Left atrial appendage aneurysm enlarged in the neonatal period.

We describe a newborn with a congenital left atrial appendage aneurysm. The aneurysm size did not change prenatally. However, it rapidly enlarged after birth. MRI was useful for assessing the aneurysm extent and exact size, and for diagnosis. Respiratory distress and feeding difficulties appeared, and surgery was performed. These symptoms disappeared post-operatively. The patient is alive without complications or recurrence.

Novel Strategy Involving High-Dose Chemotherapy with Stem Cell Rescue Followed by Intrathecal Topotecan Maintenance Therapy without Whole-Brain Irradiation for Atypical Teratoid/Rhabdoid Tumors.

Atypical teratoid/rhabdoid tumor (AT/RT) is a rare aggressive central nervous system tumor that typically affects children under three years old and has poor survival with a high risk for neurologic deficits. The primary purpose of this study was to successfully treat the disease and delay or avoid whole-brain radiotherapy for children with AT/RT. A retrospective analysis was performed for six children diagnosed with AT/RT and treated with multimodal treatment at a single institute between 2014 and 2020. Furthermore, germline SMARCB1 aberrations and MGMT methylation status of the tumors were analyzed. One patient who did not receive a modified IRS-III regimen replaced with ifosphamide, carboplatin, and etoposide (ICE) in induction chemotherapy was excluded from this analysis. Five patients who received ICE therapy were under three years old. After a surgical approach, they received intensive chemotherapy and high-dose chemotherapy with autologous peripheral blood stem cell transplantation (HDCT/autoPBSCT) followed by intrathecal topotecan maintenance therapy. Three patients underwent single HDCT/autoPBSCT, and the other two received sequential treatment. Two patients with germline SMARCB1 aberrations and metastases died of progressive AT/RT or therapy-related malignancy, while 3 with localized tumors without germline SMARCB1 aberrations remained alive. One survivor received local radiotherapy only, while the other two did not undergo radiotherapy. All three surviving patients were able to avoid whole-brain radiotherapy. Our results suggest that AT/RT patients with localized tumors without germline SMARCB1 aberrations can be rescued with multimodal therapy, including induction therapy containing ICE followed by HDCT/autoPBSCT and intrathecal topotecan maintenance therapy without radiotherapy. Further large-scale studies are necessary to confirm this hypothesis.

[Steroid-refractory gastrointestinal acute graft-versus-host disease treated with vedolizumab and ruxolitinib in a pediatric patient with therapy-related acute myeloid leukemia].

A 12-year-old girl developed Philadelphia chromosome-positive acute myeloid leukemia due to therapy-related myelodysplastic syndrome with monosomy 7 following neuroblastoma treatment. She underwent allogenic bone marrow transplantation from a human leukocyte antigens-DR1 locus-mismatched unrelated donor. However, on day 49 post transplantation, she presented with diarrhea due to gastrointestinal acute graft-versus-host disease (aGVHD), and treatments with prednisolone, budesonide rectal foam, and human mesenchymal stem cells were ineffective. Therefore, vedolizumab was administered from day 100, which improved the symptoms from gut stage 3 to gut stage 1. Consequently, prednisolone was withdrawn without any serious adverse effects. However, the symptoms worsened to gut stage 3 again; therefore, ruxolitinib was administered to achieve complete remission. Vedolizumab exhibits gut-selective action without systemic immunosuppressive activity. Hence, vedolizumab administration before other systemic immunosuppressive agents may be recommended in patients with steroid-refractory gastrointestinal aGVHD. Thus far, only a few reports have been published regarding the administration of vedolizumab and ruxolitinib for steroid-refractory gastrointestinal aGVHD in children. Further evidence should be obtained from patients treated with vedolizumab and ruxolitinib to confirm their effectiveness for pediatric steroid-refractory gastrointestinal aGVHD.

[Successful treatment of eltrombopag following immunosuppressive therapy in pediatric aplastic anemia].

Immunosuppressive therapy (IST) is the first-line treatment for patients with aplastic anemia (AA) who require blood transfusion when a human leukocyte antigen-matched related donor is unavailable. However, the proportion of patients with AA who are refractory to IST remains high (30%). IST in combination with eltrombopag has been studied in adults, but its efficacy and safety in children have not been established. We present three cases of AA that were initially refractory to IST but improved with additional eltrombopag administration. These patients were successfully managed using this strategy without the use of hematopoietic cell transplantation (HCT). The first patient achieved a complete response within one month after receiving eltrombopag. When the second and third patients were given eltrombopag, they were able to safely reduce the amount of cyclosporin they were given. They avoided blood transfusions, but no measurable response was obtained. The conjunctival icterus was detected and treated using a dose reduction of eltrombopag. Eltrombopag may be effective in children with AA who are refractory to IST, allowing them to avoid blood transfusions and HCT. More cases treated with this strategy are needed to confirm its efficacy and safety for children with AA.

