A Hematogenous Route for Medulloblastoma Leptomeningeal Metastases.

While the preponderance of morbidity and mortality in medulloblastoma patients are due to metastatic disease, most research focuses on the primary tumor due to a dearth of metastatic tissue samples and model systems. Medulloblastoma metastases are found almost exclusively on the leptomeningeal surface of the brain and spinal cord; dissemination is therefore thought to occur through shedding of primary tumor cells into the cerebrospinal fluid followed by distal re-implantation on the leptomeninges. We present evidence for medulloblastoma circulating tumor cells (CTCs) in therapy-naive patients and demonstrate in vivo, through flank xenografting and parabiosis, that medulloblastoma CTCs can spread through the blood to the leptomeningeal space to form leptomeningeal metastases. Medulloblastoma leptomeningeal metastases express high levels of the chemokine CCL2, and expression of CCL2 in medulloblastoma in vivo is sufficient to drive leptomeningeal dissemination. Hematogenous dissemination of medulloblastoma offers a new opportunity to diagnose and treat lethal disseminated medulloblastoma.

Molecular subgroups of atypical teratoid rhabdoid tumours in children: an integrated genomic and clinicopathological analysis.

BACKGROUND: Rhabdoid brain tumours, also called atypical teratoid rhabdoid tumours, are lethal childhood cancers with characteristic genetic alterations of SMARCB1/hSNF5. Lack of biological understanding of the substantial clinical heterogeneity of these tumours restricts therapeutic advances. We integrated genomic and clinicopathological analyses of a cohort of patients with atypical teratoid rhabdoid tumours to find out the molecular basis for clinical heterogeneity in these tumours. METHODS: We obtained 259 rhabdoid tumours from 37 international institutions and assessed transcriptional profiles in 43 primary tumours and copy number profiles in 38 primary tumours to discover molecular subgroups of atypical teratoid rhabdoid tumours. We used gene and pathway enrichment analyses to discover group-specific molecular markers and did immunohistochemical analyses on 125 primary tumours to evaluate clinicopathological significance of molecular subgroup and ASCL1-NOTCH signalling. FINDINGS: Transcriptional analyses identified two atypical teratoid rhabdoid tumour subgroups with differential enrichment of genetic pathways, and distinct clinicopathological and survival features. Expression of ASCL1, a regulator of NOTCH signalling, correlated with supratentorial location (p=0·004) and superior 5-year overall survival (35%, 95% CI 13-57, and 20%, 6-34, for ASCL1-positive and ASCL1-negative tumours, respectively; p=0·033) in 70 patients who received multimodal treatment. ASCL1 expression also correlated with superior 5-year overall survival (34%, 7-61, and 9%, 0-21, for ASCL1-positive and ASCL1-negative tumours, respectively; p=0·001) in 39 patients who received only chemotherapy without radiation. Cox hazard ratios for overall survival in patients with differential ASCL1 enrichment treated with chemotherapy with or without radiation were 2·02 (95% CI 1·04-3·85; p=0·038) and 3·98 (1·71-9·26; p=0·001). Integrated analyses of molecular subgroupings with clinical prognostic factors showed three distinct clinical risk groups of tumours with different therapeutic outcomes. INTERPRETATION: An integration of clinical risk factors and tumour molecular groups can be used to identify patients who are likely to have improved long-term radiation-free survival and might help therapeutic stratification of patients with atypical teratoid rhabdoid tumours. FUNDING: C17 Research Network, Genome Canada, b.r.a.i.n.child, Mitchell Duckman, Tal Doron and Suri Boon foundations.

Abnormal megakaryocyte development and platelet function in Nbeal2(-/-) mice.

