Outcomes in children with first-relapsed acute lymphoblastic leukemia in Japan: Results from JCCG Study JPLSG-ALL-R08.

BACKGROUND/OBJECTIVES: The Berlin-Frankfurt-Münster (BFM)-S classification is a crucial prognostic indicator in children experiencing first-relapsed acute lymphoblastic leukemia (ALL). Early molecular response to therapy, evaluated by measurable/minimal residual disease (MRD), has a significant impact on the survival of patients with childhood ALL. Applying risk stratification based on the BFM-S classification and MRD response after induction, the first nationwide prospective multicenter study, ALL-R08, was conducted in children with first-relapsed ALL in Japan. METHODS: The ALL-R08 study comprised two parts: ALL-R08-I, an observational study aimed at obtaining an overall picture of outcomes in first-relapsed childhood ALL, and ALL-R08-II, a clinical trial for the non-T-ALL S2 risk group. In ALL-R08-II, patients with an MRD level of ≥10-3 at the end of induction therapy were assigned to undergo allogeneic hematopoietic stem cell transplantation (allo-HCT), whereas those with an MRD level less than 10-3 and isolated extramedullary relapse continued to receive chemotherapy. RESULTS: In total, 163 patients were enrolled in the ALL-R08 study, and 82 and 81 patients were enrolled in the ALL-R08-I and the ALL-R08-II, respectively. In ALL-R08-I, the probability of 3-year event-free survival (EFS) for patients with S1, S2, S3, S4, and post-HCT groups was 83% ± 15%, 37% ± 11%, 28% ± 8%, 14% ± 7%, and 0%, respectively. In the ALL-R08-II trial, 3-year EFS in patients with post-induction MRD less than 10-3 and ≥10-3 was 70% ± 9% (n = 27) and 68% ± 8% (n = 31) (p = .591), respectively. CONCLUSIONS: ALL-REZ BFM-type treatment is equally effective for children with first-relapsed ALL treated according to the Japanese frontline protocols and for children with first-relapsed ALL treated according to the BFM-type frontline protocols.

A Retrospective Study of Pediatric Patients With Low- or Intermediate-Risk Acute Myeloid Leukemia Who Underwent Allogeneic Hematopoietic Cell Transplantation for the AML-05 Study Conducted by the Japanese Pediatric Leukemia/Lymphoma Study Group.

The AML-05 study aimed to examine the efficacy and safety of a therapeutic strategy based on risk stratification for low-, intermediate-, or high-risk acute myeloid leukemia (AML) pediatric patients. Allogeneic hematopoietic cell transplantation (allo-HCT) was not indicated for low- or intermediate-risk AML patients in first complete remission. The present retrospective study for the AML-05 study aimed to identify prognostic factors for survival and to determine optimal allo-HCT according to multivariate analysis on overall survival (OS), event-free survival (EFS), cumulative incidence of relapse (CIR), and cumulative incidence of nonrelapse mortality for and between low- and intermediate-risk AML group patients in the AML-05 study who had undergone allo-HCT after its completion and relapse. The unique patient numbers (UPNs) of the AML-05 study were matched with the Transplant Registry Unified Management Program (TRUMP)-registered numbers, and the tied data on the AML-05 study's UPNs and the TRUMP-registered numbers were analyzed. The primary endpoint was 3-yr OS. Among 443 AML patients in the AML-05 study, 79 (32 low-risk AML and 47 intermediate-risk AML) were analyzed. The following statistically favorable prognostic factors were identified by multivariate analysis on the low- and intermediate-risk AML groups, respectively: UCB (OS-hazard ratio [HR], 0.105; 95% CI, 0.011 to 0.941; P = .004 and EFS-HR, 0.065, 95% CI, 0.007 to 0.577, P = .014) and late relapse (OS-HR, 0.212; 95% CI, 0.072 to 0.626; P = .005 and EFS-HR, 0.236; 95% CI, 0.088 to 0.630; P = .004). Three-year OS, 3-yr EFS, and 3-yr CIR were significantly different between the low- and intermediate-risk AML groups. UCB may be a safe and beneficial donor source for low-risk AML patients, while late relapse was a favorable prognostic factor for intermediate-risk AML patients. Intermediate-risk AML patients with late relapse and low-risk AML patients may benefit from allo-HCT after relapse.

