Molecular Features Of Glioblastoma Research Articles

Establishment of a Prediction Model Based on Preoperative MRI Radiomics for Diffuse Astrocytic Glioma, IDH-Wildtype, with Molecular Features of Glioblastoma.

In 2021, the WHO central nervous system (CNS) tumor classification criteria added the diagnosis of diffuse astrocytic glioma, IDH wild-type, with molecular features of glioblastoma, WHO grade 4 (DAG-G). DAG-G may exhibit the aggressiveness and malignancy of glioblastoma (GBM) despite the lower histological grade, and thus a precise preoperative diagnosis can help neurosurgeons develop more refined individualized treatment plans. This study aimed to establish a predictive model for the non-invasive identification of DAG-G based on preoperative MRI radiomics. Patients with pathologically confirmed glioma in Huashan Hospital, Fudan University, between September 2019 and July 2021 were retrospectively analyzed. Furthermore, two external validation datasets from Wuhan Union Hospital and Xuzhou Cancer Hospital were also utilized to verify the reliability and accuracy of the prediction model. Two regions of interest (ROI) were delineated on the preoperative MRI images of the patients using the semi-automatic tool ITK-SNAP (version 4.0.0), which were named the maximum anomaly region (ROI1) and the tumor region (ROI2), and Pyradiomics 3.0 was applied for feature extraction. Feature selection was performed using a least absolute shrinkage and selection operator (LASSO) filter and a Spearman correlation coefficient. Six classifiers, including Gauss naive Bayes (GNB), K-nearest neighbors (KNN), Random forest (RF), Adaptive boosting (AB), and Support vector machine (SVM) with linear kernel and multilayer perceptron (MLP), were used to build the prediction models, and the prediction performance of the six classifiers was evaluated by fivefold cross-validation. Moreover, the performance of prediction models was evaluated using area under the curve (AUC), precision (PRE), and other metrics. According to the inclusion and exclusion criteria, 172 patients with grade 2-3 astrocytoma were finally included in the study, and a total of 44 patients met the diagnosis of DAG-G. In the prediction task of DAG-G, the average AUC of GNB classifier was 0.74 ± 0.07, that of KNN classifier was 0.89 ± 0.04, that of RF classifier was 0.96 ± 0.03, that of AB classifier was 0.97 ± 0.02, that of SVM classifier was 0.88 ± 0.05, and that of MLP classifier was 0.91 ± 0.03, among which, AB classifier achieved the best prediction performance. In addition, the AB classifier achieved AUCs of 0.91 and 0.89 in two external validation datasets obtained from Wuhan Union Hospital and Xuzhou Cancer Hospital, respectively. The prediction model constructed based on preoperative MRI radiomics established in this study can basically realize the prospective, non-invasive, and accurate diagnosis of DAG-G, which is of great significance to help further optimize treatment plans for such patients, including expanding the extent of surgery and actively administering radiotherapy, targeted therapy, or other treatments after surgery, to fundamentally maximize the prognosis of patients.

Magnetic resonance spectroscopic correlates of progression free and overall survival in "glioblastoma, IDH-wildtype, WHO grade-4".

The 2021 World Health Organization (WHO) Central Nervous System (CNS) Tumor Classification has suggested that isocitrate dehydrogenase wildtype (IDH-wt) WHO grade-2/3 astrocytomas with molecular features of glioblastoma should be designated as "Glioblastoma, IDH-wildtype, WHO grade-4." This study analyzed the metabolic correlates of progression free and overall survival in "Glioblastoma, IDH-wildtype, WHO grade-4" patients using short echo time single voxel 1H-MRS. Fifty-seven adult patients with hemispheric glioma fulfilling the 2021 WHO CNS Tumor Classification criteria for "Glioblastoma, IDH-wildtype, WHO grade-4" at presurgery time point were included. All patients were IDH1/2-wt and TERTp-mut. 1H-MRS was performed on a 3 T MR scanner and post-processed using LCModel. A Mann-Whitney U test was used to assess the metabolic differences between gliomas with or without contrast enhancement and necrosis. Cox regression analysis was used to assess the effects of age, extent of resection, presence of contrast enhancement and necrosis, and metabolic intensities on progression-free survival (PFS) and overall survival (OS). Machine learning algorithms were employed to discern possible metabolic patterns attributable to higher PFS or OS. Contrast enhancement (p = 0.015), necrosis (p = 0.012); and higher levels of Glu/tCr (p = 0.007), GSH/tCr (p = 0.019), tCho/tCr (p = 0.032), and Glx/tCr (p = 0.010) were significantly associated with shorter PFS. Additionally, necrosis (p = 0.049), higher Glu/tCr (p = 0.039), and Glx/tCr (p = 0.047) were significantly associated with worse OS. Machine learning models differentiated the patients having longer than 12 months OS with 81.71% accuracy and the patients having longer than 6 months PFS with 77.41% accuracy. Glx and GSH have been identified as important metabolic correlates of patient survival among "IDH-wt, TERT-mut diffuse gliomas" using single-voxel 1H-MRS on a clinical 3 T MRI scanner.

