Pediatric Central Nervous System Cancers, Version 2.2023, NCCN Clinical Practice Guidelines in Oncology.

Central nervous system (CNS) cancers account for approximately one quarter of all pediatric tumors and are the leading cause of cancer-related death in children. More than 4,000 brain and CNS tumors are diagnosed each year in children and teens, and the incidence rate has remained stagnant in recent years. The most common malignant pediatric CNS tumors are gliomas, embryonal tumors consisting of predominately medulloblastomas, and germ cell tumors. The inaugural version of the NCCN Guidelines for Pediatric Central Nervous System Cancers focuses on the diagnosis and management of patients with pediatric diffuse high-grade gliomas. The information contained in the NCCN Guidelines is designed to help clinicians navigate the complex management of pediatric patients with diffuse high-grade gliomas. The prognosis for these highly aggressive tumors is generally poor, with 5-year survival rates of <20% despite the use of combined modality therapies of surgery, radiation therapy and systemic therapy. Recent advances in molecular profiling has expanded the use of targeted therapies in patients whose tumors harbor certain alterations. However, enrollment in a clinical trial is the preferred treatment for eligible patients.

Advances in the Treatment of Pediatric Brain Tumors.

Pediatric brain tumors are the most common solid malignancies in children. Advances in the treatment of pediatric brain tumors have come in the form of imaging, biopsy, surgical techniques, and molecular profiling. This has led the way for targeted therapies and immunotherapy to be assessed in clinical trials for the most common types of pediatric brain tumors. Here we review the latest efforts and challenges in targeted molecular therapy, immunotherapy, and newer modalities such as laser interstitial thermal therapy.

Congenital presentation of synchronous Atypical Teratoid Rhabdoid Tumor and Malignant Rhabdoid Tumor of the urinary bladder in a term infant.

Atypical teratoid/rhabdoid tumor (AT/RT) is a rare central nervous system (CNS) tumor diagnosed primarily in infants and usually portends a poor prognosis. Despite being the most common embryonal tumor in children less than 1 year old, diagnosis is difficult to make based on clinical findings or imaging alone. A complete diagnosis of AT/RT requires identification of loss of integrase interactor 1 (INI1) protein or the SWI/SNF-related, matrix-associated, actin-dependent regulator of chromatin, subfamily b, member 1 (SMARCB1) gene, in its most common presentation. Moreover, their presentation with other primary rhabdoid tumors in the body raises significant suspicion for rhabdoid tumor predisposition syndrome (RTPS). We report a case of a one-month-old infant admitted for worsening emesis and failure to thrive, who was later found to have brain and bladder masses on radiologic imaging. Autopsy with subsequent immunoprofile and molecular testing were crucial in establishing the absence of INI1 nuclear expression and possible homozygous deletion of SMARCB1 in the urinary bladder tumor tissue. Sequencing of the peripheral blood demonstrated probable single copy loss at the SMARCB1 locus. The constellation of findings in tumor and peripheral blood sequencing suggested the possibility of germline single copy SMARCB1 loss, followed by somatic loss of the remaining SMARCB1 allele due to copy neutral loss-of-heterozygosity. Such a sequence of genetic events has been described in malignant rhabdoid tumors (MRT). Dedicated germline testing of this patient's family members could yield answers as to whether rhabdoid tumor predisposition syndrome will continue to have implications for the patient's family.

Pediatric bithalamic gliomas have a distinct epigenetic signature and frequent EGFR exon 20 insertions resulting in potential sensitivity to targeted kinase inhibition.

Brain tumors are the most common solid tumors of childhood, and the genetic drivers and optimal therapeutic strategies for many of the different subtypes remain unknown. Here, we identify that bithalamic gliomas harbor frequent mutations in the EGFR oncogene, only rare histone H3 mutation (in contrast to their unilateral counterparts), and a distinct genome-wide DNA methylation profile compared to all other glioma subtypes studied to date. These EGFR mutations are either small in-frame insertions within exon 20 (intracellular tyrosine kinase domain) or missense mutations within exon 7 (extracellular ligand-binding domain) that occur in the absence of accompanying gene amplification. We find these EGFR mutations are oncogenic in primary astrocyte models and confer sensitivity to specific tyrosine kinase inhibitors dependent on location within the kinase domain or extracellular domain. We initiated treatment with targeted kinase inhibitors in four children whose tumors harbor EGFR mutations with encouraging results. This study identifies a promising genomically-tailored therapeutic strategy for bithalamic gliomas, a lethal and genetically distinct brain tumor of childhood.