Ruxolitinib in treatment-naive or corticosteroid-refractory paediatric patients with chronic graft-versus-host disease (REACH5): interim analysis of a single-arm, multicentre, phase 2 study.

BACKGROUND: Chronic graft-versus-host disease (GVHD) is a debilitating, and sometimes life threatening, complication of allogeneic haematopoietic stem-cell transplantation (HSCT). We aimed to investigate the activity, pharmacokinetics, and safety of ruxolitinib added to corticosteroids in paediatric patients (ie, <18 years) with moderate-to-severe chronic GVHD. METHODS: In this single-arm, phase 2 study, patients were recruited at 21 hospitals or clinics across 14 countries in Asia, Europe, and Canada. Eligible patients were aged 28 days to younger than 18 years, had undergone allogenic HSCT, and had been diagnosed with treatment-naive or corticosteroid-refractory moderate-to-severe chronic GVHD, per 2014 National Institutes of Health consensus criteria. Patients received oral ruxolitinib dosing on the basis of their age at the start of treatment: those aged 12 years to younger than 18 years received 10 mg twice daily (age ≥12 to <18 years group), those aged 6 years to younger than 12 years (age ≥6 to <12 years group) received 5 mg twice daily, and those aged 2 years to younger than 6 years received 4 mg/m2 twice daily (age ≥2 to <6 years group). Treatment was to be administered in 28-day cycles for approximately 36 months, alongside supportive treatment per institutional guidelines. The primary activity endpoint was overall response rate at cycle 7 day 1. Activity and safety analyses are reported in the full analysis set, which included all patients who received at least one dose of ruxolitinib. Here we report the prespecified interim analysis, scheduled to occur after all patients had completed 1 year of treatment or discontinued treatment, and the results for the primary endpoint evaluation reported here is to be considered final. This study is registered with ClinicalTrials.gov, NCT03774082, enrolment is complete, and the study is ongoing. FINDINGS: Between May 20, 2020, and Sept 17, 2021, 48 patients were screened, of whom 45 were enrolled and received at least one dose of study drug (median age was 11·0 years [IQR 7·2-14·3], 16 [36%] were female, 29 [64%] were male, 21 [47%] were White, one [2%] was Black or African American, 23 [51%] were Asian, 17 [38%] were treatment-naive, 28 [62%] were corticosteroid-refractory). As of data cutoff (Oct 19, 2022), after a median ruxolitinib exposure of 55·1 weeks (IQR 13·1-75·3), the overall response rate at cycle 7 day 1 was 40·0% (18 of 45; 90% CI 27·7-53·3), with responses seen in seven (41%) of 17 treatment-naive patients and 11 (39%) of 28 corticosteroid-refractory patients. The most common treatment-related adverse events of grade 3 or worse were neutropenia (eight [18%] of 45) and thrombocytopenia (six [13%]). Seven (16%) patients had grade 3 or worse serious treatment-related adverse events; the most common was hyponatraemia (two [4%] of 45). Three (7%) patients died while on-treatment (within 30 days of treatment discontinuation), one due to Aspergillus infection, one due to septic shock, and one due to acute respiratory distress syndrome; none were considered to be related to study drug. INTERPRETATION: Pending final analysis, this study suggests that ruxolitinib is active and well tolerated in both treatment-naive and corticosteroid-refractory patients aged 2 years to younger than 18 years with chronic GVHD, thereby supporting its use in this patient population. The safety profile of ruxolitinib in this patient population is consistent with that of adults. Final analysis of this study will provide further information on the long-term benefits of ruxolitinib in children with chronic GVHD. FUNDING: Novartis.

Ruxolitinib for pediatric patients with treatment-naïve and steroid-refractory acute graft-versus-host disease (REACH4).

