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.

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.

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.

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.

Successful treatment of metastatic alveolar rhabdomyosarcoma with MGMT gene promoter methylation by temozolomide-based combination chemotherapy.

A 3-year-old male presented with a large retroperitoneal mass and multiple metastases. Biopsy results suggested alveolar rhabdomyosarcoma bearing a methylated O6-methylguanine-DNA methyltransferase (MGMT) gene promoter. Serum microRNA-206 levels were elevated and remained high after three cycles of vincristine, dactinomycin, and cyclophosphamide (VAC). Replacement of vincristine, irinotecan, and temozolomide (VIT) for VAC induced a marked tumor reduction and normalization of the miR-206 levels. The patient completed 14 cycles of VIT with local radiotherapy and has been in remission for 31 months. Temozolomide could be effective for tumors with a methylated MGMT gene promoter. Individualized therapy is warranted for such patients.

Relapsed childhood acute myeloid leukemia patient with inversion of chromosome 16 harboring a low FLT3 internal tandem duplication allelic burden and KIT mutations.

Inversion of chromosome 16 [inv(16)] has a good prognosis in acute myeloid leukemia (AML), but additional genetic aberrations influence the outcome. We herein describe the case of a 15-year-old Japanese boy with inv(16) harboring a low-allelic burden internal tandem duplication of FLT3 (FLT3-ITD) and KIT mutations. Conventional chemotherapy eradicated a clone with a low-allelic burden FLT3-ITD mutation, although another clone with a KIT mutation occurred 17 months later. Further investigation is necessary to identify AML with inv(16) conferring poor prognosis, to facilitate appropriate treatment with additional drugs, such as dasatinib or gemtuzumab ozogamicin.

Proposed strategy for the use of high-dose chemotherapy with stem cell rescue and intrathecal topotecan without whole-brain irradiation for infantile classic medulloblastoma.

We describe a 6-month-old infant with classic medulloblastoma. Gross total resection of the left cerebellar tumor was performed; however, relapse occurred during the administration of intrathecal and intravenous methotrexate-based chemotherapy. After undergoing resection, high-dose chemotherapy was administered consisting of topotecan, melphalan, and cyclophosphamide with autologous peripheral stem cell rescue followed by local irradiation and intrathecal topotecan, which resulted in a complete response for more than two years. The administration of high-dose chemotherapy followed by intrathecal topotecan as maintenance therapy is an effective strategy, without losses in the cognitive function, for avoiding the use of whole-brain irradiation for infantile classic medulloblastoma.

Cytomegalovirus retinitis as an adverse immunological effect of pulses of vincristine and dexamethasone in maintenance therapy for childhood acute lymphoblastic leukemia.

We describe a 5-year-old female with acute lymphoblastic leukemia (ALL) who suffered from cytomegalovirus (CMV) retinitis during maintenance therapy consisting of 6-mercaptopurine (6-MP) and methotrexate (MTX) with pulses of vincristine (VCR) and dexamethasone (DEX). Administration of anticytomegaloviral drugs led to a complete regression of active retinitis. Her low CD4 positive T cells and serum immunoglobulin G (IgG) recovered when maintenance therapy was resumed without VCR and DEX. The patient has been in complete remission (CR) for more than 5 months after completion of maintenance therapy without recurrence of CMV retinitis.

[Refractory acute myeloid leukemia developed malignancy-associated hemophagocytic lymphohistiocytosis during treatment of invasive fungal infection].

