PATH-38. ROSETTE-FORMING GLIONEURONAL TUMOR IS DEFINED BY FGFR1 ACTIVATING ALTERATIONS WITH FREQUENT ACCOMPANYING PI3K AND MAPK PATHWAY MUTATIONS

Abstract BACKGROUND Rosette-forming glioneuronal tumor (RGNT) is an uncommon CNS tumor originally described in the fourth ventricle characterized by a low-grade glial neoplasm admixed with a rosette-forming neurocytic component. METHODS We reviewed clinicopathologic features of 42 patients with RGNT. Targeted next-generation sequencing was performed, and genome-wide methylation profiling is underway. RESULTS The 20 male and 22 female patients had a mean age of 25 years (range 3–47) at time of diagnosis. Tumors were located within or adjacent to the lateral ventricle (n=16), fourth ventricle (15), third ventricle (9), and spinal cord (2). All 31 tumors assessed to date contained FGFR1 activating alterations, either in-frame gene fusion, kinase domain tandem duplication, or hotspot missense mutation in the kinase domain (p.N546 or p.K656). While 7 of these 31 tumors harbored FGFR1 alterations as the solitary pathogenic event, 24 contained additional pathogenic alterations within PI3-kinase or MAP kinase pathway genes: 5 with additional PIK3CA and NF1 mutations, 4 with PIK3CA mutation, 3 with PIK3R1 mutation (one of which also contained focal RAF1 amplification), 5 with PTPN11 mutation (one with additional PIK3R1 mutation), and 2 with NF1 deletion. The other 5 cases demonstrated anaplastic features including hypercellularity and increased mitotic activity. Among these anaplastic cases, 3 harbored inactivating ATRX mutations and two harbored CDKN2A homozygous deletion, in addition to the FGFR1 alterations plus other PI3-kinase and MAP kinase gene mutations seen in those RGNT without anaplasia. CONCLUSION Independent of ventricular location, RGNT is defined by FGFR1 activating mutations or rearrangements, which are frequently accompanied by mutations involving PIK3CA, PIK3R1, PTPN11, NF1, and KRAS. Whereas pilocytic astrocytoma and ganglioglioma are characterized by solitary activating MAP kinase pathway alterations (e.g. BRAF fusion or mutation), RGNT are genetically more complex with dual PI3K-Akt-mTOR and Ras-Raf-MAPK pathway activation. Rare anaplastic examples may show additional ATRX and/or CDKN2A inactivation

Screening and social prescribing in healthcare and social services to address housing issues among children and families: a systematic review

ObjectivesHousing is a social determinant of health that impacts the health and well-being of children and families. Screening and referral to address social determinants of health in clinical and social service settings has been proposed to support families with housing problems. This study aims to identify housing screening questions asked of families in healthcare and social services, determine validated screening tools and extract information about recommendations for action after screening for housing issues.MethodsThe electronic databases MEDLINE, PsycINFO, EMBASE, Ovid Emcare, Scopus and CINAHL were searched from 2009 to 2021. Inclusion criteria were peer-reviewed literature that included questions about housing being asked of children or young people aged 0-18 years and their families accessing any healthcare or social service. We extracted data on the housing questions asked, source of housing questions, validity and descriptions of actions to address housing issues.ResultsForty-nine peer-reviewed papers met the inclusion criteria. The housing questions in social screening tools vary widely. There are no standard housing-related questions that clinical and social service providers ask families. Fourteen screening tools were validated. An action was embedded as part of social screening activities in 27 of 42 studies. Actions for identified housing problems included provision of a community-based or clinic-based resource guide, and social prescribing included referral to a social worker, care coordinator or care navigation service, community health worker, social service agency, referral to a housing and child welfare demonstration project or provided intensive case management and wraparound services.ConclusionThis review provides a catalogue of housing questions that can be asked of families in the clinical and/or social service setting, and potential subsequent actions

The role of histone modifications and telomere alterations in the pathogenesis of diffuse gliomas in adults and children