In REACH4 (NCT03491215), a phase 1/2, open-label, single-arm, multicenter study, the pharmacokinetics (PK), efficacy, and safety of ruxolitinib were evaluated in treatment-naïve and steroid-refractory pediatric patients with grade II-IV acute graft-versus-host disease (aGVHD; n=45). Ruxolitinib dosing was based on age and targeted the exposure in adults receiving 10 mg twice daily; group 1 (≥12 to <18 years) received 10 mg twice daily and preliminary starting doses for groups 2 (≥6 to <12 years) and 3 (≥2 to <6 years) were 5 mg twice daily and 4 mg/m2 twice daily, respectively. Phase 1 primary objective was to assess ruxolitinib PK parameters and define an age-appropriate recommended phase 2 dose (RP2D) for patients <12 years of age. Phase 2 primary objective was to measure the activity of ruxolitinib as assessed by overall response rate (ORR) at day 28; the key secondary objective was to assess the durable ORR at day 56. Ruxolitinib exposure was comparable across age groups; starting doses were confirmed as the RP2D. The median duration of ruxolitinib exposure was 3.8 months (range 0.3-11.2). ORR in all patients was 84.4% (90% confidence interval [CI], 72.8-92.5) at day 28, with a durable ORR at day 56 of 66.7% (90% CI, 53.4-78.2); high response rates were observed across age groups and in both treatment-naïve and steroid-refractory subgroups. Adverse events were consistent with those expected in ruxolitinib-treated patients with aGvHD (anemia, decreased neutrophil and leukocyte count). In pediatric patients with aGvHD, ruxolitinib showed clinically meaningful efficacy with no new safety signals.

Differential impact of asparaginase discontinuation on outcomes of children with T-cell acute lymphoblastic leukemia and T-cell lymphoblastic lymphoma.

BACKGROUND: Asparaginase is essential for treating T-cell acute lymphoblastic leukemia (T-ALL). Despite the ongoing debate on whether T-ALL and T-cell lymphoblastic lymphoma (T-LBL) are the same disease entity or two distinct diseases, patients with T-LBL often receive the same or similar treatment protocols as those with T-ALL. METHODS: The outcomes of patients with or without L-asparaginase discontinuation were retrospectively analyzed among four national protocols: Japan Association of Childhood Leukemia Study (JACLS) ALL-02 and ALL-97 for T-ALL and Japanese Pediatric Leukemia/Lymphoma Study Group ALB-NHL03 and JACLS NHL-98 for T-LBL. The hazard ratio (HR) was calculated with the Cox regression model by considering L-asparaginase discontinuation as a time-dependent variable. RESULTS: In total, 199 patients with T-ALL, and 133 patients with T-LBL were included. L-asparaginase discontinuation compromised event-free survival (EFS) of T-ALL patients (ALL-02: HR 3.32, 95% confidence interval [CI] 1.40-7.90; ALL-97: HR 3.39, 95%CI 1.19-9.67). Conversely, EFS compromise was not detected among T-LBL patients (ALB-NHL03: HR 1.39, 95%CI 0.41-4.68; NHL-98: HR 0.92, 95%CI 0.11-7.60). CONCLUSION: The effects of L-asparaginase discontinuation differed between T-ALL and T-LBL. We assume that the differential impact results from (1) the inherent differential response to L-asparaginase between them and/or (2) a less stringent assessment of early treatment response in T-LBL than in T-ALL. Given the poor salvage rate of refractory or relapsed T-ALL and T-LBL, optimization of the frontline therapy is critical, and the current study provides a new suggestion for further treatment modifications. However, larger studies in contemporary intensified treatment protocols are required.

Regular prophylaxis with activated prothrombin complex concentrates in pediatric hemophilia.

BACKGROUND: Regular prophylaxis with activated prothrombin complex concentrates (aPCCs) is effective in adult patients with hemophilia with inhibitors; however, data in children are scarce. METHODS: This was a single-center retrospective study at Saitama Children's Medical Center. Patients with severe and moderate hemophilia with inhibitors aged <15 years at the start of aPCCs prophylaxis were included. Medical records were retrospectively reviewed. RESULTS: We treated nine pediatric patients with hemophilia with inhibitors (median age, 1.9 years; age range, 1.3-12.9 years; inhibitor titers before treatment with aPCCs, 5.9-69 BU/mL) using prophylactic aPCCs (doses, 50-100 U/kg; 2-3 times/week). The median prophylactic period was 13 months (range: 5-31 months). The median annualized bleeding rate (ABR) during prophylactic treatment with aPCCs was 2 (range, 0-17). In four patients, ABR was reduced by 19%-100% with prophylactic aPCCs compared to on-demand aPCCs. An adverse effect of treatment was that a patient with hemophilia B developed nephrotic syndrome 34 months after starting regular prophylaxis with aPCCs. CONCLUSIONS: Regular prophylactic aPCCs reduced the ABR even in younger children with hemophilia A and B. Serious adverse events include nephrotic syndrome, which requires caution.