We here report a 2-year-old female with relapsed acute myeloid leukemia (AML) with MLL gene rearrangement in the bone marrow and central nervous system. The 3'-RACE (Rapid Amplification of cDNA Ends) method identified the MLLT10 gene as a fusion partner of the MLL gene. The patient was complicated with hemophagocytic lymphohistiocytosis (HLH) and invasive aspergillosis (IPA) after re-induction treatment with FLAG-IDA following etoposide, cytarabine, and mitoxantrone. Although treatment with systemic anti-fungal drugs was effective for IPA, HLH did not improve. We considered tumor-associated HLH to be initiated from leukemic stem cells (LSCs) in the bone marrow niche because reverse transcription-polymerase chain reaction (RT-PCR) analysis of a bone marrow biopsy sample was positive for MLL-MLLT10. Gemtuzumab ozogamicin and sorafenib had no major effect on acquiring complete remission, and the patient died of progressive AML with an exacerbation of HLH and aspergillosis. LSCs are known to be resistant to conventional chemotherapy due to their quiescence in the cell cycle. Novel therapeutic concepts are important to eradicate LSCs in order to cure AML patients.

Severe Traumatic Brain Injury in a Patient with von Willebrand Disease Type 2A Successfully Treated with Factor VIII/von Willebrand Factor Concentrates: A Case Report.

BACKGROUND von Willebrand disease (VWD) is characterized by a bleeding tendency due to abnormalities in von Willebrand factor (VWF). Severe traumatic brain injury (TBI) can induce secondary coagulopathy and hemostatic disorders. We herein present a rare case of multiple trauma, including severe TBI, in a patient with VWD who was successfully treated with repeated factor VIII/VWF transfusion in addition to standard critical care. CASE REPORT A 22-year-old man with type 2A VWD sustained head and lower limb injuries in a traffic accident and was comatose. Computed tomography indicated multiple trauma, including severe TBI (left-sided traumatic epidural hematoma, left-sided traumatic subdural hematoma, traumatic subarachnoid hemorrhage, skull fracture, and skull base fracture). The patient underwent emergency craniotomy for hematoma removal, external decompression, and intracranial pressure monitoring along with massive transfusion and repeated perioperative transfusion of factor VIII/VWF concentrates according to the level of bleeding. He recovered consciousness and eventually survived without neurological deficits. CONCLUSIONS Multiple trauma including TBI in patients with VWD is a critical condition. The active transfusion of factor VIII/VWF is essential for controlling hemorrhage early and in the perioperative period.

C-MYC rearrangement may induce an aggressive phenotype in anaplastic lymphoma kinase positive anaplastic large cell lymphoma: Identification of a novel fusion gene ALO17/C-MYC.

Anaplastic lymphoma kinase (ALK) positive anaplastic large cell lymphoma (ALCL) is usually associated with a favorable prognosis. We describe an 11-year-old girl patient with ALK positive ALCL bearing t(2;5)(p23;q35) and t(8;17)(q24;q25) translocations who had an aggressive clinical course despite various combinations of intensive chemotherapy. Southern blot analysis identified C-MYC rearrangement. Immunohistochemistry and Northern and Western blot analyses revealed cmyc overexpression. A new fusion between ALO17 (ALK lymphoma oligomerization partner on chromosome 17) and C-MYC was identified by the 50-rapid amplification of cDNA ends. This new fusion may have possibly provoked the poor prognosis in this patient with ALK positive ALCL, and C-MYC rearrangement may indicate poor prognosis in ALCL.

Cytomegalovirus infection mimicking juvenile myelomonocytic leukemia showing hypersensitivity to granulocyte-macrophage colony stimulating factor.

We describe an infant with cytomegalovirus (CMV) infection presenting as transient myeloproliferation resembling juvenile myelomonocytic leukemia (JMML). The patient fulfilled the international diagnostic criteria of JMML, including hypersensitivity to granulocyte-macrophage colony-stimulating factor (GM-CSF). Viral studies using serologic assays and polymerase chain reaction (PCR) were positive for CMV. Clinical symptoms disappeared and laboratory values returned to normal without specific treatment within 1 year. Follow-up showing a decrease in viral titers suggested CMV infection as an etiologic factor for the development of myeloproliferative features. We conclude that the CMV infection transiently induced abnormal myelopoiesis in this infant.