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Background Plexiform neurofibromas (PN) are a manifestation of neurofibromatosis type 1 (NF1) that may cause morbidity and impact health-related quality of life (HRQoL). Selumetinib (ARRY-142886, AZD6244) is an orally available, selective, mitogen-activated protein kinase kinase (MEK) 1/2 inhibitor approved for children with NF1 and symptomatic, inoperable PN in regions including the USA (aged ≥2 years), EU (≥3 years), and Japan (≥3 years). This open-label, single-arm, phase 1 study evaluated selumetinib in Japanese children with NF1 and symptomatic, inoperable PN. Methods Eligible patients (aged 3–18 years) received oral selumetinib (25 mg/m 2 BID) continuously in 28-day cycles in a fasted state. Primary objectives were safety and tolerability. Secondary objectives included pharmacokinetics, efficacy, PN-related morbidities, and HRQoL. Results Twelve patients (median age 13.3 years) were enrolled, received ≥1 selumetinib dose (data cut-off: Cycle 13 Day 1) with median follow-up of 11.5 months. All patients had baseline PN-related morbidities, most commonly disfigurement (91.7%) and pain (58.3%). Most frequently reported any-grade adverse events were dermatologic and gastrointestinal. Objective response rate was 33.3%; median duration of response was not reached. Most patients (83.3%) had target PN volume reduction versus baseline. No patients reported worsening of PN-related morbidities. Selumetinib was rapidly absorbed with moderate-to-high inter-patient variability in maximum plasma concentration (Cmax) and area under the concentration–time curve from time 0–6 hours (AUC)0–6. Conclusions Consistent with results of the phase 2 SPRINT trial, 25 mg/m 2 selumetinib BID was well tolerated with a manageable safety profile in Japanese children with NF1 and symptomatic, inoperable PN.

Supplementary Tables S1-S13. Supplementary Table S1. Clinical information and the summary of experiments performed on each sample. Supplementary Table S2. List of genes and regions captured for targeted deep sequencing. Supplementary Table S3. dbSNP ID list for which target baits were designed. Supplementary Table S4. Non-silent mutations detected in a validation cohort by targeted deep sequencing. Supplementary Table S5. Validated non-silent somatic mutations by PCR-based deep sequencing. Supplementary Table S6. Validated silent/non-silent somatic mutations used for clonal analysis of multiple samples from PBL001. Supplementary Table S7. Significantly hypo-/hyper-methylated gene sets in PBL compared to normal pancreas. Supplementary Table S8. Fusion genes detected by whole transcriptome sequencing in PBL. Supplementary Table S9. Genes with a significant differential expression between PBL and normal pancreatic samples. Supplementary Table S10. Significant gene set enrichment in comparison between PBL and normal pancreas. Supplementary Table S11. List of differentially expressed genes in each gene cluster identified by hierarchical clustering. Supplementary Table S12. Top 20 significantly enriched pathways in each gene cluster. Supplementary Table S13. Gene coefficients of PC1 and PC2.

Pancreatoblastoma is a rare pediatric pancreatic malignancy for which the molecular pathogenesis is not understood. In this study, we report the findings of an integrated multiomics study of whole-exome and RNA sequencing as well as genome-wide copy number and methylation analyses of ten pancreatoblastoma cases. The pancreatoblastoma genome was characterized by a high frequency of aberrant activation of the Wnt signaling pathway, either via somatic mutations of CTNNB1 (90%) and copy-neutral loss of heterozygosity (CN-LOH) of APC (10%). In addition, imprinting dysregulation of IGF2 as a consequence of CN-LOH (80%), gain of paternal allele (10%), and gain of methylation (10%) was universally detected. At the transcriptome level, pancreatoblastoma exhibited an expression profile characteristic of early pancreas progenitor-like cells along with upregulation of the R-spondin/LGR5/RNF43 module. Our results offer a comprehensive description of the molecular basis for pancreatoblastoma and highlight rational therapeutic targets for its treatment.Significance: Molecular genetic analysis of a rare untreatable pediatric tumor reveals Wnt/IGF2 aberrations and features of early pancreas progenitor-like cells, suggesting cellular origins and rational strategies for therapeutic targeting. Cancer Res; 78(4); 865–76. ©2017 AACR.

Supplementary Figures S1-S10. Supplementary Figure S1. Depths and coverages of targeted deep sequencing. Supplementary Figure S2. Sequencing coverages and numbers of mutations detected by WES. Supplementary Figure S3. Tumor subclonal populations in multiple samples from PBL001 estimated by PyClone. Supplementary Figure S4. Mutational signatures of primary and metastatic PBL. Supplementary Figure S5. SNP array-based copy number analysis of PBL. Supplementary Figure S6. Targeted deep sequencing based allele-specific copy number analysis of chromosome 11. Supplementary Figure S7. Bisulfite Sanger sequencing of ICR1 on chromosome 11p15.5. Supplementary Figure S8. Relative expression levels of IGF2 in CN-LOH-negative samples. Supplementary Figure S9. Aberrant activation of Wnt signaling pathway in PBL009. Supplementary Figure S10. Global DNA methylation profile of PBL.

