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Glycine 34-to-tryptophan (G34W) substitutions in H3.3 arise in approximately 90% of giant cell tumor of bone (GCT). Here, we show H3.3 G34W is necessary for tumor formation. By profiling the epigenome, transcriptome, and secreted proteome of patient samples and tumor-derived cells CRISPR–Cas9-edited for H3.3 G34W, we show that H3.3K36me3 loss on mutant H3.3 alters the deposition of the repressive H3K27me3 mark from intergenic to genic regions, beyond areas of H3.3 deposition. This promotes redistribution of other chromatin marks and aberrant transcription, altering cell fate in mesenchymal progenitors and hindering differentiation. Single-cell transcriptomics reveals that H3.3 G34W stromal cells recapitulate a neoplastic trajectory from a SPP1+ osteoblast-like progenitor population toward an ACTA2+ myofibroblast-like population, which secretes extracellular matrix ligands predicted to recruit and activate osteoclasts. Our findings suggest that H3.3 G34W leads to GCT by sustaining a transformed state in osteoblast-like progenitors, which promotes neoplastic growth, pathologic recruitment of giant osteoclasts, and bone destruction. Significance: This study shows that H3.3 G34W drives GCT tumorigenesis through aberrant epigenetic remodeling, altering differentiation trajectories in mesenchymal progenitors. H3.3 G34W promotes in neoplastic stromal cells an osteoblast-like progenitor state that enables undue interactions with the tumor microenvironment, driving GCT pathogenesis. These epigenetic changes may be amenable to therapeutic targeting in GCT. See related commentary by Licht, p. 1794. This article is highlighted in the In This Issue feature, p. 1775

Glioblastoma multiforme (GBM) is the most common primary malignant brain tumor in adults, with a median survival of just over one year. The failure of available treatments to achieve remission in patients with GBM has been attributed to the presence of cancer stem cells (CSCs), which are thought to play a central role in tumor development and progression and serve as a treatment-resistant cell repository capable of driving tumor recurrence; in fact, the property of “stemness” itself may be responsible for treatment resistance. In this study, we identify a novel lncRNA, Cancer stem cell associated distal enhancer of SOX2 (CASCADES) that functions as an epigenetic regulator in glioma CSCs (GSCs). CASCADES is expressed in IDH-wild type GBM and significantly enriched in GSCs. Knockdown of CASCADES in GSCs results in differentiation towards a neuronal lineage in a cell- and cancer-specific manner. Bioinformatics analysis reveals that CASCADES functions as a super-enhancer associated lncRNA epigenetic regulator of SOX2. Our findings identify CASCADES as a critical regulator of stemness in GSCs and represent a novel epigenetic and therapeutic target for disrupting the cancer stem cell compartment in GBM.

Atypical teratoid/rhabdoid tumours (ATRT) are a rare class of central nervous system malignant tumours which are comprised of elements of ectoderm and mesoderm germ-cell layers, but exhibit microscopic similarity to skeletal muscle. These tumours are more commonly seen in pediatric patients, with few case reports recently describing adult patients with this condition, in particular middle-aged women.1–3 We present the case of a previously healthy 59-year-old woman who was found incidentally to have a pituitary mass on CT head, with retrospective symptoms of headaches, polyuria, polydipsia, diplopia, and low blood pressure. At presentation, she was found biochemically to have pan-hypopituitarism with a left cranial nerve six deficit, with an MRI depicting a 19.5 x 22 x 11 mm suprasellar mass extending into the infundibulum and hypothalamus, with displacement of the optic chiasm; repeat imaging ruled out apoplexy. She was started on supplemental levothyroxine and hydrocortisone replacement therapy, and sent for urgent transsphenoidal resection, which was complicated afterwards by hypernatremia from diabetes insipidus. Preliminary reports were suggestive of germinoma given the diffuse presence of Oct 3/4 and C-kit, with a proliferation index of 99%; further cytology of lumbar puncture revealed no malignant cells. However, upon further pathological analysis, her tumour demonstrated loss of INI-1 expression, which is diagnostic of ATRT. Given the mixed features on immunohistochemistry, the final diagnosis was concluded as an atypical teratoid/rhabdoid tumour of the sella turcica with germinoma differentiation. A multi-disciplinary approach consisted of initial radiotherapy, with chemotherapy targeted towards a germinoma-type tumour, and pituitary hormone replacement including treatment for central diabetes insipidus. This represents a unique case of a rare tumour with germinoma differentiation in an older patient that has not been previously reported. References 1. Journal of Clinical Neuroscience 49 (2018) 16–21 2. Acta Neurochir (Wien) (2008) 150: 491–496 3. Surgical Neurology International 2014, 5:75

Congenital cytomegalovirus (CMV) infection in the 2supnd/supand 3suprd/suptrimester results in catastrophic CNS abnormalities. This susceptibility is thought to result from the high proportion of neural stem cells in the developing brain. In immunocompromised adults, CNS infection by CMV preferentially affects ependymal surfaces, from where it expands to involve the parenchyma. Experimental models of murine CMV infection demonstrate viral tropism for the dentate gyrus (DG) and subventricular zone, the areas in which adult neurogenesis occurs. We present two cases of CMV infection of the DG of immunocompromised allogeneic stem cell transplant recipients. Both cases showed CMV-positive neurons in the DG granular cell layer, as well as contiguous layers. The majority of infected cells contained Nissl substance and expressed nestin, glial fibrillary acidic protein (GFAP), neuron-specific enolase (NSE), and neurofilament. These cases demonstrate that CMV infects the DG in humans. Co-expression of nestin and GFAP, indicative of early neurogenesis, is consistent with experimental models showing neural stem cells as the target of CMV, providing further histological evidence of neurogenesis in the human dentate. Finally, the cases suggest that CMV infection produces abnormal migration of newly formed neurons as evidenced by the finding of virally infected neurons in the molecular layer of the dentate. .

We report two different cases of IgG4-related hypophysitis. In the first case, a pituitary lesion was accompanied by lymphocytic meningitis possibly mimicking tuberculous meningitis. The second case was unassociated with involvement of other organs. No histologic differences were noted between the two cases indicating that the morphologic features of the hypophysial lesion do not depend on the presence of other lesions. The pathogenesis of IgG4 hypophysitis is not known, and further study is necessary to explore the cause, progression, and influencing factors of this disease.

Objective To describe successful therapeutic strategies in statin-induced anti-HMGCR myopathy. Methods Retrospective data from a cohort of 55 patients with statin-induced anti-HMGCR myopathy, sequentially stratified by the presence of proximal weakness, early remission, and corticosteroid and IVIG use at treatment induction, were analyzed for optimal successful induction and maintenance of remission strategies. Results A total of 14 patients achieved remission with a corticosteroid-free induction strategy (25%). In 41 patients treated with corticosteroids, only 4 patients (10%) failed an initial triple steroid/IVIG/steroid-sparing immunosuppressant (SSI) induction strategy. Delay in treatment initiation was independently associated with lower odds of successful maintenance with immunosuppressant monotherapy (OR 0.92, 95% CI 0.85 to 0.97, P = 0.015). While 22 patients (40%) presented with normal strength, only 9 had normal strength at initiation of treatment. Conclusion While corticosteroid-free treatment of anti-HMGCR myopathy is now a safe option in selected cases, initial triple steroid/IVIG/SSI was very efficacious in induction. Delays in treatment initiation and, as a corollary, delays in achieving remission decrease the odds of achieving successful maintenance with an SSI alone. Avoiding such delays, most notably in patients with normal strength, may reset the natural history of anti-HMGCR myopathy from a refractory entity to a treatable disease.