A higher CD34 + cell dose correlates with better event-free survival after KIR-ligand mismatched cord blood transplantation for childhood acute myeloid leukemia.

Although killer Ig-like receptor ligands (KIR-L) mismatch has been associated with alloreactive natural killer cell activity and potent graft-versus-leukemia (GVL) effect among adults with acute myeloid leukemia (AML), its role among children with AML receiving cord blood transplantation (CBT) has not been determined. We conducted a retrospective study using a nationwide registry of the Japanese Society for Transplantation and Cellular Therapy. Patients who were diagnosed with de novo non-M3 AML and who underwent their first CBT in remission between 2000 and 2021 at under 16 years old were included. A total of 299 patients were included; 238 patients were in the KIR-L match group, and 61 patients were in the KIR-L mismatch group. The cumulative incidence rates of neutrophil recovery, platelet engraftment, and acute/chronic graft-versus-host disease did not differ significantly between the groups. The 5-year event-free survival (EFS) rate was 69.8% in the KIR-L match group and 74.0% in the KIR-L mismatch group (p = 0.490). Stratification by CD34 + cell dose into four groups revealed a significant correlation between CD34 + cell dose and EFS in the KIR-L mismatch group (p = 0.006) but not in the KIR-L match group (p = 0.325). According to our multivariate analysis, KIR-L mismatch with a high CD34 + cell dose (≥ median dose) was identified as an independent favorable prognostic factor for EFS (hazard ratio = 0.19, p = 0.029) and for the cumulative incidence of relapse (hazard ratio = 0.09, p = 0.021). Our results suggested that higher CD34 + cell doses are crucial for achieving a potent GVL effect in the context of KIR-L-mismatched CBT.

Magnesium supplementation therapy to prevent cisplatin-induced acute nephrotoxicity in pediatric cancer: a randomized phase-2 trial.

BACKGROUND: The present study aimed to examine the effect of magnesium (Mg) supplementation on cisplatin-induced nephrotoxicity (CIN) in pediatric cancer patients. METHODS: The present phase-2, open-label, multicenter, randomized controlled trial enrolled patients aged less than 20 years who were scheduled to receive cisplatin-containing chemotherapy and randomly allocated them at a ratio of 1:1 to a Mg supplementation arm with even-numbered chemotherapy courses (arm AB) or another arm with odd-numbered courses (arm BA). Analysis objects were reconstructed into two groups depending on whether the chemotherapy course had Mg supplementation (group B) or not (group A). The primary outcome was the proportion of chemotherapy courses resulting in elevated serum creatinine per chemotherapy course. The secondary outcomes included efficacies evaluated using other biomarkers and the safety of the Mg supplementation. RESULTS: Twenty-eight patients were randomly allocated to either group (16 to arm AB and 12 to arm BA). The baseline characteristics of the groups were similar. There was no significant difference in the proportion of courses with increased serum creatinine between the groups (group A: 10% vs. group B: 6%; P = 0.465) nor was any significant difference observed in other biomarkers during any chemotherapy course. The Mg value during chemotherapy was significantly higher in group B than that in group A. No adverse events related to magnesium administration were observed. CONCLUSIONS: The study design, which treated a single chemotherapy course as a study object, failed to detect a statistically significant benefit of Mg supplementation for preventing CIN in pediatric cancer patients. TRIAL REGISTRATION: JRCT ( https://jrct.niph.go.jp/ ) Identifier UMIN000029215 jRCTs031180251. UMIN-CTR ( http://www.umin.ac.jp/icdr/index.html ) Identifier UMIN000029215.

Efficacy of off-the-shelf bone marrow mesenchymal stem cells for pediatric steroid-refractory acute graft-versus-host disease.