Hepatosplenic T-cell lymphoma (HSTCL) is a rare subtype of peripheral T-cell lymphoma that occurs most often in adolescents and young adults and is rare in children. Because of the aggressive clinical course, resistance to conventional chemotherapy and poor prognosis of HSTCL, an effective treatment has not been established. We report the case of a 3-year-old girl with HSTCL presenting with trilineage myelodysplasia. Although the HSTCL was refractory to conventional chemotherapy, remission was achieved with salvage chemotherapy that included fludarabine and cytarabine, which were shown to be effective in the drug sensitivity assay. After undergoing umbilical cord blood transplantation with a conditioning regimen consisting of etoposide, cyclophosphamide and total body irradiation, the patient has remained in complete remission for 8 years. Single-nucleotide polymorphism array analysis revealed heterozygous deletions of PAX5 (9p), ETV6 (12p) and homozygous deletions of CDKN2A (9p). Exome analysis showed a heterozygous nonsense c.2961C>G (p.Tyr987Ter) variant of the KMT2C gene. To improve the poor prognosis of HSTCL, the chemotherapeutic regimen can be selected for each patient on the basis of drug sensitivity and molecular genetic characteristics.

Developmental venous anomaly (DVA) is a venous malformation that is usually asymptomatic and rarely requires treatment. We report a case of a rare subtype DVA with arteriovenous shunt, presenting with headache, nausea, aphasia, and seizure in a 15-year-old girl. Contrast-enhanced magnetic resonance imaging (MRI) showed a well-defined T2 prolongation area with heterogeneous swelling mainly in the cortex and white matter of the left inferior frontal gyrus; a brain tumor was suspected. However, MRI performed 10 days later showed a slightly smaller and less swollen lesion in the left inferior frontal gyrus, cortical laminar necrosis, gyrus enhancement, cortical and subcortical hemorrhage, and an elevated apparent diffusion coefficient in the acute phase; with these findings, venous infarction was diagnosed. Finally, with angiographic findings, DVA with an arteriovenous shunt was diagnosed. The present case shows the importance of being aware of the possibility of both malignancy and venous infarction for the differential diagnosis of a mass lesion in the cerebrum. Moreover, the anticardiolipin antibody level was continuously increased, suggesting thrombophilia as a possible cause of venous infarction, in addition to abnormal venous return caused by DVA with an arteriovenous shunt.

Background The appendix and ovaries are rarely involved simultaneously in malignancies. The decision to perform an ovarian biopsy or a surgical resection in young patients can be challenging without sufficient clinical information. Case We describe an 11-year-old girl with bilateral ovarian masses, an enlarged appendix, associated pleural effusion, and ascites. Appendectomy and biopsy of the bilateral ovarian masses led to a diagnosis of aggressive B-cell non-Hodgkin lymphoma. The patient was treated with chemotherapy, which achieved complete remission and bilateral ovarian preservation. Summary and Conclusion If ovarian involvement in malignant lymphoma is suspected, diagnostic methods should spare the ovary and prevent a loss of fertility. To evaluate for possible chemotherapy-induced ovarian damage, including infertility and premature menopause, an interdisciplinary approach is needed for the long-term follow-up of adolescent girls.

Molecular mechanisms involved in the relapse of T-cell acute lymphoblastic leukemia (T-ALL) are not fully understood, although activating NOTCH1 signaling due to NOTCH1/FBXW7 alterations is a major oncogenic driver. To unravel the relevance of NOTCH1/FBXW7 mutations associated with relapse, we performed whole-exome sequencing in 30 pediatric T-ALL cases, among which 11 diagnosis-relapse paired cases were further investigated to track the clonal evolution of relapse using amplicon-based deep sequencing. NOTCH1/FBXW7 alterations were detected in 73.3% (diagnosis) and 72.7% (relapse) of cases. Single nucleotide variations in the heterodimerization domain were the most frequent (40.0%) at diagnosis, whereas proline, glutamic acid, serine, threonine-rich (PEST) domain alterations were the most frequent at relapse (54.5%). Comparison between non-relapsed and relapsed cases at diagnosis showed a predominance of PEST alterations in relapsed cases (P = .045), although we failed to validate this in the TARGET cohort. Based on the clonal analysis of diagnosis-relapse samples, we identified NOTCH1 "switching" characterized by different NOTCH1 mutations in a major clone between diagnosis and relapse samples in 2 out of 11 diagnosis-relapse paired cases analyzed. We found another NOTCH1 "switching" case in a previously reported Berlin-Frankfurt-Munster cohort (n = 13), indicating NOTCH1 importance in both the development and progression of T-ALL. Despite the limitations of having a small sample size and a non-minimal residual disease-based protocol, our results suggest that the presence of NOTCH1 mutations might contribute to the disease relapse of T-ALL.

Hepatosplenic T-cell lymphoma (HSTCL) is a rare subtype of peripheral T-cell lymphoma that occurs most often in adolescents and young adults and is rare in children. Because of the aggressive clinical course, resistance to conventional chemotherapy and poor prognosis of HSTCL, an effective treatment has not been established. We report the case of a 3-year-old girl with HSTCL presenting with trilineage myelodysplasia. Although the HSTCL was refractory to conventional chemotherapy, remission was achieved with salvage chemotherapy that included fludarabine and cytarabine, which were shown to be effective in the drug sensitivity assay. After undergoing umbilical cord blood transplantation with a conditioning regimen consisting of etoposide, cyclophosphamide and total body irradiation, the patient has remained in complete remission for 8 years. Single-nucleotide polymorphism array analysis revealed heterozygous deletions of PAX5 (9p), ETV6 (12p) and homozygous deletions of CDKN2A (9p). Exome analysis showed a heterozygous nonsense c.2961CG (p.Tyr987Ter) variant of the KMT2C gene. To improve the poor prognosis of HSTCL, the chemotherapeutic regimen can be selected for each patient on the basis of drug sensitivity and molecular genetic characteristics.

