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Structural evolution of Nd2NiO4.23 with temperature, indicating several 1st order phase transitions with sub-mesoscopic oxygen ordering and instant ordering kinetics below 800 K.

Treatment of meningiomas refractory to surgery and irradiation is challenging and effective chemotherapies are still lacking. Recently, in vitro analyses revealed decitabine (DCT, 5-aza-2’–deoxycytidine) to be effective in high-grade meningiomas and, moreover, to induce hypomethylation of distinct oncogenes only sparsely described in meningiomas in vivo yet.Expression of the corresponding onco- and tumor suppressor genes TRIM58, FAM84B, ELOVL2, MAL2, LMO3, and DIO3 were analyzed and scored by immunohistochemical staining and RT-PCR in samples of 111 meningioma patients. Correlations with clinical and histological variables and prognosis were analyzed in uni- and multivariate analyses.All analyzed oncogenes were highly expressed in meningiomas. Expression scores of TRIM58 tended to be higher in benign than in high-grade tumors 20 vs 16 (p = .002) and all 9 samples lacking TRIM58 expression displayed WHO grade II/III histology. In contrast, median expression scores for both FAM84B (6 vs 4, p ≤ .001) and ELOVL2 (9 vs 6, p DIO3 expression was distinctly higher in all analyzed samples as compared to the reference decitabine-resistant Ben-Men 1 cell line. Increased ELOVL2 expression (score ≥ 8) correlated with tumor relapse in both uni- (HR: 2.42, 95%CI 1.18–4.94; p = .015) and multivariate (HR: 2.09, 95%CI 1.01–4.44; p = .046) analyses.All oncogenes involved in DCT efficacy in vitro are also widely expressed in vivo, and expression is partially associated with histology and prognosis. These results strongly encourage further analyses of DCT efficiency in meningiomas in vitro and in situ.

Supplementary Table S1 from The Transcription Factor Evi-1 Is Overexpressed, Promotes Proliferation, and Is Prognostically Unfavorable in Infratentorial Ependymomas

Purpose: Ependymomas are glial tumors of presumably radial glial origin that share morphologic similarities with ependymal cells. The molecular genetics of ependymomas of supratentorial, infratentorial, and spinal location is heterogeneous. We aimed at identifying pathways operative in the development of infratentorial ependymomas.Experimental Design: To do so, gene expression profiles of tumor cells laser microdissected from infratentorial ependymomas (n = 15) were compared with that of nonneoplastic ependymal cells laser microdissected from autopsy tissue (n = 7).Results: Among 31 genes significantly overexpressed (>5-fold) in ependymomas, transcription factor EVI1 (ecotropic viral integration site 1) showed the highest overexpression (35-fold). Evi-1 protein expression could be confirmed in formalin-fixed, paraffin-embedded samples of 26 of 28 infratentorial ependymomas but only in 7 of 47 nonependymal glial tumors (P < 0.001). Furthermore, MDS1/EVI1 fusion transcripts were detectable in 17 of 28 infratentorial ependymomas and significantly correlated with MGMT (O6-methylguanine-DNA-methyltransferase) promoter hypermethylation (P < 0.05). In primary infratentorial ependymoma cells, transfection with EVI1-specific siRNAs resulted in significant growth inhibition [48 hours: 87% ± 2% and 74% ± 10% as compared with control (mean ± SD; P < 0.001)]. The prognostic role of EVI1 could further be validated in an independent cohort of 39 infratentorial and 26 supratentorial ependymomas on the basis of mRNA expression profiling. Although in supratentorial ependymomas EVI1 expression status had no prognostic impact, in infratentorial ependymomas, high EVI1 expression was associated with shorter overall survival and progression-free survival.Conclusions: To conclude, the transcription factor Evi-1 is overexpressed in infratentorial ependymomas, promotes proliferation of ependymal tumor cells, and is prognostically unfavorable. Clin Cancer Res; 17(11); 3631–7. ©2011 AACR.

