Molecular classification of anaplastic oligodendroglioma using next-generation sequencing: a report of the prospective randomized EORTC Brain Tumor Group 26951 phase III trial

Expanded Use of Vorasidenib in Non-Enhancing Recurrent CNS WHO Grade 3 Oligodendroglioma

Background/Objectives: Anaplastic oligodendrogliomas (AOs) are central nervous system (CNS) World Health Organization (WHO) grade 3 gliomas characterized by isocitrate dehydrogenase (IDH) mutation (m)IDH and 1p/19q codeletion. AOs are typically treated with surgery and chemoradiation. However, chemoradiation can cause detrimental late neurocognitive morbidities and an accelerated disease course. The recently regulatory-approved vorasidenib, a brain-penetrating oral inhibitor of IDH1/2, has altered the treatment paradigm for recurrent/residual non-enhancing surgically resected CNS WHO grade 2 mIDH gliomas. Though vorasidenib can delay the time to chemoradiation for grade 2 gliomas, the implications for vorasidenib in non-grade 2 mIDH gliomas are not well understood. Results: We present a case of a 71-year-old male with a grade 3 non-enhancing oligodendroglioma successfully treated with vorasidenib with an 11% reduction in residual tumor volume. Vorasidenib was well tolerated in our patient with a mild elevation in his liver transaminases that resolved following a brief interruption in treatment. Conclusions: Our case suggests that vorasidenib may impart therapeutic benefits in this setting. This case illustrates the need for further investigation into these less commonly addressed scenarios and treatment strategies that extend beyond current guidelines.

Recent Advancements and Future Perspectives on Molecular Biomarkers in Adult Lower-Grade Gliomas

ABSTRACT

There has been a significant paradigm shift in the clinical management of lower-grade glioma patients given the recent updates to the 2021 World Health Organization classification along with long-term results from randomized phase III clinical trials. As a result, we are now better able to diagnose and assign patients to the most appropriate treatment course. This review provides a comprehensive summary of the most robust and reliable molecular biomarkers for adult lower-grade gliomas and discusses current challenges facing this patient population that future correlative biology studies combined with advancements in technologies could help overcome.

Novel signature of ferroptosis-related long non-coding RNA to predict lower-grade glioma overall survival

BACKGROUND

Ferroptosis is a novel type of programmed cell death in various tumors; however, underlying mechanisms remain unclear. We aimed to develop ferroptosis-related long non-coding RNA (FRlncRNA) risk scores to predict lower-grade glioma (LGG) prognosis and to conduct functional analyses to explore potential mechanisms.

METHODS

LGG-related RNA sequencing data were extracted from The Cancer Genome Atlas (TCGA) and Chinese Glioma Genome Atlas (CGGA) databases. Pearson correlation analysis was used to identify the FRlncRNAs, univariate Cox regression analysis was for identify the prognostic FRlncRNAs, and then intersection FRlncRNAs were screened between TCGA and CGGA. Least absolute shrinkage and selection operator (LASSO) Cox regression was used to develop a risk score to predict LGG prognosis.

RESULTS

A total of nine FRlncRNAs were screened to construct the novel prognostic risk score of LGG, and high-risk score patients had a worse overall survival than low-risk score patients both in TCGA and CGGA datasets. The risk score was quite correlated with clinicopathological characteristics (age, WHO grade, status of MGMT Methtlation, IDH mutation, 1p/19q codeletion, and TMB), and could promote current molecular subtyping systems. Comprehensive analyses revealed that signaling pathways of B-cell receptor and T-cell receptor, immune cells of macrophage cell and CD4+ T cell, tumor microenvironment of stroma score and immune score, and immune checkpoints of PD-1, PD-L1, and CTLA4 were all enriched in the high-risk score group.

CONCLUSION

The nine FRlncRNAs risk scores was a promising biomarker to predict the LGG's prognosis and distinguish the characteristics of molecular and immune.

The biological significance of tumor grade, age, enhancement, and extent of resection in IDH-mutant gliomas: How should they inform treatment decisions in the era of IDH inhibitors?

The 2016 and 2021 World Health Organization 2021 Classification of central nervous system tumors have resulted in a major improvement in the classification of isocitrate dehydrogenase (IDH)-mutant gliomas. With more effective treatments many patients experience prolonged survival. However, treatment guidelines are often still based on information from historical series comprising both patients with IDH wild-type and IDH-mutant tumors. They provide recommendations for radiotherapy and chemotherapy for so-called high-risk patients, usually based on residual tumor after surgery and age over 40. More up-to-date studies give a better insight into clinical, radiological, and molecular factors associated with the outcome of patients with IDH-mutant glioma. These insights should be used today for risk stratification and for treatment decisions. In many patients with IDH-mutant grades 2 and 3 glioma, if carefully monitored postponing radiotherapy and chemotherapy is safe, and will not jeopardize the overall outcome of patients. With the INDIGO trial showing patient benefit from the IDH inhibitor vorasidenib, there is a sizable population in which it seems reasonable to try this class of agents before recommending radio-chemotherapy with its delayed adverse event profile affecting quality of survival. Ongoing trials should help to further identify the patients that are benefiting from this treatment.

Clinical applicability of signal heterogeneity and tumor border assessment on T2-weighted MR images to distinguish astrocytic from oligodendroglial origin of gliomas

BACKGROUND AND PURPOSE

Radiological features on magnetic resonance imaging (MRI) were attributed to oligodendroglioma, although the diagnostic accuracy in a real-world clinical setting remains partially elusive. This study investigated the accuracy and robustness of tumor heterogeneity and tumor border delineation on T2-weighted MRI to distinguish oligodendroglioma from astrocytoma.

MATERIALS AND METHODS

Eight readers from three different specialties (radiology, neurology, neurosurgery) with varying levels of experience blindly rated 79 T2-weighted MR images of patients with either oligodendroglioma or astrocytoma. After the first reading session, all readers were re-invited for a second reading session within three weeks. Diagnostic accuracy, including area under the receiver operator characteristics curve (AUC), and intra-observer variability and inter-observer variability were used as outcome measures.

RESULTS

Pooled sensitivity and specificity to distinguish oligodendroglioma from astrocytoma for the use of tumor heterogeneity were 59.9 % respectively 74.5 %, and 85.7 % respectively 40.1 % for tumor border. A second reading session did not result in a significant change in sensitivity or specificity for tumor heterogeneity (P = 0.752 and P = 0.733, respectively) or tumor border (P = 0.309 and P = 0.271, respectively). An AUC of 0.825 was achieved with regard to predicting oligodendroglial origin of gliomas. Intra-observer agreement ranged from moderate to very good for tumor heterogeneity (kappa-value 0.43-0.87) and tumor border (0.40-0.84). A moderate inter-oberserver agreement was achieved for tumor heterogeneity and tumor border (kappa-value of 0.50 and 0.45, respectively).

CONCLUSION

This study demonstrates that tumor heterogeneity and tumor borders on T2-weighted MRI could be used with moderate Finter-observer agreement to non-invasively distinguish oligodendroglioma from astrocytoma.

Super T2-FLAIR mismatch sign: a prognostic imaging biomarker for non-enhancing astrocytoma, IDH-mutant

PURPOSE

The T2-FLAIR mismatch sign is a highly specific diagnostic imaging biomarker for astrocytoma, IDH-mutant. However, a definitive prognostic imaging biomarker has yet to be identified. This study investigated imaging prognostic markers, specifically analyzing T2-weighted and FLAIR images of this tumor.

METHODS

We retrospectively analyzed 31 cases of non-enhancing astrocytoma, IDH-mutant treated at our institution, and 30 cases from The Cancer Genome Atlas (TCGA)/The Cancer Imaging Archive (TCIA). We defined "super T2-FLAIR mismatch sign" as having a significantly strong low signal comparable to cerebrospinal fluid at non-cystic lesions rather than just a pale FLAIR low-signal tumor lesion as in conventional T2-FLAIR mismatch sign. Cysts were defined as having a round or oval shape and were excluded from the criteria for the super T2-FLAIR mismatch sign. We evaluated the presence or absence of the T2-FLAIR mismatch sign and super T2-FLAIR mismatch sign using preoperative MRI and analyzed the progression-free survival (PFS) and overall survival (OS) by log-rank test.

RESULTS

The T2-FLAIR mismatch sign was present in 17 cases (55%) in our institution and 9 cases (30%) within the TCGA-LGG dataset without any correlation with PFS or OS. However, the super T2-FLAIR mismatch sign was detected in 8 cases (26%) at our institution and 13 cases (43%) in the TCGA-LGG dataset. At our institution, patients displaying the super T2-FLAIR mismatch sign showed significantly extended PFS (122.7 vs. 35.9 months, p = 0.0491) and OS (not reached vs. 116.7 months, p = 0.0232). Similarly, in the TCGA-LGG dataset, those with the super T2-FLAIR mismatch sign exhibited notably longer OS (not reached vs. 44.0 months, p = 0.0177).