Demonstration of wavelength-swept laser using cholesteric liquid-crystal cavity and its application for laser scanning.

A cholesteric liquid-crystal gel (ChLCG) is fabricated by photopolymerizing a ChLC doped with a mesogenic monomer at a high concentration of 38.2 wt%. The reflection band of the ChLCG exhibits a fast, continuous, and time-varying wavelength shift of the order of kilohertz by applying a sine wave voltage. Swept lasing at a swept rate of 100 Hz and with a swept range of 12 nm can be achieved by irradiating a dye-doped ChLCG with a quasi-continuous-wave laser. When the swept laser light is introduced to a diffracting grating, a laser scanning device is demonstrated.

A Metastatic Neuroblastic Tumor in a 28-Month-old Boy: Unusual Spontaneous Regression From Neuroblastoma to Ganglioneuroma?

Neuroblastoma with bone metastasis is well known to have an extremely poor prognosis. We experienced the case of a patient with adrenal ganglioneuroblastoma (GNB) with metastases of subcutaneous nodules, a lymph node, and multiple bones. A pathologic examination of tumors from different sites revealed both GNB and ganglioneuroma. A genetic comparison between these tumors identified the same molecular signatures, suggesting the possibility of spontaneous differentiation in the remaining GNB. The patient has been healthy without aggressive chemotherapy, and the patient's pathologic urinary catecholamines normalized. Even if unusual, we have to recognize probable spontaneous differentiation from neuroblastoma to GNB and then to ganglioneuroma, even in sites of bone metastasis.

Mannose and phosphomannose isomerase regulate energy metabolism under glucose starvation in leukemia.

Diverse metabolic changes are induced by various driver oncogenes during the onset and progression of leukemia. By upregulating glycolysis, cancer cells acquire a proliferative advantage over normal hematopoietic cells; in addition, these changes in energy metabolism contribute to anticancer drug resistance. Because leukemia cells proliferate by consuming glucose as an energy source, an alternative nutrient source is essential when glucose levels in bone marrow are insufficient. We profiled sugar metabolism in leukemia cells and found that mannose is an energy source for glycolysis, the tricarboxylic acid (TCA) cycle, and the pentose phosphate pathway. Leukemia cells express high levels of phosphomannose isomerase (PMI), which mobilizes mannose to glycolysis; consequently, even mannose in the blood can be used as an energy source for glycolysis. Conversely, suppression of PMI expression or a mannose load exceeding the processing capacity of PMI inhibited transcription of genes related to mitochondrial metabolism and the TCA cycle, therefore suppressing the growth of leukemia cells. High PMI expression was also a poor prognostic factor for acute myeloid leukemia. Our findings reveal a new mechanism for glucose starvation resistance in leukemia. Furthermore, the combination of PMI suppression and mannose loading has potential as a novel treatment for driver oncogene-independent leukemia.

Predisposition to prolonged neutropenia after chemotherapy for paediatric acute myeloid leukaemia is associated with better prognosis in the Japanese Paediatric Leukaemia/Lymphoma Study Group AML-05 study.

The variability in myelosuppression after chemotherapy for acute myeloid leukaemia (AML) can affect its prognosis; however, the underlying mechanism remains controversial. In the Japanese Paediatric Leukaemia/Lymphoma Study Group AML-05 study, we showed that prolonged neutropenia was associated with high overall survival (P = 0·011) and low frequency of relapse (P = 0·042) in patients without granulocyte-colony stimulating factor (G-CSF) who completed the indicated treatment protocol. Our data indicate that predisposition to prolonged neutropenia after chemotherapy is correlated with a better outcome of AML treatment. Our results promote the usage of individualised drug dosing strategies to improve the therapeutic outcome in AML patients.

The outcomes of relapsed acute myeloid leukemia in children: Results from the Japanese Pediatric Leukemia/Lymphoma Study Group AML-05R study.