Introduction: Temcell is a mesenchymal stem cell (MSC) product approved for steroid-refractory acute graft-versus-host disease (SR-aGVHD) in Japan. However, reports regarding Temcell's efficacy in pediatric patients have been scarce, and the appropriate use of MSC therapy against pediatric SR-aGVHD also remains to be determined. Patients and Methods: We retrospectively assessed a cohort of pediatric patients treated with Temcell for SR-aGVHD following allogeneic hematopoietic transplantation. MSCs were infused intravenously at a dose of 2 × 106 cells/kg according to the manufacturer's instructions. Results: Twelve patients received eighteen cycles of MSC therapy (median age, 10.3 [1.7-17.8] years), with four receiving additional cycles (one cycle: n = 3, three cycles: n = 1). The severity of aGVHD before MSC therapy was grade I-II in three patients and grade III-IV in nine patients (gut stage 3-4, n= 7; liver stage 3-4; n =2). The median number of immunosuppressive therapy regimens received prior to MSC administration was two (range: 1-5). The first MSC cycle displayed the best overall response rate of 83%, including six patients with a complete response (CR) and with a 49% reduction in the mean daily dose of prednisone after eight weeks. The median time to first response was 3.5 days (range: 2-15 days). Two of the four patients who were re-administered MSCs for recurrent or persistent GVHD achieved a CR. The three-year overall survival rate was 69.4%, while the three-year failure free survival (FFS) rate was 22.2%, with a median FFS of 4.9 months. There were no observable side effects of MSC therapy. Conclusions: MSC therapy appears to be an effective and safe treatment for pediatric SR-aGVHD, with a steroid-sparing effect and satisfactory efficacy upon re-administration. Further studies are needed to determine its appropriate combination with additional treatments and the optimal use of re-administration of MSCs.

Landscape of driver mutations and their clinical effects on Down syndrome-related myeloid neoplasms.

ABSTRACT: Transient abnormal myelopoiesis (TAM) is a common complication in newborns with Down syndrome (DS). It commonly progresses to myeloid leukemia (ML-DS) after spontaneous regression. In contrast to the favorable prognosis of primary ML-DS, patients with refractory/relapsed ML-DS have poor outcomes. However, the molecular basis for refractoriness and relapse and the full spectrum of driver mutations in ML-DS remain largely unknown. We conducted a genomic profiling study of 143 TAM, 204 ML-DS, and 34 non-DS acute megakaryoblastic leukemia cases, including 39 ML-DS cases analyzed by exome sequencing. Sixteen novel mutational targets were identified in ML-DS samples. Of these, inactivations of IRX1 (16.2%) and ZBTB7A (13.2%) were commonly implicated in the upregulation of the MYC pathway and were potential targets for ML-DS treatment with bromodomain-containing protein 4 inhibitors. Partial tandem duplications of RUNX1 on chromosome 21 were also found, specifically in ML-DS samples (13.7%), presenting its essential role in DS leukemia progression. Finally, in 177 patients with ML-DS treated following the same ML-DS protocol (the Japanese Pediatric Leukemia and Lymphoma Study Group acute myeloid leukemia -D05/D11), CDKN2A, TP53, ZBTB7A, and JAK2 alterations were associated with a poor prognosis. Patients with CDKN2A deletions (n = 7) or TP53 mutations (n = 4) had substantially lower 3-year event-free survival (28.6% vs 90.5%; P < .001; 25.0% vs 89.5%; P < .001) than those without these mutations. These findings considerably change the mutational landscape of ML-DS, provide new insights into the mechanisms of progression from TAM to ML-DS, and help identify new therapeutic targets and strategies for ML-DS.

Nelarabine-containing salvage therapy and conditioning regimen in transplants for pediatric T-cell acute lymphoblastic leukemia and lymphoma.