Despite advances in therapy, glioblastoma remains an incurable disease with a dismal prognosis. Recent studies have implicated cancer stem cells within glioblastoma (glioma stem cells, GSCs) as mediators of therapeutic resistance and tumor progression. In this study, we investigated the role of the transforming growth factor-β (TGF-β) superfamily, which has been found to play an integral role in the maintenance of stem cell homeostasis within multiple stem cell systems, as a mediator of stem-like cells in glioblastoma. We find that BMP and TGF-β signaling define divergent molecular and functional identities in glioblastoma, and mark relatively quiescent and proliferative GSCs, respectively. Treatment of GSCs with BMP inhibits cell proliferation, but does not abrogate their stem-ness, as measured by self-renewal and tumorigencity. Further, BMP pathway activation confers relative resistance to radiation and temozolomide chemotherapy. Our findings define a quiescent cancer stem cell population in glioblastoma that may be a cellular reservoir for tumor recurrence following cytotoxic therapy.

Objective Recessive null variants of the slow skeletal muscle troponin T1 (TNNT1) gene are a rare cause of nemaline myopathy that is fatal in infancy due to respiratory insufficiency. Muscle biopsy shows rods and fiber type disproportion. We report on 4 French Canadians with a novel form of recessive congenital TNNT1 core-rod myopathy. Methods Patients underwent full clinical characterization, lower limb magnetic resonance imaging (MRI), muscle biopsy, and genetic testing. A zebrafish loss-of-function model using morpholinos was created to assess the pathogenicity of the identified variant. Wild-type or mutated human TNNT1 mRNAs were coinjected with morpholinos to assess their abilities to rescue the morphant phenotype. Results Three adults and 1 child shared a novel missense homozygous variant in the TNNT1 gene (NM_003283.6: c.287T > C; p.Leu96Pro). They developed from childhood very slowly progressive limb-girdle weakness with rigid spine and disabling contractures. They suffered from restrictive lung disease requiring noninvasive mechanical ventilation in 3 patients, as well as recurrent episodes of rhabdomyolysis triggered by infections, which were relieved by dantrolene in 1 patient. Older patients remained ambulatory into their 60s. MRI of the leg muscles showed fibrofatty infiltration predominating in the posterior thigh and the deep posterior leg compartments. Muscle biopsies showed multiminicores and lobulated fibers, rods in half the patients, and no fiber type disproportion. Wild-type TNNT1 mRNA rescued the zebrafish morphants, but mutant transcripts failed to do so. Interpretation This study expands the phenotypic spectrum of TNNT1 myopathy and provides functional evidence for the pathogenicity of the newly identified missense mutation. ANN NEUROL 2020;87:568-583.

Histone H3.3 glycine 34 to arginine/valine (G34R/V) mutations drive deadly gliomas and show exquisite regional and temporal specificity, suggesting a developmental context permissive to their effects. Here, we show that 50% of G34R/V-tumours (n=95) bear activating PDGFRA mutations that display strong selection pressure at recurrence. While considered gliomas, G34R/V-tumours actually arise in GSX2/DLX-expressing interneuron progenitors, where G34R/V-mutations impair neuronal differentiation. The lineage-of-origin may facilitate PDGFRA co-option through a chromatin loop connecting PDGFRA to GSX2 regulatory elements, promoting PDGFRA overexpression and mutation. At the single-cell level, G34R/V-tumours harbour dual neuronal/astroglial identity and lack oligodendroglial programs, actively repressed by GSX2/DLX-mediated cell-fate specification. G34R/V may become dispensable for tumour maintenance, while mutant-PDGFRA is potently oncogenic. Collectively, our results open novel research avenues in deadly tumours. G34R/V-gliomas are neuronal malignancies, where interneuron progenitors are stalled in differentiation by G34R/V-mutations, and malignant gliogenesis is promoted by co-option of a potentially targetable pathway, PDGFRA signalling.

Background Angiocentric lymph proliferative disorder (ALPD) is a granulomatous lymphoproliferative condition associated with various primary and secondary immunodeficiency states. ALPD is so rare that its prevalence has not been established. Typically affecting middle-aged adults, this condition is often found in the context of Epstein Bar Virus infection and consists of angiocentric and angioinvasive pulmonary infiltrates. Herein, we present a biopsy-proven case of a patient manifesting with a viral meningoencephalomyelitis-like picture with brain, spinal cord, renal and splenic lesions. The diagnosis was confirmed to be ALPD in the context of newly diagnosed HIV infection. Case presentation A 35 year-old homosexual man presented with a 5-week history of headaches followed by a 3-week history of horizontal diplopia, limb weakness and right 6th cranial nerve palsy. Lumbar puncture revealed a lymphocytic pleocytosis, high protein and low glucose. Magnetic Resonance Imaging showed scattered lesions throughout the brain and spinal cord and Computed Tomography of the abdomen and pelvis revealed hypodensities involving the kidneys and spleen. HIV testing was positive, with a viral load of 11,096 copies/mL and CD4 count of 324 cells/μL. Serum Epstein Bar virus PCR was positive with 12,434 copies/ml. Right frontal brain biopsy revealed gray matter containing angiogentric cerebritis with organizing infarction but Epstein Bar Virus-in situ preparations were negative and no viral inclusions were identified. A diagnosis of ALPD (also known as lymphomatoid granulomatosis) was made. The patient was initiated on antiretroviral therapy and treated with intravenous rituximab every 3 weeks for 4 cycles and made progressive improvements. By the time of discharge his strength had improved and he was ambulating again although with a walker. Within 2 months, his HIV viral load was suppressed. Magnetic Resonance Imaging of the brain 6 months later revealed interval improvement. At his most recent follow-up, 34 months later, his neurological symptoms had almost completed resolved. Conclusion Albeit rare, ALPD should be considered in the differential diagnosis of central nervous system lesions in persons with HIV once common etiologies have been eliminated. Furthermore, ALPD involving the central nervous system may occur in in the absence of documented EBV infection in the central nervous system.

VPS13 protein family members VPS13A through VPS13C have been associated with various recessive movement disorders. We describe the first disease association of rare recessive VPS13D variants including frameshift, missense, and partial duplication mutations with a novel complex, hyperkinetic neurological disorder. The clinical features include developmental delay, a childhood onset movement disorder (chorea, dystonia, or tremor), and progressive spastic ataxia or paraparesis. Characteristic brain magnetic resonance imaging shows basal ganglia or diffuse white matter T2 hyperintensities as seen in Leigh syndrome and choreoacanthocytosis. Muscle biopsy in 1 case showed mitochondrial aggregates and lipidosis, suggesting mitochondrial dysfunction. These findings underline the importance of the VPS13 complex in neurological diseases and a possible role in mitochondrial function. Ann Neurol 2018;83:1089-1095.

Glioblastoma is the most common and deadly type of brain cancer. Over the past decade, several divergent genetic pathways have been implicated in the initiation, progression and clinical outcome of this disease. As our understanding of GBM expands and identifies actionable targets specific to individual tumors, there will be a pressing need for the development of new tools that will maximize the use of limited clinical samples to enable the employment of personalized care paradigms. We used PrimePCR validated assays to generate a custom real-time PCR screening panel, containing 74 previously published mRNA targets showing gene expression changes in glioblastoma, and five house-keeping genes. A cohort of 19 frozen brain specimens were analyzed, including WHO Grade II oligodendroglioma (n = 3), WHO Grade II astrocytoma (n = 2), WHO Grade III astrocytoma (n = 1), and glioblastoma (n = 13). Four normal brain samples were also analyzed. We performed RNA extraction, followed by cDNA synthesis, multiplexed pre-amplification and SYBR-based qPCR, to generate expression profiles on all samples. We demonstrated that the workflow shows high tolerance to variation in RNA quality (RIN 8.5-4) and high sensitivity in detection. cDNA input that is equivalent to 3 ng of starting RNA was sufficient to conduct accurate semiquantitative analysis of the panel of 79 assays. Using principal component analysis, we were able to accurately separate glioblastoma from low-grade glioma. The two WHO Grade III tumors analyzed clustered with glioblastoma, but showed more similarity to Grade II gliomas. In this study, we have shown the feasibility of consolidating high-throughput data into a single functional panel capable of accurately classifying glioma specimens based solely on semiquantitative gene expression profiling.