The pathogenesis of choroid plexus papillomas, intraventricular papillary neoplasms most often occurring sporadically in children and young adults, remains poorly understood. To identify pathways operative in the development of choroid plexus papillomas, gene expression profiles obtained from laser-microdissected human choroid plexus papilloma cells (n = 7) were compared with that of normal choroid plexus epithelial cells laser microdissected from autopsy tissue (n = 8). On DNA microarray data analysis, 53 probe sets were differentially expressed in choroid plexus papilloma tumor cells (>7-fold). Up-regulation of TWIST1, WIF1, TRPM3, BCLAF1, and AJAP1, as well as down-regulation of IL6ST was confirmed using quantitative reverse transcription-PCR. Knockdown of Twist1 gene expression in the rat choroid plexus epithelial cell line Z310 significantly reduced proliferation as assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and cell invasion in a Matrigel assay, whereas cell migration was not affected. Screening for expressional changes of cancer-related genes upon Twist1 knockdown revealed up-regulation of Cdkn1a, Cflar, and Serpinb2 and down-regulation of Figf. To conclude, using gene expression profiling, several genes differentially expressed in human choroid plexus papillomas could be identified. Among those, TWIST1 is highly expressed in choroid plexus papillomas and promotes proliferation and invasion. [Cancer Res 2009;69(6):2219–23]

Supplementary Table 1 from TWIST-1 Is Overexpressed in Neoplastic Choroid Plexus Epithelial Cells and Promotes Proliferation and Invasion

Synchronous or metachronous growth of multiple tumors (≥ 2) is found in up to 20% of meningioma patients. However, biological as well as histological features and prognosis are largely unexplored. Clinical and histological characteristics were retrospectively investigated in 95 patients harboring 226 multiple meningiomas (MMs) and compared with 135 cases of singular meningiomas (SM) using uni- and multivariate analyses. In MM, tumors occurred synchronously and metachronously in 62% and 38%, respectively. WHO grade was intra-individually constant in all but two MMs, and histological subtype varied in 13% of grade 1 tumors. MM occurred more commonly in convexity/parasagittal locations, while SM were more frequent at the skull base (p p = .014) and high-grade histology in MM were associated with a prolonged time to progression (p p ≥ .05, each). Multivariate analyses showed synchronous/metachronous meningioma growth (HR 4.50, 95% CI 2.26–8.96; p p = .224), but exponentially raised in patients with 3–4 (HR 3.25, 1.22–1.62; p = .018) and ≥ 5 tumors (HR 13.80, 4.06–46.96; p

Background A methylation-based classification of ependymoma has recently found broad application. However, the diagnostic advantage and implications for treatment decisions remain unclear. Here, we retrospectively evaluate the impact of surgery and radiotherapy on outcome after molecular reclassification of adult intracranial ependymomas. Methods Tumors diagnosed as intracranial ependymomas from 170 adult patients collected from 8 diagnostic institutions were subjected to DNA methylation profiling. Molecular classes, patient characteristics, and treatment were correlated with progression-free survival (PFS). Results The classifier indicated an ependymal tumor in 73.5%, a different tumor entity in 10.6%, and non-classifiable tumors in 15.9% of cases, respectively. The most prevalent molecular classes were posterior fossa ependymoma group B (EPN-PFB, 32.9%), posterior fossa subependymoma (PF-SE, 25.9%), and supratentorial ZFTA fusion-positive ependymoma (EPN-ZFTA, 11.2%). With a median follow-up of 60.0 months, the 5- and 10-year-PFS rates were 64.5% and 41.8% for EPN-PFB, 67.4% and 45.2% for PF-SE, and 60.3% and 60.3% for EPN-ZFTA. In EPN-PFB, but not in other molecular classes, gross total resection (GTR) (P = .009) and postoperative radiotherapy (P = .007) were significantly associated with improved PFS in multivariable analysis. Histological tumor grading (WHO 2 vs. 3) was not a predictor of the prognosis within molecularly defined ependymoma classes. Conclusions DNA methylation profiling improves diagnostic accuracy and risk stratification in adult intracranial ependymoma. The molecular class of PF-SE is unexpectedly prevalent among adult tumors with ependymoma histology and relapsed as frequently as EPN-PFB, despite the supposed benign nature. GTR and radiotherapy may represent key factors in determining the outcome of EPN-PFB patients.

