[Successful management of acute chest syndrome in a patient with sickle cell disease].

Although sickle cell disease (SCD) is common in endemic areas of malaria, it is one of the rare diseases in Japan. Hence, SCD and its complications are not well established in Japan. An 11-year-old girl was referred to the specialized pediatric center of our hospital. She was born in Brazil and diagnosed with SCD after birth. However, she did not have a routine checkup in Japan. Owing to influenza viral infection, she developed vaso-occlusive pain crisis (VPC) and needed hospitalization for pain management. After admission, she developed dyspnea, needing intratracheal intubation and mechanical ventilation. A chest X-ray revealed bilateral pulmonary infiltration, suggesting acute chest syndrome (ACS) complicated with SCD. Intensive care, including transfusion of red blood cells, successfully improved her condition. Reportedly, half cases of VPC develop ACS, and the mortality of ACS is very high. Hence, when managing VPC cases, the prevention of ACS, through transfusion of red blood cells or infectious control, is imperative. Thus, Japanese hematologists and pediatricians should recognize SCD and its complications owing to an anticipated increase of foreign travelers or migrants in the future.

A case of malignant rhabdoid tumor mimicking yolk sac tumor.

Malignant rhabdoid tumors (MRTs) are rare, highly aggressive embryonal neoplasms caused by biallelic alterations of the SMARCB1 gene. MRTs may occur in any soft tissue, but extracranial extrarenal MRTs are extremely rare. Diagnosis of MRTs in unusual locations and with an uncharacteristic cytomorphology that mimics other tumors is difficult. This was an atypical case of MRT in a 15-year-old female with tumors that closely resembled yolk sac tumors. It was extremely challenging to diagnose the tumors without confirming the SMARCB1 status.

Characteristics of methotrexate-induced stroke-like neurotoxicity.

Intrathecal administration of methotrexate (IT-MTX) can lead to neurotoxicity. MTX-induced neurotoxicity occasionally manifests with a stroke-like presentation that is difficult to distinguish from genuine stroke. We retrospectively reviewed records of nine patients with leukemia or lymphoma and episodes of stroke-like presentation at our institute between 2010 and 2015 for whom magnetic resonance imaging (MRI) data were available. Coagulation test results were compared between the two diagnostic groups. Four patients were diagnosed with MTX-induced stroke-like neurotoxicity. The first neurological event occurred 10-13 days after the fourth or later IT-MTX treatment. All four patients had hemiparalysis, two exhibited disturbed consciousness and three presented with speech disorders. Fibrin/fibrinogen degradation products (FDP) and D-dimer values were within normal ranges. MRI revealed bilateral lesions with restricted diffusion in all four cases. Neurological symptoms fluctuated and resolved within 5 days, and IT-MTX was subsequently re-initiated in all four cases. One patient developed transient hemiparalysis after a subsequent IT-MTX treatment, but this did not recur thereafter. Bilateral lesions on MRI and normal coagulation are indicative of MTX-induced stroke-like neurotoxicity. Continuation of IT-MTX after these events is generally feasible, but adverse event risk should be carefully weighed against anti-tumor benefits.

[Allogeneic hematopoietic stem cell transplantation using myeloablative conditioning including total body irradiation for pediatric acute lymphoblastic leukemia: a single-center retrospective analysis].

This study aimed to investigate the clinical outcomes of hematopoietic stem cell transplantation (HSCT) with total body irradiation-based myeloablative conditioning (TBI-MAC) in pediatric patients with acute lymphoblastic leukemia (ALL). We retrospectively examined patients with ALL who underwent HSCT with TBI-MAC from January 2000 to August 2016 at our institute. We enrolled 67 patients with a median follow-up period of 8 years. The 5-year event-free survival (EFS) and overall survival (OS) were 51.2% and 59.6%, respectively. At the first complete remission, HSCT exhibited significantly superior EFS and OS in our patients than that in patients with other diseases. We encountered 57.9% of patients with at least one late complication. Major late complications were short stature (26.3%) and hypogonadism (18.4%). While late complications were observed in several recipients of HSCT, late complication-related deaths occurred in three patients. The TBI-MAC regimen led to favorable clinical outcomes in pediatric patients with ALL who underwent HSCT. Thus, proper evaluation and management of late complications are mandatory.