Gray platelet syndrome (GPS) is an inherited bleeding disorder associated with macrothrombocytopenia and α-granule-deficient platelets. GPS has been linked to loss of function mutations in NEABL2 (neurobeachin-like 2), and we describe here a murine GPS model, the Nbeal2(-/-) mouse. As in GPS, Nbeal2(-/-) mice exhibit splenomegaly, macrothrombocytopenia, and a deficiency of platelet α-granules and their cargo, including von Willebrand factor (VWF), thrombospondin-1, and platelet factor 4. The platelet α-granule membrane protein P-selectin is expressed at 48% of wild-type levels and externalized upon platelet activation. The presence of P-selectin and normal levels of VPS33B and VPS16B in Nbeal2(-/-) platelets suggests that NBEAL2 acts independently of VPS33B/VPS16B at a later stage of α-granule biogenesis. Impaired Nbeal2(-/-) platelet function was shown by flow cytometry, platelet aggregometry, bleeding assays, and intravital imaging of laser-induced arterial thrombus formation. Microscopic analysis detected marked abnormalities in Nbeal2(-/-) bone marrow megakaryocytes, which when cultured showed delayed maturation, decreased survival, decreased ploidy, and developmental abnormalities, including abnormal extracellular distribution of VWF. Our results confirm that α-granule secretion plays a significant role in platelet function, and they also indicate that abnormal α-granule formation in Nbeal2(-/-) mice has deleterious effects on megakaryocyte survival, development, and platelet production.

Diffusely infiltrating astrocytomas: pathology, molecular mechanisms and markers.

Diffusely infiltrating astrocytomas include diffuse astrocytomas WHO grade II and anaplastic astrocytomas WHO grade III and are classified under astrocytic tumours according to the current WHO Classification. Although the patients generally have longer survival as compared to those with glioblastoma, the timing of inevitable malignant progression ultimately determines the prognosis. Recent advances in molecular genetics have uncovered that histopathologically diagnosed astrocytomas may consist of two genetically different groups of tumours. The majority of diffusely infiltrating astrocytomas regardless of WHO grade have concurrent mutations of IDH1 or IDH2, TP53 and ATRX. Among these astrocytomas, no other genetic markers that may distinguish grade II and grade III tumours have been identified. Those astrocytomas without IDH mutation tend to have a distinct genotype and a poor prognosis comparable to that of glioblastomas. On the other hand, diffuse astrocytomas that arise in children do not harbour IDH/TP53 mutations, but instead display mutations of BRAF or structural alterations involving MYB/MYBL1 or FGFR1. A molecular classification may thus help delineate diffusely infiltrating astrocytomas into distinct pathogenic and prognostic groups, which could aid in determining individualised therapeutic strategies.

CNS-PNETs with C19MC amplification and/or LIN28 expression comprise a distinct histogenetic diagnostic and therapeutic entity.

Amplification of the C19MC oncogenic miRNA cluster and high LIN28 expression has been linked to a distinctly aggressive group of cerebral CNS-PNETs (group 1 CNS-PNETs) arising in young children. In this study, we sought to evaluate the diagnostic specificity of C19MC and LIN28, and the clinical and biological spectra of C19MC amplified and/or LIN28+ CNS-PNETs. We interrogated 450 pediatric brain tumors using FISH and IHC analyses and demonstrate that C19MC alteration is restricted to a sub-group of CNS-PNETs with high LIN28 expression; however, LIN28 immunopositivity was not exclusive to CNS-PNETs but was also detected in a proportion of other malignant pediatric brain tumors including rhabdoid brain tumors and malignant gliomas. C19MC amplified/LIN28+ group 1 CNS-PNETs arose predominantly in children <4 years old; a majority arose in the cerebrum but 24 % (13/54) of tumors had extra-cerebral origins. Notably, group 1 CNS-PNETs encompassed several histologic classes including embryonal tumor with abundant neuropil and true rosettes (ETANTR), medulloepithelioma, ependymoblastoma and CNS-PNETs with variable differentiation. Strikingly, gene expression and methylation profiling analyses revealed a common molecular signature enriched for primitive neural features, high LIN28/LIN28B and DNMT3B expression for all group 1 CNS-PNETs regardless of location or tumor histology. Our collective findings suggest that current known histologic categories of CNS-PNETs which include ETANTRs, medulloepitheliomas, ependymoblastomas in various CNS locations, comprise a common molecular and diagnostic entity and identify inhibitors of the LIN28/let7/PI3K/mTOR axis and DNMT3B as promising therapeutics for this distinct histogenetic entity.