World Health Organization Classification of Central Nervous System Tumours, 5th Edition:Points of the Update and the Current Status

The World Health Organization Classification of the Tumours, 5th Edition Central Nervous System Tumours(WHO CNS5), has undergone ground-breaking changes in collaboration with cIMPACT-NOW(the Consortium to Inform Molecular and Practical Approaches to CNS Tumor Taxonomy). Tumors are now classified and named according to the tumor type alone, and the tumor grading is defined within each tumor type. CNS WHO grading is based on either histological or molecular criteria. WHO CNS5 promotes the molecular finding-based classification system and diagnostic criteria, including DNA methylation-based molecular classification. In particular, the classification and CNS WHO grades have extensively been restructured for gliomas. Adult gliomas are now classified into three tumor types according to the IDH and 1p/19q status. Diffuse gliomas with morphological features of glioblastoma and IDH mutation are no longer classified as glioblastoma, IDH-mutant, but as astrocytoma, IDH-mutant, CNS WHO grade 4. Diffuse gliomas without IDH mutation but with molecular features of glioblastoma are classified as glioblastoma, IDH-wildtype. Pediatric-type gliomas are classified separately from adult-type gliomas. Although the shift toward the molecular classification is inevitable, the current WHO classification system has limitations. WHO CNS5 should be regarded as an intermediate stage toward further refined, better structured classification systems in the future.

Impact of new molecular criteria on diagnosis and survival of adult glioma patients.

The fifth edition WHO classification of Tumors of the Central nervous system (WHO-CNS5) integrated new molecular parameters to refine CNS tumor classification. This study aimed to reclassify a retrospective cohort of adult glioma patients according to WHO-CNS5, and assess if overall survival (OS) correlated with the revised diagnosis. Further, the diagnostic impact of methylation profiling (MP) was evaluated. Adult gliomas diagnosed according to 2016 WHO-CNS (n = 226) were evaluated according to WHO-CNS5 criteria. All patients had diagnostic NGS performed. 29 patients had 850k MP performed due to challenging tumor cases. OS was analyzed using Kaplan-Meier plots and log-rank test. 19 patients were reclassified. Specifically, diffuse astrocytic glioma, IDH-wildtype, with molecular features of glioblastoma (DAG-G) were reclassified as glioblastoma (n = 15). Shifts to glioblastoma were because of TERT promoter (TERTp) mutation (n = 9), EGFR amplification (n = 2), EGFR amplification and TERTp mutation (n = 1), and TERTp mutation with gain of chromosome 7, but uncertain chromosome 10 status due to lack of NGS coverage (n = 3). Lower grade IDH-mutant astrocytomas were reclassified as astrocytoma IDH-mutant, WHO grade 4 due to CDKN2A/B homozygous deletion (n = 4). No significant difference in OS was found for reclassified DAG-G in whole group (p = 0.59) and for TERTp mutation only (p = 0.44), compared to glioblastoma. MP resulted in revised diagnosis (n = 2), confirmed diagnosis (n = 15) and no match (n = 12). Our study showed similar overall survival for glioblastoma and DAG patients, supporting that isolated TERTp mutation may have a prognostic role in IDH-wildtype gliomas. Further, our study suggests MP is useful for confirming the diagnoses in challenging tumors.

Prospective genomically guided identification of "early/evolving" and "undersampled" IDH-wildtype glioblastoma leads to improved clinical outcomes.

BackgroundGenomic profiling studies of diffuse gliomas have led to new improved classification schemes that better predict patient outcomes compared to conventional histomorphology alone. One example is the recognition that patients with IDH-wildtype diffuse astrocytic gliomas demonstrating lower-grade histologic features but genomic and/or epigenomic profile characteristic of glioblastoma typically have poor outcomes similar to patients with histologically diagnosed glioblastoma. Here we sought to determine the clinical impact of prospective genomic profiling for these IDH-wildtype diffuse astrocytic gliomas lacking high-grade histologic features but with molecular profile of glioblastoma.MethodsClinical management and outcomes were analyzed for 38 consecutive adult patients with IDH-wildtype diffuse astrocytic gliomas lacking necrosis or microvascular proliferation on histologic examination that were genomically profiled on a prospective clinical basis revealing criteria for an integrated diagnosis of “diffuse astrocytic glioma, IDH-wildtype, with molecular features of glioblastoma, WHO grade IV” per cIMPACT-NOW criteria.ResultsWe identified that this diagnosis consists of two divergent clinical scenarios based on integration of radiologic, histologic, and genomic features that we term “early/evolving” and “undersampled” glioblastoma, IDH-wildtype. We found that prospective genomically guided identification of early/evolving and undersampled IDH-wildtype glioblastoma resulted in more aggressive patient management and improved clinical outcomes compared to a biologically matched historical control patient cohort receiving standard-of-care therapy based on histomorphologic diagnosis alone.ConclusionsThese results support routine use of genomic and/or epigenomic profiling to accurately classify glial neoplasms, as these assays not only improve diagnostic classification but critically lead to more appropriate patient management that can improve clinical outcomes.