BACKGROUND: The prognosis of children with acute myeloid leukemia (AML) has improved with the efficacy of hematopoietic cell transplantation (HCT) as a second-line therapy and improvements in supportive care following anthracycline- and cytarabine-based chemotherapy; however, the outcomes of children with relapsed AML still remain unsatisfactory. PROCEDURE: In order to identify prognostic factors and improve their prognosis, we analyzed 111 patients who relapsed after treatment with the Japanese Pediatric Leukemia/Lymphoma Study Group (JPLSG) AML-05 protocol and who were registered in the retrospective JPLSG AML-05R study. RESULTS: The 5-year overall survival rate was 36.1%. The major determinant of survival was duration from the diagnosis to relapse. The mean duration in the nonsurviving group (10.1 ± 4.1 months) was shorter than that in the surviving group (16.3 ± 8.3 months) (P < .01). Moreover, achieving a second complete remission (CR2) prior to HCT was associated with a good prognosis (P < .01). Etoposide, cytarabine, and mitoxantrone (ECM)- or fludarabine, cytarabine, and granulocyte colony-stimulating factor (FLAG)-based regimens were therefore recommended for reinduction therapy (P < .01). A genetic analysis also revealed the prognostic significance of FMS-like tyrosine kinase 3 (FLT3)-internal tandem duplication as a poor prognostic marker (P = .04) and core binding factor-AML, t(8;21), and inv(16) as good prognostic markers (P < .01). CONCLUSIONS: Achieving a CR2 prior to HCT is important in order to improve the prognosis of relapsed pediatric AML. Recent molecular targeted therapies, such as FLT3 inhibitors, may contribute to overcome their prognoses. Larger prospective investigations are necessary to establish individualized treatment strategies for patients with relapsed childhood AML.

Measurement of methotrexate in human cerebrospinal fluid using a chemiluminescence immunoassay intended for serum and plasma matrices.

BACKGROUND: The concentration of MTX in blood is often measured quickly and easily by immunoassays. Thus, immunoassays may facilitate the easy determination of the concentration of MTX in the cerebrospinal fluid (CSF). In this study, we measured methotrexate (MTX) concentrations in the CSF using a high-performance liquid chromatography (HPLC) method intended for analyzing CSF matrices and a chemiluminescence immunoassay (CLIA) method intended for assessing serum and plasma matrices and verified the differences in the results of the two methods. METHODS: HPLC analysis for MTX in the CSF was performed using a Prominence UFLC system with a C18 column. The HPLC method was validated in accordance with the 2018 FDA guideline. The CLIA method was performed using an ARCHITECT i1000SR system intended for serum and plasma matrices. A total of 47 CSF samples (14 clinical and 33 spiked specimens) were analyzed using the two methods. RESULTS: The HPLC method passed the validation criteria. The concentration of MTX in the same sample, determined using the HPLC and CLIA methods, differed proportionally; the percent difference in the concentrations averaged -23.0% (95% confidence interval: -36.9% to -9.1%) as revealed by the Bland-Altman plot. The relationship between the measured values, evaluated using the Passing-Bablok regression, was as follows: HPLC = 1.205 × CLIA - 0.024. CONCLUSION: The equation deduced in this study can be used to correct the concentration of MTX measured using the CLIA method.

Highly sensitive detection of GATA1 mutations in patients with myeloid leukemia associated with Down syndrome by combining Sanger and targeted next generation sequencing.

Myeloid leukemia associated with Down syndrome (ML-DS) is characterized by a predominance of acute megakaryoblastic leukemia, the presence of GATA1 mutations and a favorable outcome. Because DS children can also develop conventional acute myeloid leukemia with unfavorable outcome, detection of GATA1 mutations is important for diagnosis of ML-DS. However, myelofibrosis and the significant frequency of dry taps have hampered practical screening of GATA1 mutations using bone marrow (BM) samples. In response to those problems, 82 patients were enrolled in the Japanese Pediatric Leukemia/Lymphoma Study Group AML-D11 study. GATA1 mutations were analyzed by Sanger sequencing (SS) using genomic DNA (gDNA) from BM and cDNA from peripheral blood (PB) followed by targeted next-generation sequencing (NGS) using pooled diagnostic samples. BM and PB samples were obtained from 71 (87%) and 82 (100%) patients, respectively. GATA1 mutations were detected in 46 (56%) and 58 (71%) patients by SS using BM gDNA and PB cDNA, respectively. Collectively, GATA1 mutations were identified in 73/82 (89%) patients by SS. Targeted NGS detected GATA1 mutations in 74/82 (90%) patients. Finally, combining the results of SS with those of targeted NGS, GATA1 mutations were identified in 80/82 (98%) patients. These results indicate that SS using BM gDNA and PB cDNA is a rapid and useful method for screening for GATA1 mutations in ML-DS patients. Thus, a combination of SS and targeted NGS is a sensitive and useful method to evaluate the actual incidence and clinical significance of GATA1 mutations in ML-DS patients.