We report on a 16-year-old Japanese boy in whom an esophageal squamous cell carcinoma (ESCC) developed 12 years after allogeneic hematopoietic stem cell transplantation was performed for aplastic anemia. A high frequency of microsatellite instability was detected in samples of ESCC. Moreover, the detection of pathogenic variants, including single nucleotide substitution of TP53 (c.346C>T) and BRCA2 (c.6952C>T) and splicing of KDM6A (c.1194+2T>G), suggest that the development of ESCC in the patient was triggered by impairment of checkpoint and repair for DNA damage and epigenetic modification through accumulation of gene mutations induced by chronic graft-versus-host disease and prolonged administration of tacrolimus.

BACKGROUND/OBJECTIVES Relapsed or refractory brain tumors in childhood continue to have a dismal prognosis in spite of intensive multidisciplinary treatment. Cancer immunotherapy is newly developed to be expected as next promising treatment for highly aggressive pediatric cancer. This trial was designed to evaluate the safety and effectiveness of an immunotherapy with fusions of dendritic cells (DCs) and tumor cells in patients with malignant brain tumors. METHODS Patients with histopathologically confirmed malignant and recurrent/refractory brain tumor were eligible for this immunotherapy trial. Autologous cultured tumor cells obtained from surgical specimens were fused with autologous DCs using polyethylene glycol. The fusion cells (FC) were inoculated intradermally in the cervical region and repeated 3–10 times in each 28–84 days cycle. Treatment-related toxicity, progression-free survival (PFS), and overall survival (OS) were evaluated. RESULTS Six patients were enrolled, three with high grade glioma and three with ependymoma. Median age at first course of immunotherapy was 10 years (range 8–25 years) and median follow-up time from the first course of immunotherapy was 13.5 months (range 3–33 months). All patients with immunotherapy were well tolerated to this treatment with no adverse events except local erythema in injected site. Median progression free survival and overall survival were 18 months and 18.5 months, respectively. CONCLUSIONS FC immunotherapy with autologous DCs and tumor cells for brain tumor in children and young adults were extremely well tolerated and showed encouraging responses in this series. Further phase II study of FC immunotherapy is planned to improve survival and reduce treatment related morbidity.

Herein is described the cases of three children with central nervous system (CNS) tumor, who had switch in handedness occurring before diagnostic confirmation. Although the onset, age, tumor location, and histology were heterogeneous, the diagnosis of CNS tumor was delayed in all three patients. The present experience indicates that switch in handedness should be recognized as a sign of CNS tumor in pediatric patients, and which might prevent delay in diagnosis. Pediatricians should carefully examine such patients who present with some suggestive symptoms of CNS tumor, even when they are unusual, in order to make a timely and appropriate diagnosis.

Background/Objectives: Relapse or refractory brain tumor in childhood continue to have a dismal prognosis in spite of developing multidisciplinary treatment. Cancer immunotherapy is newly expected as next promising treatment for highly aggressive pediatric cancer. This trial was designed to evaluate the safety and clinical responses to an immunotherapy with fusions of dendritic cells (DCs) and tumor cells in patients with malignant brain tumors. Design/Methods: Patients with histopathologically confirmed high-grade or recurrent brain tumor were eligible for our immunotherapy. Autologous cultured tumor cells obtained from surgical specimens were fused with autologous DCs using polyethylene glycol. The fusion cells (FC) were inoculated intradermally in the cervical region and repeated 3–10 times in each 28–84 days cycle. Toxicity, progression-free survival (PFS), and overall survival (OS) of this trial were evaluated. Results: Six patients were enrolled, three with high grade glioma and three with ependymoma. Median age at first course of immunotherapy was 10 years (range 8–25 years) and median time of follow-up from first course of immunotherapy was 13.5 months (range 3–33 months). All patients with immunotherapy were well tolerated and no adverse event without local erythema in injected site. Median progression free survival and overall survival were 18 months and 18.5 months, respectively. Conclusions: FC immunotherapy with autologous DCs and tumor cells for brain tumor in children and young adults were extremely well tolerated and encouraging. Further phase II study of FC immunotherapy is planned to improve prognosis and overcome treatment related neurological sequelae for highly malignant tumors.

BACKGROUND Brainstem tumours account for 10–15% of brain tumors in childhood. Diffuse intrinsic pontine glioma (DIPG) accounts for 60–80% of them and are diagnosed based on clinical findings and radiologic features. All the rest of tumours excluding DIPG are very rare, heterogeneous group of tumours including low-grade glioma and malignant embryonal tumors. It is often difficult to diagnose and decide treatment strategy for their rarity. METHODS To present our experience with atypical brainstem tumours, a retrospective chart review was conducted to identify eligible cases treated over a ten-year period. All tumors involving brainstem, felt not to be DIPGs for absence of clinical/neuroimaging features were included. Demographic information, pathological findings, neuroimaging characteristics, surgical and nonsurgical management plans, and survival data were collected for analysis. RESULTS Between April 2007 and March 2017, 16 patients (14 initial and 2 recurrent) aged from 3 to 20 years were identified. 14 of them were symptomatic and 4 of them were asymptomatic at reference. Of 10 symptomatic cases, 10 were biopsied and pathological diagnosis was low-grade glioma in 8, glioblastoma in 2 cases. They had treatment depending on the pathological diagnosis. Of 4 asymptomatic cases, one with small focal tumour, with no findings suggesting malignant tumour with 11C-methioninePET or MRS, progressed to show typical clinical and image findings of DIPG in a year. For other three, they remain asymptomatic without progression with no treatment for 25months, 60months, and 65 months respectively. Malignant transformation was observed in one with biopsy-conformed oligoastrocytoma with no K27M-H3 mutations treated with chemotherapy and another with pilocytic astrocytoma treated with chemotherapy and radiotherapy. CONCLUSIONS Though molecular findings such as K27M-H3 mutations can predict clinical outcome in some cases, it still remains difficult to diagnose and find treatment strategy of atypical brainstem tumours. The need and usefulness of nationwide registry study is warranted.