About 25% of patients with intracranial meningioma display seizures at the time of initial presentation. Hence, identification of risk factors for preoperative seizures is crucial during perioperative care of meningioma patients.Associations of preoperative seizures with clinical, radiological and histological variables were analyzed in 945 patients (689 females, 73% and 256 males, 27%; median age: 58 years) who underwent surgery for primary diagnosed intracranial meningioma.Preoperative seizures were found in 189 patients (20%). In univariate analyses, male gender (OR: 1.91, 95%CI 1.37-2.68; p.001), grade II/III histology (OR: 2.24, 95%CI 1.46-3.46; p.001), brain invasion (OR: 2.59, 95%CI 1.45-4.63; p=001), non-skull base tumor location (OR: 3.07, 95%CI 2.13-4.41; p.001), heterogeneous contrast-enhancement (OR: 1.60, 95%CI 1.04-2.46; p=.031), intratumoral calcifications (OR: 1.91, 95%CI 1.17-3.10; p=.009), an irregular shape (OR: 2.07, 95%CI 1.32-3.26; p=.002) as well as tumor (OR: 1.01 per ccm, 95%CI 1.00-1.02; p=.001) and edema volumes (OR: 1.01 per ccm, 95%CI 1.00-1.01; p.001) were correlated with seizures. Semiology was not related to any of the analyzed variables (p.05, each). No associations were found between seizures and histological subtype of 832 grade I meningiomas (p=.391). In multivariate analyses, only non-skull base tumor location (OR: 3.12, 95%CI 1.74-5.59; p.001) and a rising peritumoral edema volume (OR: 1.01 per ccm, 95%CI 1.00-1.01; p.001) were identified as independent predictors for preoperative seizures.Several mostly radiological variables were identified as risk factors for epilepsy. However, multivariate analyses confirmed only peritumoral edema and non-skull base tumor location as independent predictors for preoperative seizures. None of the variables predicts semiology.

For oxygen conducting materials applied in solid oxide fuel cells and chemical-looping processes, the understanding of the oxygen diffusion mechanism and the materials' crystal structure at different stages of the redox reactions is a key parameter to control their performance. In this paper we report the first ever in situ 3D electron diffraction (ED) experiment in a gas environment and with it uncover the structure evolution of SrFeO2.5 as notably different from that reported from in situ X-ray and in situ neutron powder diffraction studies in gas environments. Using in situ 3D ED on submicron sized single crystals, we observe the transformation under O-2 flow of brownmillerite SrFeO2.5 with an intra- and interlayer ordering of the left and right twisted (FeO4)(infinity) tetrahedral chains (space group Pcmb) into consecutively SrFeO2.75 with space group Cmmm (at 350 degrees C, 33% O-2) and SrFeO3-delta with space group Pm3m (at 400 degrees C, 100% O-2). Upon reduction in H-2 flow, the crystals return to the brownmillerite structure with intralayer order, but without regaining the interlayer order of the pristine crystals. Therefore, redox cycling of SrFeO2.5 crystals in O-2 and H-2 introduces stacking faults into the structure, resulting in an I2/m(0 beta gamma)0s symmetry with variable beta.