EVI1 triggers metabolic reprogramming associated with leukemogenesis and increases sensitivity to L-asparaginase.

Metabolic reprogramming of leukemia cells is important for survival, proliferation, and drug resistance under conditions of metabolic stress in the bone marrow. Deregulation of cellular metabolism, leading to development of leukemia, occurs through abnormally high expression of transcription factors such as MYC and Ecotropic Virus Integration site 1 protein homolog (EVI1). Overexpression of EVI1 in adults and children with mixed lineage leukemia-rearrangement acute myeloid leukemia (MLL-r AML) has a very poor prognosis. To identify a metabolic inhibitor for EVI1-induced metabolic reprogramming in MLL-r AML, we used an XFp extracellular flux analyzer to examine metabolic changes during leukemia development in mouse models of AML expressing MLL-AF9 and Evi1 (Evi1/MF9). Oxidative phosphorylation (OXPHOS) in Evi1/MF9 AML cells accelerated prior to activation of glycolysis, with a higher dependency on glutamine as an energy source. Furthermore, EVI1 played a role in glycolysis as well as driving production of metabolites in the tricarboxylic acid cycle. L-asparaginase (L-asp) exacerbated growth inhibition induced by glutamine starvation and suppressed OXPHOS and proliferation of Evi1/MF9 both in vitro and in vivo; high sensitivity to L-asp was caused by low expression of asparagine synthetase (ASNS) and L-asp-induced suppression of glutamine metabolism. In addition, samples from patients with EVI1+MF9 showed low ASNS expression, suggesting that it is a sensitive marker of L-asp treatment. Clarification of metabolic reprogramming in EVI1+ leukemia cells may aid development of treatments for EVI1+MF9 refractory leukemia.

Attempts to optimize postinduction treatment in childhood acute myeloid leukemia without core-binding factors: A report from the Japanese Pediatric Leukemia/Lymphoma Study Group (JPLSG).

We previously reported that risk-stratified therapy and intensive postremission chemotherapy (PRC) contributed to the improved survival of childhood acute myeloid leukemia (AML) in the AML99 study, which led us to consider a reduction in the number of PRC courses with more restrictive indications for stem cell transplantation (SCT) in the successor AML-05 study. We here report the outcome of AML patients without core-binding factor mutation (non-CBF AML) in the AML-05 study. Two-hundred eighty-nine children (age < 18 years old) with non-CBF AML were eligible. Patients with unfavorable cytogenetics and/or poor bone marrow response to the first induction course were candidates for SCT in the AML-05 study. After two courses of induction, a further three courses of PRC were given in AML-05, while four courses were given in the AML99 study. The 3-year event-free survival (EFS) rate in the AML-05 study (46.7%, 95% CI: 40.6-52.6%) was comparable to that of non-CBF AML in the AML99 study (51.5%, 95% CI: 42.7-59.6%) (P = .16). However, the 3-year overall survival (OS) rate in the AML-05 study (62.9%, 95% CI: 56.3-68.8%) was slightly lower than that in the AML99 study (71.6%, 95% CI: 63.2-78.5%) (P = .060), mainly due to decreased remission induction rate and increased nonrelapsed mortality. In conclusion, reductions in the number of PRC courses from four to three, together with repetitive cycles of high-dose cytarabine, were acceptable for non-CBF childhood AML.

Temozolomide and etoposide combination for the treatment of relapsed osteosarcoma.

The prognosis of patients with relapsed osteosarcoma is extremely poor and the optimal treatment remains to be identified. Here, we retrospectively analysed the clinical outcomes of nine patients with relapsed osteosarcoma treated with temozolomide/etoposide. Of the two patients who received temozolomide/etoposide as palliative therapy for unresectable tumours, one remained alive with stable disease for >4 years. The remaining seven patients received temozolomide/etoposide as adjuvant therapy following resection of relapsed metastatic disease; of these, one was free from disease for 41 months. Potentially beneficial effects were observed in two of three O6-methylguanine-DNA methyltransferase protein-negative patients, whereas all five O6-methylguanine-DNA methyltransferase-positive patients experienced subsequent relapse. None of the patients experienced severe adverse effects requiring hospitalization. Temozolomide/etoposide is a feasible candidate as salvage therapy for relapsed osteosarcoma. Further studies are needed to verify the utility of O6-methylguanine-DNA methyltransferase protein expression as a biomarker for predicting the response to this treatment.