Novel epigenetic therapies targeting bromodomain and extra-terminal (BET) family proteins have shown therapeutic efficacy in diverse hematologic malignancies and solid cancers. However, the mechanism of resistance remains poorly understood. In the present study, we evaluated the mechanism of resistance to the BET inhibitor I-BET151 and its signaling pathway to overcome resistance in U937 cells. Treatment with 10 μM I-BET151 significantly induced growth inhibition, apoptosis, and cell cycle modulation, including increases in sub-G1 and G1 phases and decreases in S and G2/M phases, in U937 cells. However, no significant changes in these factors were detected in I-BET151-resistant U937 (U937R) cells. Combined treatment with I-BET151 and IKK inhibitor VII synergistically induced apoptosis in U937 and U937R cells. Increased expression of bromodomain-containing protein (BRD) 2, BRD4, and nuclear NF-κBp65 proteins was detected in U937R cells. IKK inhibitor VII inhibited the activation of NF-κBp65 protein in the nuclear fraction of U937R cells. These findings suggest that resistance to I-BET151 in U937R cells is related to constitutive activation of the NF-κB signaling pathway via increased expression of both BRD2 and BRD4. Targeting the NF-κB signaling pathway may be an effective therapeutic strategy to enhance or restore the sensitivity to I-BET151 in U937 cells.

Acute lymphoblastic leukemia (ALL) occasionally develops before or after the onset of Langerhans cell histiocytosis (LCH). The mechanism of LCH developing after ALL remains unclear; thus the clonality of LCH developing during maintenance chemotherapy for T-cell ALL (T-ALL) was investigated. The T-ALL and LCH cells tested had the same T-cell receptor (TCR) gamma rearrangement. Mutation analysis of the NOTCH1 gene revealed 7213C>T (Q2405X) in exon 34 in T-ALL and LCH cells, but 5156T>C (I1719T) in exon 27 only in T-ALL. Polymerase chain reaction-restriction fragment length polymorphism analysis revealed three patterns of NOTCH1 mutations in T-ALL cells. The results suggest that the T-ALL and LCH cells were derived from a common precursor with TCR rearrangement and a single NOTCH1 mutation, rather than LCH cells developing from a minor clone of T-ALL with single NOTCH1 mutation.

Mucopolysaccharidosis type II (MPS II) is a lysosomal storage disorder caused by deficient activity of the iduronate-2-sulfatase. This leads to accumulation of glycosaminoglycans (GAGs) in the lysosomes of various cells. Although it has been proposed that bone marrow transplantation (BMT) may have a beneficial effect for patients with MPS II, the requirement for donor-cell chimerism to reduce GAG levels is unknown. To address this issue, we transplanted various ratios of normal and MPS II bone marrow cells in a mouse model of MPS II and analyzed GAG accumulation in various tissues. Chimerism of whole leukocytes and each lineage of BMT recipients' peripheral blood was similar to infusion ratios. GAGs were significantly reduced in the liver, spleen, and heart of recipients. The level of GAG reduction in these tissues depends on the percentage of normal-cell chimerism. In contrast to these tissues, a reduction in GAGs was not observed in the kidney and brain, even if 100 % donor chimerism was achieved. These observations suggest that a high degree of chimerism is necessary to achieve the maximum effect of BMT, and donor lymphocyte infusion or enzyme replacement therapy might be considered options in cases of low-level chimerism in MPS II patients.

Pancreatoblastoma is a rare pediatric pancreatic malignancy for which the molecular pathogenesis is not understood. In this study, we report the findings of an integrated multiomics study of whole-exome and RNA sequencing as well as genome-wide copy number and methylation analyses of ten pancreatoblastoma cases. The pancreatoblastoma genome was characterized by a high frequency of aberrant activation of the Wnt signaling pathway, either via somatic mutations of CTNNB1 (90%) and copy-neutral loss of heterozygosity (CN-LOH) of APC (10%). In addition, imprinting dysregulation of IGF2 as a consequence of CN-LOH (80%), gain of paternal allele (10%), and gain of methylation (10%) was universally detected. At the transcriptome level, pancreatoblastoma exhibited an expression profile characteristic of early pancreas progenitor-like cells along with upregulation of the R-spondin/LGR5/RNF43 module. Our results offer a comprehensive description of the molecular basis for pancreatoblastoma and highlight rational therapeutic targets for its treatment. Significance: Molecular genetic analysis of a rare untreatable pediatric tumor reveals Wnt/IGF2 aberrations and features of early pancreas progenitor-like cells, suggesting cellular origins and rational strategies for therapeutic targeting. Cancer Res; 78(4); 865–76. ©2017 AACR.

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-β-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.