Overcoming resistance to Sonic Hedgehog inhibition by targeting p90 ribosomal S6 kinase in pediatric medulloblastoma.

BACKGROUND: Molecular subtyping has allowed for the beginning of personalized treatment in children suffering from medulloblastoma (MB). However, resistance inevitably emerges against these therapies, particularly in the Sonic Hedgehog (SHH) subtype. We found that children with SHH subtype have the worst outcome underscoring the need to identify new therapeutic targets. PROCEDURE: High content screening of a 129 compound library identified agents that inhibited SHH MB growth. Lead molecular target levels, p90 ribosomal S6 kinase (RSK) were characterized by immunoblotting and qRT-PCR. Comparisons were made to human neural stem cells (hNSC). Impact of inhibiting RSK with the small molecule BI-D1870 or siRNA was assessed in growth assays (monolayer, neurosphere, and soft agar). NanoString was used to detect RSK in a cohort of 66 patients with MB. To determine BI-D1870 pharmacokinetics/pharmacodynamics, 100 mg/kg was I.P. injected into mice and tissues were collected at various time points. RESULTS: Daoy, ONS76, UW228, and UW426 MB cells were exquisitely sensitive to BI-D1870 but unresponsive to SHH inhibitors. Anti-tumor growth corresponded with inactivation of RSK in MB cells. BI-D1870 had no effect on hNSCs. Inhibiting RSK with siRNA or BI-D1870 suppressed growth, induced apoptosis, and sensitized cells to SHH agents. Notably, RSK expression is correlated with SHH patients. In mice, BI-D1870 was well-tolerated and crossed the blood-brain barrier (BBB). CONCLUSIONS: RSK inhibitors are promising because they target RSK which is correlated with SHH patients as well as cause high levels of apoptosis to only MB cells. Importantly, BI-D1870 crosses the BBB, acting as a scaffold for development of more long-lived RSK inhibitors.

Markers of survival and metastatic potential in childhood CNS primitive neuro-ectodermal brain tumours: an integrative genomic analysis.

BACKGROUND: Childhood CNS primitive neuro-ectodermal brain tumours (PNETs) are very aggressive brain tumours for which the molecular features and best treatment approaches are unknown. We assessed a large cohort of these rare tumours to identify molecular markers to enhance clinical management of this disease. METHODS: We obtained 142 primary hemispheric CNS PNET samples from 20 institutions in nine countries and examined transcriptional profiles for a subset of 51 samples and copy number profiles for a subset of 77 samples. We used clustering, gene, and pathway enrichment analyses to identify tumour subgroups and group-specific molecular markers, and applied immunohistochemical and gene-expression analyses to validate and assess the clinical significance of the subgroup markers. FINDINGS: We identified three molecular subgroups of CNS PNETs that were distinguished by primitive neural (group 1), oligoneural (group 2), and mesenchymal lineage (group 3) gene-expression signatures with differential expression of cell-lineage markers LIN28 and OLIG2. Patients with group 1 tumours were most often female (male:female ratio 0·61 for group 1 vs 1·25 for group 2 and 1·63 for group 3; p=0·043 [group 1 vs groups 2 and 3]), youngest (median age at diagnosis 2·9 years [95% CI 2·4-5·2] for group 1 vs 7·9 years [6·0-9·7] for group 2 and 5·9 years [4·9-7·8] for group 3; p=0·005), and had poorest survival (median survival 0·8 years [95% CI 0·5-1·2] in group 1, 1·8 years [1·4-2·3] in group 2 and 4·3 years [0·8-7·8] in group 3; p=0·019). Patients with group 3 tumours had the highest incidence of metastases at diagnosis (no distant metastasis:metastasis ratio 0·90 for group 3 vs 2·80 for group 1 and 5·67 for group 2; p=0·037). INTERPRETATION: LIN28 and OLIG2 are promising diagnostic and prognostic molecular markers for CNS PNET that warrant further assessment in prospective clinical trials. FUNDING: Canadian Institute of Health Research, Brainchild/SickKids Foundation, and the Samantha Dickson Brain Tumour Trust.