Genetic profiling is an increasingly useful tool for sub-classification of gliomas in adults and children. Specific gene mutations, structural rearrangements, DNA methylation patterns, and gene expression profiles are now recognized to define molecular subgroups of gliomas that arise in distinct anatomic locations and patient age groups, and also provide a better prediction of clinical outcomes for glioma patients compared to histologic assessment alone. Understanding the role of these distinctive genetic alterations in gliomagenesis is also important for the development of potential targeted therapeutic interventions. Mutations including K27M and G34R/V that affect critical amino acids within the N-terminal tail of the histone H3 variants, H3.3 and H3.1 (encoded by H3F3A and HIST1H3B genes), are prime examples of mutations in diffuse gliomas with characteristic clinical associations that can help diagnostic classification and guide effective patient management. These histone H3 mutations frequently co-occur with inactivating mutations in ATRX in association with alternative lengthening of telomeres. Telomere length can also be maintained through upregulation of telomerase reverse transcriptase (TERT) expression driven by mutation within the TERT gene promoter region, an alteration most commonly found in oligodendrogliomas and primary glioblastomas arising in adults. Interestingly, the genetic alterations perturbing histone and telomere function in pediatric gliomas tend to be different from those present in adult tumors. We present a review of these mutations affecting the histone code and telomere length, highlighting their importance in prognosis and as targets for novel therapeutics in the treatment of diffuse gliomas

Vascular Endothelial Growth Factor and Spinal Cord Injury Pain

Vascular endothelial growth factor (VEGF)-A mRNA was previously identified as one of the significantly upregulated transcripts in spinal cord injured tissue from adult rats that developed allodynia. To characterize the role of VEGF-A in the development of pain in spinal cord injury (SCI), we analyzed mechanical allodynia in SCI rats that were treated with either vehicle, VEGF-A isoform 165 (VEGF165), or neutralizing VEGF165-specific antibody. We have observed that exogenous administration of VEGF165 increased both the number of SCI rats that develop persistent mechanical allodynia, and the level of hypersensitivity to mechanical stimuli. Our analysis identified excessive and aberrant growth of myelinated axons in dorsal horns and dorsal columns of chronically injured spinal cords as possible mechanisms for both SCI pain and VEGF165-induced amplification of SCI pain, suggesting that elevated endogenous VEGF165 may have a role in the development of allodynia after SCI. However, the neutralizing VEGF165 antibody showed no effect on allodynia or axonal sprouting after SCI. It is possible that another endogenous VEGF isoform activates the same signaling pathway as the exogenously-administered 165 isoform and contributes to SCI pain. Our transcriptional analysis revealed that endogenous VEGF188 is likely to be the isoform involved in the development of allodynia after SCI. To the best of our knowledge, this is the first study to suggest a possible link between VEGF, nonspecific sprouting of myelinated axons, and mechanical allodynia following SCI