Phosphoglycerate kinase (PGK) deficiency, a rare X-linked inherited disorder, manifests as various combinations of hemolytic anemia, neurological dysfunction, and myopathy. We report a Japanese boy with PGK deficiency presenting as chronic hemolytic anemia. The diagnosis of PGK1 deficiency was made at 11 months of age on the basis of low PGK enzyme activity (36.7 IU/g Hb; normal, 264–326 IU/g Hb) and the identification through PGK1 gene sequencing of a novel missense mutation: c. 1180A>G at exon 10. The mutation, which has been designated PGK-Aoto, results in a Thr394Ala amino-acid substitution at β-strand L. Because β-strand L plays an important role in the function of the hinge connecting the two domains of PGK, the Thr394Ala substitution may perturb this motion. At 3 years of age the patient has transfusion-dependent hemolytic anemia but no evidence of neuromuscular disease or developmental delay. Long-term follow-up will be needed to identify possible future clinical manifestations.

Background Although complete resection offers the best chance for controlling head and neck Ewing sarcoma family tumors (ESFTs), it is occasionally unfeasible because of possible functional and cosmetic side effects. Planning multidisciplinary treatment for head and neck ESFT is challenging. Methods and Results A 4-year-old girl had left-sided excessive tearing, nasal obstruction, and exophthalmos for 4 months. A CT scan showed a mass filling the left maxillary sinus and extending to the left orbital wall. After a diagnosis of ESFT was established with biopsy, the patient was treated with vincristine, doxorubicin, cyclophosphamide/ifosfamide etoposide (VDC/IE) regimen over 50 weeks; partial maxillectomy was performed at week 15 and was followed by proton radiotherapy. The patient has remained tumor-free for 16 months, with preservation of facial form and function. Conclusion Partial resection combined with proton radiotherapy may enable maximal tumor control and minimal functional and cosmetic side effects in children with head and neck ESFT. © 2013 Wiley Periodicals, Inc. Head Neck 35: E386–E390, 2013

We report an 11-month-old breast-fed boy with feeding difficulties, lethargy, and developmental delay. Blood examination showed pancytopenia and decreased serum levels of vitamin B12. Anisocytosis and poikilocytes were detected in his peripheral blood, and increased megaloblastosis without leukemic cells was detected in his bone marrow. After the diagnosis of megaloblastic anemia due to vitamin B12 deficiency, symptoms were improved by vitamin B12 administration. Further investigation of the mother identified Crohn's disease and suggested that the supply of vitamin B12 from the mother to the infant, via the placenta during pregnancy and via breast milk after birth, was decreased due to impaired absorption of vitamin B12 in the mother's small intestine. Magnetic resonance imaging of the boy's brain on admission showed cerebral cortex atrophy which had improved by the age of 1 year and 10 months after vitamin B12 treatment, though developmental delay was still evident at the age of 3 years. Infantile vitamin B12 deficiency often presents with nonspecific manifestations, such as developmental delay and failure to thrive, in addition to anemia and is thus not easily diagnosed. To prevent severe neurological sequelae, this condition must be rapidly diagnosed, because a prolonged duration increases the risk of permanent disabilities.

Adult T-cell leukemia (ATL) is a heterogeneous tumor that is resistant to chemotherapy. Telomerase activity plays a critical role in tumorigenesis and is associated with the prognosis of ATL patients. Interleukin (IL)-2 commonly promotes tumor growth in chronic ATL cells. The signaling pathways involved in IL-2–regulated telomerase activation were studied in ATL cells derived from chronic ATL patients. IL-2 challenge enhanced tyrosine phosphorylation of Janus-activated kinase (JAK)1–3 and STAT5, and induced JAK1 and JAK2 to associate with STAT5 in IL-2–dependent ATL cells. Chromatin immunoprecipitation assays revealed that STAT5 directly bound to the human telomerase reverse transcriptase (hTERT) promoter. STAT5 short interfering RNA inhibited hTERT transcription in IL-2–stimulated ATL cells. Inhibitors of PI3K, HSP90, and mTOR reduced IL-2–induced hTERT mRNA, protein expression, and telomerase activity. AKT, HSP90, mTOR, S6 kinase, and hTERT immunoprecipitate from IL-2–stimulated cells contained telomerase activity, suggesting that hTERT directly interacts with, and is regulated by, these proteins. Binding of the p85 regulatory subunit of PI3K to JAK2 was enhanced in an IL-2–dependent manner, indicating that JAK2 propagates activation signals from the IL-2 receptor and links hTERT activation to both the STAT5 and PI3K pathways. Finally, IL-2–induced activation of telomerase and STAT5 was observed in primary leukemic cells. These results indicate that IL-2 stimulation induces hTERT activation through the JAK/STAT pathway and the JAK/PI3K/AKT/HSP90/mTORC1 pathway in IL-2–responsive ATL cells. These signaling proteins represent novel and promising molecular therapeutic targets for IL-2–dependent ATL. Mol Cancer Ther; 11(5); 1112–21. ©2012 AACR.