CONCLUSION

The super T2-FLAIR mismatch is a promising prognostic imaging biomarker for non-enhancing astrocytoma, IDH-mutant.

Long-term outcomes of CNS WHO grade 2 oligodendroglioma in adult patients: a single-institution experience

PURPOSE

Oligodendrogliomas (ODGs) are a subtype of diffuse lower-grade gliomas with overall survival of > 10 years. This study aims to analyze long-term outcomes and identify prognostic factors in patients with WHO grade 2 ODG.

METHODS

We retrospectively reviewed 138 adult patients diagnosed with 1p/19q co-deleted ODG who underwent surgical resection or biopsy between 1994 and 2021, analyzing clinical data, treatment details, and outcomes. Progression-free survival (PFS) and overall survival (OS) were evaluated using Kaplan-Meier analysis. Univariate and multivariate Cox regression analyses were utilized to identify significant prognostic factors.

RESULTS

In the gross total resection (GTR) group, 63 (45.7%) underwent observation and 5 (3.6%) received postoperative treatment; in the non-GTR group, 37 (26.8%) were observed and 33 (23.9%) received postoperative treatment. The median PFS and OS were 6.8 and 18.4 years, respectively. Between adjuvant treatment and observation, there was no significant difference in PFS or OS. However, GTR or STR with less than 10% residual tumor exhibited significantly better PFS and OS compared to PR or biopsy (p = 0.022 and 0.032, respectively). Multivariate analysis revealed that contrast enhancement on MRI was associated with worse PFS (HR = 2.36, p < 0.001) and OS (HR = 5.89, p = 0.001). And the presence of seizures at presentation was associated with improved OS (HR = 0.28, p = 0.006).

CONCLUSION

This study underscores favorable long-term outcomes for patients with 1p/19q co-deleted ODG WHO grade 2. Our findings indicate that the EOR plays a crucial role as a significant prognostic factor in enhancing PFS and OS outcomes in WHO grade 2 ODG.

Amide proton transfer weighted and diffusion weighted imaging based radiomics classification algorithm for predicting 1p/19q co-deletion status in low grade gliomas

BACKGROUND

1p/19q co-deletion in low-grade gliomas (LGG, World Health Organization grade II and III) is of great significance in clinical decision making. We aim to use radiomics analysis to predict 1p/19q co-deletion in LGG based on amide proton transfer weighted (APTw), diffusion weighted imaging (DWI), and conventional MRI.

METHODS

This retrospective study included 90 patients histopathologically diagnosed with LGG. We performed a radiomics analysis by extracting 8454 MRI-based features form APTw, DWI and conventional MR images and applied a least absolute shrinkage and selection operator (LASSO) algorithm to select radiomics signature. A radiomics score (Rad-score) was generated using a linear combination of the values of the selected features weighted for each of the patients. Three neuroradiologists, including one experienced neuroradiologist and two resident physicians, independently evaluated the MR features of LGG and provided predictions on whether the tumor had 1p/19q co-deletion or 1p/19q intact status. A clinical model was then constructed based on the significant variables identified in this analysis. A combined model incorporating both the Rad-score and clinical factors was also constructed. The predictive performance was validated by receiver operating characteristic curve analysis, DeLong analysis and decision curve analysis. P < 0.05 was statistically significant.

RESULTS

The radiomics model and the combined model both exhibited excellent performance on both the training and test sets, achieving areas under the curve (AUCs) of 0.948 and 0.966, as well as 0.909 and 0.896, respectively. These results surpassed the performance of the clinical model, which achieved AUCs of 0.760 and 0.766 on the training and test sets, respectively. After performing Delong analysis, the clinical model did not significantly differ in predictive performance from three neuroradiologists. In the training set, both the radiomic and combined models performed better than all neuroradiologists. In the test set, the models exhibited higher AUCs than the neuroradiologists, with the radiomics model significantly outperforming resident physicians B and C, but not differing significantly from experienced neuroradiologist.

CONCLUSIONS

Our results suggest that our algorithm can noninvasively predict the 1p/19q co-deletion status of LGG. The predictive performance of radiomics model was comparable to that of experienced neuroradiologist, significantly outperforming the diagnostic accuracy of resident physicians, thereby offering the potential to facilitate non-invasive 1p/19q co-deletion prediction of LGG.

Prognostic and predictive biomarkers in central nervous system tumours: the molecular state of play

Central nervous system (CNS) tumours were one of the first cancer types to adopt and integrate molecular profiling into routine clinical diagnosis in 2016. The vast majority of these biomarkers, used to discriminate between tumour types, also offered prognostic information. With the advent of The Cancer Genome Atlas (TCGA) and other large genomic datasets, further prognostic sub-stratification was possible within tumour types, leading to increased precision in CNS tumour grading. This review outlines the evolution of the molecular landscape of adult CNS tumours, through the prism of World Health Organization (WHO) Classifications. We begin our journey in the pre-molecular era, where high-grade gliomas were divided into 'primary' and 'secondary' glioblastomas. Molecular alterations explaining these clinicopathological observations were the first branching points of glioma diagnostics, with the discovery of IDH1/2 mutations and 1p/19q codeletion. Subsequently, the rigorous characterisation of paediatric gliomas led to the unearthing of histone H3 alterations as a key event in gliomagenesis, which also had implications for young adult patients. Simultaneously, studies investigating prognostic biomarkers within tumour types were undertaken. Certain genomic phenotypes were found to portend unfavourable outcomes, for example, MYCN amplification in spinal ependymoma. The arrival of methylation profiling, having revolutionised the diagnosis of CNS tumours, now promises to bring increased prognostic accuracy, as has been shown in meningiomas. While MGMT promoter hypermethylation has remained a reliable biomarker of response to cytotoxic chemotherapy, targeted therapy in CNS tumours has unfortunately not had the success of other cancers. Therefore, predictive biomarkers have lagged behind the identification of prognostic biomarkers in CNS tumours. Emerging research from new clinical trials is cause for guarded optimism and may shift our conceptualisation of predictive biomarker testing in CNS tumours.

Efficient diagnosis of IDH-mutant gliomas: 1p/19qNET assesses 1p/19q codeletion status using weakly-supervised learning

Accurate identification of molecular alterations in gliomas is crucial for their diagnosis and treatment. Although, fluorescence in situ hybridization (FISH) allows for the observation of diverse and heterogeneous alterations, it is inherently time-consuming and challenging due to the limitations of the molecular method. Here, we report the development of 1p/19qNET, an advanced deep-learning network designed to predict fold change values of 1p and 19q chromosomes and classify isocitrate dehydrogenase (IDH)-mutant gliomas from whole-slide images. We trained 1p/19qNET on next-generation sequencing data from a discovery set (DS) of 288 patients and utilized a weakly-supervised approach with slide-level labels to reduce bias and workload. We then performed validation on an independent validation set (IVS) comprising 385 samples from The Cancer Genome Atlas, a comprehensive cancer genomics resource. 1p/19qNET outperformed traditional FISH, achieving R2 values of 0.589 and 0.547 for the 1p and 19q arms, respectively. As an IDH-mutant glioma classifier, 1p/19qNET attained AUCs of 0.930 and 0.837 in the DS and IVS, respectively. The weakly-supervised nature of 1p/19qNET provides explainable heatmaps for the results. This study demonstrates the successful use of deep learning for precise determination of 1p/19q codeletion status and classification of IDH-mutant gliomas as astrocytoma or oligodendroglioma. 1p/19qNET offers comparable results to FISH and provides informative spatial information. This approach has broader applications in tumor classification.

Research on application of radiomics in glioma: a bibliometric and visual analysis

Background

With the continuous development of medical imaging informatics technology, radiomics has become a new and evolving field in medical applications. Radiomics aims to be an aid to support clinical decision making by extracting quantitative features from medical images and has a very wide range of applications. The purpose of this study was to perform a bibliometric and visual analysis of scientific results and research trends in the research application of radiomics in glioma.

Methods

We searched the Web of Science Core Collection (WOScc) for publications related to glioma radiomics. A bibliometric and visual analysis of online publications in this field related to countries/regions, authors, journals, references and keywords was performed using CiteSpace and R software.

Results

A total of 587 relevant literature published from 2012 to September 2022 were retrieved in WOScc, and finally a total of 484 publications were obtained according to the filtering criteria, including 393 (81.20%) articles and 91 (18.80%) reviews. The number of relevant publications increases year by year. The highest number of publications was from the USA (171 articles, 35.33%) and China (170 articles, 35.12%). The research institution with the highest number of publications was Chinese Acad Sci (24), followed by Univ Penn (22) and Fudan Univ (21). WANG Y (27) had the most publications, followed by LI Y (22), and WANG J (20). Among the 555 co-cited authors, LOUIS DN (207) and KICKINGEREDER P (207) were the most cited authors. FRONTIERS IN ONCOLOGY (42) was the most published journal and NEURO-ONCOLOGY (412) was the most co-cited journal. The most frequent keywords in all publications included glioblastoma (187), survival (136), classification (131), magnetic resonance imaging (113), machine learning (100), tumor (82), and feature (79), central nervous system (66), IDH (57), and radiomics (55). Cluster analysis was performed on the basis of keyword co-occurrence, and a total of 16 clusters were formed, indicating that these directions are the current hotspots of radiomics research applications in glioma and may be the future directions of continuous development.