Clinical and radiographic characteristics of diffuse astrocytic glioma, IDH-wildtype, with molecular features of glioblastoma: a single institution review.

Genetic analyses of gliomas have identified key molecular features that impact treatment paradigms beyond conventional histomorphology. Despite at-times lower grade histopathologic appearances, IDH-wildtype infiltrating gliomas expressing certain molecular markers behave like higher-grade tumors. For IDH-wildtype infiltrating gliomas lacking traditional features of glioblastoma, these markers form the basis for the novel diagnosis of diffuse astrocytic glioma, IDH-wildtype (wt), with molecular features of glioblastoma (GBM), WHO grade-IV (DAG-G). However, given the novelty of this approach to diagnosis, literature detailing the exact clinical, radiographic, and histopathologic findings associated with these tumors remain in development. Data for 25 patients matching the DAG-G diagnosis were obtained from our institution's retrospective database. Information regarding patient demographics, treatment regimens, radiographic imaging, and genetic pathology were analyzed to determine association with clinical outcomes. The initial radiographic findings, histopathology, and symptomatology of patients with DAG-G were similar to lower-grade astrocytomas (WHO grade 2/3). Overall survival (OS) and progression free survival (PFS) associated with our cohort, however, were similar to that of IDH-wt GBM, indicating a more severe clinical course than expected from other associated features (15.1 and 5.39months respectively). Despite multiple features similar to lower-grade gliomas, patients with DAG-G experience clinical courses similar to GBM. Such findings reinforce the need for biopsy and subsequent analysis of molecular features associated with any astrocytoma regardless of presenting characteristics.

Detecting molecular subtypes from multi-omics datasets using SUMO

SummaryWe present a data integration framework that uses non-negative matrix factorization of patient-similarity networks to integrate continuous multi-omics datasets for molecular subtyping. It is demonstrated to have the capability to handle missing data without using imputation and to be consistently among the best in detecting subtypes with differential prognosis and enrichment of clinical associations in a large number of cancers. When applying the approach to data from individuals with lower-grade gliomas, we identify a subtype with a significantly worse prognosis. Tumors assigned to this subtype are hypomethylated genome wide with a gain of AP-1 occupancy in demethylated distal enhancers. The tumors are also enriched for somatic chromosome 7 (chr7) gain, chr10 loss, and other molecular events that have been suggested as diagnostic markers for “IDH wild type, with molecular features of glioblastoma” by the cIMPACT-NOW consortium but have yet to be included in the World Health Organization (WHO) guidelines.

HLA-E and HLA-F Are Overexpressed in Glioblastoma and HLA-E Increased After Exposure to Ionizing Radiation.

Glioblastoma (GBM) is one of the deadliest human cancers responding very poorly to therapy. Although the central nervous system has been traditionally considered an immunologically privileged site with an enhanced immune response, GBM appears to benefit from this immunosuppressive milieu. Immunomodulatory molecules play an important role in immune tumor-host interactions. Non-classical human leukocyte antigens (HLA) class Ib molecules HLA-E, HLA-F, and HLA-G have been previously described to be involved in protecting semi-allogeneic fetal allografts from the maternal immune response and in transplant tolerance as well as tumoral immune escape. Unfortunately, their role in GBM remains poorly understood. Our study, therefore, aimed to characterize the relationship between the expression of these molecules in GBM on the transcriptional level and clinicopathological and molecular features of GBM as well as the effect of ionizing radiation. We performed the analysis of HLA-E, HLA-F, and HLA-G mRNA expression in 69 GBM tissue samples and 21 non-tumor brain tissue samples (controls) by reverse transcription polymerase chain reaction. Furthermore, two primary GBM cell cultures had been irradiated to identify the effect of ionizing radiation on the expression of non-classical HLA molecules. Analyses revealed that both HLA-E and HLA-F are significantly up-regulated in GBM samples. Subsequent survival analysis showed a significant association between low expression of HLA-E and shorter survival of GBM patients. The dysregulated expression of both molecules was also observed between patients with methylated and unmethylated O-6-methylguanine-DNA methyltransferase (MGMT) promoter. Finally, we showed that ionizing radiation increased HLA-E expression level in GBM cells in vitro. HLA-E and HLA-F play an important role in GBM biology and could be used as diagnostic biomarkers, and in the case of HLA-E also as a prognostic biomarker.

Radiologic-pathologic association of tumor-like lesions with inflammation in cerebral white matter: Comparison of two cases with distinct clinical outcomes.