Therapy for relapsed or refractory (r/r) T-cell acute lymphoblastic leukemia (T-ALL) and T-cell lymphoblastic lymphoma (T-LBL) in children is challenging, and new treatment methods are needed. We retrospectively analyzed eight patients with r/r T-ALL (five patients) and T-LBL (three patients) who were treated with nelarabine (NEL) plus etoposide, cyclophosphamide, and intrathecal therapy, administered 3 days apart. Five patients achieved a complete response, and the other three achieved a partial response (PR). All patients underwent hematopoietic stem cell transplantation (HSCT) after two cycles of treatment, except for one patient who received one cycle. Three patients who had previously received HSCT were treated with reduced-intensity conditioning regimens, including fludarabine, melphalan, and NEL; one survived for over 5 years after the second HSCT. Grade 2 neuropathy occurred in one patient, but other severe toxicities commonly associated with NEL were not observed during NEL administration in combination with chemotherapy. The 2-year overall survival and event-free survival rates were 60.0% and 36.5%, respectively. The addition of NEL to reinduction chemotherapy was useful in achieving remission and did not lead to excessive toxicity. In addition, a conditioning regimen, including NEL, appeared to be effective in patients who had previously undergone HSCT.

Scoring system for diagnosis and pretreatment risk assessment of neuroblastoma using urinary biomarker combinations.

The urinary catecholamine metabolites, homovanillic acid (HVA) and vanillylmandelic acid (VMA), are used for the adjunctive diagnosis of neuroblastomas. We aimed to develop a scoring system for the diagnosis and pretreatment risk assessment of neuroblastoma, incorporating age and other urinary catecholamine metabolite combinations. Urine samples from 227 controls (227 samples) and 68 patients with neuroblastoma (228 samples) were evaluated. First, the catecholamine metabolites vanillactic acid (VLA) and 3-methoxytyramine sulfate (MTS) were identified as urinary marker candidates through comprehensive analysis using liquid chromatography-mass spectrometry. The concentrations of these marker candidates and conventional markers were then compared among controls, patients, and numerous risk groups to develop a scoring system. Participants were classified into four groups: control, low risk, intermediate risk, and high risk, and the proportional odds model was fitted using the L2-penalized maximum likelihood method, incorporating age on a monthly scale for adjustment. This scoring model using the novel urine catecholamine metabolite combinations, VLA and MTS, had greater area under the curve values than the model using HVA and VMA for diagnosis (0.978 vs. 0.964), pretreatment risk assessment (low and intermediate risk vs. high risk: 0.866 vs. 0.724; low risk vs. intermediate and high risk: 0.871 vs. 0.680), and prognostic factors (MYCN status: 0.741 vs. 0.369, histology: 0.932 vs. 0.747). The new system also had greater accuracy in detecting missing high-risk neuroblastomas, and in predicting the pretreatment risk at the time of screening. The new scoring system employing VLA and MTS has the potential to replace the conventional adjunctive diagnostic method using HVA and VMA.

Rare TCF3 variants associated with pediatric B cell acute lymphoblastic leukemia.

Germline genetic variants influence development of pediatric B cell acute lymphoblastic leukemia (B-ALL). Genome-wide association studies (GWAS) have identified several pediatric B-ALL susceptibility loci. IKZF1 and PAX5, transcription factors involved in B cell development, have been reported as susceptibility genes for B-ALL development. Therefore, we hypothesized that rare variants of genes involved in B cell development would be candidate susceptibility loci for pediatric B-ALL. Thus, we sequenced TCF3, a key transcription factor gene involving in B cell development. Saliva DNA from 527 pediatric patients with pediatric B-ALL in remission who were registered with the Tokyo Children's Cancer Study Group (TCCSG) were examined. As a TCF3 gene-based evaluation, the numbers of rare deleterious germline TCF3 sequence variants in patients with pediatric B-ALL were compared with those in cancer-free individuals using data in public databases. As a TCF3 single-variant evaluation, the frequencies of rare deleterious germline TCF3 sequence variants in patients with pediatric B-ALL were also compared with those in control data. TCF3 gene-based analysis revealed significant associations between rare deleterious variants and pediatric B-ALL development. In addition, TCF3 variant-based analysis showed particularly strong association between variant rs372168347 (three in 521 TCCSG and three in the 15780 gnomAD whole genome analysis cohort, p = 0.0006) and pediatric B-ALL development. TCF3 variants are known to influence B cell maturation and may increase the risk of preleukemic clone emergence.

Early chemotherapeutic intervention to avoid thyroidectomy in pediatric Langerhans cell histiocytosis with thyroid involvement accompanying tracheal stenosis: a report of two cases.