Conclusion

In the past decade, radiomics has received much attention in the medical field and has been widely used in clinical research applications. Cooperation and communication between countries/regions need to be enhanced in future research to promote the development of radiomics in the field of medicine. In addition, the application of radiomics has improved the accuracy of pre-treatment diagnosis, efficacy prediction and prognosis assessment of glioma and helped to promote the development into precision medicine, the future still faces many challenges.

MRI-Based Deep Learning Method for Classification of IDH Mutation Status

Isocitrate dehydrogenase (IDH) mutation status has emerged as an important prognostic marker in gliomas. This study sought to develop deep learning networks for non-invasive IDH classification using T2w MR images while comparing their performance to a multi-contrast network. Methods: Multi-contrast brain tumor MRI and genomic data were obtained from The Cancer Imaging Archive (TCIA) and The Erasmus Glioma Database (EGD). Two separate 2D networks were developed using nnU-Net, a T2w-image-only network (T2-net) and a multi-contrast network (MC-net). Each network was separately trained using TCIA (227 subjects) or TCIA + EGD data (683 subjects combined). The networks were trained to classify IDH mutation status and implement single-label tumor segmentation simultaneously. The trained networks were tested on over 1100 held-out datasets including 360 cases from UT Southwestern Medical Center, 136 cases from New York University, 175 cases from the University of Wisconsin-Madison, 456 cases from EGD (for the TCIA-trained network), and 495 cases from the University of California, San Francisco public database. A receiver operating characteristic curve (ROC) was drawn to calculate the AUC value to determine classifier performance. Results: T2-net trained on TCIA and TCIA + EGD datasets achieved an overall accuracy of 85.4% and 87.6% with AUCs of 0.86 and 0.89, respectively. MC-net trained on TCIA and TCIA + EGD datasets achieved an overall accuracy of 91.0% and 92.8% with AUCs of 0.94 and 0.96, respectively. We developed reliable, high-performing deep learning algorithms for IDH classification using both a T2-image-only and a multi-contrast approach. The networks were tested on more than 1100 subjects from diverse databases, making this the largest study on image-based IDH classification to date.

The Impact of Adjuvant Radiotherapy on Clinical Performance Status in Patients With Grade II Spinal Cord Astrocytoma - A Nationwide Analysis by the Neurospinal Society of Japan

OBJECTIVE

The impact of adjuvant radiotherapy on overall survival (OS) and progression-free survival (PFS) of patients with grade II spinal cord astrocytomas remains controversial. Additionally, the relationship between progression and clinical deterioration after radiotherapy has not been well investigated.

METHODS

This study included 53 patients with grade II intramedullary spinal cord astrocytomas treated by either subtotal, partial resection or open biopsy. Their clinical performance status was assessed immediately before operation and 1, 6, 12, 24, and 60 months after surgery by Karnofsky Performance Scale (KPS). Patients with and without adjuvant radiotherapy were compared.

RESULTS

The groups with and without radiation comprised 23 and 30 patients with a mean age of 50.3 ± 22.6 years (range, 2-88 years). The mean overall disease progression rate was 47.1% during a mean follow-up period of 48.4 ± 39.8 months (range, 2.5-144.5 months). In the radiation group, 11 patients (47.8%) presented with progressive disease, whereas 14 patients (46.7%) presented with progressive disease in the group without radiation. There were no significant differences in OS or PFS among patients with or without adjuvant radiotherapy. KPS in both groups, especially radiation group, gradually decreased after operation and deteriorated before the confirmation of disease progression.

CONCLUSION

Adjuvant radiotherapy did not show effectiveness regarding PFS or OS in patients with grade II spinal cord astrocytoma according to classical classification based on pathohistological findings.

Low-coverage and cost-effective whole-genome sequencing assay for glioma risk stratification

PURPOSE

To investigate chromosomal instability (CIN) as a biomarker for glioma risk stratifications, with cost-effective, low-coverage whole-genome sequencing assay (WGS).

METHODS

Thirty-five formalin-fixed paraffin-embedded glioma samples were collected from Huashan Hospital. DNA was sent for WGS by Illumina X10 at low (median) genome coverage of 1.86x (range: 1.03-3.17×), followed by copy number analyses, using a customized bioinformatics workflow-Ultrasensitive Copy number Aberration Detector.

RESULTS

Among the 35 glioma patients, 12 were grade IV, 10 grade III, 11 grade II, and 2 Grade I cases, with high chromosomal instability (CIN +) in 24 (68.6%) of the glioma patients. The other 11 (31.4%) had lower chromosomal instability (CIN-). CIN significantly correlates with overall survival (P = 0.00029). Patients with CIN + /7p11.2 + (12 grade IV and 3 grade III) had the worst survival ratio (hazard ratio:16.2, 95% CI:6.3-41.6) with a median overall survival of 24 months. Ten (66.7%) patients died during the first two follow-up years. In the CIN + patients without 7p11.2 + (6 grade III, 3 grade II), 3 (33.3%) patients died during follow-up, and the estimated overall survival was around 65 months. No deaths were reported in the 11 CIN- patients (2 grade I, 8 grade II, 1 grade III) during the 80-month follow-up period. In this study, chromosomal instability served as a prognosis factor for gliomas independent of tumor grades.

CONCLUSION

It is feasible to use cost-effective, low-coverage WGS for risk stratification of glioma. Elevated chromosomal instability is associated with poor prognosis.

Association of MGMT Promoter Methylation With Survival in Low-grade and Anaplastic Gliomas After Alkylating Chemotherapy

Importance

O6-methylguanine-DNA methyltransferase (MGMT [OMIM 156569]) promoter methylation (mMGMT) is predictive of response to alkylating chemotherapy for glioblastomas and is routinely used to guide treatment decisions. However, the utility of MGMT promoter status for low-grade and anaplastic gliomas remains unclear due to molecular heterogeneity and the lack of sufficiently large data sets.

Objective

To evaluate the association of mMGMT for low-grade and anaplastic gliomas with chemotherapy response.

Design, Setting, and Participants

This cohort study aggregated grade II and III primary glioma data from 3 prospective cohort studies with patient data collected from August 13, 1995, to August 3, 2022, comprising 411 patients: MSK-IMPACT, EORTC (European Organization of Research and Treatment of Cancer) 26951, and Columbia University. Statistical analysis was performed from April 2022 to January 2023.

Exposure

MGMT promoter methylation status.

Main Outcomes and Measures

Multivariable Cox proportional hazards regression modeling was used to assess the association of mMGMT status with progression-free survival (PFS) and overall survival (OS) after adjusting for age, sex, molecular class, grade, chemotherapy, and radiotherapy. Subgroups were stratified by treatment status and World Health Organization 2016 molecular classification.

Results

A total of 411 patients (mean [SD] age, 44.1 [14.5] years; 283 men [58%]) met the inclusion criteria, 288 of whom received alkylating chemotherapy. MGMT promoter methylation was observed in 42% of isocitrate dehydrogenase (IDH)-wild-type gliomas (56 of 135), 53% of IDH-mutant and non-codeleted gliomas (79 of 149), and 74% of IDH-mutant and 1p/19q-codeleted gliomas (94 of 127). Among patients who received chemotherapy, mMGMT was associated with improved PFS (median, 68 months [95% CI, 54-132 months] vs 30 months [95% CI, 15-54 months]; log-rank P < .001; adjusted hazard ratio [aHR] for unmethylated MGMT, 1.95 [95% CI, 1.39-2.75]; P < .001) and OS (median, 137 months [95% CI, 104 months to not reached] vs 61 months [95% CI, 47-97 months]; log-rank P < .001; aHR, 1.65 [95% CI, 1.11-2.46]; P = .01). After adjusting for clinical factors, MGMT promoter status was associated with chemotherapy response in IDH-wild-type gliomas (aHR for PFS, 2.15 [95% CI, 1.26-3.66]; P = .005; aHR for OS, 1.69 [95% CI, 0.98-2.91]; P = .06) and IDH-mutant and codeleted gliomas (aHR for PFS, 2.99 [95% CI, 1.44-6.21]; P = .003; aHR for OS, 4.21 [95% CI, 1.25-14.2]; P = .02), but not IDH-mutant and non-codeleted gliomas (aHR for PFS, 1.19 [95% CI, 0.67-2.12]; P = .56; aHR for OS, 1.07 [95% CI, 0.54-2.12]; P = .85). Among patients who did not receive chemotherapy, mMGMT status was not associated with PFS or OS.