Here, we report two cases showing tumor-like white matter lesions; one case was diagnosed as having inflammatory disease, and the other was diagnosed as having astrocytoma. Their outcomes were completely distinct despite similar pathology. Prior to biopsy, perfusion computed tomography (CT) and magnetic resonance imaging (MRI) were conducted. The two mass-forming lesions were distinct in edema level and vascularity patterns on CT and MRI. However, pathological examination of brain biopsy specimens revealed commonalities, including (1) proliferation of glial cells, (2) perivascular lymphocytic infiltration, and (3) appearance of numerous macrophages. Although atypical astrocytes proliferated in both cases, nuclear atypia was more distinct in case 2 than in case 1. The immunohistochemical results were the same for both cases: isocitrate dehydrogenase 1 (IDH1) R132H mutation was negative, and alpha thalassaemia mental retardation X-linked (ATRX) was retained. Faint immunoreactivity for p53 was observed in a few glial cells, and Ki-67 immunoreactive cells were markedly reduced in numbers (< 1%). Inflammatory reactions were evident in both cases: T cells dominantly infiltrated over B cells in the perivascular area in case 1, whereas both T and B cells infiltrated in case 2. Molecular analysis revealed wild-type IDH1 and IDH2 in both cases. However, a telomerase reverse transcriptase (TERT) sequence mutation was detected in case 2 but not in case 1. Eventually, case 1 was diagnosed as having inflammatory lesions, whereas case 2 was diagnosed as having diffuse astrocytoma associated with inflammatory reactions. The prognosis was favorable for case 1, whereas case 2 died 10 months following biopsy. These data indicated the diagnostic value of molecular analysis, for example, a TERT mutation, in association with the radiological findings. Although in case 2, histopathological evidence did not suggest high-grade glioma, the case met the new diagnostic criteria: "diffuse astrocytic glioma, IDH wild-type, with molecular features of glioblastoma, World Health Organization (WHO) grade IV," according to cIMPACT-NOW, update 3. Thus, interdisciplinary approaches are essential for accurate diagnosis of newly categorized white matter diseases.

P14.12 Gyriform infiltration as imaging biomarker for adult diffuse astrocytic glioma, IDH wildtype, with molecular features of glioblastoma

Abstract BACKGROUND Diffuse astrocytic gliomas, IDH wildtype, with molecular features of glioblastoma (molecular glioblastomas) are associated with a poor prognosis. We previously found that these tumors frequently display gyriform infiltration, defined as areas of elective cortical hypersignal on MRI FLAIR sequence. The objective of the present study was to assess the diagnostic value of gyriform infiltration as an imaging marker for these tumors. MATERIAL AND METHODS MRI scans from 430 patients with newly diagnosed glioma (molecular glioblastoma n = 31, IDH wildtype glioblastoma n = 298, IDH-mutant astrocytoma n = 50, IDH-mutant and 1p19q codeleted oligodendroglioma n= 51) were evaluated for the presence of a gyriform infiltration by 2 independent reviewers. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated to assess the performance of the presence of a gyriform infiltration for identifying molecular glioblastoma. RESULTS A gyriform infiltration was observed in 16/31 (52%) patients with a molecular glioblastoma, 40/298 (13%) patients with an IDH-wildtype glioblastoma but in none of the patients with an IDH-mutant astrocytomas or an IDH-mutant and 1p19q codeleted oligodendroglioma. Among the 56 patients with a gyriform infiltration, 54 patients had an IDH wildtype pTERT mutant glioma and 2 an IDH wildtype pTERT wildtype glioma. Interrater agreement was good (κ= 0.68, P &amp;lt; 0.001). Specificity, sensitivity, PPV and NPV of the presence of a gyriform infiltration for the diagnosis of molecular glioblastoma were 90%, 29%, 52% and 96% and for the diagnosis of an IDHwt pTERT mutant glioma were 97%, 15%, 96% and 20%. The presence of a gyriform infiltration was associated with a worse prognosis in the entire cohort (13.6 months vs 29.3 months, P = .001). CONCLUSION Gyriform infiltration is a specific imaging marker of molecular glioblastomas and IDH wildtype pTERT mutant diffuse gliomas.