Gastric and gastroesophageal junction (GEJ) adenocarcinomas have been shown to display significant HER2 genetic heterogeneity (GH). This is typically seen as a cluster of HER2-positive cells but can also take the form of intermingled cells, referred to a "mosaic" pattern. GH is not well defined in gastric/GEJ tumors and the "mosaic" pattern has never been studied. We sought to evaluate the frequency and distribution of the "mosaic" pattern of GH in gastric/GEJ tumors using the College of American Pathologists-endorsed breast criteria of 5% to

Clear cell renal cell carcinoma (ccRCC) is associated with high mortality, although individual outcomes are highly variable. Identification of patients with increased risk of disease progression can guide customizing management plan according to disease severity. Profilin-1 (Pfn1) has been recently identified as overexpressed in metastatic ccRCC compared with primary tumors. We examined Pfn1 expression in a tissue microarray of 384 cases of histologically confirmed primary ccRCC with detailed clinical follow-up. Profilin-1 expression showed both cytoplasmic and nuclear staining patterns. The immunoexpression of Pfn1 was scored in a semiquantitative fashion. There was no significant difference in Pfn1 expression between normal kidney and kidney ccRCC. Our results show that strong cytoplasmic Pfn1 expression is associated with high-grade (P.001) and high-stage (III-IV) (P = .018) disease. Univariate analysis of the data set showed that higher Pfn1 expression is associated with significantly shorter disease-free survival (hazard ratio 7.36, P = .047) and also lower overall survival. Kaplan-Meier analysis showed that high cytoplasmic expression of Pfn1 was also associated with a statistically significant lower disease-free survival (P = .018). It was also associated with lower overall survival, although this was not statistically significant. Profilin-1 lost its prognostic significance in the multivariate analysis when controlling for grade and stage. Profilin-1 expression was not associated with significant prognostic deference in the subgroup of patients with stage 1 disease. Our results suggest that the evaluation of Pfn1 by immunohistochemistry may help to identify patients with an increased risk of disease progression. We validated our results at the messenger RNA level on an independent patient cohort. Higher messenger RNA expression of Pfn1 is associated with significantly lower survival.

Brain metastasis is an uncommon but increasing manifestation of ovarian epithelial carcinoma and neuropathologists' collective experience with these tumors is limited. We present clinicopathological characteristics of 13 cases of brain metastases from ovarian epithelial carcinoma diagnosed at two academic institutions. The mean ages at diagnosis of the ovarian carcinoma and their subsequent brain metastases were 58.7 and 62.8 years, respectively. At the time of initial diagnosis of ovarian carcinoma the majority of patients had an advanced stage and none had brain metastases as their first manifestation of malignancy. Brain metastases tended to be multiple with ring-enhancing features on neuroimaging. Primary tumors and their brain metastases were all high-grade histologically and the histologic subtypes were: nine high-grade serous carcinoma (HGSC) cases, two clear cell carcinoma (CCC) cases and a single case each of carcinosarcoma and high-grade adenocarcinoma. A recommended histo- and immunopathological approach to these tumours are provided to aid neuropathologists in the recognition and classification of metastatic ovarian carcinoma to the brain.

Chordoid meningioma (CM) is a rare subtype of meningioma, classified as grade II, which exhibits a high rate of recurrence following subtotal resection. We retrospectively examined nine cases of chordoid meningioma over a case series of 1743 meningiomas (0.52%) operated upon at our institution from 1995 to 2013. All the reported clinicopathological findings were analyzed. Two hundred and twenty-one CM cases have been published to date worldwide and few single-center large case series have been issued. Seventy-five percent of the cases that underwent subtotal resection at our institution had recurrence within 1 year. Total resection of the tumor should be the major objective of surgery to reduce the possibility of tumor recurrence. The percentage of chordoid features within the tumor specimen could assist in predicting the pathogenesis of the lesion. The correlation of the index of proliferation to recurrence rate is still controversial. Much debate exists with regard to the role of adjuvant radiotherapy in CM cases. Immunohistochemical, cytological and ultrastructural studies should be used in combination to assure a correct diagnosis of CM. Owing to the rare occurrence of this meningioma subtype, larger case series are required to assist in providing a reference for diagnosis and to improve the therapeutic management of CM.

Pediatric high-grade gliomas (pHGGs) are aggressive neoplasms representing approximately 20% of brain tumors in children. Current therapies offer limited disease control, and patients have a poor prognosis. Empiric use of targeted therapy, especially at progression, is increasingly practiced despite a paucity of data regarding temporal and therapy-driven genomic evolution in pHGGs. To study the genetic landscape of pHGGs at recurrence, we performed whole exome and methylation analyses on matched primary and recurrent pHGGs from 16 patients. Tumor mutational profiles identified three distinct subgroups. Group 1 (n = 7) harbored known hotspot mutations in Histone 3 (H3) (K27M or G34V) or IDH1 (H3/IDH1 mutants) and co-occurring TP53 or ACVR1 mutations in tumor pairs across the disease course. Group 2 (n = 7), H3/IDH1 wildtype tumor pairs, harbored novel mutations in chromatin modifiers (ZMYND11, EP300 n = 2), all associated with TP53 alterations, or had BRAF V600E mutations (n = 2) conserved across tumor pairs. Group 3 included 2 tumors with NF1 germline mutations. Pairs from primary and relapsed pHGG samples clustered within the same DNA methylation subgroup. ATRX mutations were clonal and retained in H3G34V and H3/IDH1 wildtype tumors, while different genetic alterations in this gene were observed at diagnosis and recurrence in IDH1 mutant tumors. Mutations in putative drug targets (EGFR, ERBB2, PDGFRA, PI3K) were not always shared between primary and recurrence samples, indicating evolution during progression. Our findings indicate that specific key driver mutations in pHGGs are conserved at recurrence and are prime targets for therapeutic development and clinical trials (e.g. H3 post-translational modifications, IDH1, BRAF V600E). Other actionable mutations are acquired or lost, indicating that re-biopsy at recurrence will provide better guidance for effective targeted therapy of pHGGs. Electronic supplementary material The online version of this article (10.1186/s40478-017-0479-8) contains supplementary material, which is available to authorized users.

Glioblastoma (GBM, WHO grade IV astrocytoma) is among the most common adult brain tumors and one that is invariably fatal. GBM is classified as either primary (de novo) or secondary in origin. Secondary GBMs are derived from previously lower grade (WHO grades II or III) gliomas. While secondary GBMs present with similar clinical characteristics as their primary counterparts, the molecular pathways involved in their pathogenesis distinguish the two and have functional consequences for their behavior. Although a large number of histologic markers are routinely utilized to distinguish primary from secondary GBM, advances in genomic and bioinformatics techniques have drastically improved classification of high-grade gliomas and our understanding of the molecular pathways that influence tumor behavior and response to treatment. The significant influence of molecular identity on tumor behavior has been recognized by the most recent WHO classification of CNS tumors, wherein specific molecular markers have been integrated as part of tumor subtype identification process, as a supplement to traditional histological analysis. Indeed, the change heralds a new era for neuro-oncology, one that is moving toward targeted therapeutics as part of the standard of care. Thus, a comprehensive grasp of this diverse landscape is necessary. In this chapter, we provide an overview of our latest understanding of the molecular diversity of GBM, specifically as it pertains to primary and secondary GBMs, and how it influences prognostication and therapeutic decision-making.