Conclusions and Relevance

This study suggests that mMGMT is associated with response to alkylating chemotherapy for low-grade and anaplastic gliomas and may be considered as a stratification factor in future clinical trials of patients with IDH-wild-type and IDH-mutant and codeleted tumors.

A Multigene Signature Associated with Progression-Free Survival after Treatment for IDH Mutant and 1p/19q Codeleted Oligodendrogliomas

BACKGROUND

IDH mutant and 1p/19q codeleted oligodendrogliomas are the gliomas associated with the best prognosis. However, despite their sensitivity to treatment, patient survival remains heterogeneous. We aimed to identify gene expressions associated with response to treatment from a national cohort of patients with oligodendrogliomas, all treated with radiotherapy +/- chemotherapy.

METHODS

We extracted total RNA from frozen tumor samples and investigated enriched pathways using KEGG and Reactome databases. We applied a stability selection approach based on subsampling combined with the lasso-pcvl algorithm to identify genes associated with progression-free survival and calculate a risk score.

RESULTS

We included 68 patients with oligodendrogliomas treated with radiotherapy +/- chemotherapy. After filtering, 1697 genes were obtained, including 134 associated with progression-free survival: 35 with a better prognosis and 99 with a poorer one. Eight genes (ST3GAL6, QPCT, NQO1, EPHX1, CST3, S100A8, CHI3L1, and OSBPL3) whose risk score remained statistically significant after adjustment for prognostic factors in multivariate analysis were selected in more than 60% of cases were associated with shorter progression-free survival.

CONCLUSIONS

We found an eight-gene signature associated with a higher risk of rapid relapse after treatment in patients with oligodendrogliomas. This finding could help clinicians identify patients who need more intensive treatment.

Microvasculature Features Derived from Hybrid EPI MRI in Non-Enhancing Adult-Type Diffuse Glioma Subtypes

In this study, we used the vessel size imaging (VSI) MRI technique to characterize the microvasculature features of three subtypes of adult-type diffuse glioma lacking enhancement. Thirty-eight patients with confirmed non-enhancing glioma were categorized into three subtypes: Oligo (IDH-mut&1p/19q-codeleted), Astro (IDH-mut), and GBM (IDH-wt). The VSI technique provided quantitative maps of cerebral blood volume (CBV), microvasculature (µCBV), and vessel size for each patient. Additionally, tissue samples of 21 patients were histopathologically analyzed, and microvasculature features were quantified. Both MRI- and histology-derived features were compared across the three glioma subtypes with ANOVA or Kruskal–Wallis tests. Group averages of CBV, μCBV, and vessel size were significantly different between the three glioma subtypes (p < 0.01). Astro (IDH-mut) had a significantly lower CBV and µCBV compared to Oligo (IDH-mut&1p/19q-codeleted) (p = 0.004 and p = 0.001, respectively), and a higher average vessel size compared to GBM (IDH-wt) (p = 0.01). The histopathological analysis showed that GBM (IDH-wt) possessed vessels with more irregular shapes than the two other subtypes (p < 0.05). VSI provides a good insight into the microvasculature characteristics of the three adult-type glioma subtypes even when lacking enhancement. Further investigations into the specificity of VSI to differentiate glioma subtypes are thus warranted.

The Glioma-IRE project − Molecular profiling in patients with glioma: steps toward an individualized diagnostic and therapeutic approach

Background

This study aimed to characterize the genetic profile of patients with glioma and discuss the impact of next-generation sequencing in glioma diagnosis and treatment.

Methods

Between 2019 and 2022, we analyzed the genetic profile of 99 patients with glioma through the Oncomine Focus Assay. The assay enables the detection of mutations in 52 driver genes, including single nucleotide variants (SNVs), copy number variants (CNVs), and gene fusions. We also collected and analyzed patients’ clinic characteristics and treatment outcomes.

Results

Over a period of 35 months, 700 patients with glioma followed by our neuro-oncology unit were screened, and 99 were enrolled in the study; most of the patients were excluded for inadequate non-morphological MRI or lack/inadequacy of the tissue samples. Based on our findings, most patients with glioma present mutations, such as SNVs, CNVs or gene fusions. Our data were similar to those reported by The Cancer Genome Atlas Program in terms of frequency of SNVs and CNVs, while we observed more cases of gene fusions. Median overall survival, progression-free survival, and time to progression were significantly lower for patients with grade VI glioblastoma than those with other gliomas. Only four patients were offered a targeted treatment based on the mutation detected; however, only one received treatment, the others could not receive the selected treatment because of worsening clinical status.

Conclusion

Routine timely molecular profiling in patients with glioma should be implemented to offer patients an individualized diagnostic approach and provide them with advanced targeted therapy options if available.

Tumor Microenvironment in Gliomas: A Treatment Hurdle or an Opportunity to Grab?

Gliomas are the most frequent central nervous system (CNS) primary tumors. The prognosis and clinical outcomes of these malignancies strongly diverge according to their molecular alterations and range from a few months to decades. The tumor-associated microenvironment involves all cells and connective tissues surrounding tumor cells. The composition of the microenvironment as well as the interactions with associated neoplastic mass, are both variables assuming an increasing interest in these last years. This is mainly because the microenvironment can mediate progression, invasion, dedifferentiation, resistance to treatment, and relapse of primary gliomas. In particular, the tumor microenvironment strongly diverges from isocitrate dehydrogenase (IDH) mutated and wild-type (wt) tumors. Indeed, IDH mutated gliomas often show a lower infiltration of immune cells with reduced angiogenesis as compared to IDH wt gliomas. On the other hand, IDH wt tumors exhibit a strong immune infiltration mediated by several cytokines and chemokines, including CCL2, CCL7, GDNF, CSF-1, GM-CSF, etc. The presence of several factors, including Sox2, Oct4, PD-L1, FAS-L, and TGF β2, also mediate an immune switch toward a regulatory inhibited immune system. Other important interactions are described between IDH wt glioblastoma cells and astrocytes, neurons, and stem cells, while these interactions are less elucidated in IDH-mutated tumors. The possibility of targeting the microenvironment is an intriguing perspective in terms of therapeutic drug development. In this review, we summarized available evidence related to the glioma microenvironment, focusing on differences within different glioma subtypes and on possible therapeutic development.

NCCN Guidelines® Insights: Central Nervous System Cancers, Version 2.2022

The NCCN Guidelines for Central Nervous System (CNS) Cancers focus on management of the following adult CNS cancers: glioma (WHO grade 1, WHO grade 2-3 oligodendroglioma [1p19q codeleted, IDH-mutant], WHO grade 2-4 IDH-mutant astrocytoma, WHO grade 4 glioblastoma), intracranial and spinal ependymomas, medulloblastoma, limited and extensive brain metastases, leptomeningeal metastases, non-AIDS-related primary CNS lymphomas, metastatic spine tumors, meningiomas, and primary spinal cord tumors. The information contained in the algorithms and principles of management sections in the NCCN Guidelines for CNS Cancers are designed to help clinicians navigate through the complex management of patients with CNS tumors. Several important principles guide surgical management and treatment with radiotherapy and systemic therapy for adults with brain tumors. The NCCN CNS Cancers Panel meets at least annually to review comments from reviewers within their institutions, examine relevant new data from publications and abstracts, and reevaluate and update their recommendations. These NCCN Guidelines Insights summarize the panel's most recent recommendations regarding molecular profiling of gliomas.

Cell-Population Dynamics in Diffuse Gliomas during Gliomagenesis and Its Impact on Patient Survival

Diffuse gliomas continue to be an important problem in neuro-oncology. To solve it, studies have considered the issues of molecular pathogenesis from the intratumoral heterogeneity point. Here, we carried out a comparative dynamic analysis of the different cell populations' content in diffuse gliomas of different molecular profiles and grades, considering the cell populations' functional properties and the relationship with patient survival, using flow cytometry, immunofluorescence, multiparametric fluorescent in situ hybridization, polymerase chain reaction, and cultural methods. It was shown that an increase in the IDH-mutant astrocytomas and oligodendrogliomas malignancy is accompanied by an increase in stem cells' proportion and mesenchymal cell populations' appearance arising from oligodendrocyte-progenitor-like cells with cell plasticity and cells' hypoxia response programs' activation. In glioblastomas, malignancy increase is accompanied by an increase in both stem and definitive cells with mesenchymal differentiation, while proneuronal glioma stem cells are the most likely the source of mesenchymal glioma stem cells, which, in hypoxic conditions, further give rise to mesenchymal-like cells. Clinical confirmation was a mesenchymal-like cell and mesenchymal glioma stem cell number, and the hypoxic and plastic molecular programs' activation degree had a significant effect on relapse-free and overall survival. In general, we built a multi-vector model of diffuse gliomas' pathogenetic tracing up to the practical plane.