Excellent prognosis of patients with intermediate-risk neuroblastoma and residual tumor postchemotherapy.

BACKGROUND/PURPOSE: The prognosis of patients with intermediate-risk neuroblastoma is favorable; therefore, a reduction therapy is desired. However, the long-term prognosis of those with residual tumor is unclear. The aim of this study was to clarify the necessity of residual tumor resection. METHODS: We retrospectively reviewed the records of patients diagnosed with intermediate-risk neuroblastoma who either were treated by chemotherapy only (nonresection group; n=16), or received postchemotherapy tumor resection (resection group; n=9). RESULTS: In the nonresection group, tumor size decreased in 14 patients; 5 had no detectable local tumor at the end of the follow-up period. Tumor size increased in 2 patients 1.5-2.5years postchemotherapy. Both patients received additional treatment and survived. All patients survived during the median follow-up time of 127months. In the resection group, 5 patients received complete resections and 4 patients received nearly complete resections. All patients survived during the median follow-up time of 84months. In 8 out of 9 resected tumors, regression or maturation was pathologically induced by chemotherapy-only treatment. CONCLUSION: Patients with intermediate-risk neuroblastoma with or without postchemotherapy residual tumor resection had an excellent long-term outcome. The tumor pathology with intermediate-risk neuroblastoma might be susceptible to change to regression or maturation by chemotherapy. LEVEL OF EVIDENCE: IV.

Loss of DNA Damage Response in Neuroblastoma and Utility of a PARP Inhibitor.

Background: Neuroblastoma (NB) is the most common solid tumor found in children, and deletions within the 11q region are observed in 11% to 48% of these tumors. Notably, such tumors are associated with poor prognosis; however, little is known regarding the molecular targets located in 11q. Methods: Genomic alterations of ATM , DNA damage response (DDR)-associated genes located in 11q ( MRE11A, H2AFX , and CHEK1 ), and BRCA1, BARD1, CHEK2, MDM2 , and TP53 were investigated in 45 NB-derived cell lines and 237 fresh tumor samples. PARP (poly [ADP-ribose] polymerase) inhibitor sensitivity of NB was investigated in in vitro and invivo xenograft models. All statistical tests were two-sided. Results: Among 237 fresh tumor samples, ATM, MRE11A, H2AFX , and/or CHEK1 loss or imbalance in 11q was detected in 20.7% of NBs, 89.8% of which were stage III or IV. An additional 7.2% contained ATM rare single nucleotide variants (SNVs). Rare SNVs in DDR-associated genes other than ATM were detected in 26.4% and were mutually exclusive. Overall, samples with SNVs and/or copy number alterations in these genes accounted for 48.4%. ATM-defective cells are known to exhibit dysfunctions in homologous recombination repair, suggesting a potential for synthetic lethality by PARP inhibition. Indeed, 83.3% NB-derived cell lines exhibited sensitivity to PARP inhibition. In addition, NB growth was markedly attenuated in the xenograft group receiving PARP inhibitors (sham-treated vs olaprib-treated group; mean [SD] tumor volume of sham-treated vs olaprib-treated groups = 7377 [1451] m 3 vs 298 [312] m 3 , P = .001, n = 4). Conclusions: Genomic alterations of DDR-associated genes including ATM, which regulates homologous recombination repair, were observed in almost half of NBs, suggesting that synthetic lethality could be induced by treatment with a PARP inhibitor. Indeed, DDR-defective NB cell lines were sensitive to PARP inhibitors. Thus, PARP inhibitors represent candidate NB therapeutics.

Recurrent SPI1 (PU.1) fusions in high-risk pediatric T cell acute lymphoblastic leukemia.