Pediatric high-grade gliomas (pHGG) are aggressive malignant neoplasms representing approximately 20% of all pediatric central nervous system tumors. Current therapies offer limited disease control, and patients with recurrent disease have a particularly poor prognosis. While the empiric use of targeted therapy, especially at progression, is being increasingly practiced, there is a paucity of data regarding temporal and therapy-driven genomic evolution in pHGGs. To better understand the genetic landscape of pHGGs at recurrence, we performed whole exome, transcriptome and methylation analyses on pHGG matched primary and recurrent tumors from 16 patients, median age of 15 years (range: 4–29). Matched normal tissue, where available, was evaluated to determine mutation somatic status. Genetic mutational results suggested that our cohort could be segregated into 3 groups. Group 1 tumor pairs (n=6) carry driver mutations in histone 3 (H3F3A, HIST1H3B) or IDH1 that were retained between the primary tumor and recurrence. In tumors with H3F3A and IDH1 mutations, their obligate partner TP53 or ATRX mutations were also conserved. Group 2 tumor pairs (n=8) were histone 3 or IDH1 wild-type, but most harbored mutations in genes that are modifiers of histone or chromatin (KMT2D, ZMYND11, EP300, BCOR). TP53 and ATRX driver mutations were present in 50% (n=4) of tumors, and 25% (n=2) had a BRAF V600E mutation. Mutations in other putative drug targets (EGFR, ERBB2, PI3-kinase mutations) were not always shared between primary and recurrent tumors, indicating evolution during tumor progression. Group 3 samples (n=2) carried germline mutations in NF1. Mutational burden, gene ontology analysis and correlation with treatment exposure are ongoing. The finding that key driver mutations, some of which are targetable (e.g. IDH1, BRAF V600E) are conserved at recurrence, while other targetable mutations are acquired, indicates that re-biopsy at recurrence may provide better guidance for effective treatment of pHGG with targeted therapy.

Background:Radiotherapy with procarbazine, lomustine, and vincristine improves overall survival (OS) in patients with 1p19q co-deleted anaplastic oligodendroglioma/anaplastic oligoastrocytoma.Methods:This retrospective analysis investigated outcomes in patients with 1p19q co-deleted/partially deleted oligodendroglioma, oligoastrocytoma, anaplastic oligodendroglioma, or anaplastic oligoastrocytoma. OS and progression-free survival (PFS) were analyzed using the Kaplan-Meier method and prognostic factors using the Cox proportional hazard model.Results:A total of 106 patients (between December 1997 and December 2013) were included. Median age was 40 years (19-66), 58 were male (55%), Eastern Cooperative Oncology Group performance status was 0 in 80 patients (75%). 1p19q status was co-deleted in 66 (62%), incompletely co-deleted in 27 (25%), and 1p or 19q loss alone in four (4%) and nine (8%) patients, respectively. Isocitrate dehydrogenase-1 R132H mutation was found in 67 of 85 patients with sufficient material. Upfront treatment was given in 72 (68%) patients and temozolomide alone in 52 (49%). Median time to radiotherapy in 47 patients (44%) was 34.7 months and 41.2 months in 9 patients with co-deleted/incompletely co-deleted anaplastic oligodendroglioma/anaplastic oligoastrocytoma who received upfront temozolomide alone. Median OS was not reached and 5-year OS was 91% for all groups (median follow-up, 5.1 years). On multivariable analysis for all patients, receipt of therapy upfront versus none (p=0.04), PS 1 versus 0 (pConclusions:With similar survival patterns in low-grade/anaplastic gliomas, molecular characteristics may be more important than histological grade. Longer follow-up and results of prospective trials are needed for definitive guidance on treatment of these patients.

Congenital myopathies define a heterogeneous group of neuromuscular diseases with neonatal or childhood hypotonia and muscle weakness. The genetic cause is still unknown in many patients, precluding genetic counselling and better understanding of the physiopathology. To identify novel genetic causes of congenital myopathies, exome sequencing was performed in three consanguineous families. We identified two homozygous frameshift mutations and a homozygous nonsense mutation in the mitogen-activated protein triple kinase ZAK. In total, six affected patients carry these mutations. Reverse transcription polymerase chain reaction and transcriptome analyses suggested nonsense mRNA decay as a main impact of mutations. The patients demonstrated a generalized slowly progressive muscle weakness accompanied by decreased vital capacities. A combination of proximal contractures with distal joint hyperlaxity is a distinct feature in one family. The low endurance and compound muscle action potential amplitude were strongly ameliorated on treatment with anticholinesterase inhibitor in another patient. Common histopathological features encompassed fibre size variation, predominance of type 1 fibre and centralized nuclei. A peculiar subsarcolemmal accumulation of mitochondria pointing towards the centre of the fibre was a novel histological hallmark in one family. These findings will improve the molecular diagnosis of congenital myopathies and implicate the mitogen-activated protein kinase (MAPK) signalling as a novel pathway altered in these rare myopathies.

Background Cerebral cavernous malformations (CCMs) are angiographically occult vascular malformations of the central nervous system. As a result of hemorrhage and mass effect, patients may present with focal neurologic deficits, seizures, and other symptoms necessitating treatment. Once symptomatic, most often from hemorrhage, CCMs are treated with microsurgical resection. Orbital cavernous hemangiomas (OCHs) are similar but distinct vascular malformations that present within the orbital cavity. Even though CCMs and OCHs are both marked by dilated endothelial-lined vascular channels, they are infrequently seen in the same patient. Case description We provide a brief overview of the two related pathologies in the context of a patient presenting to our care with concomitant lesions, which were both resected in full without complication. Conclusion This is the first known report that describes a case of concomitant CCM and OCH and explores the origins of two pathologies that are rarely encountered together in neurosurgical practice. Recognition of disparate symptomatologies is important for properly managing these patients.

Background Lasers have a long history in neurosurgery, yet bulky designs and difficult ergonomics limit their use. With its ease of manipulation and multiple applications, the OmniGuide CO2 laser has reintroduced laser technology to the microsurgical resection of brain and spine lesions. This laser, delivered through a hollow-core fiber lined with a unidirectional mirror, minimizes energy loss and allows precise targeting. Objective To analyze resections performed by the senior author from April 2009 to March 2013 of 58 cavernous malformations (CMs) in the brain and spine with the use of the OmniGuide CO2 laser, to reflect on lessons learned from laser use in eloquent areas, and to share data on comparisons of laser power calibration and histopathology. Methods Data were collected from electronic medical records, radiology reports, operative room records, OmniGuide CO2 laser case logs, and pathology records. Results Of 58 CMs, approximately 50% were in the brainstem (30) and the rest were in supratentorial (26) and intramedullary spinal locations (2). Fifty-seven, ranging from 5 to 45 mm, were resected, with a subtotal resection in 1. Laser power ranged from 2 to 10 W. Pathology specimens showed minimal thermal damage compared with traditionally resected specimens with bipolar coagulation. Conclusion The OmniGuide CO2 laser is safe and has excellent precision for the resection of supratentorial, brainstem, and spinal intramedullary CMs. No laser-associated complications occurred, and very low energy was used to dissect malformations from their surrounding hemosiderin-stained parenchymas. The authors recommend its use for deep-seated and critically located CMs, along with traditional tools.

Background: In experimental models of glioblastoma multiforme (GBM), irradiation (IR) induces local expression of the chemokine CXCL12/SDF-1, which promotes tumour recurrence. The role of CXCR7, the high-affinity receptor for CXCL12, in the tumour's response to IR has not been addressed. Methods: We tested CXCR7 inhibitors for their effects on tumour growth and/or animal survival post IR in three rodent GBM models. We used immunohistochemistry to determine where CXCR7 protein is expressed in the tumours and in human GBM samples. We used neurosphere formation assays with human GBM xenografts to determine whether CXCR7 is required for cancer stem cell (CSC) activity in vitro. Results: CXCR7 was detected on tumour cells and/or tumour-associated vasculature in the rodent models and in human GBM. In human GBM, CXCR7 expression increased with glioma grade and was spatially associated with CXCL12 and CXCL11/I-TAC. In the rodent GBM models, pharmacological inhibition of CXCR7 post IR caused tumour regression, blocked tumour recurrence, and/or substantially prolonged survival. CXCR7 expression levels on human GBM xenograft cells correlated with neurosphere-forming activity, and a CXCR7 inhibitor blocked sphere formation by sorted CSCs. Conclusions: These results indicate that CXCR7 inhibitors could block GBM tumour recurrence after IR, perhaps by interfering with CSCs.