A proteomic analysis of pediatric seizure cases associated with astrocytic inclusions.

Cerebral hyaline astrocytic inclusions have been observed in a subset of patients with early onset epilepsy, brain structural anomalies, and developmental delay, which indicates that it may represent a unique clinicopathologic entity. To further characterize this condition we use proteomics to investigate differentially expressed proteins in epileptic brain tissue from three pediatric epileptic patients with cerebral hyaline astrocytic inclusions, ranging in age from 5-13 years, and compare to brain tissue from two normal controls. Catalase and carbonic anhydrase I both exhibited increased expression in epileptic brain tissue compared to controls. These findings were confirmed by Western blot analysis. Furthermore, both proteins were localized to astrocytes and in epileptic brain were located within the cerebral hyaline astrocytic inclusions, suggesting a potential role in the generation of this pathologic feature of early onset epilepsy with cerebral hyaline astrocytic inclusions.

Thrombospondin-1 mimetics are promising novel therapeutics for MYC-associated medulloblastoma.

BACKGROUND: Medulloblastoma (MB) comprises four subtypes of which group 3 MB are the most aggressive. Although overall survival for MB has improved, the outcome of group 3 MB remains dismal. C-MYC (MYC) amplification or MYC overexpression which characterizes group 3 MB is a strong negative prognostic factor and is frequently associated with metastases and relapses. We previously reported that MYC expression alone promotes highly aggressive MB phenotypes, in part via repression of thrombospondin-1 (TSP-1), a potent tumor suppressor. METHODS: In this study, we examined the potential role of TSP-1 and TSP-1 peptidomimetic ABT-898 in MYC-amplified human MB cell lines and two distinct murine models of MYC-driven group 3 MBs. RESULTS: We found that TSP-1 reconstitution diminished metastases and prolonged survival in orthotopic xenografts and promoted chemo- and radio-sensitivity via AKT signaling. Furthermore, we demonstrate that ABT-898 can recapitulate the effects of TSP-1 expression in MB cells in vitro and specifically induced apoptosis in murine group 3 MB tumor cells. CONCLUSION: Our data underscore the importance of TSP-1 as a critical tumor suppressor in MB and highlight TSP-1 peptidomimetics as promising novel therapeutics for the most lethal subtype of MB.

Mutations in the RAS/MAPK Pathway Drive Replication Repair-Deficient Hypermutated Tumors and Confer Sensitivity to MEK Inhibition.

The RAS/MAPK pathway is an emerging targeted pathway across a spectrum of both adult and pediatric cancers. Typically, this is associated with a single, well-characterized point mutation in an oncogene. Hypermutant tumors that harbor many somatic mutations may obscure the interpretation of such targetable genomic events. We find that replication repair-deficient (RRD) cancers, which are universally hypermutant and affect children born with RRD cancer predisposition, are enriched for RAS/MAPK mutations (P = 10-8). These mutations are not random, exist in subclones, and increase in allelic frequency over time. The RAS/MAPK pathway is activated both transcriptionally and at the protein level in patient-derived RRD tumors, and these tumors responded to MEK inhibition in vitro and in vivo. Treatment of patients with RAS/MAPK hypermutant gliomas reveals durable responses to MEK inhibition. Our observations suggest that hypermutant tumors may be addicted to oncogenic pathways, resulting in favorable response to targeted therapies. SIGNIFICANCE: Tumors harboring a single RAS/MAPK driver mutation are targeted individually for therapeutic purposes. We find that in RRD hypermutant cancers, mutations in the RAS/MAPK pathway are enriched, highly expressed, and result in sensitivity to MEK inhibitors. Targeting an oncogenic pathway may provide therapeutic options for these hypermutant polyclonal cancers.This article is highlighted in the In This Issue feature, p. 1307.