Early Postoperative Treatment versus Initial Observation in CNS WHO Grade 2 and 3 Oligodendroglioma: Clinical Outcomes and DNA Methylation Patterns

PURPOSE

The treatment of oligodendroglioma consists of tumor resection and radiochemotherapy. The timing of radiochemotherapy remains unclear, and predictive biomarkers are limited.

EXPERIMENTAL DESIGN

Adult patients diagnosed with isocitrate dehydrogenase (IDH)-mutated, 1p/19q-codeleted CNS WHO grade 2 and 3 oligodendroglioma at the Medical University of Vienna and the Kepler University Hospital Linz (Austria) in 1992 to 2019 were included. Progression-free (PFS) and overall survival (OS) between early postoperative treatment and initial observation were compared using propensity score-weighted Cox regression models. DNA methylation analysis of tumor tissue was performed using Illumina MethylationEPIC 850k microarrays.

RESULTS

One hundred thirty-one out of 201 (65.2%) patients with CNS WHO grade 2 and 70 of 201 (34.8%) with grade 3 oligodendroglioma were identified. Eighty-three of 201 (41.3%) patients underwent early postoperative treatment, of whom 56 of 83 (67.5%) received radiochemotherapy, 15 of 84 (18.1%) radiotherapy (RT) only and 12 of 83 (14.5%) chemotherapy only. Temozolomide-based treatment was administered to 64 of 68 (94.1%) patients, whereas RT + procarbazine, lomustine (CCNU), and vincristine (PCV) were applied in 2 of 69 (3.5%) patients. Early treatment was not associated with PFS [adjusted hazard ratio (HR) 0.74; 95% CI, 0.33-1.65, P = 0.459] or OS (adjusted HR: 2.07; 95% CI, 0.52-8.21, P = 0.302) improvement. Unsupervised clustering analysis of DNA methylation profiles from patients receiving early treatment revealed two methylation clusters correlating with PFS, whereas no association of clustering with O6-methylguanine methyltransferase (MGMT) promoter methylation, CNS WHO grade, extent of resection, and treating center could be observed.

CONCLUSIONS

In this retrospective study, early postoperative treatment was not associated with improved PFS/OS in oligodendroglioma. The potentially predictive value of whole-genome methylation profiling should be validated in prospective trials.

Current and promising treatment strategies in glioma

Gliomas are the most common primary central nervous system tumors; despite recent advances in diagnosis and treatment, glioma patients generally have a poor prognosis. Hence there is a clear need for improved therapeutic options. In recent years, significant effort has been made to investigate immunotherapy and precision oncology approaches. The review covers well-established strategies such as surgery, temozolomide, PCV, and mTOR inhibitors. Furthermore, it summarizes promising therapies: tumor treating fields, immune therapies, tyrosine kinases inhibitors, IDH(Isocitrate dehydrogenase)-targeted approaches, and others. While there are many promising treatment strategies, none fundamentally changed the management of glioma patients. However, we are still awaiting the outcome of ongoing trials, which have the potential to revolutionize the treatment of glioma.

Joint Final Report of EORTC 26951 and RTOG 9402: Phase III Trials With Procarbazine, Lomustine, and Vincristine Chemotherapy for Anaplastic Oligodendroglial Tumors

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the basis of the primary end point, may be published when key planned co-primary or secondary analyses are not yet available. Clinical Trial Updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported.Anaplastic oligodendroglial tumors (AOTs) are chemotherapy-sensitive brain tumors. We report the final very long-term survival results from European Organization for the Research and Treatment of Cancer 26951 and Radiation Therapy Oncology Group 9402 phase III trials initiated in 1990s, which both studied radiotherapy with/without neo/adjuvant procarbazine, lomustine, and vincristine (PCV) for newly diagnosed anaplastic oligodendroglial tumors. The median follow-up duration in both was 18-19 years. For European Organization for the Research and Treatment of Cancer 26951, median, 14-year, and probable 20-year overall survival rates without versus with PCV were 2.6 years, 13.4%, and 10.1% versus 3.5 years, 25.1%, and 16.8% (N = 368 overall; hazard ratio [HR] 0.78; 95% CI, 0.63 to 0.98; P = .033), with 1p19q codeletion 9.3 years, 26.2%, and 13.6% versus 14.2 years, 51.0%, and 37.1% (n = 80; HR 0.60; 95% CI, 0.35 to 1.03; P = .063), respectively. For Radiation Therapy Oncology Group 9402, analogous results were 4.8 years, 16.5%, and 11.2% versus 4.8 years, 29.1%, and 24.6% (N = 289 overall; HR 0.79; 95% CI, 0.61 to 1.03; P = .08), with codeletion 7.3 years, 25.0%, and 14.9% versus 13.2 years, 46.1%, and 37% (n = 125; HR 0.61; 95% CI, 0.40 to 0.94; P = .02), respectively. With that, the studies show similar long-term survival even without tumor recurrence in a significant proportion of patients after first-line treatment with radiotherapy/PCV.

Combined molecular subtyping, grading, and segmentation of glioma using multi-task deep learning

BACKGROUND

Accurate characterization of glioma is crucial for clinical decision making. A delineation of the tumor is also desirable in the initial decision stages but is time-consuming. Previously, deep learning methods have been developed that can either non-invasively predict the genetic or histological features of glioma, or that can automatically delineate the tumor, but not both tasks at the same time. Here, we present our method that can predict the molecular subtype and grade, while simultaneously providing a delineation of the tumor.

METHODS

We developed a single multi-task convolutional neural network that uses the full 3D, structural, preoperative MRI scans to predict the IDH mutation status, the 1p/19q co-deletion status, and the grade of a tumor, while simultaneously segmenting the tumor. We trained our method using a patient cohort containing 1508 glioma patients from 16 institutes. We tested our method on an independent dataset of 240 patients from 13 different institutes.

RESULTS

In the independent test set, we achieved an IDH-AUC of 0.90, an 1p/19q co-deletion AUC of 0.85, and a grade AUC of 0.81 (grade II/III/IV). For the tumor delineation, we achieved a mean whole tumor Dice score of 0.84.

CONCLUSIONS

We developed a method that non-invasively predicts multiple, clinically relevant features of glioma. Evaluation in an independent dataset shows that the method achieves a high performance and that it generalizes well to the broader clinical population. This first-of-its-kind method opens the door to more generalizable, instead of hyper-specialized, AI methods.

Molecular Biomarker Testing for the Diagnosis of Diffuse Gliomas

CONTEXT.—

The diagnosis and clinical management of patients with diffuse gliomas (DGs) have evolved rapidly over the past decade with the emergence of molecular biomarkers that are used to classify, stratify risk, and predict treatment response for optimal clinical care.

OBJECTIVE.—

To develop evidence-based recommendations for informing molecular biomarker testing for pediatric and adult patients with DGs and provide guidance for appropriate laboratory test and biomarker selection for optimal diagnosis, risk stratification, and prediction.

DESIGN.—

The College of American Pathologists convened an expert panel to perform a systematic review of the literature and develop recommendations. A systematic review of literature was conducted to address the overarching question, "What ancillary tests are needed to classify DGs and sufficiently inform the clinical management of patients?" Recommendations were derived from quality of evidence, open comment feedback, and expert panel consensus.

RESULTS.—

Thirteen recommendations and 3 good practice statements were established to guide pathologists and treating physicians on the most appropriate methods and molecular biomarkers to include in laboratory testing to inform clinical management of patients with DGs.

CONCLUSIONS.—

Evidence-based incorporation of laboratory results from molecular biomarker testing into integrated diagnoses of DGs provides reproducible and clinically meaningful information for patient management.

Molecular, Histological, and Clinical Characteristics of Oligodendrogliomas: A Multi-Institutional Retrospective Study

BACKGROUND

Reports suggest that phosphatidylinositol 3-kinase pathway alterations confer increased risk of progression and poor prognosis in oligodendroglioma, IDH-mutant, and 1p/19q-codeleted molecular oligodendrogliomas (mODG). However, factors that affect prognosis in mODG have not been thoroughly studied. In addition, the benefits of adjuvant radiation and temozolomide (TMZ) in mODGs remain to be determined.

OBJECTIVE

To evaluate the role of PIK3CA mutations in mODGs.

METHODS

One hundred seven mODGs (2008-2019) diagnosed at 2 institutions were included. A retrospective review of clinical characteristics, molecular alterations, treatments, and outcomes was performed.

RESULTS

The median age was 37 years, and 61 patients (57%) were male. There were 64 (60%) World Health Organization (WHO) grade 2 and 43 (40%) WHO grade 3 tumors. Eighty-two patients (77%) were stratified as high risk (age 40 years or older and/or subtotal resection per Radiation Treatment Oncology Group-9802). Gross-total resection was achieved in 47 patients (45%). Treatment strategies included observation (n = 15), TMZ (n = 11), radiation (n = 13), radiation/TMZ (n = 62), and others (n = 6). Our results show a benefit of TMZ vs observation in progression-free survival (PFS). No difference in PFS or overall survival (OS) was observed between radiation and radiation/TMZ. PIK3CA mutations were detected in 15 (14%) mODG, and shorter OS was observed in PIK3CA-mutant compared with PIK3CA wild-type mODGs (10.7 years vs 15.1 years, P = .009). WHO grade 3 tumors showed a shorter PFS, but no significant difference in OS was observed between WHO grades.