Background: Axial myopathy is a rare neuromuscular disorder of variable etiology characterised by preferential involvement of the paraspinal muscles. We reviewed clinical features of patients with axial myopathies and the diagnostic yield of myositis-associated antibodies and targeted next generation sequencing panels. Methods: We performed a retrospective review of patients presenting with axial myopathy at the Montreal Neurological Hospital from 2011-2018. Data collection included clinical presentation, disease course, results of electromyography, imaging, laboratory and genetic testing, and histopathology on muscle biopsy. Results: Twenty-five patients were identified. Initial manifestation of axial weakness was head drop (15), camptocormia (8), and rigid spine (2). Autoimmune myositis was diagnosed in 9 patients, seropositive in 7 out of 7 tested for myositis-associated antibodies. Genetic testing was consistent with oculopharyngeal muscular dystrophy in one patient and RYR-1 (ryanodine receptor 1) related core myopathy in another. Local radiotherapy or spine surgery preceded the onset of axial weakness in 1 and 6 patients, respectively. Muscle biopsies were available in 17 patients and revealed myopathic changes (16), inflammatory changes (6), and myopathy with vacuoles (3). Conclusions: Recent advancements in genetic and antibody testing, combined with paraspinal muscle biopsy, allow for more precise classification and identification of potentially treatable axial myopathies.

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.

Aims: Pathologists are under increasing pressure to accurately subclassify sarcomas, yet neuropathologists have limited collective experience with rare sarcoma types such as synovial sarcoma. We reviewed 9 synovial sarcomas affecting peripheral nerve diagnosed by neuropathologists and explored the morphologic and immunohistochemical differences between these and MPNST. Our goal was to make practical recommendations for neuropathologists regarding which spindle cell tumors affecting nerve should be sent for SYT-SSX testing. Methods: Clinical records and genetics were reviewed retrospectively and central pathology review of 9 synovial sarcomas and 6 MPNST included immunohistochemistry for SOX10, S100, BAF47, CK (lmw, pan, CK7, CK19), EMA, CD34, bcl2, CD99, and neurofilament. Results: Common synovial sarcoma sites were brachial plexus, spinal and femoral nerve, none were “intra-neural”, all had the SYT-SSX1 translocation, and 6/9 were monophasic with myxoid stroma and distinct collagen. Half of the monophasic synovial sarcomas expressed CK7, CK19 or panCK in a “rare positive cells pattern”, 8/9 (89%) expressed EMA, and all were SOX10 immunonegative with reduced but variable BAF47 expression. Conclusions: We recommend that upon encountering a cellular spindle cell tumor affecting nerve neuropathologists consider the following: 1) SYT-SSX testing should be performed on any case with morphology suspicious for monophasic synovial sarcoma including wiry or thick bands of collagen and relatively monomorphous nuclei; 2) neuropathologists should employ a screening immunohistochemical panel including one of CK7, panCK or CK19, plus EMA, S100 and SOX10, and 3) SYT-SSX testing should be performed on any spindle cell tumor with CK and/or EMA immunopositivity if SOX10 immunostaining is negative or only labels entrapped nerve elements.

Purpose: Ficlatuzumab is a novel therapeutic agent targeting the hepatocyte growth factor (HGF)/c-MET pathway. We summarize extensive preclinical work using this agent in a mouse brain orthotopic model of glioblastoma. Experimental Design: Sequential experiments were done using eight- to nine-week-old nude mice injected with 3 × 105 U87 MG (glioblastoma) cells into the brain. Evaluation of ficlatuzumab dose response for this brain tumor model and comparison of its response to ficlatuzumab and to temozolamide were conducted first. Subsequently, various small-animal imaging modalities, including bioluminescence imaging (BLI), positron emission tomography (PET), and MRI, were used with a U87 MG-Luc 2 stable cell line, with and without the use of ficlatuzumab, to evaluate the ability to noninvasively assess tumor growth and response to therapy. ANOVA was conducted to evaluate for significant differences in the response. Results: There was a survival benefit with ficlatuzumab alone or in combination with temozolamide. BLI was more sensitive than PET in detecting tumor cells. Fluoro-D-thymidine (FLT) PET provided a better signal-to-background ratio than 2[18F]fluoro-2-deoxy-d-glucose (FDG) PET. In addition, both BLI and FLT PET showed significant changes over time in the control group as well as with response to therapy. MRI does not disclose any time-dependent change. Also, the MRI results showed a temporal delay in comparison to the BLI and FLT PET findings, showing similar results one drug cycle later. Conclusions: Targeting the HGF/c-MET pathway with the novel agent ficlatuzumab appears promising for the treatment of glioblastoma. Various clinically applicable imaging modalities including FLT, PET, and MRI provide reliable ways of assessing tumor growth and response to therapy. Given the clinical applicability of these findings, future studies on patients with glioblastoma may be appropriate. Clin Cancer Res; 19(20); 5711–21. ©2013 AACR.

Data sharing is becoming more of a requirement as technologies mature and as global research and communications diversify. As a result, researchers are looking for practical solutions, not only to enhance scientific collaborations, but also to acquire larger amounts of data, and to access specialized datasets. In many cases, the realities of data acquisition present a significant burden, therefore gaining access to public datasets allows for more robust analyses and broadly enriched data exploration. To answer this demand, the Montreal Neurological Institute has announced its commitment to Open Science, harnessing the power of making both clinical and research data available to the world (Owens, 2016a,b). As such, the LORIS and CBRAIN (Das et al., 2016) platforms have been tasked with the technical challenges specific to the institutional-level implementation of open data sharing, including: Comprehensive linking of multimodal data (phenotypic, clinical, neuroimaging, biobanking, and genomics, etc.) Secure database encryption, specifically designed for institutional and multi-project data sharing, ensuring subject confidentiality (using multi-tiered identifiers). Querying capabilities with multiple levels of single study and institutional permissions, allowing public data sharing for all consented and de-identified subject data. Configurable pipelines and flags to facilitate acquisition and analysis, as well as access to High Performance Computing clusters for rapid data processing and sharing of software tools. Robust Workflows and Quality Control mechanisms ensuring transparency and consistency in best practices. Long term storage (and web access) of data, reducing loss of institutional data assets. Enhanced web-based visualization of imaging, genomic, and phenotypic data, allowing for real-time viewing and manipulation of data from anywhere in the world. Numerous modules for data filtering, summary statistics, and personalized and configurable dashboards. Implementing the vision of Open Science at the Montreal Neurological Institute will be a concerted undertaking that seeks to facilitate data sharing for the global research community. Our goal is to utilize the years of experience in multi-site collaborative research infrastructure to implement the technical requirements to achieve this level of public data sharing in a practical yet robust manner, in support of accelerating scientific discovery.

Dysembryoplastic neuroepithelial tumor (DNET) is a benign brain tumor associated with intractable drug-resistant epilepsy. In order to identify underlying genetic alterations and molecular mechanisms, we examined three family members affected by multinodular DNETs as well as 100 sporadic tumors from 96 patients, which had been referred to us as DNETs. We performed whole-exome sequencing on 46 tumors and targeted sequencing for hotspot FGFR1 mutations and BRAF p.V600E was used on the remaining samples. FISH, copy number variation assays and Sanger sequencing were used to validate the findings. By whole-exome sequencing of the familial cases, we identified a novel germline FGFR1 mutation, p.R661P. Somatic activating FGFR1 mutations (p.N546K or p.K656E) were observed in the tumor samples and further evidence for functional relevance was obtained by in silico modeling. The FGFR1 p.K656E mutation was confirmed to be in cis with the germline p.R661P variant. In 43 sporadic cases, in which the diagnosis of DNET could be confirmed on central blinded neuropathology review, FGFR1 alterations were also frequent and mainly comprised intragenic tyrosine kinase FGFR1 duplication and multiple mutants in cis (25/43; 58.1 %) while BRAF p.V600E alterations were absent (0/43). In contrast, in 53 cases, in which the diagnosis of DNET was not confirmed, FGFR1 alterations were less common (10/53; 19 %; p