Risk factors to predict late-onset tumor recurrence in meningioma patients are urgently needed to schedule control intervals during long-term follow-up. We therefore analyzed the value of established risk factors for postoperative meningioma recurrence for the prediction of long-term prognosis. Correlations of clinical and histopathological variables with tumor relapse after 3, 5, and 10 years following microsurgery were analyzed in uni- and multivariate analyses, and compared to findings in the entire cohort. In the entire cohort (N = 1218), skull base location (HR: 1.51, 95%CI 1.05–2.16; p = .026), Simpson ≥ IV resections (HR: 2.41, 95%CI 1.52–3.84; p p p = .042) were independent risk factors for recurrence. Skull base location (HR: 1.92, 95%CI 1.17–3.17; p = .010 and HR: 2.02, 95%CI 1.04–3.95; p = .038) and high-grade histology (HR: 1.87, 95%CI 1.04–3.38; p = .038 and HR: 2.29, 95%CI 1.07–4.01; p = .034) but not subtotal resection (HR: 1.53, 95%CI .68–3.45; p = .303 and HR: 1.75, 95%CI .52–5.96; p = .369) remained correlated with recurrence after a recurrence-free follow-up of ≥ 3 and ≥ 5 years, respectively. Postoperative tumor volume was related with recurrence in general (p p > .05). In 147 patients with a follow-up of ≥ 10 years, ten recurrences occurred and were not correlated with any of the analyzed variables. Skull base tumor location and high-grade histology but not the extent of resection should be considered when scheduling the long-term follow-up after meningioma surgery. Recurrences ≥ 10 years after surgery are rare, and predictors are lacking.

Background: The usefulness of 5-ALA-mediated fluorescence-guided resection (FGR) in meningiomas is controversial, and information on the molecular background of fluorescence is sparse. Methods: Specimens obtained during 44 FGRs of intracranial meningiomas were analyzed for the presence of tumor tissue and fluorescence. Protein/mRNA expression of key transmembrane transporters/enzymes involved in PpIX metabolism (ABCB6, ABCG2, FECH, CPOX) were investigated using immunohistochemistry/qPCR. Results: Intraoperative fluorescence was observed in 70 of 111 specimens (63%). No correlation was found between fluorescence and the WHO grade (p = 0.403). FGR enabled the identification of neoplastic tissue (sensitivity 84%, specificity 67%, positive and negative predictive value of 86% and 63%, respectively, AUC: 0.75, p < 0.001), and was improved in subgroup analyses excluding dura specimens (86%, 88%, 96%, 63% and 0.87, respectively; p < 0.001). No correlation was found between cortical fluorescence and tumor invasion (p = 0.351). Protein expression of ABCB6, ABCG2, FECH and CPOX was found in meningioma tissue and was correlated with fluorescence (p < 0.05, each), whereas this was not confirmed for mRNA expression. Aberrant expression was observed in the CNS. Conclusion: FGR enables the intraoperative identification of meningioma tissue with limitations concerning dura invasion and due to ectopic expression in the CNS. ABCB6, ABCG2, FECH and CPOX are expressed in meningioma tissue and are related to fluorescence.

OBJECTIVE Chemotherapeutic options for meningiomas refractory to surgery or irradiation are largely unknown. Human telomerase reverse transcriptase (hTERT) promoter methylation with subsequent TERT expression and telomerase activity, key features in oncogenesis, are found in most high-grade meningiomas. Therefore, the authors investigated the impact of the demethylating agent decitabine (5-aza-2′-deoxycytidine) on survival and DNA methylation in meningioma cells. METHODS hTERT promoter methylation, telomerase activity, TERT expression, and cell viability and proliferation were investigated prior to and after incubation with decitabine in two benign (HBL-52 and Ben-Men 1) and one malignant (IOMM-Lee) meningioma cell line. The global effects of decitabine on DNA methylation were additionally explored with DNA methylation profiling. RESULTS High levels of TERT expression, telomerase activity, and hTERT promoter methylation were found in IOMM-Lee and Ben-Men 1 but not in HBL-52 cells. Decitabine induced a dose-dependent significant decrease of proliferation and viability after incubation with doses from 1 to 10 μM in IOMM-Lee but not in HBL-52 or Ben-Men 1 cells. However, effects in IOMM-Lee cells were not related to TERT expression, telomerase activity, or hTERT promoter methylation. Genome-wide methylation analyses revealed distinct demethylation of 14 DNA regions after drug administration in the decitabine-sensitive IOMM-Lee but not in the decitabine-resistant HBL-52 cells. Differentially methylated regions covered promoter regions of 11 genes, including several oncogenes and tumor suppressor genes that to the authors' knowledge have not yet been described in meningiomas. CONCLUSIONS Decitabine decreases proliferation and viability in high-grade but not in benign meningioma cell lines. The effects of decitabine are TERT independent but related to DNA methylation changes of promoters of distinct tumor suppressor genes and oncogenes.