Congenital presentation of synchronous Atypical Teratoid Rhabdoid Tumor and Malignant Rhabdoid Tumor of the urinary bladder in a term infant

Atypical teratoid/rhabdoid tumor (AT/RT) is a rare central nervous system (CNS) tumor diagnosed primarily in infants and usually portends a poor prognosis. Despite being the most common embryonal tumor in children less than 1 year old, diagnosis is difficult to make based on clinical findings or imaging alone. A complete diagnosis of AT/RT requires identification of loss of integrase interactor 1 (INI1) protein or the SWI/SNF-related, matrix-associated, actin-dependent regulator of chromatin, subfamily b, member 1 (SMARCB1) gene, in its most common presentation. Moreover, their presentation with other primary rhabdoid tumors in the body raises significant suspicion for rhabdoid tumor predisposition syndrome (RTPS). We report a case of a one-month-old infant admitted for worsening emesis and failure to thrive, who was later found to have brain and bladder masses on radiologic imaging. Autopsy with subsequent immunoprofile and molecular testing were crucial in establishing the absence of INI1 nuclear expression and possible homozygous deletion of SMARCB1 in the urinary bladder tumor tissue. Sequencing of the peripheral blood demonstrated probable single copy loss at the SMARCB1 locus. The constellation of findings in tumor and peripheral blood sequencing suggested the possibility of germline single copy SMARCB1 loss, followed by somatic loss of the remaining SMARCB1 allele due to copy neutral loss-of-heterozygosity. Such a sequence of genetic events has been described in malignant rhabdoid tumors (MRT). Dedicated germline testing of this patient's family members could yield answers as to whether rhabdoid tumor predisposition syndrome will continue to have implications for the patient's family.

Chronic radiation exposure of neuroblastoma cells reduces nMYC copy number.

Neuroblastoma accounts for >15% of cancer-associated mortalities of children in the USA. Despite aggressive treatment regimens, the long-term survival for these children remains <40%. The identification of v-Myc avian myelocytomatosis viral oncogene neuroblastoma-derived homolog (nMYC) gene amplification during diagnosis is associated with poor prognosis in neuroblastoma. There are limited studies examining changes in nMYC copy numbers in response to therapy and its biological effect on cancer cells. The aim of the present study was to evaluate the effect of radiation on nMYC expression and amplification status in high-risk neuroblastoma. The effect of acute (5 Gy) and chronic (25 Gy) radiation on two nMYC-amplified cell lines, SK-N-BE (2) and NB-1691, was investigated. The results demonstrate that, following chronic but not acute radiation, the two cell lines regained their proliferation potential similar to the controls. This increased proliferation was characterized by loss of nMYC mRNA and protein expression. It was also revealed that nMYC loss was accompanied by nuclear localization of c-Myc. Using fluorescent in situ hybridization and quantitative polymerase chain reaction analysis, the results of the present study demonstrated that chronic radiation causes a severe loss of nMYC gene copy number. The present study is the first to provide experimental evidence that prolonged radiation therapy affects nMYC gene copy number in high-risk neuroblastoma but does not significantly improve the prognostic outlook.

SPARC overexpression suppresses radiation-induced HSP27 and induces the collapse of mitochondrial Δψ in neuroblastoma cells.

Neuroblastoma is the cause of >15% of cancer-associated mortality in children in the USA. Despite aggressive treatment regimens, the long-term survival rate for these children remains at <40%. The current study demonstrates that secreted protein acidic and rich in cysteine (SPARC) suppresses radiation-induced expression of heat shock protein 27 (HSP27) in vivo and suppresses mitochondrial membrane potential (Δψ) in neuroblastoma cells. In the present study, the overexpression of SPARC in SK-N-BE(2) and NB1691 neuroblastoma cell lines suppresses radiation-induced G2M cell cycle arrest, proliferation, HSP27 expression (in vitro and in vivo) and induces the collapse of the mitochondrial Δψ. Gene ontology analysis demonstrated that the overexpression of SPARC combined with irradiation, induces the expression of dissimilar molecular function genes in SK-N-BE(2) and NB1691 cells, providing evidence of a dissimilar response signaling pathway. These results demonstrate that overexpression of SPARC suppresses radiation-induced HSP27 expression in neuroblastoma cells and the combination of SPARC and radiation induces the expression of protein 21, but suppresses neuroblastoma tumor density in in vivo mouse models. SPARC also induces mitochondrial Δψ collapse in SK-N-BE(2) and NB1691 neuroblastoma cells.

Novel targeted therapy for neuroblastoma: silencing the MXD3 gene using siRNA.