We have shown previously that PI3K/Akt pathway is active after cell differentiation in HL60 cells. In the present study, we have investigated whether additional molecules, such as protein kinase C (PKC), are involved in the regulation, not only of telomerase, but also of leukemia cell differentiation. We show that PKC activates telomerase and is, itself, activated following VD3- or ATRA-induced differentiation of HL60 cells, as was observed for PI3K/Akt. To clarify the significance of PI3K/Akt and PKC pathway activation in leukemia cell differentiation, we examined the active proteins in either the downstream or upstream regulation of these pathways. In conjunction with the activation of Akt or PKC, mTOR and S6K were phosphorylated and the protein expression levels of Rictor were increased, compared with Raptor, following cell differentiation. Silencing by Rictor siRNA resulted in the attenuation of Akt phosphorylation on Ser473 and PKCα/βII phosphorylation, as well as the inhibition of Rictor itself, suggesting that Rictor is an upstream regulator of both Akt and PKC. In addition, in cells induced to differentiate by ATRA or VD3, Nitroblue-tetrazolium (NBT) reduction and esterase activity, were blocked either by LY294002, a PI3K inhibitor, or by BIM, a PKC inhibitor, without affecting cell surface markers such as CD11b or CD14. Intriguingly, the silencing of Rictor by its siRNA also suppressed the reducing ability of NBT following VD3-induced cell differentiation. Taken together, our results show that Rictor associated with mTOR (mTORC2) regulates the activity of both Akt and PKC that are involved in cell functions such as NBT reduction and esterase activity induced by leukemia cell differentiation.

Infantile myofibromatosis is the most common fibrous tumor of infancy and early childhood. It typically occurs in skin, subcutaneous tissue, muscle, bone, and/or viscera. In patients without visceral involvement, the prognosis is excellent, generally with spontaneous regression of the tumor nodules in 1 to 2 years [1]. However, they show unfavorable prognosis within the first few months of life if there is visceral involvement [1]. Intracranial involvement is rare, and to our knowledge, only 17 such cases have been reported [1–15]. Although lesions usually arise from the dura [16] and grow in one direction, either epidural or subdural, in our case, there was equal growth epidurally and subdurally. Spontaneous regression occurred at the same time as that of a lumbar lesion 3 months after biopsy. This unique course has never been reported, and the rate of regression in this case was remarkable. Case report

BACKGROUND: Central nervous system germ cell tumors (CNS-GCT) are a heterogeneous group of diseases. The management of CNS-GCT remains controversial. Objective: To clarify the relapse pattern and outcome of patients with recurrent CNS-GCT in order to find problems with current initial management. METHODS: Chart review of patients with recurrent CNS-GCTs treated in two institutions from 2007 to 2017. RESULTS: There were 19 germinomas and six non-germinomatous germ cell tumors (NGGCT), referred to us for the first (n=19), second (n=4), third (n=1) and fourth (n=1) relapse. The time from the diagnosis to the first relapse was within three years for 15 patients (range 6- 24 months) and over three years (range 36 -144 months) for 10 patients. The site of recurrence was outside the irradiation field for 13 germinoma cases, and inside for six germinoma and six NGGCT patients. Thirteen patients with first recurrent germinoma survived with chemotherapy and re-irradiation, and one failed with high-dose chemotherapy only. Two patients with second relapse of germinoma were successfully treated with high-dose chemotherapy only. One patient with second relapse of germinoma refractory to chemotherapy and re-irradiation is alive with oral metronomic etoposide for nine years. Only one of six NGGCT patients survived in spite of intensive treatments. CONCLUSIONS: Germinoma patients treated with reduced radiotherapy and chemotherapy can relapse both within and outside irradiation fields, very early and very late in longer follow-up. These results can teach us not only the optimal management of recurrent disease, but also suggest possible novel management of initial disease.

The cationic porphyrin TMPyP4 can bind to and stabilize DNA guanine-quadruplexes. We investigated the molecular mechanism of the antitumor activity of TMPyP4 in K562 cells and human telomere reverse transcriptase subunit (hTERT)-transfected K562 cells in which telomerase activity, followed by telomere elongation, was enhanced. Treatment with 100 microM TMPyP4 significantly inhibited the growth of both types of cell, with decreases of cells in the G(1) phase and increases of those in the S and G(2)/M phases after 48 h, preceding cell death after 72 h. cDNA microarray analysis revealed upregulation of 33 genes and downregulation of 54 genes in K562 cells treated with 100 microM TMPyP4 for 48 h. Moreover, TMPyP4 decreased c-Myc protein expression, increased the expression of p21(CIP1) and p57(KIP2) proteins, and activated p38 mitogen-activated protein kinase, c-Jun N-terminal kinase, and extracellular signal-regulated kinase. These findings may provide a rationale for the development of guanine-quadruplex-interactive agents as novel antileukemic therapies.

Using three different differentiation agents (1α, 25 dihydroxyvitamin D3, all-trans-retinoic acid, and Am80), down-regulation of telomerase activity was found to be a common response during the monocytic or granulocytic differentiation of human acute myeloblastic leukemia cell line 60 (HL60) cells. Rapid down-regulation of telomerase transcription occurred during early differentiation of HL60 cells prior to G1 arrest. Akt kinase activity was suppressed after 6 h of differentiation along with inhibition of telomerase activity, and the extent of the suppression that occurred while maintaining telomerase protein expression suggested the post-translational regulation of telomerase activity. Recombinant Akt dose-dependently increased telomerase activity, and telomerase was inhibited at the transcriptional and post-translational levels by LY294002, suggesting that PI-3K/Akt is one of the key signaling proteins involved in telomerase regulation. Each of the three differentiation agents caused a significant increase of signaling proteins (including Akt) at 3 days after the initiation of differentiation. Changes of acetyl-histone H4, which regulates transcription of the telomerase gene, were observed before the activation of Akt. This finding suggests that epigenetic control of telomerase transcription occurs before activation of Akt during the late stage of differentiation. These results indicate that telomerase activity is regulated by at least two mechanisms during granulocytic and monocytic differentiation, with one mechanism being transcriptional and the other being post-translational.