Multifocal high-grade glioma radiotherapy safety and efficacy

BackgroundMultifocal manifestation of high-grade glioma is a rare disease with very unfavourable prognosis. The pathogenesis of multifocal glioma and pathophysiological differences to unifocal glioma are not fully understood. The optimal treatment of patients suffering from multifocal high-grade glioma is not defined in the current guidelines, therefore individual case series may be helpful as guidance for clinical decision-making.MethodsPatients with multifocal high-grade glioma treated with conventionally fractionated radiation therapy (RT) in our institution with or without concomitant chemotherapy between April 2011 and April 2019 were retrospectively analysed. Multifocality was neuroradiologically assessed and defined as at least two independent contrast-enhancing foci in the MRI T1 contrast-enhanced sequence. IDH mutational status and MGMT methylation status were assessed from histopathology records. GTV, PTV as well as the V30Gy, V45Gy and D2% volumes of the brain were analysed. Overall and progression-free survival were calculated from the diagnosis until death and from start of radiation therapy until diagnosis of progression of disease in MRI for all patients.Results20 multifocal glioma cases (18 IDH wild-type glioblastoma cases, one diffuse astrocytic glioma, IDH wild-type case with molecular features of glioblastoma and one anaplastic astrocytoma, IDH wild-type case) were included into the analysis. Resection was performed in two cases and stereotactic biopsy only in 18 cases before the start of radiation therapy. At the start of radiation therapy patients were 61 years old in median (range 42–84 years). Histopathological examination showed IDH wild-type in all cases and MGMT promotor methylation in 11 cases (55%). Prescription schedules were 60 Gy (2 Gy × 30), 59.4 Gy (1.8 Gy × 33), 55 Gy (2.2 Gy × 25) and 50 Gy (2.5 Gy × 20) in 15, three, one and one cases, respectively. Concomitant temozolomide chemotherapy was applied in 16 cases, combined temozolomide/lomustine chemotherapy was applied in one case and concomitant bevacizumab therapy in one case. Median number of GTVs was three. Median volume of the sum of the GTVs was 26 cm3. Median volume of the PTV was 425.7 cm3 and median PTV to brain ratio 32.8 percent. Median D2% of the brain was 61.5 Gy (range 51.2–62.7) and median V30Gy and V45 of the brain were 59.9 percent (range 33–79.7) and 40.7 percent (range 14.9–64.1), respectively. Median survival was eight months (95% KI 3.6–12.4 months) and median progression free survival after initiation of RT five months (95% CI 2.8–7.2 months). Grade 2 toxicities were detected in eight cases and grade 3 toxicities in four cases consisting of increasing edema in three cases and one new-onset seizure. One grade 4 toxicity was detected, which was febrile neutropenia related to concomitant chemotherapy.ConclusionConventionally fractionated RT with concomitant chemotherapy could safely be applied in multifocal high-grade glioma in this case series despite large irradiation treatment fields.

TERT promoter mutation status is necessary and sufficient to diagnose IDH-wildtype diffuse astrocytic glioma with molecular features of glioblastoma.

The Consortium to Inform Molecular and Practical Approaches to CNS Tumor Taxonomy (cIMPACT-NOW) update 3 recommends that histologic grade II and III IDH-wildtype diffuse astrocytic gliomas that harbor EGFR amplification, the combination of whole chromosome 7 gain and whole chromosome 10 loss (7 + /10 -), or TERT promoter (pTERT) mutations should be considered as glioblastomas (GBM), World Health Organization grade IV. In this retrospective study, we examined the utility of molecular classification based on pTERT status and copy-number alterations (CNAs) in IDH-wildtype lower grade gliomas (LGGs, grade II, and III). The impact on survival was evaluated for the pTERT mutation and CNAs, including EGFR gain/amplification, PTEN loss, CDKN2A homozygous deletion, and PDGFRA gain/amplification. We analyzed 46 patients with IDH-wildtype/pTERT-mutant (mut) LGGs and 85 with IDH-wildtype/pTERT-wildtype LGGs. EGFR amplification and a combination of EGFR gain and PTEN loss (EGFR + /PTEN -) were significantly more frequent in pTERT-mut patients (p < 0.0001). Cox regression analysis showed that the pTERT mutation was a significant predictor of poor prognosis (hazard ratio [HR] 2.79, 95% confidence interval [CI] 1.55-4.89, p = 0.0008), but neither EGFR amplification nor EGFR + /PTEN - was an independent prognostic factor in IDH-wildtype LGGs. PDGFRA gain/amplification was a significant poor prognostic factor in IDH-wildtype/pTERT-wildtype LGGs (HR 2.44, 95% CI 1.09-5.27, p = 0.03, Cox regression analysis). The IDH-wildtype LGGs with either pTERT-mut or PDGFRA amplification were mostly clustered with GBM by DNA methylation analysis. Thus, our study suggests that analysis of pTERT mutation status is necessary and sufficient to diagnose IDH-wildtype diffuse astrocytic gliomas with molecular features of glioblastoma. The PDGFRA status may help further delineate IDH-wildtype/pTERT-wildtype LGGs. Methylation profiling showed that IDH-wildtype LGGs without molecular features of GBM were a heterogeneous group of tumors. Some of them did not fall into existing categories and had significantly better prognoses than those clustered with GBM.

Deconvolution of cell type-specific drug responses in human tumor tissue with single-cell RNA-seq

BackgroundPreclinical studies require models that recapitulate the cellular diversity of human tumors and provide insight into the drug sensitivities of specific cellular populations. The ideal platform would enable rapid screening of cell type-specific drug sensitivities directly in patient tumor tissue and reveal strategies to overcome intratumoral heterogeneity.MethodsWe combine multiplexed drug perturbation in acute slice culture from freshly resected tumors with single-cell RNA sequencing (scRNA-seq) to profile transcriptome-wide drug responses in individual patients. We applied this approach to drug perturbations on slices derived from six glioblastoma (GBM) resections to identify conserved drug responses and to one additional GBM resection to identify patient-specific responses.ResultsWe used scRNA-seq to demonstrate that acute slice cultures recapitulate the cellular and molecular features of the originating tumor tissue and the feasibility of drug screening from an individual tumor. Detailed investigation of etoposide, a topoisomerase poison, and the histone deacetylase (HDAC) inhibitor panobinostat in acute slice cultures revealed cell type-specific responses across multiple patients. Etoposide has a conserved impact on proliferating tumor cells, while panobinostat treatment affects both tumor and non-tumor populations, including unexpected effects on the immune microenvironment.ConclusionsAcute slice cultures recapitulate the major cellular and molecular features of GBM at the single-cell level. In combination with scRNA-seq, this approach enables cell type-specific analysis of sensitivity to multiple drugs in individual tumors. We anticipate that this approach will facilitate pre-clinical studies that identify effective therapies for solid tumors.

