 patients, we identified somatic alterations in paediatric PTCL including Epstein-Barr virus (EBV)-negative (EBV- ) and EBV-positive (EBV+ ) patients. As recurrent mutational targets for PTCL, we identified several previously unreported genes, including TNS1, ZFHX3, LRP2, NCOA2 and HOXA1, as well as genes previously reported in adult patients, e.g. TET2, CDKN2A, STAT3 and TP53. However, for other reported mutations, VAV1-related abnormalities were absent and mutations of NRAS, GATA3 and JAK3 showed a low frequency in our cohort. Concerning the association of EBV infection, two novel fusion genes: STAG2-AFF2 and ITPR2-FSTL4, and deletion and alteration of CDKN2A/2B, LMO1 and HOXA1 were identified in EBV- PTCL, but not in EBV+ PTCL. Conversely, alterations of PCDHGA4, ADAR, CUL9 and TP53 were identified only in EBV+ PTCL. Our observations suggest a clear difference in the molecular mechanism of onset between paediatric and adult PTCL and a difference in the characteristics of genetic alterations between EBV- and EBV+ paediatric PTCL.

Droplet digital polymerase chain reaction assay for the detection of the minor clone of KIT D816V in paediatric acute myeloid leukaemia especially showing RUNX1-RUNX1T1 transcripts.

KIT D816V mutation within exon 17 has been particularly reported as one of the poor prognostic factors in pediatric acute myeloid leukemia (AML) with RUNX1-RUNX1T1. The exact frequency and the prognostic impact of KIT D816V minor clones at diagnosis were not examined. In this study, the minor clones were examined and the prognostic significance of KIT D816V mutation in pediatric patients was investigated. Consequently, 24 KIT D816V mutations (7.2%) in 335 pediatric patients were identified, and 12 of 24 were only detected via the digital droplet polymerase chain reaction method. All 12 patients were confined in core binding factor (CBF)-AML patients. The 5 year event-free survival of the patients with KIT D816V mutation was significantly inferior to those without KIT D816V mutation (44.1% [95% confidence interval (CI), 16.0%-69.4%] vs. 74.7% [95% CI, 63.0%-83.2%] P-value = 0.02, respectively). The 5 year overall survival was not different between the two groups (92.9% [95% CI, 59.0%-NA vs. 89.7% [95% CI, 69.6%-96.8%] P-value = 0.607, respectively). In this study, KIT D816V minor clones in patients with CBF-AML were confirmed and KIT D816V was considered as a risk factor for relapse in patients with RUNX1-RUNX1T1-positive AML.

Clinical features of 35 Down syndrome patients with transient abnormal myelopoiesis at a single institution.

Transient abnormal myelopoiesis (TAM) is a unique clonal myeloproliferation characterized by immature megakaryoblasts that occurs in 5-10% of neonates with Down syndrome (DS). Although TAM regresses spontaneously in most patients, approximately 20% of TAM cases result in early death, and approximately 20% of survivors develop acute megakaryoblastic leukemia (AMKL). We retrospectively reviewed records of 35 DS patients with TAM to determine the correlation between clinical characteristics and blast percentage. Thirteen of the 35 patients were classified as low blast percentage TAM (LBP-TAM), defined as TAM with a peak peripheral blast percentage ≤ 10%. Although no patient with LBP-TAM experienced systemic edema, disseminated intravascular coagulation, or early death, eight patients had elevated direct bilirubin levels (> 2 mg/dl) and one developed AMKL. All patients with LBP-TAM had serum markers of liver fibrosis that exceeded the normal limits, and two patients underwent liver biopsy to clarify the etiology of pathological jaundice. Taken together, our results suggest that patients with LBP-TAM may be at risk of liver fibrosis and liver failure, similarly to patients with classical TAM. Although these patients generally have a good prognosis, they should be carefully monitored for potential development of liver disease and leukemia.