Specific detection of methionine 27 mutation in histone 3 variants (H3K27M) in fixed tissue from high-grade astrocytomas

Studies in pediatric high-grade astrocytomas (HGA) by our group and others have uncovered recurrent somatic mutations affecting highly conserved residues in histone 3 (H3) variants. One of these mutations leads to analogous p.Lys27Met (K27M) mutations in both H3.3 and H3.1 variants, is associated with rapid fatal outcome, and occurs specifically in HGA of the midline in children and young adults. This includes diffuse intrinsic pontine gliomas (80 %) and thalamic or spinal HGA (>90 %), which are surgically challenging locations with often limited tumor material available and critical need for specific histopathological markers. Here, we analyzed formalin-fixed paraffin-embedded tissues from 143 pediatric HGA and 297 other primary brain tumors or normal brain. Immunohistochemical staining for H3K27M was compared to tumor genotype, and also compared to H3 tri-methylated lysine 27 (H3K27me3) staining, previously shown to be drastically decreased in samples carrying this mutation. There was a 100 % concordance between genotype and immunohistochemical analysis of H3K27M in tumor samples. Mutant H3K27M was expressed in the majority of tumor cells, indicating limited intra-tumor heterogeneity for this specific mutation within the limits of our dataset. Both H3.1 and H3.3K27M mutants were recognized by this antibody while non-neoplastic elements, such as endothelial and vascular smooth muscle cells or lymphocytes, did not stain. H3K27me3 immunoreactivity was largely mutually exclusive with H3K27M positivity. These results demonstrate that mutant H3K27M can be specifically identified with high specificity and sensitivity using an H3K27M antibody and immunohistochemistry. Use of this antibody in the clinical setting will prove very useful for diagnosis, especially in the context of small biopsies in challenging midline tumors and will help orient care in the context of the extremely poor prognosis associated with this mutation. Electronic supplementary material The online version of this article (doi:10.1007/s00401-014-1337-4) contains supplementary material, which is available to authorized users

Clinical, radiologic, pathologic, and molecular characteristics of long-term survivors of diffuse intrinsic pontine glioma (DIPG): a collaborative report from the International and European Society for Pediatric Oncology DIPG registries

Purpose Diffuse intrinsic pontine glioma (DIPG) is a brainstem malignancy with a median survival of < 1 year. The International and European Society for Pediatric Oncology DIPG Registries collaborated to compare clinical, radiologic, and histomolecular characteristics between short-term survivors (STSs) and long-term survivors (LTSs). Materials and Methods Data abstracted from registry databases included patients from North America, Australia, Germany, Austria, Switzerland, the Netherlands, Italy, France, the United Kingdom, and Croatia. Results Among 1,130 pediatric and young adults with radiographically confirmed DIPG, 122 (11%) were excluded. Of the 1,008 remaining patients, 101 (10%) were LTSs (survival ≥ 2 years). Median survival time was 11 months (interquartile range, 7.5 to 16 months), and 1-, 2-, 3-, 4-, and 5-year survival rates were 42.3% (95% CI, 38.1% to 44.1%), 9.6% (95% CI, 7.8% to 11.3%), 4.3% (95% CI, 3.2% to 5.8%), 3.2% (95% CI, 2.4% to 4.6%), and 2.2% (95% CI, 1.4% to 3.4%), respectively. LTSs, compared with STSs, more commonly presented at age < 3 or > 10 years (11% v 3% and 33% v 23%, respectively; P < .001) and with longer symptom duration ( P < .001). STSs, compared with LTSs, more commonly presented with cranial nerve palsy (83% v 73%, respectively; P = .008), ring enhancement (38% v 23%, respectively; P = .007), necrosis (42% v 26%, respectively; P = .009), and extrapontine extension (92% v 86%, respectively; P = .04). LTSs more commonly received systemic therapy at diagnosis (88% v 75% for STSs; P = .005). Biopsies and autopsies were performed in 299 patients (30%) and 77 patients (10%), respectively; 181 tumors (48%) were molecularly characterized. LTSs were more likely to harbor a HIST1H3B mutation (odds ratio, 1.28; 95% CI, 1.1 to 1.5; P = .002). Conclusion We report clinical, radiologic, and molecular factors that correlate with survival in children and young adults with DIPG, which are important for risk stratification in future clinical trials