[Novel therapies for pediatric acute myeloid leukemia: building future strategies through incorporation of treatment currently used in adults].

In Japan, acute myeloid leukemia (AML) accounts for approximately 25% of all pediatric leukemias, with approximately 150 cases of newly diagnosed AML occurring annually. Approximately 10% of patients have primary induction failure and 30% of patients, who initially achieve remission in primary treatments, subsequently relapse. Novel treatment modalities need to be developed to further improve the prognosis of pediatric AML patients. AML is a heterogeneous genetic disease characterized by changes in the genome of hematopoietic progenitor cells. Recent studies that have made progress in research related to the pathogenesis of AML have suggested that genotype-specific treatment strategies are associated with increased efficacy. Potential new therapeutic alternatives for pediatric AML include: tyrosine kinase inhibitors, monoclonal or bispecific T-cell engager antibodies, chimeric antigen receptor T-cell therapy, and metabolic agents. This review highlights the current landscape of novel therapeutic approaches for childhood AML, including the results of both preclinical and clinical trials, as well as introducing the results of several preceding adult clinical studies, which could potentially be translated into pediatric AML patients.

Clinical and biological features of paediatric acute myeloid leukaemia (AML) with primary induction failure in the Japanese Paediatric Leukaemia/Lymphoma Study Group AML-05 study.

The prognosis of paediatric acute myeloid leukaemia (AML) with primary induction failure (PIF) is extremely poor, and effective treatment strategies have not been established. We investigated the clinical and biological features of paediatric AML patients with PIF registered to the Japanese Paediatric Leukaemia/Lymphoma Study Group AML-05 study. The 3-year overall survival rate of the 41 PIF patients was 19.0%. High leucocyte count, M7 morphology, and unfavourable genetic aberrations, such as FLT3-internal tandem duplication, NUP98-NSD1 and high MECOM or PRDM16 expression, were risk factors for PIF. More effective treatment strategies based on leukaemia biology need to be urgently explored.

Long-term remission of bilateral Wilms tumors that developed from premature separation of chromatids/mosaic variegated aneuploidy syndrome due to bilateral nephrectomy and peritoneal dialysis.

We report a 38-month-old Japanese male with premature chromatid separation/mosaic variegated aneuploidy syndrome bearing biallelic BUB1B germline mutations who suffered from bilateral Wilms tumor. After right nephrectomy, dactinomycin monotherapy was administered for the left Wilms tumor; however, severe adverse reaction prevented the patient from receiving further chemotherapy. Left nephrectomy was then performed without postoperative chemotherapy. The patient survived for 15 months after bilateral nephrectomy without peritoneal relapse, metastasis of Wilms tumor, or the occurrence of rhabdomyosarcoma and maintained a good quality of life while receiving peritoneal dialysis at home.

Long-term Remission of Acute Myeloid Leukemia Developed From Systemic Mastocytosis by Conventional Chemotherapy.

Systemic mastocytosis (SM) is a disorder characterized by abnormal proliferation of mast cells with KIT mutations, especially in codon 816. The prognosis of patients developing acute myeloid leukemia (AML) from SM is extremely poor, and hematopoietic cell transplantation is recommended. Herein, we describe a case of an 8-year-old female diagnosed with SM developing AML. A KIT M541L variant in SM was identified in leukemic cells, normal hematopoietic cells, and buccal mucosal cells, suggesting a germline polymorphism. The patient has remained in complete remission for 39 months after completion of chemotherapy. SM developing AML without a KIT D816 mutation may be not necessarily associated with a poor prognosis.

[Acute myeloid leukemia evolving from KIT D816-mutated systemic mastocytosis relapsing two months after completion of chemotherapy].

Here, we report the case of a 9-year-old girl with acute myeloid leukemia (AML) developed from systemic mastocytosis (SM). She experienced bladder and rectal disturbance due to an extramedullary nodule in the paraspinal region of the sacrum. Cytogenetic and genetic analyses of leukemic cells revealed the KIT D816Y mutation besides t (8;21) (q22:q22) /RUNX1-RUNX1T1. Despite receiving proton beam therapy after conventional chemotherapy, the patient relapsed after 2 months. As SM-AML with the KIT D816 mutation in adults exhibits a poor prognosis, hematopoietic stem cell transplantation is recommended. Owing to a few reports of SM-AML in children, the standard therapy for pediatric cases has not been established to date. Based on our experience and the related literature, the prognosis of childhood SM-AML could be as poor as in adults. Hence, further investigation, including mutational analyses of the KIT gene, is warranted to establish a risk-oriented strategy for managing childhood SM-AML.