Diffuse astrocytic glioma, IDH-Wildtype, with molecular features of glioblastoma, WHO grade IV: A single-institution case series and review.

In 2018, cIMPACT-NOW update 3 concluded that WHO grade II/III IDH-wildtype diffuse astrocytomas that contain TERT promoter mutations, chromosome 7 gain/10 loss, and/or EGFR amplification, correspond to a WHO grade IV diagnosis and should be classified as Diffuse astrocytic glioma, IDH-wildtype, with molecular features of glioblastoma, WHO grade IV (DAG-G). We present a single-institution series of patients with DAG-G and IDH-mutant astrocytomas and compare their clinical, molecular, and radiographic characteristics. Patient data was retrospectively extracted from the EMR for all patients undergoing surgical biopsy/resection of a diffuse astrocytoma at our institution from 2018 to 2020. Clinical presentation, molecular alterations, radiographic appearance, surgery, and survival were reviewed for each patient. Six DAG-G patients were identified in our cohort. All patients had diffuse disease, and presented with expansile, T2 hyperintense lesions with minimal enhancement. Compared to patients with classic IDH-mutant astrocytomas, mean age for DAG-G patients was older (68 vs 33years, p< 0.0001), tumors were more diffuse (p= 0.02), with patients more likely to present with focal deficits and receive a biopsy only (p= 0.005). Overall survival was significantly shorter for DAG-G patients (p= 0.03). Patients with DAG-G are more likely to be older than typical IDH-mutant diffuse astrocytoma patients. They are more likely to present with tumors in a diffuse pattern with focal deficits. When such patients are encountered, prompt biopsy/resection to confirm the diagnosis and immediate initiation of adjuvant therapy is recommended, as the disease progression and overall prognosis is similar to glioblastoma.

CTNI-23. IDH1/2wt ANAPLASTIC GLIOMAS OF THE EORTC RANDOMIZED PHASE III INTERGROUP CATNON TRIAL: OVERALL SURVIVAL RELATED TO TREATMENT, MGMT STATUS AND MOLECULAR FEATURES OF GLIOBLASTOMA

Abstract BACKGROUND The phase III CATNON trial randomized 751 adult patients with newly diagnosed 1p/19q non-codeleted anaplastic glioma to 59.4 Gy radiotherapy +/- concurrent and/or adjuvant TMZ. Here, we present the molecular analysis of the IDH1/2wt subgroup, and associations between molecular characteristics and patient outcomes. METHODS CNV data and MGMT promoter methylation status were assessed from EPIC methylation array data. IDH1/2 and H3F3A mutation status were determined with a glioma tailored next-generation sequencing panel and TERT promoter mutation status using a SNaPshot assay. Overall survival (OS) was measured from date of randomization. RESULTS Of 654 assessed tumors, 211 (32%) were IDH1/2wt. An H3F3A mutation was present in 14 tumors (K27M: n=10; G34R: n=4). Of the remaining 197 patients, 154 tumors had molecular features of glioblastoma according to cIMPACT-NOW 3 criteria (‘IDH1/2wt astrocytomas WHO IV’), 39 tumors did not (‘IDH1/2wt astrocytomas WHO III’), and 4 had inconclusive molecular data. IDH1/2wt astrocytomas WHO III patients had significantly better survival than WHO IV patients: median OS of 2.83 yrs vs 1.43 yrs respectively [log-rank test: p&amp;lt; 0.001]. Of the 154 IDH1/2wt astrocytoma WHO IV, 55 (36%) were found MGMT promoter methylated. MGMT promoter methylation was prognostic in IDH1/2wt astrocytomas WHO IV patients, with a median OS of 1.86 yrs for methylated vs 1.34 yrs for unmethylated [HR 1.62, p=0.006]. In the IDH1/2wt astrocytomas WHO IV, no effect of concurrent and/or adjuvant TMZ was observed; the HR for OS after RT with any TMZ vs RT alone was 1.31 [95% CI 0.73–2.36, p=0.4] for MGMT promoter methylated and 0.90 [95% CI 0.55–1.45, p=0.7] for unmethylated glioma patients. CONCLUSIONS Our study validated the prognostic value of the cIMPACT-NOW 3 criteria. MGMT promoter methylation is prognostic but not predictive for outcome to TMZ treatment in this cohort of IDH1/2wt anaplastic gliomas with molecular features of glioblastoma.