IDH2 R172 mutations occur in sinonasal undifferentiated carcinoma (SNUC), large-cell neuroendocrine carcinoma (LCNEC), sinonasal adenocarcinomas, and olfactory neuroblastoma (ONB). We performed a clinical, pathologic, and genetic/epigenetic analysis of a large IDH2-mutated sinonasal tumor cohort to explore their distinct features. A total 165 sinonasal/skull base tumors included 40 IDH2 mutants studied by light microscopy, immunohistochemistry, and genome-wide DNA methylation, and 125 IDH2 wild-type tumors used for comparison. Methylation profiles were analyzed by unsupervised hierarchical clustering, t-distributed stochastic neighbor embedding dimensionality reduction and assessed for copy number alterations (CNA). Thirty-nine histologically assessable cases included 25 (64.1%) SNUC, 8 (20.5%) LCNEC, 2 (5.1%) poorly differentiated adenocarcinomas, 1 (2.7%) ONB, and 3 (7.7%) IDH2-mutated tumors with ONB features. All cases were high-grade showing necrosis (82.4%), prominent nucleoli (88.9%), and median 21 mitoses/10 HPFs. AE1/AE3 and/or CAM 5.2 were positive in all and insulinoma-associated protein 1 (INSM1) in 80% cases. All IDH2 mutants formed one distinct group by t-distributed stochastic neighbor embedding dimensionality reduction separating from all IDH2 wild-type tumors. There was no correlation between methylation clusters and histopathologic diagnoses. Recurrent CNA included 1q gain (79.3%), 17p loss (75.9%), and 17q gain (58.6%). No CNA differences were observed between SNUC and LCNEC. IDH2 mutants showed better disease-specific survival than SMARCB1-deficient (P=0.027) and IDH2 wild-type carcinomas overall (P=0.042). IDH2-mutated sinonasal tumors are remarkably homogeneous at the molecular level and distinct from IDH2 wild-type sinonasal malignancies. Biology of IDH2-mutated sinonasal tumors might be primarily defined by their unique molecular fingerprint rather than by their respective histopathologic diagnoses.

For oxygen conducting materials applied in solid oxide fuel cells and chemical-looping processes, the understanding of the oxygen diffusion mechanism and the materials’ crystal structure at different stages of the redox reactions is a key parameter to control their performance. In this paper we report the first ever in situ 3D ED experiment in a gas environment and with it uncover the structure evolution of SrFeO2.5 as notably different from that reported from in situ X-ray and in situ neutron powder diffraction studies in gas environments. Using in situ 3D ED on submicron sized single crystals obtained from a high quality monodomain SrFeO2.5 single crystal, we observe the transformation under O2 flow of SrFeO2.5 with an intra- and interlayer ordering of the left and right twisted (FeO4) tetrahedral chains (space group Pcmb) into consecutively SrFeO2.75 (space group Cmmm) and SrFeO3- (space group Pm3 ̅m). Upon reduction in H2 flow, the crystals return to the brownmillerite structure with intralayer order, but without regaining the interlayer order of the pristine crystals. Therefore, redox cycling of SrFeO2.5 crystals in O2 and H2 introduces stacking faults into the structure, resulting in an I2/m(0βγ)0s symmetry with variable β.