The outcome of treatment-refractory and/or relapsed pediatric T cell acute lymphoblastic leukemia (T-ALL) is extremely poor, and the genetic basis for this is not well understood. Here we report comprehensive profiling of 121 cases of pediatric T-ALL using transcriptome and/or targeted capture sequencing, through which we identified new recurrent gene fusions involving SPI1 (STMN1-SPI1 and TCF7-SPI1). Cases positive for fusions involving SPI1 (encoding PU.1), accounting for 3.9% (7/181) of the examined pediatric T-ALL cases, showed a double-negative (DN; CD4-CD8-) or CD8+ single-positive (SP) phenotype and had uniformly poor overall survival. These cases represent a subset of pediatric T-ALL distinguishable from the known T-ALL subsets in terms of expression of genes involved in T cell precommitment, establishment of T cell identity, and post-ß-selection maturation and with respect to mutational profile. PU.1 fusion proteins retained transcriptional activity and, when constitutively expressed in mouse stem/progenitor cells, induced cell proliferation and resulted in a maturation block. Our findings highlight a unique role of SPI1 fusions in high-risk pediatric T-ALL.

Identification of the genetic and clinical characteristics of neuroblastomas using genome-wide analysis.

To provide better insight into the genetic signatures of neuroblastomas, we analyzed 500 neuroblastomas (included specimens from JNBSG) using targeted-deep sequencing for 10 neuroblastoma-related genes and SNP arrays analysis. ALK expression was evaluated using immunohistochemical analysis in 259 samples. Based on genetic alterations, the following 6 subgroups were identified: groups A (ALK abnormalities), B (other gene mutations), C (MYCN amplification), D (11q loss of heterozygosity [LOH]), E (at least 1 copy number variants), and F (no genetic changes). Groups A to D showed advanced disease and poor prognosis, whereas groups E and F showed excellent prognosis. Intriguingly, in group A, MYCN amplification was not a significant prognostic marker, while high ALK expression was a relevant indicator for prognosis (P = 0.033). Notably, the co-existence of MYCN amplification and 1p LOH, and the co-deletion of 3p and 11q were significant predictors of relapse (P = 0.043 and P = 0.040). Additionally, 6q/8p LOH and 17q gain were promising indicators of survival in patients older than 5 years, and 1p, 4p, and 11q LOH potentially contributed to outcome prediction in the intermediate-risk group. Our genetic overview clarifies the clinical impact of genetic signatures and aids in the better understanding of genetic basis of neuroblastoma.

Addition of High-Dose Cytarabine to Fludarabine-Based Conditioning for Hematopoietic Stem Cell Transplantation for Treating Fanconi Anemia Patients with Advanced Myeloid Malignancy: A Single-Center Experience and Literature Review.

The complication of Fanconi anemia (FA) with acute leukemia is rare and challenging to treat because of high relapse rates, despite the improved outcome of hematopoietic stem cell transplantation with fludarabine-based conditioning for treating FA patients with hematological abnormalities. We added high-dose cytarabine to fludarabine-based conditioning to promote an enhanced antitumor effect and successfully subjected 4 patients with FA, including 3 with acute leukemia, to hematopoietic stem cell transplantation. All patients remain alive without treatment-related mortality or evidence of disease. Adding high-dose cytarabine to fludarabine-based conditioning may be tolerable and effective for treating FA patients with acute leukemia.

Low Frequency of Programmed Death Ligand 1 Expression in Pediatric Cancers.

Programmed death 1 (PD-1)/programmed death ligand 1 (PD-L1) pathway blockade has become a promising therapeutic target in adult cancers. We evaluated PD-L1 expression and tumor-infiltrating CD8(+) T cells in formalin-fixed, paraffin-embedded tumor specimens from 53 untreated pediatric patients with eight cancer types: neuroblastoma, extracranial malignant germ cell tumor, hepatoblastoma, germinoma, medulloblastoma, renal tumor, rhabdomyosarcoma, and atypical teratoid/rhabdoid tumor. One rhabdomyosarcoma with the shortest survival exhibited membranous PD-L1 expression and germinoma contained abundant tumor-infiltrating CD8(+) T cells and PD-L1-positive macrophages. The PD-1/PD-L1 pathway tended to be inactive in pediatric cancers.