CONCLUSION

Our findings suggest that mODGs harboring PIK3CA mutations have worse OS. Except for an advantage in PFS with TMZ treatment, adjuvant TMZ, radiation, or a combination of the two showed no significant improvement in OS.

Detection of TERT Promoter Mutations as a Prognostic Biomarker in Gliomas: Methodology, Prospects, and Advances

This article reviews the existing approaches to determining the TERT promoter mutational status in patients with various tumoral diseases of the central nervous system. The operational characteristics of the most common methods and their transferability in medical practice for the selection or monitoring of personalized treatments based on the TERT status and other related molecular biomarkers in patients with the most common tumors, such as glioblastoma, oligodendroglioma, and astrocytoma, are compared. The inclusion of new molecular markers in the course of CNS clinical management requires their rapid and reliable assessment. Availability of molecular evaluation of gliomas facilitates timely decisions regarding patient follow-up with the selection of the most appropriate treatment protocols. Significant progress in the inclusion of molecular biomarkers for their subsequent clinical application has been made since 2016 when the WHO CNS classification first used molecular markers to classify gliomas. In this review, we consider the methodological approaches used to determine mutations in the promoter region of the TERT gene in tumors of the central nervous system. In addition to classical molecular genetical methods, other methods for determining TERT mutations based on mass spectrometry, magnetic resonance imaging, next-generation sequencing, and nanopore sequencing are reviewed with an assessment of advantages and disadvantages. Beyond that, noninvasive diagnostic methods based on the determination of the mutational status of the TERT promoter are discussed.

A Custom DNA-Based NGS Panel for the Molecular Characterization of Patients With Diffuse Gliomas: Diagnostic and Therapeutic Applications

The management of patients with Central Nervous System (CNS) malignancies relies on the appropriate classification of these tumors. Recently, the World Health Organization (WHO) has published new criteria underlining the importance of an accurate molecular characterization of CNS malignancies, in order to integrate the information generated by histology. Next generation sequencing (NGS) allows single step sequencing of multiple genes, generating a comprehensive and specific mutational profile of the tumor tissue. We developed a custom NGS-based multi-gene panel (Glio-DNA panel) for the identification of the correct glioma oncotype and the detection of its essential molecular aberrations. Specifically, the Glio-DNA panel targets specific genetic and chromosomal alterations involving ATRX chromatin remodeler (ATRX), cyclin dependent kinase inhibitor 2A (CDKN2A), isocitrate dehydrogenase (NADP+) 1 (IDH1) and the telomerase reverse transcriptase (TERT) promoter while also recognizing the co-deletion of 1p/19q, loss of chromosome 10 and gain of chromosome 7. Furthermore, the Glio-DNA panel also evaluates the methylation level of the O-6-methylguanine-DNA methyltransferase (MGMT) gene promoter that predicts temozolomide efficacy. As knowledge of the mutational landscape of each glioma is mandatory to define a personalized therapeutic strategy, the Glio-DNA panel also identifies alterations involving “druggable” or “actionable” genes. To test the specificity of our panel, we used two reference mutated DNAs verifying that NGS allele frequency measurement was highly accurate and sensitive. Subsequently, we performed a comparative analysis between conventional techniques - such as immunohistochemistry or fluorescence in situ hybridization - and NGS on 60 diffuse glioma samples that had been previously characterized. The comparison between conventional testing and NGS showed high concordance, suggesting that the Glio-DNA panel may replace multiple time-consuming tests. Finally, the identification of alterations involving different actionable genes matches glioma patients with potential targeted therapies available through clinical trials. In conclusion, our analysis demonstrates NGS efficacy in simultaneously detecting different genetic alterations useful for the diagnosis, prognosis and treatment of adult patients with diffuse glioma.

Temozolomide and radiotherapy versus radiotherapy alone in patients with glioblastoma, IDH-wildtype: post-hoc analysis of the EORTC randomized phase 3 CATNON trial

PURPOSE

In a post-hoc analysis of the CATNON trial (NCT00626990), we explored whether adding temozolomide to radiotherapy improves outcome in patients with IDH1/2wt anaplastic astrocytomas with molecular features of glioblastoma (redesignated as glioblastoma, IDH-wildtype in the 2021 WHO classification of CNS tumors).

EXPERIMENTAL DESIGN

From the randomized phase 3 CATNON study examining the addition of adjuvant and concurrent temozolomide to radiotherapy in anaplastic astrocytomas, we selected a subgroup of IDH1/2wt and H3F3Awt tumors with presence of TERT promoter mutations and/or EGFR amplifications and/or combined gain of chromosome 7 and loss of chromosome 10. Molecular abnormalities including MGMT promoter methylation status were determined by next-generation sequencing, DNA methylation profiling, and SNaPshot analysis.

RESULTS

Of the 751 patients entered in the CATNON study, 670 had fully molecularly characterized tumors. 159 of these tumors met the WHO 2021 molecular criteria for glioblastoma, IDH-wildtype. Of these patients, 47 received radiotherapy only and 112 received a combination of radiotherapy and temozolomide. There was no added effect of temozolomide on either overall survival (HR 1.19, 95%CI 0.82-1.71) or progression-free survival (HR 0.87, 95%CI 0.61-1.24). MGMT promoter methylation was prognostic for overall survival, but was not predictive for outcome to temozolomide treatment either with respect to overall survival or progression-free survival.

CONCLUSIONS

In this cohort of patients with glioblastoma, IDH-wildtype temozolomide treatment did not add benefit beyond that observed from radiotherapy, regardless of MGMT promoter status. These findings require a new well-powered prospective clinical study to explore the efficacy of temozolomide treatment in this patient population.

Surveillance imaging frequency in adult patients with lower-grade (WHO Grade 2 and 3) gliomas

With improved outcome following aggressive treatment in patients with grade 2 and 3 IDH-mutant (IDHmt), 1p/19q codeleted oligodendroglioma and IDHmt, non-codeleted astrocytoma, prolonged surveillance is desirable for early detection of tumor growth and malignant transformation. Current National Comprehensive Cancer Network (NCCN) guidelines provide imaging follow-up recommendations based on molecular classification of lower-grade gliomas, although individualized imaging guidelines based on treatments received and after tumor recurrence are not clearly specified. Other available guidelines have yet to incorporate the molecular biomarkers that inform the WHO classification of gliomas, and in some cases do not adequately consider current knowledge on IDHmt glioma growth rate and recurrence patterns. Moreover, these guidelines also do not provide specific recommendations for concerning clinical symptoms or radiographic findings warranting imaging studies out of prespecified intervals. Focusing on molecularly defined grade 2 and 3 IDHmt astrocytomas and oligodendrogliomas, we review current knowledge of tumor growth rates and time to tumor progression for each tumor type and propose a range of recommended MRI surveillance intervals for both the newly diagnosed and recurrent tumor setting. Additionally, we summarize situations in which imaging is advisable outside of these intervals.

Therapy for Diffuse Astrocytic and Oligodendroglial Tumors in Adults: ASCO-SNO Guideline

Purpose

To provide guidance to clinicians regarding therapy for diffuse astrocytic and oligodendroglial tumors in adults.

Methods

ASCO and the Society for Neuro-Oncology convened an Expert Panel and conducted a systematic review of the literature.

Results

Fifty-nine randomized trials focusing on therapeutic management were identified.

Recommendations

Adults with newly diagnosed oligodendroglioma, isocitrate dehydrogenase (IDH)–mutant, 1p19q codeleted CNS WHO grade 2 and 3 should be offered radiation therapy (RT) and procarbazine, lomustine, and vincristine (PCV). Temozolomide (TMZ) is a reasonable alternative for patients who may not tolerate PCV, but no high-level evidence supports upfront TMZ in this setting. People with newly diagnosed astrocytoma, IDH-mutant, 1p19q non-codeleted CNS WHO grade 2 should be offered RT with adjuvant chemotherapy (TMZ or PCV). People with astrocytoma, IDH-mutant, 1p19q non-codeleted CNS WHO grade 3 should be offered RT and adjuvant TMZ. People with astrocytoma, IDH-mutant, CNS WHO grade 4 may follow recommendations for either astrocytoma, IDH-mutant, 1p19q non-codeleted CNS WHO grade 3 or glioblastoma, IDH-wildtype, CNS WHO grade 4. Concurrent TMZ and RT should be offered to patients with newly diagnosed glioblastoma, IDH-wildtype, CNS WHO grade 4 followed by 6 months of adjuvant TMZ. Alternating electric field therapy, approved by the US Food and Drug Administration, should be considered for these patients. Bevacizumab is not recommended. In situations in which the benefits of 6-week RT plus TMZ may not outweigh the harms, hypofractionated RT plus TMZ is reasonable. In patients age ≥ 60 to ≥ 70 years, with poor performance status or for whom toxicity or prognosis are concerns, best supportive care alone, RT alone (for MGMTpromoter unmethylated tumors), or TMZ alone (for MGMT promoter methylated tumors) are reasonable treatment options. Additional information is available at www.asco.org/neurooncology-guidelines.