To understand oxygen diffusion mechanisms in non-stoichiometric oxides, the possibility to explore structural changes as a function of the oxygen partial pressure with temperature and related oxygen bulk stoichiometry is mandatory. This article reports on the realization of a high-temperature furnace, suitable for single-crystal neutron diffraction, working continuously at temperatures of up to 1000°C at different and adjustable partial gas pressures of up to 2 bar (1 bar = 100 kPa). This allows exploration of the phase diagrams of non-stoichiometric oxides under in situ conditions and controlled oxygen partial pressure. As a pilot study, the structural changes of Pr2NiO4+δ were explored at room temperature (δ ≃ 0.24) and at 900°C under 1 bar P(O2) (δ ≃ 0.13) as well as under secondary vacuum (approximately 10−5 mbar) conditions yielding a δ close to zero. The strong anharmonic displacements of the apical oxygen atoms along the [110] shallow diffusion pathway, which were previously observed at room temperature and 400°C, become more isotropic at 900°C. The study shows that the anisotropic oxygen displacements, here related to lattice instabilities, play a major role in understanding oxygen diffusion pathways and related activation energies at moderate temperatures. This also shows the importance of the availability of reaction cells for single-crystal neutron diffraction to explore the phase diagram and associated structural changes of non-stoichiometric oxygen ion conductors and respective diffusion mechanisms.

Loss of nuclear SMARCB1 (INI1/hSNF5/BAF47) protein expression due to biallelic mutations of the SMARCB1 tumor suppressor gene is a hallmark of atypical teratoid/rhabdoid tumors (ATRT), but the presence of cytoplasmic SMARCB1 protein in these tumors has not yet been described. In a series of 102 primary ATRT, distinct cytoplasmic SMARCB1 staining on immunohistochemistry was encountered in 19 cases (19%) and was highly over-represented in cases showing pathogenic sequence variants leading to truncation or mutation of the C-terminal part of SMARCB1 (15/19 vs. 4/83; Chi-square: 56.04, p = 1.0E−10) and, related to this, in tumors of the molecular subgroup ATRT-TYR (16/36 vs. 3/66; Chi-square: 24.47, p = 7.6E−7). Previous reports have indicated that while SMARCB1 lacks a bona fide nuclear localization signal, it harbors a masked nuclear export signal (NES) and that truncation of the C-terminal region results in unmasking of this NES leading to cytoplasmic localization. To determine if cytoplasmic localization found in ATRT is due to unmasking of NES, we generated GFP fusions of one of the SMARCB1 truncating mutations (p.Q318X) found in the tumors along with a p.L266A mutation, which was shown to disrupt the interaction of SMARCB1-NES with exportin-1. We found that while the GFP-SMARCB1(Q318X) mutant localized to the cytoplasm, the double mutant GFP-SMARCB1(Q318X;L266A) localized to the nucleus, confirming NES requirement for cytoplasmic localization. Furthermore, cytoplasmic SMARCB1(Q318X) was unable to cause senescence as determined by morphological observations and by senescence-associated β-galactosidase assay, while nuclear SMARCB1(Q318X;L266A) mutant regained this function. Selinexor, a selective exportin-1 inhibitor, was effective in inhibiting the nuclear export of SMARCB1(Q318X) and caused rapid cell death in rhabdoid tumor cells. In conclusion, inhibition of nuclear export restores nuclear localization and residual tumor suppressor function of truncated SMARCB1. Therapies aimed at preventing nuclear export of mutant SMARCB1 protein may represent a promising targeted therapy in ATRT harboring truncating C-terminal SMARCB1 mutations.