Despite a well-characterized lack of specificity, pathologists routinely employ S100 in the diagnosis of neural crest-derived tumors. Recent studies have shown that Sox10 is a reliable marker of neural crest differentiation that is consistently expressed in schwannian and melanocytic tumors. We sought to validate these results in a larger series of soft tissue neoplasms of both neural crest and non-neural crest origin, and to further characterize the sensitivity and specificity of Sox10 for use in clinical diagnosis. We evaluated Sox10 and S100 mRNA levels in 122 cases of peripheral nerve sheath tumors and synovial sarcoma and used immunohistochemistry for Sox10 and S100 protein expression in 1012 tissue specimens. This study includes 174 tissue microarray cases previously reported by Nonaka and colleagues, which include cases of melanoma, dermatofibrosarcoma protuberans, neurofibroma, synovial sarcoma, clear-cell sarcoma, malignant peripheral nerve sheath tumor (MPNST), perineurioma, and schwannoma. Synovial sarcomas expressed significantly higher levels of S100B than Sox10 (P=7.9×10), and no significant Sox10 mRNA expression was identified in synovial sarcoma (n=40), whereas 18/40 cases showed comparatively increased levels of S100 mRNA. The majority of schwannomas (n=26) and neurofibromas (n=28) showed relatively an increased expression of both Sox10 and S100 mRNA. MPNSTs (n=28) showed variable levels of Sox10 and S100 mRNA expression, and these expression levels were highly correlated (Pearson correlation coefficient r=0.79). In contrast, immunohistochemistry performed on a larger and more varied number of cases highlighted significant differences between the 2 proteins. We identified 5 non-neural, nonmelanocytic sarcoma types in which a subset of cases showed S100 protein expression: synovial sarcoma (12/79, 15%), Ewing sarcoma (3/14, 21%), rhabdomyosarcoma (4/17, 24%), chondrosarcoma (3/4, 75%), and extraskeletal myxoid chondrosarcoma (5/11, 45%). For each of these entities, we identified cases with strong and diffuse S100 staining. Of these cases, only 1 case of rhabdomyosarcoma showed focal Sox10 positivity. In 78 cases of MPNST, S100 increased the sensitivity (31/78, 40%) as compared with Sox10 (21/78, 27%), but the majority of these cases were negative for both Sox10 and S100 (44/78, 56%). Sox10 proved superior to S100 in the detection of desmoplastic melanoma (7/9, 78%) and clear-cell sarcoma (4/7, 57%). We also report for the first time Sox10 expression in 26 cases of granular cell tumor, further supporting the neural crest derivation of this tumor. Excluding MPNST, S100 and Sox10 showed similar sensitivity in tumors of neural crest origin (140/148, 95% and 137/148, 93%, respectively). In summary, Sox10 shows an increased specificity for tumors of neural crest origin compared with S100: Sox10 was positive in only 5 of 668 cases (99% specificity) in nonschwannian, nonmelanocytic tumors, whereas S100 was positive in 53 of 668 cases (91% specificity). Sox10 should be used in the place of or along with S100 in soft tissue tumor diagnosis.

IgG4-related sclerosing disease has been described in the orbit and ocular adnexa. Of 164 biopsies of the ocular region for suspected lymphoma, we identified 6 cases of IgG4 disease, 4 of which were previously unrecognized. All 6 cases demonstrated increased plasma cells in a background of sclerosis and increased absolute numbers of IgG4-expressing cells. Our results confirm the difficulty in diagnosing IgG4-related sclerosing disease in the ocular region. Based on the findings, we suggest that specimens from biopsies of the eye and ocular adnexa for which a definitive diagnosis of lymphoma is not established undergo further workup for IgG and IgG4, particularly if increased plasma cells and sclerosis are present. When IgG4-expressing plasma cells account for greater than 50% of IgG-expressing plasma cells, a diagnosis of IgG4 disease should be considered. Timely recognition would benefit patients by allowing appropriate management with corticosteroid therapy and avoiding more aggressive or unnecessary therapeutic options.

Brachyury is recognized as a specific marker for notochord-derived tissues and neoplasms, and has become a defining immunohistochemical feature of chordoma. The main differential diagnostic consideration for chordoma is chondrosarcoma, which is known to lack brachyury expression. However, within the spectrum of genitourinary neoplasia, metastatic germ cell tumors and clear cell renal cell carcinoma may also be close morphological mimics of chordoma, particularly given the increasing prevalence of small tissue samples from image-guided biopsies. Although immunoreactivity for brachyury has been reported in a few germ cell tumors, a thorough characterization of staining by specific subtype has not been performed in a large series. Additionally, brachyury expression in clear cell renal cell carcinoma has not been well studied. In this study, immunohistochemical expression with the brachyury antibody was evaluated in 111 germ cell tumors, 30 non-neoplastic and neoplastic (non-germ cell) testicular tissues, and 184 metastatic clear cell renal cell carcinomas using tissue microarray technology. In addition, immunoreactivity for PAX-8 and SALL-4 was evaluated in 12 chordomas on whole section. No nuclear brachyury expression was identified in any of the 101 germ cell tumors within the tissue microarray (including choriocarcinoma (1), embryonal carcinoma (20), intratubular germ cell neoplasia unclassified (2), seminoma (64), spermatocytic seminoma (1), teratoma (5) and yolk sac tumor (8)), in any of the 30 non-neoplastic and neoplastic (non-germ cell) testicular tissues, or in any of the 10 whole-section seminomas. All 184 metastatic clear cell renal cell carcinomas were also non-reactive for brachyury. All 12 chordomas showed strong nuclear immunoreactivity for brachyury, but no expression of SALL-4. In all, 1 of 12 chordoma cases showed patchy, 1+ nuclear immunoreactivity for PAX-8. This study confirms the specificity of brachyury for chordoma in the differential diagnostic distinction from the potential genitourinary mimics, germ cell tumors and metastatic clear cell renal cell carcinoma.

We report the presence of pituitary tissue in a benign ovarian cystic teratoma removed surgically from a 43-year-old woman. The pituitary consisted of non-tumorous neurohypophysis and adenohypophysis containing mainly prolactin (PRL)-immunopositive cells (80 % of cells) and a small PRL-producing adenoma. The ultrastructure of the tumor cells differed significantly from PRL cells in the non-tumorous and adenomatous intrasellar pituitary. It appears that cells differing in ultrastructure from intrasellar pituitary PRL cells can also produce PRL.

The diagnosis of metastatic clear cell renal cell carcinoma may be difficult in some cases, particularly in the small image-guided biopsies that are becoming more common. As targeted therapies for renal cell carcinoma are now standard treatment, the recognition and diagnosis of renal cell carcinoma has become even more critical. Many adjunctive immunohistochemical markers of renal epithelial lineage such as CD10 and RCCma have been proposed as aids in the diagnosis of metastatic renal cell carcinoma, but low specificities often limit their utility. More recently described markers (PAX-2, PAX-8, human kidney injury molecule-1, hepatocyte nuclear factor-1-β, and carbonic anhydrase-IX) offer the potential for greater sensitivity and specificity in this diagnostic setting; however, knowledge of their expected staining in other neoplasms and tissues is critical for appropriate use. In this review, we discuss the most widely used immunohistochemical markers of renal lineage with an emphasis on their sensitivity and specificity for metastatic clear cell renal cell carcinoma. Subsequently, we present a variety of organ-specific differential diagnostic scenarios in which metastatic clear cell renal cell carcinoma might be considered and we propose immunopanels for use in each situation.

Langerhans cell histiocytosis (LCH) is a rare proliferative disorder that occurs most commonly in the pediatric population as a result of pathological clonal proliferation of Langerhans cells with subsequent damage and destruction to surrounding tissue. Clinically, LCH presents in a variety of ways, which often results in prolonged time to diagnosis and subsequently poorer outcomes. In this case report, the authors describe an unusually early presentation of multisystem LCH in a patient at birth, which resulted in a 5-month delay to diagnosis and treatment. This patient presented both atypically young and with an uncommon initial manifestation of multisystem disease with multiple soft-tissue swellings rather than early skin involvement. Additionally, this patient had an unusual radiographic appearance with biparietal skull destruction on initial skull radiographs and biparietal soft-tissue lesions on CT resembling cephalohematoma at 3 months of age. The clinical and radiological evaluation, pathology, and treatment strategies are discussed, with particular attention paid to the importance of further workup of atypical nonresolving cephalohematomas to prevent disease progression and poorer outcomes.