DNA Polymerase and Mismatch Repair Exert Distinct Microsatellite Instability Signatures in Normal and Malignant Human Cells.

Although replication repair deficiency, either by mismatch repair deficiency (MMRD) and/or loss of DNA polymerase proofreading, can cause hypermutation in cancer, microsatellite instability (MSI) is considered a hallmark of MMRD alone. By genome-wide analysis of tumors with germline and somatic deficiencies in replication repair, we reveal a novel association between loss of polymerase proofreading and MSI, especially when both components are lost. Analysis of indels in microsatellites (MS-indels) identified five distinct signatures (MS-sigs). MMRD MS-sigs are dominated by multibase losses, whereas mutant-polymerase MS-sigs contain primarily single-base gains. MS deletions in MMRD tumors depend on the original size of the MS and converge to a preferred length, providing mechanistic insight. Finally, we demonstrate that MS-sigs can be a powerful clinical tool for managing individuals with germline MMRD and replication repair-deficient cancers, as they can detect the replication repair deficiency in normal cells and predict their response to immunotherapy. SIGNIFICANCE: Exome- and genome-wide MSI analysis reveals novel signatures that are uniquely attributed to mismatch repair and DNA polymerase. This provides new mechanistic insight into MS maintenance and can be applied clinically for diagnosis of replication repair deficiency and immunotherapy response prediction.This article is highlighted in the In This Issue feature, p. 995.

Immunohistochemical and nanoString-Based Subgrouping of Clinical Medulloblastoma Samples.

The diagnosis of medulloblastoma incorporates the histologic and molecular subclassification of clinical medulloblastoma samples into wingless (WNT)-activated, sonic hedgehog (SHH)-activated, group 3 and group 4 subgroups. Accurate medulloblastoma subclassification has important prognostic and treatment implications. Immunohistochemistry (IHC)-based and nanoString-based subgrouping methodologies have been independently described as options for medulloblastoma subgrouping, however have not previously been directly compared. We describe our experience with nanoString-based subgrouping in a clinical setting and compare this with our IHC-based results. Study materials included FFPE tissue from 160 medulloblastomas. Clinical data and tumor histology were reviewed. Immunohistochemical-based subgrouping using ß-catenin, filamin A and p53 antibodies and nanoString-based gene expression profiling were performed. The sensitivity and specificity of IHC-based subgrouping of WNT and SHH-activated medulloblastomas was 91.5% and 99.54%, respectively. Filamin A immunopositivity highly correlated with SHH/WNT-activated subgroups (sensitivity 100%, specificity 92.7%, p < 0.001). Nuclear ß-catenin immunopositivity had a sensitivity of 76.2% and specificity of 99.23% for detection of WNT-activated tumors. Approximately 23.8% of WNT cases would have been missed using an IHC-based subgrouping method alone. nanoString could confidently predict medulloblastoma subgroup in 93% of cases and could distinguish group 3/4 subgroups in 96.3% of cases. nanoString-based subgrouping allows for a more prognostically useful classification of clinical medulloblastoma samples.

Cancers from Novel Pole-Mutant Mouse Models Provide Insights into Polymerase-Mediated Hypermutagenesis and Immune Checkpoint Blockade.

POLE mutations are a major cause of hypermutant cancers, yet questions remain regarding mechanisms of tumorigenesis, genotype-phenotype correlation, and therapeutic considerations. In this study, we establish mouse models harboring cancer-associated POLE mutations P286R and S459F, which cause rapid albeit distinct time to cancer initiation in vivo, independent of their exonuclease activity. Mouse and human correlates enabled novel stratification of POLE mutations into three groups based on clinical phenotype and mutagenicity. Cancers driven by these mutations displayed striking resemblance to the human ultrahypermutation and specific signatures. Furthermore, Pole-driven cancers exhibited a continuous and stochastic mutagenesis mechanism, resulting in intertumoral and intratumoral heterogeneity. Checkpoint blockade did not prevent Pole lymphomas, but rather likely promoted lymphomagenesis as observed in humans. These observations provide insights into the carcinogenesis of POLE-driven tumors and valuable information for genetic counseling, surveillance, and immunotherapy for patients. SIGNIFICANCE: Two mouse models of polymerase exonuclease deficiency shed light on mechanisms of mutation accumulation and considerations for immunotherapy.See related commentary by Wisdom and Kirsch p. 5459.