Although non-functioning pituitary tumors are frequent, diagnostic and therapeutic concepts are not well standardized. We here present the first German multidisciplinary guideline on this topic. The single most important message is to manage the patients by a multidisciplinary team (consisting at least of an endocrinologist, a neurosurgeon, and a (neuro-) radiologist). The initial diagnostic work-up comprises a detailed characterization of both biochemical (focusing on hormonal excess or deficiency states) and morphological aspects (with magnetic resonance imaging of the sellar region). An ophthalmological examination is only needed in presence of symptoms or large tumors affecting the visual system. Asymptomatic, hormonally inactive tumors allow for a 'wait and scan' strategy. In contrast, surgical treatment by an experienced pituitary surgeon is standard of care in case of (impending) visual impairment. Therapeutic options for incompletely resected or recurrent tumors include re-operation, radiotherapy, and observation; the individual treatment plan should be developed multidisciplinary. Irrespective of the therapeutic approach applied, patients require long-term follow-up. Patient with larger pituitary tumors or former surgery/radiotherapy should be regularly counseled regarding potential symptoms of hormonal deficiency states.

Atypical teratoid/rhabdoid tumor (ATRT) is an aggressive central nervous system tumor characterized by loss of SMARCB1/INI1 protein expression and comprises three distinct molecular groups, ATRT–TYR, ATRT–MYC and ATRT–SHH. ATRT–SHH represents the largest molecular group and is heterogeneous with regard to age, tumor location and epigenetic profile. We, therefore, aimed to investigate if heterogeneity within ATRT–SHH might also have biological and clinical importance. Consensus clustering of DNA methylation profiles and confirmatory t-SNE analysis of 65 ATRT–SHH yielded three robust molecular subgroups, i.e., SHH-1A, SHH-1B and SHH-2. These subgroups differed by median age of onset (SHH-1A: 18 months, SHH-1B: 107 months, SHH-2: 13 months) and tumor location (SHH-1A: 88% supratentorial; SHH-1B: 85% supratentorial; SHH-2: 93% infratentorial, often extending to the pineal region). Subgroups showed comparable SMARCB1 mutational profiles, but pathogenic/likely pathogenic SMARCB1 germline variants were over-represented in SHH-2 (63%) as compared to SHH-1A (20%) and SHH-1B (0%). Protein expression of proneural marker ASCL1 (enriched in SHH-1B) and glial markers OLIG2 and GFAP (absent in SHH-2) as well as global mRNA expression patterns differed, but all subgroups were characterized by overexpression of SHH as well as Notch pathway members. In a Drosophila model, knockdown of Snr1 (the fly homologue of SMARCB1) in hedgehog activated cells not only altered hedgehog signaling, but also caused aberrant Notch signaling and formation of tumor-like structures. Finally, on survival analysis, molecular subgroup and age of onset (but not ASCL1 staining status) were independently associated with overall survival, older patients (> 3 years) harboring SHH-1B experiencing relatively favorable outcome. In conclusion, ATRT–SHH comprises three subgroups characterized by SHH and Notch pathway activation, but divergent molecular and clinical features. Our data suggest that molecular subgrouping of ATRT–SHH has prognostic relevance and might aid to stratify patients within future clinical trials.

Hemangioblastomas (HBs) of the central nervous system are highly vascular neoplasms that occur sporadically or as a manifestation of von Hippel-Lindau (VHL) disease. Despite their benign nature, HBs are clinically heterogeneous and can be associated with significant morbidity due to mass effects of peritumoral cysts or tumor progression. Underlying molecular factors involved in HB tumor biology remain elusive. We investigated genome-wide DNA methylation profiles and clinical and histopathological features in a series of 47 HBs from 42 patients, including 28 individuals with VHL disease. Thirty tumors occurred in the cerebellum, 8 in the brainstem and 8 HBs were of spinal location, while 1 HB was located in the cerebrum. Histologically, 12 HBs (26%) belonged to the cellular subtype and exclusively occurred in the cerebellum, whereas 35 HBs were reticular (74%). Unsupervised clustering and dimensionality reduction of DNA methylation profiles revealed two distinct subgroups. Methylation cluster 1 comprised 30 HBs of mainly cerebellar location (29/30, 97%), whereas methylation cluster 2 contained 17 HBs predominantly located in non-cerebellar compartments (16/17, 94%). The sum of chromosomal regions being affected by copy-number alterations was significantly higher in methylation cluster 1 compared to cluster 2 (mean 262 vs. 109 Mb, p = 0.001). Of note, loss of chromosome 6 occurred in 9/30 tumors (30%) of methylation cluster 1 and was not observed in cluster 2 tumors (p = 0.01). No relevant methylation differences between sporadic and VHL-related HBs or cystic and non-cystic HBs could be detected. Deconvolution of the bulk DNA methylation profiles revealed four methylation components that were associated with the two methylation clusters suggesting cluster-specific cell-type compositions. In conclusion, methylation profiling of HBs reveals 2 distinct subgroups that mainly associate with anatomical location, cytogenetic profiles and differences in cell type composition, potentially reflecting different cells of origin.