Background: Sry-related HMG-BOX gene 10 (SOX10), a nuclear transcription factor that plays an important role in schwannian and melanocytic cell differentiation, has recently been shown to be a useful marker in the diagnosis of melanocytic and schwannian tumors. Fibroblasts and histiocytes that could histopathologically mimic melanoma cells often express S100, which complicates the evaluation of melanoma excision specimens for residual tumor. Distinguishing melanoma cells from immature fibrocytes or histiocytes is made more challenging in desmoplastic melanoma excision specimens. Methods: We compared the utility of melanoma markers [SOX10, S100, HMB-45, Melan-A and micropthalmia transcription factor (MiTF)] in 3 invasive, 9 desmoplastic and 14 intraepidermal melanomas. We also evaluated 18 excision scars. The staining intensity for all the cellular components in melanoma and scar specimens was scored. Results: SOX10 strongly highlighted all in situ, invasive and desmoplastic melanomas. In contrast, MiTF expression was weak to absent in desmoplastic melanomas. In scars, S100 highlighted background spindled fibrocytes and histiocytes with greater intensity than SOX10. MiTF highlighted multi-nucleated histiocytes, while SOX10 did not. Conclusion: Our results showed that SOX10 was strongly expressed by desmoplastic melanoma. Furthermore, SOX10 was less likely than S100 and MiTF to be expressed by background fibrocytes and histiocytes within scars. Ramos-Herberth FI, Karamchandani J, Kim J, Dadras SS. SOX10 immunostaining distinguishes desmoplastic melanoma from excision scar.

Human papillomavirus (HPV)-negative head and neck squamous cell carcinomas (HNSCCs) are deadly and common cancers. Recent genomic studies implicate multiple genetic pathways, including cell signaling, cell cycle and immune evasion, in their development. Here we analyze public data sets and uncover a previously unappreciated role of epigenome deregulation in the genesis of 13% of HPV-negative HNSCCs. Specifically, we identify novel recurrent mutations encoding p.Lys36Met (K36M) alterations in multiple H3 histone genes. We further validate the presence of these alterations in multiple independent HNSCC data sets and show that, along with previously described NSD1 mutations, they correspond to a specific DNA methylation cluster. The K36M substitution and NSD1 defects converge on altering methylation of histone H3 at K36 (H3K36), subsequently blocking cellular differentiation and promoting oncogenesis. Our data further indicate limited redundancy for NSD family members in HPV-negative HNSCCs and suggest a potential role for impaired H3K36 methylation in their development. Further investigation of drugs targeting chromatin regulators is warranted in HPV-negative HNSCCs driven by aberrant H3K36 methylation. Citation Format: Chao Lu, Simon Papillon-Cavanagh, Tenzin Gayden, Leonie G. Mikael, Denise Bechet, Christina Karamboulas, Laurie Ailles, Jason Karamchandani, Dylan M. Marchione, Benjamin A. Garcia, Ilan Weinreb, David Goldstein, Peter W. Lewis, Octavia-Maria Dancu, Sandeep Dhaliwal, William Stecho, Christopher J. Howlett, Joe S. Mymryk, John W. Barrett, Anthony C. Nichols, C David Allis, Jacek Majewski, Nada Jabado. Impaired H3K36 methylation defines a subset of head and neck squamous cell carcinomas [abstract]. In: Proceedings of the AACR-AHNS Head and Neck Cancer Conference: Optimizing Survival and Quality of Life through Basic, Clinical, and Translational Research; April 23-25, 2017; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2017;23(23_Suppl):Abstract nr 08.

Melanin concentrating hormone (MCH) is a hypothalamic neuropeptide known to play a critical role in energy balance. We have previously reported that overexpression of MCH is associated with mild obesity. In addition, mice have substantial hyperinsulinemia and islet hyperplasia that is out of proportion with their degree of obesity. In this study, we further explored the role of MCH in the endocrine pancreas. Both MCH and MCHR1 are expressed in mouse and human islets and in clonal beta-cell lines as assessed using quantitative real-time PCR and immunohistochemistry. Mice lacking MCH (MCH-KO) on either a C57Bl/6 or 129Sv genetic background showed a significant reduction in beta-cell mass and complemented our earlier observation of increased beta-cell mass in MCH-overexpressing mice. Furthermore, the compensatory islet hyperplasia secondary to a high-fat diet, which was evident in wild-type controls, was attenuated in MCH-KO. Interestingly, MCH enhanced insulin secretion in human and mouse islets and rodent beta-cell lines in a dose-dependent manner. Real-time PCR analyses of islet RNA derived from MCH-KO revealed altered expression of islet-enriched genes such as glucagon, forkhead homeobox A2, hepatocyte nuclear factor (HNF)4alpha, and HNF1alpha. Together, these data provide novel evidence for an autocrine role for MCH in the regulation of beta-cell mass dynamics and in islet secretory function and suggest that MCH is part of a hypothalamic-islet (pancreatic) axis.

Diffuse Intrinsic Pontine Gliomas (DIPGs) are deadly paediatric brain tumours where needle biopsies help guide diagnosis and targeted therapies. To address spatial heterogeneity, here we analyse 134 specimens from various neuroanatomical structures of whole autopsy brains from nine DIPG patients. Evolutionary reconstruction indicates histone 3 (H3) K27M—including H3.2K27M—mutations potentially arise first and are invariably associated with specific, high-fidelity obligate partners throughout the tumour and its spread, from diagnosis to end-stage disease, suggesting mutual need for tumorigenesis. These H3K27M ubiquitously-associated mutations involve alterations in TP53 cell-cycle (TP53/PPM1D) or specific growth factor pathways (ACVR1/PIK3R1). Later oncogenic alterations arise in sub-clones and often affect the PI3K pathway. Our findings are consistent with early tumour spread outside the brainstem including the cerebrum. The spatial and temporal homogeneity of main driver mutations in DIPG implies they will be captured by limited biopsies and emphasizes the need to develop therapies specifically targeting obligate oncohistone partnerships., Diffuse Intrinsic Pontine Gliomas are diagnosed by sampling a small portion of the tumour. Here, using multiple samples from tumours, the authors analyse the spatial and temporal distribution of driver mutations revealing that H3K27M mutations arise first in tumorigenesis followed by a specific invariable sequence of driver mutations, which are homogeneously distributed across the tumour mass.

The purpose of this chapter is to first provide an overview of the anatomy and histology of the normal spinal cord, followed by an overview of normal and abnormal MR imaging findings. Selected common primary intramedullary spinal tumors (IMST) are then discussed in detail (spinal cord ependymoma, spinal cord pilocytic astrocytoma, spinal cord low-grade glioma), in addition to a selected extramedullary intradural tumor (meningioma), as a case-based discussion providing a brief overview of the tumor type, MR imaging findings, radiotherapy treatment planning guidelines as per practice at the University of Toronto, and a discussion of selected evidence. A brief discussion of vertebral and intramedullary metastases follows and an introduction to the emerging technique of spine stereotactic body radiotherapy (SBRT). Lastly, we discuss spinal cord tolerance in the setting of both conventionally fractionated and hypofractionated radiation for both radiation naive and previously radiated patients.