PATH-05. A RETROSPECTIVE STUDY OF TREATMENT STRATEGIES AND OUTCOMES IN WHO GRADE II AND III ISOCITRATE DEHYDROGENASE (IDH) WILD-TYPE ASTROCYTOMA

Abstract BACKGROUND WHO grade II and III IDH wild-type astrocytomas behave more aggressively than their IDH mutated counterparts. A subpopulation shares molecular features with the novel entity proposed in cIMPACT-NOW Update 3 “Diffuse astrocytic glioma, IDH wild-type, with molecular features of glioblastoma (GBM), WHO IV”. METHODS We performed a retrospective analysis of clinical and molecular features, management and survival of 134 adult patients treated for grade II and III IDH wild-type astrocytoma between 06/2012 and 12/2018 at MD Anderson Cancer Center (MDACC - 112) and UT Health Science Center at Houston (UTHSC - 22). All patients had IDH1 sequenced, all but 2 had IDH2 sequenced, and 73 had further next generation sequencing. RESULTS Median age at diagnosis was 53 (interquartile range 18-83). 82 patients (61%) were male. 31 patients were histologically diagnosed with grade II astrocytoma, 102 with grade III astrocytoma, and one with diffuse glioma (insufficient tissue to render histologic grade or perform sequencing). EGFR alterations were found in 31 patients and TERT promoter mutations in 22. 84 (63%) received concurrent chemoradiation and adjuvant temozolomide (grade II, n=9; grade III, n=74; NOS, n=1). PFS overall was 12.0 months (grade II = 17.9; grade III = 10.7). OS in patients treated with concurrent chemoradiation and adjuvant temozolomide was 17.1 months versus 17.7 in patients treated with sequential radiation and temozolomide (p = NS), and 10.6 in patients treated with RT alone or surveillance (p&amp;lt; 0.016). The highest 2-year OS was seen in grade II patients treated with concurrent chemoradiation and adjuvant temozolomide (60%). CONCLUSIONS WHO grade II and III IDHwt astrocytoma survival is similar to historical GBM cohorts. The proportion meeting molecular criteria for GBM is yet undefined. Groups who received chemotherapy may perform better than those who do not. Further analysis of MGMT methylation and other molecular factors is ongoing.

PATH-27. CLINICAL, RADIOLOGIC AND PROGNOSTIC PROFILE OF IDH WILD TYPE DIFFUSE ASTROCYTOMA WITH MOLECULAR FEATURES OF GLIOBLASTOMA

Abstract BACKGROUND cIMPACT-NOW-3 recommends that IDH-wildtype diffuse astrocytic glioma Grade II or III with EGFR amplification, or combined whole chromosome 7 gain and whole chromosome 10 loss, or TERT promoter mutation should receive an integrated classification: Diffuse astrocytic glioma, IDH-wildtype with molecular features of glioblastoma, WHO grade IV. The aims of this study were: Outline the features of a cohort of patients with molecular glioblastoma according to the above criteria; Assess clinical and molecular factors that may inform prognosis; Determine if cIMPACT-NOW-3 recommendation changed clinical practice and clinical trial enrolment. METHODS 61 patients diagnosed with IDH-wildtype diffuse astrocytic glioma Grade II or III and EGFR amp or mTERT or chromosome (+7/-10) between 2011 and 2019 at MGH were included in this single center retrospective cohort study. Data collected: sex, age, extent of surgery, functional status, histological grade, molecular diagnostics and treatment. Progression was defined using RANO criteria, progression was quantified in terms of months from the initial surgery. Survival was defined in terms of months from initial surgery to date of death or last known visit. RESULTS mOS was 16 months, mPFS was 9 months. 14 patients (23%) survived &amp;gt; 24 months, 7 ≥ 36 months (mOS 32 months; 9 deceased). The probability of survival in patients with markedly enhancing tumors was 0.5 at 3 months versus 0.5 at 11 months in non-enhancing tumors. The probability of survival in patients who underwent biopsy only was 0.5 at 5 months compared to 0.5 at 12 months in patients with maximally resected tumors. 1 patient was enrolled in a clinical trial at diagnosis. 6 were enrolled at time of recurrence. CONCLUSIONS mOS and pFS in the deceased patients was comparable to historical data on survival in IDH wild-type glioblastomas. Inclusion criteria in clinical trials have not reflected the cIMPACT-NOW-3 recommendation so far.

The role of neuropathology in the management of newly diagnosed glioblastoma: a systematic review and evidence-based clinical practice guideline.