Imatinib mesylate (imatinib), previously known as STI571 (Gleevec), is currently utilized in the treatment of chronic myeloid leukemia (CML). However, its effect on telomerase activity and the correlation of this to its observed antitumor effect has yet to be defined. We investigated the effects of this agent on human telomerase reverse transcriptase (hTERT) expression and telomerase activity and found that it significantly down-regulated telomerase activity in both K562 cells and primary leukemic cells. The telomerase activity of primary leukemic cells from CML patients in blastic crisis showed less suppression than that of cells from patients in chronic phase. Additionally, data also demonstrate that inhibition of telomerase was due to the direct action of imatinib on hTERT transcription, rather than an increase in cell death. These results suggest a novel mechanism in the antitumor activity of imatinib and may provide a basis for future development of anti-telomerase therapies, as well as leading to better understanding of the regulation of telomerase in leukemic cells.

We describe a 7-year-old girl with angiomatoid fibrous histiocytoma (AFH) presenting severe inflammatory symptoms. The cytokine/chemokine profile of serum samples before and after surgery demonstrated that interleukin (IL)-6 had decreased by the greatest percentage. The AFH cells were immunopathologically positive for IL-6 and Tyr705-phosphorylation of signal transducer and activator of transcription 3. The EWSR1-CREB1 fusion gene detected in the tumor leads to continuous activation of CREB1 and IL-6 production, because the promoter region of IL-6 has a CREB binding site. Thus, IL-6 plays pivotal roles in both paraneoplastic syndrome and the oncogenesis of AFH.

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., 横紋筋肉腫におけるゲノム・エピゲノム異常の全体図を解明 -横紋筋肉腫を4群に分類-. 京都大学プレスリリース. 2015-07-03.

We report a case of central diabetes insipidus, hypothyroidism, and subsequent hypopituitarism due to lymphocytic hypophysitis masking a germinoma in a 13-year-old pubertal girl. Magnetic resonance revealed an enlarged pituitary gland and a mass lesion in the pituitary stalk and inferior hypothalamus. Open cranial surgery of the anterior pituitary showed active hypophysitis with lymphocytic infiltrates but without necrosis. Despite prednisolone therapy, 1 year later an enlarged, irregular cystic mass lesion had developed; in the pituitary stalk and inferior hypothalamus, a endoscopic biopsy revealed germinoma. Lymphocytic hypophysitis in children may be the first sign of a host reaction to an occult germinoma. The diagnosis of central diabetes insipidus with a thickened pituitary stalk requires long-term follow-up to establish the underlying cause.

We show that multiple myeloma (MM), the second most commonly diagnosed hematologic malignancy, is responsive to hsp90 inhibitors in vitro and in a clinically relevant orthotopic in vivo model, even though this disease does not depend on HER2/neu, bcr/abl, androgen or estrogen receptors, or other hsp90 chaperoning clients which are hallmarks of tumor types traditionally viewed as attractive clinical settings for use of hsp90 inhibitors, such as the geldanamycin analog 17-AAG. This class of agents simultaneously suppresses in MM cells the expression and/or function of multiple levels of insulin-like growth factor receptor (IGF-1R) and interleukin-6 receptor (IL-6R) signaling (eg, IKK/NF-kappaB, PI-3K/Akt, and Raf/MAPK) and downstream effectors (eg, proteasome, telomerase, and HIF-1alpha activities). These pleiotropic proapoptotic effects allow hsp90 inhibitors to abrogate bone marrow stromal cell-derived protection on MM tumor cells, and sensitize them to other anticancer agents, including cytotoxic chemotherapy and the proteasome inhibitor bortezomib. These results indicate that hsp90 can be targeted therapeutically in neoplasias that may not express or depend on molecules previously considered to be the main hsp90 client proteins. This suggests a more general role for hsp90 in chaperoning tumor- or tissue-type-specific constellations of client proteins with critical involvement in proliferative and antiapoptotic cellular responses, and paves the way for more extensive future therapeutic applications of hsp90 inhibition in diverse neoplasias, including MM.

We analysed a complex translocation involving chromosomes 7, 11, 19 and 22 in infant acute monocytic leukemia, and identified that the MLL gene on 11q23 was fused to the unconventional myosin type 1F, MYO1F, gene on 19p13.2-13.3. MYO1F consists of at least 28 exons and was predicted to encode a 1098-amino-acid with an N-terminal head domain containing both ATP-binding and actin-binding sequences, a neck domain with a single IQ motif, and a tail with TH1, TH2 and SH3 domains. Northern blot analysis of RNAs prepared from multiple tissues showed that the expression of approximately 4-kb transcripts appeared constant in most tissues examined. However, MYO1F was expressed in only three of 22 leukemic cell lines. The MLL-MYO1F fusion protein contains almost the entire MYO1F, however, C-terminal MYO1F has neither the transactivation domain nor the dimerization domain found in various MLL fusion partners. Further analysis of this novel type of MLL fusion protein would provide new insights into leukemogenesis. MYO1F is the fourth partner gene of MLL on 19p13. At the cytogenetic level, it may be difficult to distinguish MLL-ENL, MLL-ELL, MLL-EEN and MLL-MYO1F fusions created by t(11;19)(q23;p13), and it is likely that cases of t(11;19) lacking a known fusion gene may result in this gene fusion.