La2CoO4+δ is a strongly correlated oxide with exciting physical and electronic properties originating from the subtle interplay of the lattice, orbital, charge, and spin degrees of freedom. In particular, oxygen-rich La2CoO4.25 is a key compound for studying oxygen and electronic ordering phenomena and their correlation. Single-crystal growth of these phases has been plagued by difficulties related to their incongruent melting. In this work, we report on the growth and characterization of high-quality, centimeter-sized La2CoO4.25 single crystals, suitable for neutron scattering experiments. La2CoO4+δ single crystals were grown by the traveling solvent floating zone without the addition of a solvent but continuously stabilizing the growth conditions. Postsynthesis annealing at 500 °C in oxygen flux yielded phase-pure La2CoO4.25, which was further characterized by single-crystal neutron and X-ray diffraction, as well as by scanning electron microscopy with energy-dispersive X-ray spectroscopy, revealing its quality in terms of composition, homogeneity, and crystalline quality. For La2CoO4.25, a complex structure with a two-dimensional modulation vector related to oxygen ordering was revealed by single-crystal X-ray and neutron powder diffraction studies. In addition, magnetic measurements coupled with preliminary single-crystal elastic neutron scattering experiments exhibited antiferromagnetic ordering with a Néel temperature (TN) of 36 K with a complex magnetic structure involving the doubling of all orthorhombic axes.

Atypical teratoid/rhabdoid tumor (AT/RT) is a malignant central nervous system tumor predominantly affecting infants. Mutations of SMARCB1 or (rarely) SMARCA4 causing loss of nuclear SMARCB1 or SMARCA4 protein expression are characteristic features, but further recurrent genetic alterations are lacking. Most AT/RTs occur de novo, but secondary AT/RTs arising from other central nervous system tumors have been reported. Malignant gliomas, IDH wild-type, arising in patients with Li-Fraumeni syndrome typically show somatic mutations of TP53 as well as complex copy number alterations, but little is known about the loss of SMARCB1 or SMARCA4 protein expression in this context. Here, we report 2 children in whom malignant supratentorial brain tumors with SMARCB1 deficiency, complex copy number alterations, and somatic TP53 mutations lead to the discovery of pathogenic/likely pathogenic TP53 variants in the germline. Screening of the molecularneuropathology.org dataset for cases with similar genetic and epigenetic alterations yielded another case with SMARCA4 deficiency in a young adult with Li-Fraumeni syndrome. In conclusion, SMARCB1-deficient or SMARCA4-deficient malignant brain tumors with complex copy number alterations and somatic TP53 mutations in children and young adults may represent the first clinical manifestation of Li-Fraumeni syndrome and should prompt genetic counseling and investigation for TP53 germline status.

Low‐grade diffusely infiltrative tumour (LGDIT), SMARCB1‐mutant, is a histopathological distinct low‐grade lesion encountered in older children and young adults that shows epigenetic similarity with ATRT‐MYC and has the potential for malignant progression. image, publishedVersion