RAB42 Promotes Glioma Pathogenesis via the VEGF Signaling Pathway

Angiogenesis plays an important role in tumor initiation and progression of glioma. Seeking for biomarkers associated with angiogenesis is important in enhancing our understanding of glioma biologically and identifying its new drug targets. RNA-sequencing (RNA-seq) data and matched clinical data were downloaded from the CGGA database. A series of filtering analyses were performed to screen for reliable genes: survival, multivariate Cox, ROC curve filtration, and clinical correlation analyses. After immunohistochemical verification, RAB42 was identified as a reliable gene for further single gene analysis. Afterwards, we performed gene set enrichment analysis (GSEA) and co-expression analysis to establish the related molecular mechanisms and signal pathways in glioma. Finally, the gene functions and the mechanisms were investigated in vitro experiments. A total of 23270 mRNA expression and 1018 glioma samples were included in this study. After the three filtering analyses, we selected ten genes for immunohistochemical verification: KLHDC8A, IKIP, HIST1H2BK, HIST1H2BJ, GNG5, FAM114A1, TMEM71, RAB42, CCDC18, and GAS2L3. Immunostaining demonstrated that RAB42 was significantly expressed on the membrane of glioma tissues but not in normal tissues. These results were verified and validated in GEPIA datasets, and the association between RAB42 with clinical features was also evaluated. Analysis of gene functions indicated that RAB42 activated VEGF signaling pathways and the mechanism was associated with natural killer cell mediated cytotoxicity, JAK-STAT signaling pathway and apoptosis pathways by PI3K/AKT in gliomas. Experiments in vitro suggested that the proliferation and invasion of glioma cells might be inhibited after downregulating of RAB42. And the tumorigenesis promotion of RAB42 may relate to the activation of VEGF signaling pathway. Taken together, this study shows that the overexpression of RAB42 is an independent prognostic factor of adverse prognosis. Its pro-oncogenic mechanism may be associated with the activation of VEGF signaling pathways.

Therapy for Diffuse Astrocytic and Oligodendroglial Tumors in Adults: ASCO-SNO Guideline

PURPOSE

To provide guidance to clinicians regarding therapy for diffuse astrocytic and oligodendroglial tumors in adults.

METHODS

ASCO and the Society for Neuro-Oncology convened an Expert Panel and conducted a systematic review of the literature.

RESULTS

Fifty-nine randomized trials focusing on therapeutic management were identified.

RECOMMENDATIONS

Adults with newly diagnosed oligodendroglioma, isocitrate dehydrogenase (IDH)-mutant, 1p19q codeleted CNS WHO grade 2 and 3 should be offered radiation therapy (RT) and procarbazine, lomustine, and vincristine (PCV). Temozolomide (TMZ) is a reasonable alternative for patients who may not tolerate PCV, but no high-level evidence supports upfront TMZ in this setting. People with newly diagnosed astrocytoma, IDH-mutant, 1p19q non-codeleted CNS WHO grade 2 should be offered RT with adjuvant chemotherapy (TMZ or PCV). People with astrocytoma, IDH-mutant, 1p19q non-codeleted CNS WHO grade 3 should be offered RT and adjuvant TMZ. People with astrocytoma, IDH-mutant, CNS WHO grade 4 may follow recommendations for either astrocytoma, IDH-mutant, 1p19q non-codeleted CNS WHO grade 3 or glioblastoma, IDH-wildtype, CNS WHO grade 4. Concurrent TMZ and RT should be offered to patients with newly diagnosed glioblastoma, IDH-wildtype, CNS WHO grade 4 followed by 6 months of adjuvant TMZ. Alternating electric field therapy, approved by the US Food and Drug Administration, should be considered for these patients. Bevacizumab is not recommended. In situations in which the benefits of 6-week RT plus TMZ may not outweigh the harms, hypofractionated RT plus TMZ is reasonable. In patients age ≥ 60 to ≥ 70 years, with poor performance status or for whom toxicity or prognosis are concerns, best supportive care alone, RT alone (for MGMT promoter unmethylated tumors), or TMZ alone (for MGMT promoter methylated tumors) are reasonable treatment options. Additional information is available at www.asco.org/neurooncology-guidelines.

LUMOS - Low and Intermediate Grade Glioma Umbrella Study of Molecular Guided TherapieS at relapse: Protocol for a pilot study

Introduction

Grades 2 and 3 gliomas (G2/3 gliomas), when combined, are the second largest group of malignant brain tumours in adults. The outcomes for G2/3 gliomas at progression approach the dismal outcomes for glioblastoma (GBM), yet there is a paucity of trials for Australian patients with relapsed G2/3 gliomas compared with patients with GBM. LUMOS will be a pilot umbrella study for patients with relapsed G2/3 gliomas that aims to match patients to targeted therapies based on molecular screening with contemporaneous tumour tissue. Participants in whom no actionable or no druggable mutation is found, or in whom the matching drug is not available, will form a comparator arm and receive standard of care chemotherapy. The objective of the LUMOS trial is to assess the feasibility of this approach in a multicentre study across five sites in Australia, with a view to establishing a national molecular screening platform for patient treatment guided by the mutational analysis of contemporaneous tissue biopsies

Methods and analysis

This study will be a multicentre pilot study enrolling patients with recurrent grade 2/3 gliomas that have previously been treated with radiotherapy and chemotherapy at diagnosis or at first relapse. Contemporaneous tumour tissue at the time of first relapse, defined as tissue obtained within 6 months of relapse and without subsequent intervening therapy, will be obtained from patients. Molecular screening will be performed by targeted next-generation sequencing at the reference laboratory (PathWest, Perth, Australia). RNA and DNA will be extracted from representative formalin-fixed paraffin embedded tissue scrolls or microdissected from sections on glass slides tissue sections following a review of the histology by pathologists. Extracted nucleic acid will be quantified by Qubit Fluorometric Quantitation (Thermo Fisher Scientific). Library preparation and targeted capture will be performed using the TruSight Tumor 170 (TST170) kit and samples sequenced on NextSeq 550 (Illumina) using NextSeq V.2.5 hi output reagents, according to the manufacturer’s instructions. Data analysis will be performed using the Illumina BaseSpace TST170 app v1.02 and a custom tertiary pipeline, implemented within the Clinical Genomics Workspace software platform from PierianDx (also refer to section 3.2). Primary outcomes for the study will be the number of patients enrolled and the number of patients who complete molecular screening. Secondary outcomes will include the proportion of screened patients enrolled; proportion of patients who complete molecular screening; the turn-around time of molecular screening; and the value of a brain tumour specific multi-disciplinary tumour board, called the molecular tumour advisory panel as measured by the proportion of patients in whom the treatment recommendation was refined compared with the recommendations from the automated bioinformatics platform of the reference laboratory testing.

Ethics and dissemination

The study was approved by the lead Human Research Ethics Committee of the Sydney Local Health District: Protocol No. X19-0383. The study will be conducted in accordance with the principles of the Declaration of Helsinki 2013, guidelines for Good Clinical Practice and the National Health and Medical Research Council National Statement on Ethical Conduct in Human Research (2007, updated 2018 and as amended periodically). Results will be disseminated using a range of media channels including newsletters, social media, scientific conferences and peer-reviewed publications.

Trial registration number

ACTRN12620000087954; Pre-results.

The Erasmus Glioma Database (EGD): Structural MRI scans, WHO 2016 subtypes, and segmentations of 774 patients with glioma

The Erasmus Glioma Database (EGD) contains structural magnetic resonance imaging (MRI) scans, genetic and histological features (specifying the WHO 2016 subtype), and whole tumor segmentations of patients with glioma. Pre-operative MRI data of 774 patients with glioma (281 female, 492 male, 1 unknown, age range 19-86 years) treated at the Erasmus MC between 2008 and 2018 is available. For all patients a pre-contrast T1-weighted, post-contrast T1-weighted, T2-weighted, and T2-weighted FLAIR scan are available, made on a variety of scanners from four different vendors. All scans are registered to a common atlas and defaced. Genetic and histological data consists of the IDH mutation status (available for 467 patients), 1p/19q co-deletion status (available for 259 patients), and grade (available for 716 patients). The full WHO 2016 subtype is available for 415 patients. Manual segmentations are available for 374 patients and automatically generated segmentations are available for 400 patients. The dataset can be used to relate the visual appearance of the tumor on the scan with the genetic and histological features, and to develop automatic segmentation methods.

