provide evidence that the IDH1 status is more prognostic for overall survival than standard histological criteria that differentiate high-grade astrocytomas. We sequenced the isocitrate dehydrogenase 1 gene (IDH1) at codon 132 in 382 patients with anaplastic astrocytoma and glioblastoma from the NOA-04 trial and from a prospective translational cohort study of the German Glioma Network.Patients with anaplastic astrocytomas carried IDH1 mutations in 60%, and patients with glioblastomas in 7.2%. IDH1 was the most prominent single prognostic factor (RR=2.7; 95%-CI 1.6 to 4.5) followedby age, diagnosis and MGMT. The sequence from more favorable to poorer outcome was 1)anaplastic astrocytoma with IDH1 mutation, 2) glioblastoma with IDH1 mutation, 3) anaplastic astrocytoma without IDH1 mutation and 4) glioblastoma without IDH1 mutation (p<0.0001). In this combined set of anaplastic astrocytomas and glioblastomas both, IDH1 mutation and IDH1 expression status were of greater prognostic relevance than histological diagnosis according to the current WHO classification system. Our data indicate that much of the prognostic significance of patient age is due to the predominant occurrence of IDH1 mutations in younger patients. Immunohistochemistry using a mutation-specific antibody recognizing the R132H mutation yielded similar results. We propose to complement the current WHO classification and grading of high-grade astrocytic gliomas by the IDH1 mutation status and to use this combined histological and molecular classification in future clinical trials.

Cerebral gliomas of World Health Organization (WHO) grade II and III represent a major challenge in terms of histological classification and clinical management. Here, we asked whether largescale genomic and transcriptomic profiling improves the definition of prognostically distinct entities. We performed microarray-based genome-and transcriptome-wide analyses of primary tumor samples from a prospective German Glioma Network cohort of 137 patients with cerebral gliomas, including 61 WHO grade II and 76 WHO grade III tumors. Integrative bioinformatic analyses were employed to define molecular subgroups, which were then related to histology, molecular biomarkers, including isocitrate dehydrogenase 1 or 2 (IDH1/2) mutation, 1p/19q co-deletion and telomerase reverse transcriptase (TERT) promoter mutations, and patient outcome. Genomic profiling identified five distinct glioma groups, including three IDH1/2 mutant and two IDH1/2 wild-type groups. Expression profiling revealed evidence for eight transcriptionally different groups (five IDH1/2 mutant, three IDH1/2 wild type), which were only partially linked to the genomic groups. Correlation of DNA-based molecular stratification with clinical outcome allowed to define three major prognostic groups with characteristic genomic aberrations. The best prognosis was found in patients with IDH1/2 mutant and 1p/19q co-deleted tumors. Patients with IDH1/2 wild-type gliomas and glioblastoma-like genomic alterations, including gain on chromosome arm 7q (+7q), loss on chromosome arm 10q (-10q), TERT promoter mutation and oncogene amplification, displayed the worst outcome. Intermediate survival was seen in patients with IDH1/2 mutant, but 1p/19q intact, mostly astrocytic gliomas, and in patients with IDH1/2 wild-type gliomas lacking the +7q/-10q genotype and TERT promoter mutation. This molecular subgrouping stratified patients into prognostically distinct groups better than histological classification. Addition of gene expression data to this genomic classifier did not further improve prognostic stratification. In summary, DNA-based molecular profiling of WHO grade II and III gliomas distinguishes biologically distinct tumor groups and provides prognostically relevant information beyond histological classification as well as IDH1/2 mutation and 1p/19q co-deletion status.

Glioblastoma is the most common and most aggressive primary brain tumour. Standard of care consists of surgical resection followed by radiotherapy and concomitant and maintenance temozolomide (temozolomide/radiotherapy→temozolomide). Corticosteroids are commonly used perioperatively to control cerebral oedema and are frequently continued throughout subsequent treatment, notably radiotherapy, for amelioration of side effects. The effects of corticosteroids such as dexamethasone on cell growth in glioma models and on patient survival have remained controversial. We performed a retrospective analysis of glioblastoma patient cohorts to determine the prognostic role of steroid administration. A disease-relevant mouse model of glioblastoma was used to characterize the effects of dexamethasone on tumour cell proliferation and death, and to identify gene signatures associated with these effects. A murine anti-VEGFA antibody was used in parallel as an alternative for oedema control. We applied the dexamethasone-induced gene signature to The Cancer Genome Atlas glioblastoma dataset to explore the association of dexamethasone exposure with outcome. Mouse experiments were used to validate the effects of dexamethasone on survival in vivo Retrospective clinical analyses identified corticosteroid use during radiotherapy as an independent indicator of shorter survival in three independent patient cohorts. A dexamethasone-associated gene expression signature correlated with shorter survival in The Cancer Genome Atlas patient dataset. In glioma-bearing mice, dexamethasone pretreatment decreased tumour cell proliferation without affecting tumour cell viability, but reduced survival when combined with radiotherapy. Conversely, anti-VEGFA antibody decreased proliferation and increased tumour cell death, but did not affect survival when combined with radiotherapy. Clinical and mouse experimental data suggest that corticosteroids may decrease the effectiveness of treatment and shorten survival in glioblastoma. Dexamethasone-induced anti-proliferative effects may confer protection from radiotherapy- and chemotherapy-induced genotoxic stress. This study highlights the importance of identifying alternative agents such as vascular endothelial growth factor antagonists for managing oedema in glioblastoma patients. Beyond the established adverse effect profile of protracted corticosteroid use, this analysis substantiates the request for prudent and restricted use of corticosteroids in glioblastoma.