Residual disease detected by multidimensional flow cytometry shows prognostic significance in childhood acute myeloid leukemia with intermediate cytogenetics and negative FLT3-ITD: a report from the Tokyo Children's Cancer Study Group.

Residual disease (RD) after induction chemotherapy may predict clinical outcome in acute myeloid leukemia (AML). In the present study, we investigated the prognostic significance of RD detected by multidimensional flow cytometry (MDF) among 34 children treated for AML in a clinical trial (JPLSG AML-05) in Japan. Bone marrow samples were analyzed at the points of the end of the first induction course (BMA-1) and second induction course (BMA-2) by MDF. RD was evaluated by detecting the immature cells showing abnormal antigen expression pattern; CD34(+), CD15(+), CD7(+). Thirteen (39.4 %) of 34 patients at BMA-1 and 8 (27.6 %) of 34 at BMA-2 had RD levels ≥0.1 %. There was no significant difference in 3y-EFS and 3y-OS between patients with RD levels ≥0.1 % and those with RD levels <0.1 % (53.8 versus 70.0 %, P = 0.30 and 50.0 versus 66.7 %, P = 0.27, respectively). However, IR cytogenetics and negative FLT3-ITD patients with RD levels ≥0.1 % exhibited significantly lower 3y-EFS and 3y-OS than those with RD levels <0.1 % (33.3 versus 83.3 %, P = 0.02 and 20.0 versus 76.9 %, P = 0.005, respectively). Our study suggests that RD shows prognostic relevance in pediatric patients with IR cytogenetics and negative FLT3-ITD AML.

Safety of Live Attenuated High-Titer Varicella-Zoster Virus Vaccine in Pediatric Allogeneic Hematopoietic Stem Cell Transplantation Recipients.

Hematopoietic stem cell transplantation (HSCT) recipients have a high risk of varicella-zoster virus (VZV) infections. Although VZV vaccination may be beneficial in preventing VZV infections, data on safety and efficacy of VZV vaccines in HSCT recipients, particularly of zoster vaccine, are limited. We report our experience with the use of a single dose of an Oka strain high-titer zoster-equivalent varicella vaccine in pediatric allogeneic HSCT recipients. We administered the high-titer VZV vaccine to 31 pediatric allogeneic HSCT recipients without vaccine-type VZV infections. One patient developed varicella due to wild-type VZV 13 days after vaccination. No zoster developed after vaccination during a median follow-up period of 4.8 years from vaccination. No other adverse effects were observed. Eighteen of the 31 patients (58.1%) were seropositive after vaccination. Seventeen patients were vaccinated within 24 months after HSCT; the seropositivity of these patients did not significantly differ from that of patients vaccinated > 24 months after HSCT. VZV vaccination may be a safe and beneficial approach in preventing VZV infections after HSCT.

Integrated genetic and epigenetic analysis defines novel molecular subgroups in rhabdomyosarcoma.

Rhabdomyosarcoma (RMS) is the most common soft-tissue sarcoma in childhood. Here we studied 60 RMSs using whole-exome/-transcriptome sequencing, copy number (CN) and DNA methylome analyses to unravel the genetic/epigenetic basis of RMS. On the basis of methylation patterns, RMS is clustered into four distinct subtypes, which exhibits remarkable correlation with mutation/CN profiles, histological phenotypes and clinical behaviours. A1 and A2 subtypes, especially A1, largely correspond to alveolar histology with frequent PAX3/7 fusions and alterations in cell cycle regulators. In contrast, mostly showing embryonal histology, both E1 and E2 subtypes are characterized by high frequency of CN alterations and/or allelic imbalances, FGFR4/RAS/AKT pathway mutations and PTEN mutations/methylation and in E2, also by p53 inactivation. Despite the better prognosis of embryonal RMS, patients in the E2 are likely to have a poor prognosis. Our results highlight the close relationships of the methylation status and gene mutations with the biological behaviour in RMS.