BackgroundNeuroblastoma is the second most common extracranial cancer in children. Current therapies for neuroblastoma, which use a combination of chemotherapy drugs, have limitations for high-risk subtypes and can cause significant long-term adverse effects in young patients. Therefore, a new therapy is needed. In this study, we investigated the transcription factor MXD3 as a potential therapeutic target in neuroblastoma.MethodsMXD3 expression was analyzed in five neuroblastoma cell lines by immunocytochemistry and quantitative real-time reverse transcription PCR, and in 18 primary patient tumor samples by immunohistochemistry. We developed nanocomplexes using siRNA and superparamagnetic iron oxide nanoparticles to target MXD3 in neuroblastoma cell lines in vitro as a single-agent therapeutic and in combination with doxorubicin, vincristine, cisplatin, or maphosphamide-common drugs used in current neuroblastoma treatment.ResultsMXD3 was highly expressed in neuroblastoma cell lines and in patient tumors that had high-risk features. Neuroblastoma cells treated in vitro with the MXD3 siRNA nanocomplexes showed MXD3 protein knockdown and resulted in cell apoptosis. Furthermore, on combining MXD3 siRNA nanocomplexes with each of the four drugs, all showed additive efficacy.ConclusionThese results indicate that MXD3 is a potential new target and that the use of MXD3 siRNA nanocomplexes is a novel therapeutic approach for neuroblastoma.

SPARC overexpression combined with radiation retards angiogenesis by suppressing VEGF-A via miR­410 in human neuroblastoma cells.

Neuroblastoma (NB) is the most common extra-cranial solid tumor in children and despite aggressive therapy survival rates remain low. One of the contributing factors for low survival rates is aggressive tumor angiogenesis, which is known to increase due to radiation, one of the standard therapies for neuroblastoma. Therefore, targeting tumor angiogenesis can be a viable add-on therapy for the treatment of neuroblastomas. In the present study, we demonstrate that overexpression of secreted protein acidic and rich in cysteine (SPARC) suppresses radiation induced angiogenesis in SK-N­BE(2) and NB1691 neuroblastoma cells. We observed that overexpression of SPARC in SK-N-BE(2) and NB1691 cells reduced radiation induced angiogenesis in an in vivo mouse dorsal skin model and an ex vivo chicken CAM (chorioallantoic-membrane) model and also reduced tumor size in subcutaneous mouse tumor models of NB. We also observed that SPARC overexpression reduces VEGF-A expression, in SK-N-BE(2) and NB1691 NB cells via miR-410, a VEGF-A targeting microRNA. SPARC overexpression alone or in combination with miR-410 and radiation was shown to be effective at reducing angiogenesis. Moreover, addition of miR-410 inhibitors reversed SPARC mediated inhibition of VEGF-A in NB1691 cells but not in SK-N-BE(2) NB cells. In conclusion, the present study demonstrates that the overexpression of SPARC in combination with radiation reduced tumor angiogenesis by downregulating VEGF-A via miR-410.

Hand1 overexpression inhibits medulloblastoma metastasis.

Medulloblastoma (MB) is the most frequent malignant pediatric brain tumor. Current treatment includes surgery, radiation and chemotherapy. However, ongoing treatment in patients is further classified according to the presence or absence of metastasis. Since metastatic medulloblastoma are refractory to current treatments, there is need to identify novel biomarkers that could be used to reduce metastatic potential, and more importantly be targeted therapeutically. Previously, we showed that ionizing radiation-induced uPAR overexpression is associated with increased accumulation of ß-catenin in the nucleus. We further demonstrated that uPAR protein act as cytoplasmic sequestration factor for a novel basic helix-loop-helix transcription factor, Hand1. Among the histological subtypes classical and desmoplastic subtypes account for the majority while large cell/anaplastic variant is most commonly associated with metastatic disease. In this present study using immunohistochemical approach and patient data mining for the first time, we demonstrated that Hand1 expression is observed to be downregulated in all the subtypes of medulloblastoma. Previously we showed that Hand1 overexpression regulated medulloblastoma angiogenesis and here we investigated the role of Hand1 in the context of Epithelial-Mesenchymal Transition (EMT). Moreover, UW228 and D283 cells overexpressing Hand1 demonstrated decreased-expression of mesenchymal markers (N-cadherin, ß-catenin and SOX2); metastatic marker (SMA); and increased expression of epithelial marker (E-cadherin). Strikingly, human pluripotent stem cell antibody array showed that Hand1 overexpression resulted in substantial decrease in pluripotency markers (Nanog, Oct3/4, Otx2, Flk1) suggesting that Hand1 expression may be essential to attenuate the EMT and our findings underscore a novel role for Hand1 in medulloblastoma metastasis.

A retrospective analysis of recurrent intracranial ependymoma.