As DSWI is related to sternotomy, a MIC approach should be considered for patients at high risk for DSWI. IMA takedown as a pedicled graft should be especially avoided in patients with diabetes since the risk for postoperative mediastinitis is unacceptably high in this patient group.

Epigenetic silencing of the O 6 -methylguanine-DNA methyltransferase (MGMT) gene promoter is associated with prolonged survival in glioblastoma patients treated with temozolomide (TMZ). We investigated whether glioblastoma recurrence is associated with changes in the promoter methylation status and the expression of MGMT and the DNA mismatch repair (MMR) genes MLH1, MSH2, MSH6 and PMS2 in pairs of primary and recurrent glioblastomas of 80 patients, including 64 patients treated with radiotherapy and TMZ after the first operation. Among the primary tumors, the MGMT promoter was methylated in 31 patients and unmethylated in 49 patients. In 71 patients (89%), the MGMT promoter methylation status of the primary tumor was retained at recurrence. MGMT promoter methylation, but not MGMT protein expression, was associated with longer progression-free survival, overall survival and postrecurrence survival (PRS). Moreover, PRS was increased under salvage chemotherapy. Investigation of primary and recurrent glioblastomas of 43 patients did not identify promoter methylation in any of the four MMR genes. However, recurrent glioblastomas demonstrated significantly lower MSH2, MSH6 and PMS2 protein expression as detected by immunohistochemistry. In conclusion, reduced expression of MMR proteins, but not changes in MGMT promoter methylation, is characteristic of glioblastomas recurring after the current standards of care.Glioblastoma, the most common primary brain tumor in adults, is a rapidly progressive and fatal disease as indicated by a median overall survival (OS) of less than 1 year in a population-based study. 1 The current standard of care comprises surgical resection followed by local radiotherapy as well as concomitant and adjuvant chemotherapy with the DNA methylating agent temozolomide (TMZ). 2 Several independent studies have identified methylation of the O 6 -methylguanine-DNA methyltransferase (MGMT) gene promoter as a biomarker that strongly predicts prolonged progressionfree survival (PFS) and OS in glioblastoma patients treated with TMZ. [3][4][5] The MGMT gene encodes a DNA repair protein that removes alkyl groups from the O 6 -position of guanine (for review, see Ref. 6 ). Thereby, MGMT may counteract the therapeutic efficacy of TMZ and promote treatment failure. Aberrant MGMT promoter methylation may lead to transcriptional repression and lower MGMT protein expression in tumor cells, which may explain the clinical association of MGMT promoter methylation with longer survival of