Outcome of adolescent patients with acute myeloid leukemia treated with pediatric protocols.

As past studies of adolescent and young adults (AYA) with acute myeloid leukemia (AML) reported conflicting results, we conducted a retrospective analysis using data from three Japanese pediatric AML studies. Among the 782 patients with de novo AML, 44 were classified as AYA (age ≥15 years at diagnosis), 164 as infants (0-1 year), 413 as younger children (2-11 years), and 161 as older children (12-14 years). While the 5-year event-free survival rate of AYA was not different among the groups, the five-year survival rate (54.7 %) was significantly lower than that of the other three groups (P = 0.019): 68.7 % for infants, 73.2 % for younger children, and 75.5 % for older children. No difference in the 5-year cumulative incidence of relapse was observed, but treatment-related death (TRD) of AYA was significantly higher (29.4 %) than that in infants (14.8 %), younger children (10.2 %), and older children (13.8 %). Multivariate analysis showed age ≥15 years old at diagnosis was associated with both poor survival rate and high TRD. Adolescents with AML had inferior survival due to a higher incidence of TRD, especially after failure of initial frontline treatment.

Successful switching from eltrombopag to romiplostim in a pediatric patient with refractory chronic ITP.

Herein, we report a successful treatment experience with romiplostim in a child with immune thrombocytopenia (ITP) refractory to eltrombopag. A 9-year-old female developed chronic ITP, which was refractory to standard treatments, including intravenous immunoglobulin, cepharanthine and splenectomy, and she thus became dependent on prednisolone (PSL). At age 12 years, eltrombopag was started, but failed to increase her platelet count. Another thrombopoietin receptor agonist (TPO-RA), romiplostim, possibly having a different mechanism of action, was then administered. Platelet counts increased and PSL could thus be terminated. Our case suggests TPO-RA alteration to potentially be effective for chronic refractory ITP.

Clofarabine-based combination chemotherapy for relapse and refractory childhood acute lymphoblastic leukemia.

Clofarabine, one of the key treatment agents for refractory and relapsed acute lymphoblastic leukemia (ALL), achieves a remission rate of approximately 30% with single-agent clofarabine induction chemotherapy. However, a remission rate of approximately 50% was reported with a combination chemotherapy regimen consisting of clofarabine, etoposide, and cyclophosphamide. We treated two cases with refractory and relapsed ALL with combination chemotherapy including clofarabine; one was an induction failure but the other achieved remission. Both cases developed an infectious complication (NCI-CTCAE grade 3) and body pain with infusion. Prophylactic antibiotic and opioid infusions facilitated avoiding septic shock and pain. Further investigation of such cases is required.

Unrelated cord blood and bone marrow transplantation in pediatric leukemia.

To investigate the role of cord blood as an alternative stem cell source for hematopoietic stem cell transplantation for pediatric acute leukemia, we retrospectively analyzed the outcomes of 35 unrelated cord blood transplantations (UCBT) and 56 unrelated bone marrow transplantations (UBMT) with myeloablative conditioning. The 5 year overall survival (OS) probability was 49.8% (95% confidence interval [95%CI]: 35.6-62.4%) for UBMT and 53.8% (95%CI: 34.0-70.1%) for UCBT (P = 0.92). The 5 year event-free survival (EFS) probability was 47.3% (33.6-59.8%) for UBMT and 33.0% (15.9-51.2%) for UCBT (P = 0.38). OS and EFS were not significantly different between the groups. On multivariate analysis there was no significant difference between the groups. In conclusion, UCBT can have a role as important as that of UBMT in pediatric acute leukemia.

Long-term follow-up results of the observation program for neuroblastoma detected at 6-month mass screening.

We conducted an observation program of neuroblastoma in infants, detected by mass screening at 6 months of age; we followed up with them for 15 years. No recurrence was observed after disappearance of tumors, and persistent tumors showed no malignant transformation or metastasis. Histology of the resected tumors showed age-related differentiation.