These recommendations apply to adult patients with newly diagnosed or suspected glioblastoma (GBM) QUESTION : For adult patients with newly diagnosed GBM does testing for Isocitrate Dehydrogenase 1 or 2 (IDH 1/2) mutations afford benefit beyond standard histopathology in providing accurate classification and outcome prognostication? Level III IDH 1/2 mutational status by immunohistochemistry (IHC) and/or sequencing is suggested for classification and prognostic information. Level III Non-canonical IDH 1/2 mutations are very rare in patients aged 55 or older and universal testing of variant mutations by sequence analysis is not suggested for this age range. For adult patients with lower grade infiltrating astrocytomas (WHO grades II and III) can the IDH-wildtype status designation supersede histopathology to predict prognosis and biologic relevance to eventual behavior as a GBM? Level III The designation of infiltrating astrocytomas (WHO grades II and III) as IDH-wildtype is not suggested as sufficient for a higher grade designation alone. Level III It is suggested that IDH-wildtype WHO grades II and III astrocytomas be tested for molecular-genetic alterations typical of IDH-wildtype GBM such as EGFR amplification, gain of chromosome 7/loss of chromosome 10 and TERT-p mutation to substantiate prediction of behavior similar to IDH-wildtype glioblastoma. Level III It is suggested that a diagnosis of diffuse astrocytic glioma, IDH-wildtype, with molecular features of GBM, WHO grade IV be rendered for infiltrating astrocytomas that lack histologic criteria of GBM but harbors molecular-genetic alterations of IDH-wildtype glioblastoma. For adult patients with newly diagnosed infiltrating glioma arising in the midline does testing for H3-K27M mutations provide information beyond that gained by histopathology for accurate classification and outcome prognostication? Level III It is suggested that infiltrating gliomas arising in midline anatomic locations be tested for the H3-K27M mutation as they tend to exhibit WHO grade IV behavior even if they lack histologic criteria for glioblastoma.

Targeted next-generation sequencing of adult gliomas for retrospective prognostic evaluation and up-front diagnostics.

We aimed to reclassify a population-based cohort of 529 adult glioma patients to evaluate the prognostic impact of the 2016 World Health Organization (WHO) central nervous system tumour classification. Moreover, we evaluated the feasibility of gene panel next-generation sequencing (NGS) in daily diagnostics of 225 prospective glioma patients. The retrospective cohort was reclassified according to WHO 2016 criteria by immunohistochemistry for IDH-R132H, fluorescence in situ hybridization for 1p/19q-codeletion and gene panel NGS. All tumours of the prospective cohort were subjected to NGS analysis up-front. The entire population-based cohort was successfully reclassified according to WHO 2016 criteria. NGS results were obtained for 98% of the prospective patients. Survival analyses in the population-based cohort confirmed three major prognostic subgroups, that is, isocitrate dehydrogenase (IDH)-mutant and 1p/19q-codeleted oligodendrogliomas, IDH-mutant astrocytomas and IDH-wildtype glioblastomas. The distinction between WHO grade II and III was prognostic in patients with IDH-mutant astrocytoma. The survival of patients with IDH-wildtype diffuse astrocytomas carrying TERT promoter mutation and/or EGFR amplification overlapped with the poor survival of IDH-wildtype glioblastoma patients. Gene panel NGS proved feasible in daily diagnostics. In addition, our study confirms the prognostic role of glioma classification according to WHO 2016 in a large population-based cohort. Molecular features of glioblastoma in IDH-wildtype diffuse glioma were linked to poor survival corresponding to IDH-wildtype glioblastoma patients. The distinction between WHO grade II and III retained prognostic significance in patients with IDH-mutant diffuse astrocytic gliomas.

Clinical, radiologic &amp; prognostic profile of IDH wild type diffuse astrocytic glioma with molecular features of glioblastoma.

2557 Background: In 2018, The Consortium to Inform Molecular and Practical Approaches to CNS Tumor Taxonomy (cIMPACT-NOW) recommended that IDH-wildtype diffuse astrocytic glioma Grade II/III with either EGFR amplification, combined whole chromosome 7 gain and whole chromosome 10 loss (+7/−10), or TERT promoter mutation should receive an integrated histological and molecular grade classification: Diffuse astrocytic glioma, IDH-wildtype with molecular features of glioblastoma, WHO grade IV. The natural history, radiologic characteristics and standard management for these patients has not been well described. They are typically excluded from clinical trials for WHO Grade IV gliomas. Methods: Adults diagnosed at Massachusetts General Hospital with IDH wildtype diffuse astrocytoma and EGFR amplification or TERT promoter mutation from 2011-2019 were identified. Demographics, functional status, radiologic features, MGMT promoter methylation status, time to progression, and overall survival were collected retrospectively. Qualitative MRI data was analyzed using the VASARI feature set. Response assessment was performed using the RANO criteria. Results: 50 patients were identified (table). 37/50 patients received standard Stupp protocol, 2/50 received hypofractionated radiotherapy with temozolomide, 6/50 received radiotherapy alone, and 1 patient received a MEK inhibitor. None were enrolled in clinical trials at diagnosis. mPFS was 10 months in the 47/50 with confirmed progression and mOS in the patients with confirmed deaths (40/50) was 17.5 months (4-47). 9/50 patients are alive with survival ranging 6-52 months. Conclusions: Outcomes for patients with molecularly defined GBM were variable. Analysis of the cohort to characterize factors that led to the observed variability is in progress. More studies on molecularly defined glioblastomas are required to better understand their behavior and to provide guidance for their inclusion or exclusion in clinical trials. [Table: see text]