A potential role of karyopherin a2 in the impaired maturation of dendritic cells observed in glioblastoma patients

Aim: Patients with glioblastomas demonstrate well-documented immunological impairments including decreased numbers of mature dendritic cells (DCs). Recent data identified karyopherin a2 (KPNA2), a nucleocytoplasmic shuttling receptor, as diagnostic and prognostic biomarker for gliomas. The aim of this ongoing study is to correlate parameters of immunity and nucleocytoplasmic transport in glioblastoma patients.Methods: We preoperatively collected serum from 17 patients with glioblastomas and determined DC subsets (HLA DR+ Lin-, CD34-, CD45+, CD123+, CD11+ were analyzed) using a 6-color flow cytometry panel. Expression levels of KPNA2 and nuclear accumulation of p53 were evaluated semi-quantitatively by immunohistochemistry. O6-methylguanine DNA methyltransferase (MGMT) and isocitrate dehydrogenase-1 (IDH-1) status were assessed by pyrosequencing and immunohistochemistry, respectively.Results: Median expression levels for both KPNA2 and p53 were 5-10%. IDH-1-R132H mutation and MGMT promoter hypermethylation was detected in 3/16 and 1/9 patients, respectively. Mean counts of total mature DCs, myeloid DCs and plasmacytoid DCs were 9.6, 2.1, 3.4 cells/μL. A preliminary analysis suggests an association between low KPNA2 nuclear expression and increased numbers of mature DCs. However, this correlation did not reach statistical significance so far (P = 0.077).Conclusion: Our preliminary data may indicate a role of KPNA2 in the impaired maturation of DCs observed in glioblastoma patients

DCE-MRI in Glioma, Infiltration Zone and Healthy Brain to Assess Angiogenesis: A Biopsy Study

Purpose: To explore the focal predictability of vascular growth factor expression and neovascularization using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in glioma. Methods: 120 brain biopsies were taken in vital tumor, infiltration zone and normal brain tissue of 30 glioma patients: 17 IDH(isocitrate dehydrogenase)-wildtype glioblastoma (GBM), 1 IDH-wildtype astrocytoma °III (together prognostic group 1), 3 IDH-mutated GBM (group 2), 3 anaplastic astrocytomas IDH-mutated (group 3), 4 anaplastic oligodendrogliomas and 2 low-grade oligodendrogliomas (together prognostic group 4). A mixed linear model evaluated the predictabilities of microvessel density (MVD), vascular area ratio (VAR), mean vessel size (MVS), vascular endothelial growth factor and receptors (VEGF-A, VEGFR‑2) and vascular endothelial-protein tyrosine phosphatase (VE-PTP) expression from Tofts model kinetic and model-free curve parameters. Results: All kinetic parameters were associated with VEGF‑A (all p < 0.001) expression. K trans, k ep and v e were associated with VAR (p = 0.006, 0.004 and 0.01, respectively) and MVS (p = 0.0001, 0.02 and 0.003, respectively) but not MVD (p = 0.84, 0.74 and 0.73, respectively). Prognostic groups differed in K trans (p = 0.007) and v e (p = 0.004) values measured in the infiltration zone. Despite significant differences of VAR, MVS, VEGF‑A, VEGFR‑2, and VE-PTP in vital tumor tissue and the infiltration zone (p = 0.0001 for all), there was no significant difference between kinetic parameters measured in these zones. Conclusion: The DCE-MRI kinetic parameters show correlations with microvascular parameters in vital tissue and also reveal blood-brain barrier abnormalities in the infiltration zones adequate to differentiate glioma prognostic groups

Magnetic resonance imaging characteristics of molecular subgroups in pediatric H3 K27M mutant diffuse midline glioma