Papillary renal cell carcinoma (pRCC) is the second most common RCC subtype and can be further classified as type 1 (pRCC1) or 2 (pRCC2). There is currently minimal understanding of pRCC1 pathogenesis, and treatment decisions are mostly empirical. The aim of this study was to identify biological pathways that are involved in pRCC1 pathogenesis using an integrated genomic approach. By microarray analysis, we identified a number of significantly dysregulated genes and microRNAs (miRNAs) that were unique to pRCC1. Integrated bioinformatics analyses showed enrichment of the focal adhesion and extracellular matrix (ECM) pathways. We experimentally validated that many members of these pathways are dysregulated in pRCC1. We identified and experimentally validated the downregulation of miR-199a-3p in pRCC1. Using cell line models, we showed that miR-199a-3p plays an important role in pRCC1 pathogenesis. Gain of function experiments showed that miR-199a-3p overexpression significantly decreased cell proliferation (p = 0.013). We also provide evidence that miR-199a-3p regulates the expression of genes linked to the focal adhesion and ECM pathways, such as caveolin 2 (CAV2), integrin beta 8 (ITGB8), MET proto-oncogene and mammalian target of rapamycin (MTOR). Using a luciferase reporter assay, we further provide evidence that miR-199a-3p overexpression decreases the expression of MET and MTOR. Using an integrated gene/miRNA approach, we provide evidence linking miRNAs to the focal adhesion and ECM pathways in pRCC1 pathogenesis. This novel information can contribute to the development of effective targeted therapies for pRCC1, for which there is none currently available in the clinic.

Stem cell niches must be dynamic to enable stem cells to respond promptly and appropriately to physiologic demands. There is growing evidence to suggest that the superfamily of transforming growth factor-βs (TGF-βs) play an integral role in the maintenance of stem cell homeostasis within multiple stem cell systems. In glioblastoma, TGF-β has been shown to act as an oncogenic factor through its induction of self-renewal and proliferation in glioma stem cells (GSCs), and inhibition of GSC differentiation. Conversely, treatment of GSCs with BMP4 in vitro was found to direct these cells toward a differentiated, astrocytic phenotype, and abolish their ability to drive tumor growth following xenotransplantation. These studies suggest that TGF-β and BMP signaling direct glioma cells toward an irreversible fate choice, and that maintenance of the cancer stem cell (CSC) phenotype is necessary for tumorigenicity. We postulated that the CSC fate choices in glioblastoma are plastic, and that TGF-β and BMP signaling regulate cell glioma cell dynamics within the tumor microenvironment, as in cellular reprogramming. Further, we postulated that TGF-β and BMP might construe cell identities in glioblastoma that could be relevant to glioblastoma treatment resistance, disease evolution and disease progression. Here, we demonstrate that TGF-β and BMP signaling are active in the glioblastoma microenvironment, and regulate the shuttling of GSCs from an activated to a quiescent phenotype. At the molecular level, this process is mediated, as in EMT/MET, by the ZEB1/miR-200 double-negative feedback loop. Activation of p21 via BMP signaling is one mechanism for resistance to chemotherapy- and radiation-induced cell damage. Quiescent, BMPhi cells then give rise to TGF-βhi GSCs that drive tumour progression. Our findings demonstrate a role for BMP-mediated quiescence in glioblastoma disease resistance and recurrence, and suggest that targeted inhibition of BMP during chemoradiation could favorably alter the natural history of this disease.

BACKGROUND: Radiotherapy with procarbazine, lomustine and vincristine improves overall survival (OS) in patients with 1p19q codeleted anaplastic oligodendroglioma (AOD)/anaplastic oligoastrocytoma (AOA). This retrospective study investigates outcomes with upfront temozolomide (TMZ) deferring radiotherapy in 1p19q codeleted/partially deleted AOD, AOA, oligodendroglioma (OD) or oligoastrocytoma (OA). METHODS: Patients with 1p19q codeleted/partially deleted AOD, AOA, OD and OA were analyzed for OS and progression-free survival (PFS) using Kaplan-Meier method. RESULTS: A total of 106 patients (Dec 97-Dec 13) were included. Median age was 40 years (19-66), 58 (55%) male, performance status (PS) 0 in 80 (75%) patients. 1p19q status; codeleted in 66 (62%), incompletely codeleted in 27 (25%), 1p or 19q loss alone in 4 (4%) and 9 (8%) patients respectively. Reason for presentation was seizures in 79 (75%), frontal lobe tumor location in 62 (58%) and contrast enhancement in 50 (47%). Upfront treatment was given in 72 (68%) patients; TMZ alone in 52 (49%) was well tolerated with med 12 cycles (1-24). Median time to radiotherapy in 47 patients (44%), 34.7mo. Median time to radiotherapy in AOD, AOA, OD, OA was 22.4mo, 1.4mo, 43.2mo and 43.4 mo respectively, given in median 3rd line of treatment (range 2-4), 41.2 mo (16.3-93.2) in 9 patients with codeleted/incompletely codeleted AOD who received upfront TMZ alone. Median OS was not reached for all groups (median follow up 5.1yrs). Median time to treatment for 36 patients with 1p19q codeleted/partially deleted AOD/AOA treated with TMZ alone upfront was 49.5 days (range 9-2248), median PFS was 46.3 months. On multivariable analysis, PS 1 vs 0 (Hazard ratio [HR]2.78, 95%confidence interval[CI] 1.57-4.93, p < 0.001) and 1p19q codeletion/incomplete deletion vs 1p or 19q loss alone (HR0.36, 95%CI 0.18-0.74, p = 0.005) were prognostic for PFS. Isocitrate dehydrogenase-1 status is pending. CONCLUSION: Delaying radiotherapy in 1p19q codeleted/incompletely deleted AOD/AOA may be a treatment option.

Angiogenesis is a hallmark feature of glioblastoma. Recent data suggests that glioma stem cells (GSCs) contribute to pathologic angiogenesis through transdifferentiation into endothelial cells and vascluar pericytes. We have identified a VEGF-A-responsive lincRNA near the VEGFR1 gene, which we named LIVE1 (lincRNA-VEGFR1), that directs vascular network formation and regulates gene expression profiles in normal endothelial cells. Furthermore, LIVE1 is highly expressed in glioblastoma and enriched in CD133+ GSCs and CD133 + CD144+ neoplastic endothelial precursor cells. LIVE1 binds to the promoter of multiple VEGF targets and, through interactions with RNA helicase A and PARP1, facilitates their transciption in GSCs. LIVE1 expression directs GSCs toward a vascular pericyte fate choice. Depletion of LIVE1 in a xenograft model of glioblastoma results in a decrease in vascular denisty and perfusion, loss of pericyte coverage, and disruption of the vascular niche. Our findings demonstrate a novel role of lincRNAs in the orchestration of tumor angiogenesis, and reveal a new possible therepautic target.

The concept of oncogene addiction presupposes that cancer cells require certain dominant oncogenic signals for growth and survival. A profound implication of this hypothesis is that antagonizing this crucial pathway should have significant effects on cancer cells, while sparing normal cells that are not similarly addicted. Clinically, the recognition of oncogenes to which a cancer is addicted could have profound resonance for targeted cancer therapy. The Wnt signaling pathway has recently been described to be constitutively activated in a subgroup of glioblastomas. Here, we performed a systematic review of high-throughput screens of CSC and physiologic stem cell systems to identify possible mediators of the stem cell phenotype in glioblastoma. Of the agents identified in multiple screens, we chose to study indomethacin, a chemical inhibitor of cyclooxygenase-2, because of the well described role of COX-2 in stem cell maintenance and of prostaglandin E2 (PGE2) in glioma biology. We then found COX-2 to be expressed in glioma stem cells (GSCs), but not in normal adult neural stem cells. Activation of COX-2 signaling in vitro resulted in increased GSC proliferation, while antagonism of COX-2 using indomethacin or siRNA inhibits GSC proliferation and self-renewal. PGE2 further directs GSCs activation through its aberrant activation of the Wnt/β-catenin pathway, which then induces COX-2 expression. Blockade of the reciprocal PGE2/β-catenin signaling cycle results in inhibition of GSC proliferation, and loss of markers of stem-ness. In vivo, concurrent administration of the COX-2 antagonist, celecoxib, and the Wnt inhibitor, LGK974, enhanced the activity of temozolomide in a mouse glioblastoma xenograft model, through its antagonism of CSCs. Our findings demonstrate a central role for COX-2 and Wnt signaling in maintenance of the CSC phenotype in glioblastoma, and suggest that disruption of their reciprocal interaction has therapeutic potential in glioblastoma.