A C19MC-LIN28A-MYCN Oncogenic Circuit Driven by Hijacked Super-enhancers Is a Distinct Therapeutic Vulnerability in ETMRs: A Lethal Brain Tumor.

Embryonal tumors with multilayered rosettes (ETMRs) are highly lethal infant brain cancers with characteristic amplification of Chr19q13.41 miRNA cluster (C19MC) and enrichment of pluripotency factor LIN28A. Here we investigated C19MC oncogenic mechanisms and discovered a C19MC-LIN28A-MYCN circuit fueled by multiple complex regulatory loops including an MYCN core transcriptional network and super-enhancers resulting from long-range MYCN DNA interactions and C19MC gene fusions. Our data show that this powerful oncogenic circuit, which entraps an early neural lineage network, is potently abrogated by bromodomain inhibitor JQ1, leading to ETMR cell death.

DNA hypermethylation within TERT promoter upregulates TERT expression in cancer.

Replicative immortality is a hallmark of cancer cells governed by telomere maintenance. Approximately 90% of human cancers maintain their telomeres by activating telomerase, driven by the transcriptional upregulation of telomerase reverse transcriptase (TERT). Although TERT promoter mutations (TPMs) are a major cancer-associated genetic mechanism of TERT upregulation, many cancers exhibit TERT upregulation without TPMs. In this study, we describe the TERT hypermethylated oncological region (THOR), a 433-bp genomic region encompassing 52 CpG sites located immediately upstream of the TERT core promoter, as a cancer-associated epigenetic mechanism of TERT upregulation. Unmethylated THOR repressed TERT promoter activity regardless of TPM status, and hypermethylation of THOR counteracted this repressive function. THOR methylation analysis in 1,352 human tumors revealed frequent (>45%) cancer-associated DNA hypermethylation in 9 of 11 (82%) tumor types screened. Additionally, THOR hypermethylation, either independently or along with TPMs, accounted for how approximately 90% of human cancers can aberrantly activate telomerase. Thus, we propose that THOR hypermethylation is a prevalent telomerase-activating mechanism in cancer that can act independently of or in conjunction with TPMs, further supporting the utility of THOR hypermethylation as a prognostic biomarker.

Astrocytic inclusions in epilepsy: expanding the spectrum of filaminopathies.

We report the finding of unique astrocytic inclusions in a series of pediatric epilepsy patients, all of whom presented with seizures in their first year of life and had mild-to-moderate developmental delay. All eventually underwent surgical treatment for refractory epilepsy and, on pathological examination, were found to have distinctive, eosinophilic, globular cytoplasmic inclusions confined to cortical astrocytes. These inclusions were almost exclusively juxtanuclear, highly refractile, spared distal subpial, or perivascular astrocytic processes and were strongly and exclusively immunopositive for filamin A, an actin binding protein involved in neuronal migration. Identical inclusions have been identified and characterized in cases of Aicardi syndrome, a rare neurodevelopmental disease. The presence of the same inclusions in the cortex of epilepsy patients, some of whom had concomitant brain anomalies related to migrational problems, prompted us to consider that these patients may lie within a spectrum of disease involving dysfunction of filamin or filamin-interacting proteins. The term "filaminopathy" is tentatively proposed as a distinct pathological entity for this condition in which clinical manifestations range from epilepsy in mildly neurologically impaired patients to severe mental and physical handicap in the Aicardi syndrome. Future studies will be necessary to unravel the exact nature of the filamin A protein or gene aberrations in these patients.