PURPOSE: Recent research identified histone H3 K27M mutations to be associated with a dismal prognosis in pediatric diffuse midline glioma (pDMG); however, data on detailed MRI characteristics with respect to H3 K27 mutation status and molecular subgroups (H3.1 and H3.3 K27M mutations) are limited. METHODS: Standardized magnetic resonance imaging (MRI) parameters and epidemiologic data of 68 pDMG patients (age <18 years) were retrospectively reviewed and compared in a) H3 K27M mutant versus H3 K27 wildtype (WT) tumors and b) H3.1 versus H3.3 K27M mutant tumors. RESULTS: Intracranial gliomas (n = 58) showed heterogeneous phenotypes with isointense to hyperintense signal in T2-weighted images and frequent contrast enhancement. Hemorrhage and necrosis may be present. Comparing H3 K27M mutant to WT tumors, there were significant differences in the following parameters: i) tumor localization (p = 0.001), ii) T2 signal intensity (p = 0.021), and iii) T1 signal homogeneity (p = 0.02). No significant imaging differences were found in any parameter between H3.1 and H3.3 K27M mutant tumors; however, H3.1 mutant tumors occurred at a younger age (p = 0.004). Considering spinal gliomas (n = 10) there were no significant imaging differences between the analyzed molecular groups. CONCLUSION: With this study, we are the first to provide detailed MR imaging data on H3 K27M mutant pDMG with respect to molecular subgroup status in a large patient cohort. Our findings may support diagnosis and future targeted therapeutic trials of pDMG within the framework of the radiogenomics concept. SUPPLEMENTARY INFORMATION: The online version of this article (10.1007/s00062-021-01120-3) contains supplementary material, which is available to authorized users

High-grade glioma in very young children: a rare and particular patient population

In the past years, pediatric high-grade gliomas (HGG) have been the focus of several research articles and reviews, given the recent discoveries on the genetic and molecular levels pointing out a clinico-biological uniqueness of the pediatric population compared to their adult counterparts with HGG. On the other hand, there are only scarce data about HGG in very young children (below 3 years of age at diagnosis) due to their relatively low incidence. However, the few available data suggest further distinction of this very rare subgroup from older children and adults at several levels including their molecular and biological characteristics, their treatment management, as well as their outcome. This review summarizes and discusses the current available knowledge on the epidemiological, neuropathological, genetic and molecular data of this subpopulation. We discuss these findings and differences compared to older patients suffering from the same histologic disease. In addition, we highlight the particular clinical and neuro-radiological findings in this specific subgroup of patients as well as their current management approaches and treatment outcomes

Molecular pathological insights reveal a high number of unfavorable risk patients among children treated for medulloblastoma and CNS-PNET in Oslo 2005–2017

Background An unexplained regional difference in survival was observed in previous publications on outcome for children treated for medulloblastoma and supratentorial primitive neuroectodermal tumor (CNS-PNET) in Norway. We aimed now to reevaluate and perform a retrospective molecular-based risk stratification of all embryonal brain tumors (excluding atypical teratoid rhabdoid tumors [ATRT]) in pediatric patients, who underwent surgery and treatment at Oslo University Hospital between 2005 and 2017. Procedure Specimens from all patients <20 years of age with initial diagnosis of medulloblastoma or CNS-PNET were reviewed. Molecular analyses comprised NanoString gene expression, molecular inversion probe profiling, Sanger sequencing, and 850K-methylation analysis. Whole chromosomal aberration signatures were assessed in standard-risk non-WNT/non-SHH medullobastomas for molecular risk stratification. Results We identified 53 non-ATRT embryonal tumors among which 33 were medulloblastomas. Molecular genetic parameters including whole chromosomal aberration signatures allowed classification of 17 medulloblastomas as molecular high risk. These patients had a significantly worse 5-year overall survival than the remaining 16 medulloblastoma patients (52.9% vs. 87.1% p = 0.036). Five patients in our cohort had tumors that are considered as new entities in the 2021 classification of tumors of the central nervous system. Five tumors were re-classified as nonembryonal tumors after review. Conclusion Molecular-based risk stratification of standard-risk non-WNT/non-SHH medulloblastoma enabled superior identification of medulloblastomas with dismal prognosis. Our cohort demonstrated a significantly increased fraction of standard-risk non-WNT/non-SHH medulloblastoma with molecular high-risk profile compared to other studies, which might have contributed to previously reported unfavorable outcome data