-methylguanine-DNA-methyltransferase (MGMT) promoter methylation identifies a subpopulation of glioblastoma patients with more favorable prognosis and predicts a benefit from alkylating agent chemotherapy (CT). Little is known about its prevalence and clinical significance in older glioblastoma patients. We studied 233 glioblastoma patients aged 70 years or more (144 males, 89 females, median age: 74 years, range: 70.0-86.6 years), who were prospectively enrolled in the German Glioma Network, for MGMT promoter methylation by methylation-specific PCR (MSP) in all patients and DNA pyrosequencing in 166 patients. MGMT data were correlated with patient outcome. Median progression-free survival (PFS) was 4.8 months (95% CI: 4.3-5.3) and median overall survival (OS) was 7.7 months (95% CI: 6.3-9.0). MGMT promoter methylation was detected by MSP in 134 patients (57.5%). For the whole cohort, PFS was 5.2 versus 4.7 months (p 5 0.207) and OS was 8.4 versus 6.4 months (p 5 0.031) in patients with versus without MGMT promoter methylation. Patients with MGMT methylated tumors had longer PFS when treated with radiotherapy (RT) plus CT or CT alone compared to patients treated with RT alone. Patients with MGMT unmethylated tumors appeared to derive no survival benefit from CT, regardless of whether given at diagnosis together with RT or as a salvage treatment. Patients treated with RT plus CT or CT alone demonstrated longer OS when pyrosequencing revealed >25% MGMT methylated alleles. Taken together, MGMT promoter methylation may be a useful biomarker to stratify elderly glioblastoma patients for treatment with versus without alkylating agent CT.Age is the major therapy-independent prognostic factor in gliomas across malignancy grades II-IV. The differential distribution of isocitrate dehydrogenase 1 mutations, which are more common in younger patients, contributes to the negative prognostic effect of age.1 O 6 -methylguanine-DNAmethyltransferase (MGMT) promoter methylation is a biomarker with both prognostic and predictive aspects, depending on glioma subtype.2 The MGMT status can be determined by the assessment of promoter methylation, mRNA or protein expression or enzymatic activity. Methylation-specific PCR (MSP)-based detection of MGMT promoter methylation has provided the most meaningful results as judged by clinical correlations.2,3 Yet, the complexity of assessing the MGMT status even by MSP has prevented its broad implementation as a biomarker. Predictive power of the MGMT status was delineated in the EORTC NCIC registration trial for temozolomide (TMZ) in newly diagnosed glioblastoma where patients with MGMT promoter methylated tumors derived most benefit when treated with TMZ. 4 Moreover, we have recently proposed that specifically patients with MGMT promoter methylated tumors derive benefit from the addition of the integrin antagonist cilengitide to TMZ radiochemotherapy. 5 Yet, even in the EORTC NCIC trial, patients with MGMT promoter methylation had longer progression-free survival (PFS) of 5.9

We studied how intratumoral genetic heterogeneity shapes tumor growth and therapy response for isocitrate dehydrogenase (IDH)-wild-type glioblastoma, a rapidly regrowing tumor. We inferred the evolutionary trajectories of matched pairs of primary and relapsed tumors based on deep whole-genomesequencing data. This analysis suggests both a distant origin of de novo glioblastoma, up to 7 years before diagnosis, and a common path of early tumorigenesis, with one or more of chromosome 7 gain, 9p loss, or 10 loss, at tumor initiation. TERT promoter mutations often occurred later as a prerequisite for rapid growth. In contrast to this common early path, relapsed tumors acquired no stereotypical pattern of mutations and typically regrew from oligoclonal origins, suggesting sparse selective pressure by therapeutic measures.

OBJECTIVE: To explore whether the isocitrate dehydrogenase 1 (IDH1) or 1p/19q status determines the prognostic vs predictive role of O(6)-methylguanine-DNA methyltransferase (MGMT) promoter methylation in the Neuro-Oncology Working Group of the German Cancer Society (NOA)-04 trial anaplastic glioma biomarker cohort. METHODS: Patients (n = 183) of the NOA-04 trial with known MGMT and IDH1 status were analyzed for interdependency of the prognostic vs predictive role of MGMT promoter methylation from IDH1 or 1p/19q status and treatment, using progression-free survival (PFS) as an endpoint. An independent validation cohort of the German Glioma Network (n = 75) and the NOA-08 trial (n = 34) served as a confirmation cohort. RESULTS: In tumors with IDH1 mutation, MGMT promoter methylation was associated with prolonged PFS with chemotherapy ± radiotherapy (RT) or RT-only groups, and is thus prognostic. In tumors without IDH1 mutation, MGMT promoter methylation was associated with increased PFS in patients treated with chemotherapy, but not in those who received RT alone as the first-line treatment, and is thus chemotherapy-predictive. In contrast, 1p/19q codeletions showed no such association with the prognostic vs predictive value of MGMT. CONCLUSIONS: MGMT promoter methylation is a predictive biomarker for benefit from alkylating agent chemotherapy in patients with IDH1-wild-type, but not IDH1-mutant, malignant gliomas of World Health Organization grades III/IV. Combined IDH1/MGMT assessment may help to individualize clinical decision-making in neurooncology. Study FundingThe Charitable Hertie Foundation and National Genome Network of the BMBF provided funding. ResultsIn tumors with IDH1 mutation, MGMT promoter methylation was associated with prolonged PFS with chemotherapy ± radiotherapy (RT) or RT only groups, and thus prognostic. In tumors without IDH1 mutation, MGMT promoter methylation was associated with increased PFS in patients treated with chemotherapy, too, but not in those who received RT alone as the first-line treatment, and is thus chemotherapy-predictive. In contrast 1p/19q codeletions showed no such association with the prognostic versus predictive value of MGMT. ConclusionsMGMT promoter methylation is a predictive biomarker for benefit from alkylating agent chemotherapy in patients with IDH1-wildtype, but not IDH1-mutant malignant gliomas of WHO grades III/IV. Combined IDH1/ MGMT assessment may help to individualize clinical decision making in neurooncology.