BACKGROUND: Recurrence occurs in almost 50% of patients with intracranial ependymoma, and their outcome following recurrence is poor. METHODS: We retrospectively reviewed the medical records of 22 patients with intracranial ependymoma and subsequent relapse(s) (59 recurrences) treated at Children's Hospital Los Angeles or New York University between January 1997 and December 2012. RESULTS: Median duration of follow-up was 52 months (7-171 months). Median age at initial diagnosis was 4 years (0.3-19 years) with 8 patients younger than 3 years at presentation. Eleven patients had anaplastic and 11 cellular pathologies. Eighteen patients had infratentorial tumors at diagnosis and 3 (all infratentorial) had metastatic spinal cord involvement at presentation. Cerebrospinal fluid involvement was not identified at diagnosis or relapse. Median time to first recurrence was 16 months (1.3 to 115 months). The number of recurrences in each patient ranged from 1 to 9 (median = 2). Thirty-seven recurrences (63%) were detected asymptomatically by surveillance imaging. Fifteen recurrences (26%) arose outside the initial tumor site. Recurrences were treated by surgical resection (45), with irradiation (30), and with various oral chemotherapies (23) with (7) or without (16) conventional chemotherapy. The 5 and 10 year overall survival rates from first recurrence were 0.37 ± 0.14 and 0.25 ± 0.14. CONCLUSION: Prolonged (5-10 year) survival from first relapse was noted in over one-quarter of our patients. It remains unclear whether early radiographic diagnosis, differing treatment modalities beyond radical surgical resection or possibly unrecognized biological differences contributed towards this prolonged survival.

Vitamin D protects acute lymphoblastic leukemia cells from dexamethasone.

Vitamin D deficiency has been linked with increased cancer risk, and vitamin D has been shown to be cytotoxic to some cancer cells in vitro. In the present study we evaluated whether vitamin D would have antiproliferative or cytotoxic effects on human pre-B acute lymphoblastic leukemia cells. Contrary to our hypotheses, calcitriol, the active form of vitamin D, had no effect on leukemia cell proliferation. Calcitriol actually had a modest effect to impair dexamethasone cytotoxicity and induction of apoptosis. Further studies are needed to evaluate the effects of vitamin D on leukemia cells in vivo.

Deficiency of indoleamine 2,3-dioxygenase enhances commensal-induced antibody responses and protects against Citrobacter rodentium-induced colitis.

Indoleamine 2,3-dioxygenase (IDO) is a negative regulator of lymphocyte responses that is expressed predominantly in macrophages and dendritic cells. We detected it at high levels in the small intestine and mesenteric lymph node of young adult mice, suggesting a role in intestinal immunity. Consistent with this idea, we found that IDO-deficient mice had elevated baseline levels of immunoglobulin A (IgA) and IgG in the serum and increased IgA in intestinal secretions. These abnormalities were corrected by a course of broad-spectrum oral antibiotics started at weaning, indicating that they were dependent on the intestinal microbiota. Kynurenine and picolinic acid, two IDO-generated metabolites of tryptophan, were able to inhibit lipopolysaccharide-induced antibody production by splenocytes in vitro, and kynurenine also induced B-cell apoptosis, findings that provide an explanation for the elevated Ig levels in animals lacking IDO. The intestinal secretions of IDO-deficient mice had elevated levels of IgA antibodies that cross-reacted with the gram-negative enteric bacterial pathogen Citrobacter rodentium. In keeping with the functional importance of this natural secretory IgA, the mutant animals were more resistant to intestinal colonization by Citrobacter, developed lower levels of serum Citrobacter-specific IgM and IgG antibodies following oral infection, and had significantly attenuated Citrobacter-induced colitis. Our observations point to an important role for IDO in the regulation of immunity to the gut commensal microbiota that has a significant impact on the response to intestinal pathogens.

A role for natural killer cells in intestinal inflammation caused by infection with Salmonella enterica serovar Typhimurium.

Acute gastroenteritis caused by Salmonella infection is a significant public health problem. Using a mouse model of this condition, the authors demonstrated previously that the cytokine gamma interferon (IFN-gamma) is required for a normal intestinal inflammatory response to the pathogen. In the present study, these experiments are extended to show that natural killer (NK) cells constitute an early source of intestinal IFN-gamma during Salmonella infection, and that these cells have a significant impact on intestinal inflammation. It was found that infection of mice with Salmonella increased both intestinal IFN-gamma production and the numbers of NK cells in the intestine and mesenteric lymph nodes. NK cells, along with other types of lymphocytes, produced IFN-gamma in response to the bacteria in vitro, while antibody-mediated depletion of NK cells in vivo resulted in a significant reduction in Salmonella-induced intestinal IFN-gamma expression. In a mouse strain lacking NK cells and T and B lymphocytes, intestinal production of IFN-gamma and Salmonella-induced intestinal inflammation were both significantly decreased compared with a strain deficient only in T and B cells. The authors' observations point to an important function for NK cells and NK-derived IFN-gamma in regulating the intestinal inflammatory response to Salmonella.