Thyroid involvement is rare in pediatric Langerhans cell histiocytosis (LCH). It may cause airway narrowing, leading to acute-onset respiratory distress. Severe cases may require emergent surgical interventions such as thyroidectomy, which should be avoided in children due to higher rates of complication, particularly in infancy. There is currently no consensus on the indications for surgical treatment in LCH with thyroid involvement. In this report, we describe the cases of two children who presented with tracheal stenosis caused by thyroid LCH, both of which were successfully treated by early induction of chemotherapy, and one of which was also treated for a shorter duration. Mutation analysis detected in-frame deletions of BRAF exon 12 in both cases. These cases suggest that timely diagnosis and administration of chemotherapy may alleviate severe airway obstruction and reduce the need for thyroidectomy in pediatric patients with thyroid LCH.

Myeloid/natural killer (NK) cell precursor acute leukemia as a distinct leukemia type.

Myeloid/natural killer (NK) cell precursor acute leukemia (MNKPL) has been described on the basis of its unique immunophenotype and clinical phenotype. However, there is no consensus on the characteristics for identifying this disease type because of its rarity and lack of defined distinctive molecular characteristics. In this study, multiomics analysis revealed that MNKPL is distinct from acute myeloid leukemia, T cell acute lymphoblastic leukemia, and mixed-phenotype acute leukemia (MPAL), and NOTCH1 and RUNX3 activation and BCL11B down-regulation are hallmarks of MNKPL. Although NK cells have been classically considered to be lymphoid lineage-derived, the results of our single-cell analysis using MNKPL cells suggest that NK cells and myeloid cells share common progenitor cells. Treatment outcomes for MNKPL are unsatisfactory, even when hematopoietic cell transplantation is performed. Multiomics analysis and in vitro drug sensitivity assays revealed increased sensitivity to l-asparaginase and reduced levels of asparagine synthetase (ASNS), supporting the clinically observed effectiveness of l-asparaginase.

Subtyping of Group 3/4 medulloblastoma as a potential prognostic biomarker among patients treated with reduced dose of craniospinal irradiation: a Japanese Pediatric Molecular Neuro-Oncology Group study.

BACKGROUND: One of the most significant challenges in patients with medulloblastoma is reducing the dose of craniospinal irradiation (CSI) to minimize neurological sequelae in survivors. Molecular characterization of patients receiving lower than standard dose of CSI therapy is important to facilitate further reduction of treatment burden. METHODS: We conducted DNA methylation analysis using an Illumina Methylation EPIC array to investigate molecular prognostic markers in 38 patients with medulloblastoma who were registered in the Japan Pediatric Molecular Neuro-Oncology Group and treated with reduced-dose CSI. RESULTS: Among the patients, 23 were classified as having a standard-risk and 15 as high-risk according to the classic classification based on tumor resection rate and presence of metastasis, respectively. The median follow-up period was 71.5 months (12.0-231.0). The median CSI dose was 18 Gy (15.0-24.0) in both groups, and 5 patients in the high-risk group received a CSI dose of 18.0 Gy. Molecular subgrouping revealed that the standard-risk cohort included 5 WNT, 2 SHH, and 16 Group 3/4 cases; all 15 patients in the high-risk cohort had Group 3/4 medulloblastoma. Among the patients with Group 3/4 medulloblastoma, 9 of the 31 Group 3/4 cases were subclassified as subclass II, III, and V, which were known to an association with poor prognosis according to the novel subtyping among the subgroups. Patients with poor prognostic subtype showed worse prognosis than that of others (5-year progression survival rate 90.4% vs. 22.2%; p < 0.0001). The result was replicated in the multivariate analysis (hazard ratio12.77, 95% confidence interval for hazard ratio 2.38-99.21, p value 0.0026 for progression-free survival, hazard ratio 5.02, 95% confidence interval for hazard ratio 1.03-29.11, p value 0.044 for overall survival). CONCLUSION: Although these findings require validation in a larger cohort, the present findings suggest that novel subtyping of Group 3/4 medulloblastoma may be a promising prognostic biomarker even among patients treated with lower-dose CSI than standard treatment.