BIOM-38. PI3K/AKT/mTOR SIGNALING PATHWAY ACTIVITY IN IDH-MUTANT DIFFUSE GLIOMA

Abstract PI3K/AKT/mTOR signaling pathway activation is a common mechanism of tumor progression in diffuse lower grade glioma. Robust and accurate biomarkers are needed to stratify patients for therapies targeting this pathway. To investigate the potential of phosphoprotein quantification to provide a direct and functional pathway readout, we analyzed 90 tumors from 83 patients with IDH-mutant diffuse glioma. The cohort comprised 50 IDH-mutant astrocytomas, 40 IDH-mutant and 1p/19q-codeleted oligodendrogliomas, 7 of whom had paired samples from initial diagnosis and recurrence. We developed and validated a pipeline using multiplex immunofluorescence to quantify tumor cell-specific phospho-protein expression of 3 pathway nodes, ribosomal protein S6 (RPS6), PRAS40, and 4E-BP1. In oligodendroglioma the fraction of tumor cells expressing each of the three phosphorylated proteins increased with tumor grade (p< 0.05). Comparing tumors at initial diagnosis (n=48) and at recurrence (n=42), p-RPS6 and p-PRAS40 increased in tumor cells (p< 0.05) and there was an overall increase in intertumoral heterogeneity of signaling activity at recurrence (p< 0.04). Analysis of paired samples demonstrated increased signaling pathway activity in a subset at recurrence. Robust signaling activity, defined as a phospho-positive tumor cell fraction ≥ median for all three phosphoproteins, was identified in 71.4% of grade 3 IDH-mutant astrocytoma(5/7) and 45.4% of grade 3 IDH-mutant, 1p/19q-codeleted oligodendroglioma(5/11). In a subset of cases analyzed by targeted NGS, robust signaling pathway activity was identified in 38%(11/29) at the protein level while genetic alterations predicted to activate the pathway were present in only 17.2% (5/29). Our results demonstrate robust PI3K/AKT/mTOR signaling activity in a significant fraction of IDH-mutant diffuse glioma, an association with increasing tumor grade in oligodendroglioma, and an increase at recurrence in both oligodendroglioma and astrocytoma. Overall, our data suggest that quantitative evaluation of phosphoproteins may be a sensitive method to detect PI3K/AKT/mTOR pathway activity and may be useful for patient stratification

Amiloride Improves Locomotor Recovery after Spinal Cord Injury

Amiloride is a drug approved by the United States Food and Drug Administration, which has shown neuroprotective effects in different neuropathological conditions, including brain injury or brain ischemia, but has not been tested in spinal cord injury (SCI). We tested amiloride's therapeutic potential in a clinically relevant rat model of contusion SCI inflicted at the thoracic segment T10. Rats receiving daily administration of amiloride from 24 h to 35 days after SCI exhibited a significant improvement in hindlimb locomotor ability at 21, 28, and 35 days after injury, when compared to vehicle-treated SCI rats. Rats receiving amiloride treatment also exhibited a significant increase in myelin oligodendrocyte glycoprotein (MOG) levels 35 days after SCI at the site of injury (T10) when compared to vehicle-treated controls, which indicated a partial reverse in the decrease of MOG observed with injury. Our data indicate that higher levels of MOG correlate with improved locomotor recovery after SCI, and that this may explain the beneficial effects of amiloride after SCI. Given that amiloride treatment after SCI caused a significant preservation of myelin levels, and improved locomotor recovery, it should be considered as a possible therapeutic intervention after SCI

DNA methylation profiling demonstrates superior diagnostic classification to RNA-sequencing in a case of metastatic meningioma.

Meningiomas are the most common primary intracranial tumors, but meningioma metastases are rare. Accordingly, the clinical workup, diagnostic testing, and molecular classification of metastatic meningioma is incompletely understood. Here, we present a case report of multiply recurrent meningioma complicated by liver metastasis. We discuss the patient presentation, imaging findings, and conventional histopathologic characterization of both the intracranial lesion and the metastatic focus. Further, we perform multiplatform molecular profiling, comprised of DNA methylation arrays and RNA-sequencing, of six stereotactically-guided samples from the intracranial meningioma and a single ultrasound-guided liver metastasis biopsy. Our results show that DNA methylation clusters distinguish the liver metastasis from the intracranial meningioma samples, and identify a small focus of hepatocyte contamination with the liver biopsy. Nonetheless, DNA methylation-based classification accurately identifies the liver metastasis as a meningioma with high confidence. We also find that clustering of RNA-sequencing results distinguishes the liver metastasis from the intracranial meningiomas samples, but that differential gene expression classification is confounded by hepatocyte-specific gene expression programs in the liver metastasis. In sum, this case report sheds light on the comparative biology of intracranial and metastatic meningioma. Furthermore, our results support methylation-based classification as a robust method of diagnosing metastatic lesions, underscore the broad utility of DNA methylation array profiling in diagnostic pathology, and caution against the routine use of bulk RNA-sequencing for identifying tumor signatures in heterogeneous metastatic lesions