Diamond-Blackfan anemia (DBA) is a congenital anemia characterized by a low reticulocyte count, the absence or severe reduction of hemoglobin-containing cells in the bone marrow, and normal megakaryocytic and granulocytic differentiation. Although the anemia may initially respond to corticosteroid therapy, many patients require lifelong red blood cell (RBC) transfusion, leading to infectious complications and iron overload. Metoclopramide has recently been used to treat DBA. Treatment with metoclopramide induces the release of prolactin from the pituitary and stimulates erythropoiesis. For these reasons, we used metoclopramide to treat a 20-year-old man with DBA refractory to low and high doses of corticosteroids, cyclosporin A, and tacrolimus (FK506). The hemoglobin and hematocrit slowly increased, and he has remained asymptomatic and transfusion-independent for 8 months. Metoclopramide therapy should be considered in patients with refractory DBA before treatment-related complications develop. Am. J. Hematol. 78:295–298, 2005. © 2005 Wiley-Liss, Inc.

Thalidomide and immunomodulatory drugs (IMiDs), which target multiple myeloma (MM) cells and the bone marrow microenvironment, can overcome drug resistance. These agents also have immunomodulatory effects. Specifically, we have reported that thalidomide increased serum interleukin-2 (IL-2) levels and natural killer (NK) cell numbers in the peripheral blood of responding MM patients. In this study, we investigated the mechanisms whereby IMiDs augment NK cell cytotoxicity. NK cytotoxicity and antibody-dependent cell-mediated cytotoxicity (ADCC) of peripheral blood mononuclear cells cultured with IMiDs were examined in the presence or absence of anti-IL-2 antibody, ciclosporin A or depletion of CD56-positive cells. IMiDs-induced signalling pathways, triggering IL-2 transcription in T cells, were also delineated. IMiDs facilitated the nuclear translocation of nuclear factor of activated T cells-2 and activator protein-1 via activation of phosphoinositide-3 kinase signalling, with resultant IL-2 secretion. IMiDs enhanced both NK cell cytotoxicity and ADCC induced by triggering IL-2 production from T cells. These studies defined the mechanisms whereby IMiDs trigger NK cell-mediated tumour-cell lysis, further supporting their therapeutic use in MM.

We report familial cases with MYH9 disorders: a 1-year-old Japanese boy who presented only with macrothrombocytopenia, and his 33-year-old father who had been diagnosed with refractory chronic idiopathic thrombocytopenic purpura, and suffered from hearing loss and chronic renal failure. Peripheral blood smears revealed giant platelets but no Dohle body-like cytoplasmic inclusion bodies in neutrophils. Heterozygous MYH9 S96L mutations were found in the patient and his father, resulting in the diagnosis of a familial case with MYH9 disorders. The possibility of MYH9 disorders including Epstein syndrome should be assessed in cases of thrombocytopenia through the careful examination of hematological features.

Histone deacetylases (HDACs) affect cell growth at the transcriptional level by regulating the acetylation status of nucleosomal histones. HDAC inhibition induces differentiation and/or apoptosis in transformed cells. We recently showed that HDAC inhibitors, such as suberoylanilide hydroxamic acid (SAHA), potently induce apoptosis of human multiple myeloma (MM) cells. In this study, we focused on MM as a model to study the transcriptional profile of HDAC inhibitor treatment on tumor cells and to address their pathophysiological implications with confirmatory mechanistic and functional assays. We found that MM cells are irreversibly committed to cell death within few hours of incubation with SAHA. The molecular profile of MM cells before their commitment to SAHA-induced cell death is hallmarked by a constellation of antiproliferative and/or proapoptotic molecular events, including down-regulation of transcripts for members of the insulin-like growth factor (IGF)/IGF-1 receptor (IGF-1R) and IL-6 receptor (IL-6R) signaling cascades, antiapoptotic molecules (e.g., caspase inhibitors), oncogenic kinases, DNA synthesis/repair enzymes, and transcription factors (e.g., XBP-1, E2F-1) implicated in MM pathophysiology. Importantly, SAHA treatment suppresses the activity of the proteasome and expression of its subunits, and enhances MM cell sensitivity to proteasome inhibition by bortezomib (PS-341). SAHA also enhances the anti-MM activity of other proapoptotic agents, including dexamethasone, cytotoxic chemotherapy, and thalidomide analogs. These findings highlight the pleiotropic antitumor effects of HDAC inhibition, and provide the framework for future clinical applications of SAHA to improve patient outcome in MM.

Although c-Jun NH(2)-terminal kinase (JNK) is activated by treatment with therapeutic agents, the biologic sequelae of inhibiting constitutive activation of JNK has not yet been clarified. In this study, we examine the biologic effect of JNK inhibition in multiple myeloma (MM) cell lines. JNK-specific inhibitor SP600125 induces growth inhibition via induction of G1 or G2/M arrest in U266 and MM.1S multiple myeloma cell lines, respectively. Neither exogenous IL-6 nor insulin-like growth factor-1 (IGF-1) overcome SP600125-induced growth inhibition, and IL-6 enhances SP600125-induced G2/M phase in MM.1S cells. Induction of growth arrest is mediated by upregulation of p27(Kip1), without alteration of p53 and JNK protein expression. Importantly, SP600125 inhibits growth of MM cells adherent to bone marrow stromal cells (BMSCs). SP600125 induces NF-kappaB activation in a dose-dependent fashion, associated with phosphorylation of IkappaB kinase alpha (IKKalpha) and degradation of IkappaBalpha. In contrast, SP600125 does not affect phosphorylation of STAT3, Akt, and/or ERK. IKK-specific inhibitor PS-1145 inhibits SP600125-induced NF-kappaB activation and blocks the protective effect of SP600125 against apoptosis. Our data therefore demonstrate for the first time that inhibiting JNK activity induces growth arrest and activates NF-kappaB in MM cells.