Expression patterns of the organic cation/carnitine transporter family in adult murine brain.

UNLABELLED: Organic cation/carnitine transporters transport carnitine, drugs, and xenobiotics (e.g. choline, acetylcarnitine, betaine, valproic acid), and are expressed in muscle, heart, blood vessels, kidney, gut, etc. OBJECTIVE: To characterize expression patterns of mOctn1, -2 and -3 in murine brain. METHODS: We applied our transporter-specific antibodies to mOctn1, -2 and -3, followed by 2 0 antibody and DAB peroxidase detection to serial adult murine brain sections counterstained with hematoxylin. RESULTS: All three transporters showed strong expression in the external plexiform layer of the olfactory bulb and in olfactory nerve, the molecular layer and neuronal processes of input fibres extending vertically in motor cortex, in the dendritic arborization of the cornu ammonis and dendate gyrus (hippocampus), neuronal processes in the arcuate nucleus (hypothalamus), choroid plexus cells, and neuronal cell bodies and dendrites of cranial nerve nuclei V and VII. In the cerebellum, all three transporters were strongly expressed in dendritic processes of Purkinje cells, but Octn1 and -2 were expressed more strongly than Octn3 in Purkinje cell bodies. In spinal cord, Octn1, -2 and -3 were prominent in axons and dendritic end-arborizations of spinal cord neurons in both ascending and descending white matter tracts, whereas Octn3 was also strongly expressed in grey matter, specifically in anterior horn cell bodies. Octn3 was weakly expressed in glomerular layer neuronal cell bodies of olfactory bulb. CONCLUSIONS: hOCTN2 deficiency presents with carnitine-responsive cardiomyopathy, myopathy and hypoglycemic, hypoketotic coma with strokes, seizures and delays. In mouse, Octn1, -2 and -3 are expressed in many regions throughout the central nervous system with a pattern suggestive of roles in modulating cerebral bioenergetics and in acetylcholine generation for neurotransmission in olfactory, satiety, limbic, memory, motor and sensory functions. This distribution may play a role in the pattern of neurological injury that occurs in hOCTN2 deficiency during catabolic episodes of hypoglycemic, hypoketotic encephalopathy and which may manifest with cognitive impairment, hypotonia and seizures.

IL-13 receptors as possible therapeutic targets in diffuse intrinsic pontine glioma.

Diffuse intrinsic pontine glioma (DIPG) is a universally fatal childhood cancer of the brain. Despite the introduction of conventional chemotherapy and radiotherapy, improvements in survival have been marginal and long-term survivorship is uncommon. Thus, new targets for therapeutics are critically needed. Early phase clinical trials exploring molecularly-targeted therapies against the epidermal growth factor receptor (EGFR) and novel immunotherapies targeting interleukin receptor-13α2 (IL-13Rα2) have demonstrated activity in this disease. To identify additional therapeutic markers for cell surface receptors, we performed exome sequencing (16 new samples, 22 previously published samples, total 38 with 26 matched normal DNA samples), RNA deep sequencing (17 new samples, 11 previously published samples, total 28 with 18 matched normal RNA samples), and immunohistochemistry (17 DIPG tissue samples) to examine the expression of the interleukin-4 (IL-4) signaling axis components (IL-4, interleukin 13 (IL-13), and their respective receptors IL-4Rα, IL-13Rα1, and IL-13Rα2). In addition, we correlated cytokine and receptor expression with expression of the oncogenes EGFR and c-MET. In DIPG tissues, transcript-level analysis found significant expression of IL-4, IL-13, and IL-13Rα1/2, with strong differential expression of IL-13Rα1/2 in tumor versus normal brain. At the protein level, immunohistochemical studies revealed high content of IL-4 and IL-13Rα1/2 but notably low expression of IL-13. Additionally, a strong positive correlation was observed between c-Met and IL-4Rα. The genomic and transcriptional landscape across all samples was also summarized. These data create a foundation for the design of potential new immunotherapies targeting IL-13 cell surface receptors in DIPG.