Adjuvant and concurrent temozolomide for 1p/19q non-co-deleted anaplastic glioma (CATNON; EORTC study 26053-22054): second interim analysis of a randomised, open-label, phase 3 study

BACKGROUND

The CATNON trial investigated the addition of concurrent, adjuvant, and both current and adjuvant temozolomide to radiotherapy in adults with newly diagnosed 1p/19q non-co-deleted anaplastic gliomas. The benefit of concurrent temozolomide chemotherapy and relevance of mutations in the IDH1 and IDH2 genes remain unclear.

METHODS

This randomised, open-label, phase 3 study done in 137 institutions across Australia, Europe, and North America included patients aged 18 years or older with newly diagnosed 1p/19q non-co-deleted anaplastic gliomas and a WHO performance status of 0-2. Patients were randomly assigned (1:1:1:1) centrally using a minimisation technique to radiotherapy alone (59·4 Gy in 33 fractions; three-dimensional conformal radiotherapy or intensity-modulated radiotherapy), radiotherapy with concurrent oral temozolomide (75 mg/m2 per day), radiotherapy with adjuvant oral temozolomide (12 4-week cycles of 150-200 mg/m2 temozolomide given on days 1-5), or radiotherapy with both concurrent and adjuvant temozolomide. Patients were stratified by institution, WHO performance status score, age, 1p loss of heterozygosity, the presence of oligodendroglial elements on microscopy, and MGMT promoter methylation status. The primary endpoint was overall survival adjusted by stratification factors at randomisation in the intention-to-treat population. A second interim analysis requested by the independent data monitoring committee was planned when two-thirds of total required events were observed to test superiority or futility of concurrent temozolomide. This study is registered with ClinicalTrials.gov, NCT00626990.

FINDINGS

Between Dec 4, 2007, and Sept 11, 2015, 751 patients were randomly assigned (189 to radiotherapy alone, 188 to radiotherapy with concurrent temozolomide, 186 to radiotherapy and adjuvant temozolomide, and 188 to radiotherapy with concurrent and adjuvant temozolomide). Median follow-up was 55·7 months (IQR 41·0-77·3). The second interim analysis declared futility of concurrent temozolomide (median overall survival was 66·9 months [95% CI 45·7-82·3] with concurrent temozolomide vs 60·4 months [45·7-71·5] without concurrent temozolomide; hazard ratio [HR] 0·97 [99·1% CI 0·73-1·28], p=0·76). By contrast, adjuvant temozolomide improved overall survival compared with no adjuvant temozolomide (median overall survival 82·3 months [95% CI 67·2-116·6] vs 46·9 months [37·9-56·9]; HR 0·64 [95% CI 0·52-0·79], p<0·0001). The most frequent grade 3 and 4 toxicities were haematological, occurring in no patients in the radiotherapy only group, 16 (9%) of 185 patients in the concurrent temozolomide group, and 55 (15%) of 368 patients in both groups with adjuvant temozolomide. No treatment-related deaths were reported.

INTERPRETATION

Adjuvant temozolomide chemotherapy, but not concurrent temozolomide chemotherapy, was associated with a survival benefit in patients with 1p/19q non-co-deleted anaplastic glioma. Clinical benefit was dependent on IDH1 and IDH2 mutational status.

FUNDING

Merck Sharpe & Dohme.

Accuracy of Machine Learning Algorithms for the Classification of Molecular Features of Gliomas on MRI: A Systematic Literature Review and Meta-Analysis

Simple Summary

Glioma prognosis and treatment are based on histopathological characteristics and molecular profile. Following the World Health Organization (WHO) guidelines (2016), the most important molecular diagnostic markers include IDH1/2-genotype and 1p/19q codeletion status, although more recent publications also include ARTX genotype and TERT- and MGMT promoter methylation. Machine learning algorithms (MLAs), however, were described to successfully determine these molecular characteristics non-invasively by using magnetic resonance imaging (MRI) data. The aim of this review and meta-analysis was to define the diagnostic accuracy of MLAs with regard to these different molecular markers. We found high accuracies of MLAs to predict each individual molecular marker, with IDH1/2-genotype being the most investigated and the most accurate. Radiogenomics could therefore be a promising tool for discriminating genetically determined gliomas in a non-invasive fashion. Although encouraging results are presented here, large-scale, prospective trials with external validation groups are warranted.

Abstract

Treatment planning and prognosis in glioma treatment are based on the classification into low- and high-grade oligodendroglioma or astrocytoma, which is mainly based on molecular characteristics (IDH1/2- and 1p/19q codeletion status). It would be of great value if this classification could be made reliably before surgery, without biopsy. Machine learning algorithms (MLAs) could play a role in achieving this by enabling glioma characterization on magnetic resonance imaging (MRI) data without invasive tissue sampling. The aim of this study is to provide a performance evaluation and meta-analysis of various MLAs for glioma characterization. Systematic literature search and meta-analysis were performed on the aggregated data, after which subgroup analyses for several target conditions were conducted. This study is registered with PROSPERO, CRD42020191033. We identified 724 studies; 60 and 17 studies were eligible to be included in the systematic review and meta-analysis, respectively. Meta-analysis showed excellent accuracy for all subgroups, with the classification of 1p/19q codeletion status scoring significantly poorer than other subgroups (AUC: 0.748, p = 0.132). There was considerable heterogeneity among some of the included studies. Although promising results were found with regard to the ability of MLA-tools to be used for the non-invasive classification of gliomas, large-scale, prospective trials with external validation are warranted in the future.

Clinical Characteristics and Overall Survival Prognostic Nomogram for Oligodendroglioma: A Surveillance, Epidemiology, and End Results Population-Based Analysis

OBJECTIVE

Oligodendroglioma is a rare primary malignant brain tumor that has highly variable clinical outcomes. The aim of this study was to investigate demographics, outcomes, and prognostic factors of all oligodendroglioma cases from the Surveillance, Epidemiology, and End Results database to build a clinical prognosis model to predict survival time of patients with oligodendroglioma.

METHODS

Cases diagnosed between 1975 and 2016 were selected from the Surveillance, Epidemiology, and End Results database. Age, sex, race, insurance, year of diagnosis, marital status, tumor location, tumor size, summary stage, surgery method, and use of radiotherapy and chemotherapy were evaluated with respect to overall survival by univariate and multivariate analysis. A nomogram predicting 5- and 10-year survival probability for oligodendroglioma was constructed and validated.

RESULTS

After data cleaning, 4568 patients with oligodendroglioma were included. At the time of last follow-up, mean survival times among grade II and grade III oligodendrogliomas were 74 and 39 months, respectively. In multivariate analysis, radiotherapy, age, tumor site, summary stage, and surgery demonstrated independent associations with survival in both cohorts. Race and radiotherapy demonstrated independent associations with survival in grade II oligodendroglioma. Sex and chemotherapy demonstrated independent associations with survival in grade III oligodendroglioma. Independent factors in either cohort were selected to build a clinical nomogram. The C-index for the nomogram was 0.738 (95% confidence interval 0.718-0.757). The calibration curves of 5- and 10-year survival rates showed good agreement between the nomogram predictions and actual observations.

CONCLUSIONS

This study was the first to develop a nomogram for predicting overall survival of patients with oligodendroglioma to help clinicians predict patient prognosis accurately and conduct further treatment.

CODEL: phase III study of RT, RT + TMZ, or TMZ for newly diagnosed 1p/19q codeleted oligodendroglioma. Analysis from the initial study design

BACKGROUND

We report the analysis involving patients treated on the initial CODEL design.

METHODS

Adults (>18) with newly diagnosed 1p/19q World Health Organization (WHO) grade III oligodendroglioma were randomized to radiotherapy (RT; 5940 centigray ) alone (arm A); RT with concomitant and adjuvant temozolomide (TMZ) (arm B); or TMZ alone (arm C). Primary endpoint was overall survival (OS), arm A versus B. Secondary comparisons were performed for OS and progression-free survival (PFS), comparing pooled RT arms versus TMZ-alone arm.

RESULTS

Thirty-six patients were randomized equally. At median follow-up of 7.5 years, 83.3% (10/12) TMZ-alone patients progressed, versus 37.5% (9/24) on the RT arms. PFS was significantly shorter in TMZ-alone patients compared with RT patients (hazard ratio [HR] = 3.12; 95% CI: 1.26, 7.69; P = 0.014). Death from disease progression occurred in 3/12 (25%) of TMZ-alone patients and 4/24 (16.7%) on the RT arms. OS did not statistically differ between arms (comparison underpowered). After adjustment for isocitrate dehydrogenase (IDH) status (mutated/wildtype) in a Cox regression model utilizing IDH and RT treatment status as covariables (arm C vs pooled arms A + B), PFS remained shorter for patients not receiving RT (HR = 3.33; 95% CI: 1.31, 8.45; P = 0.011), but not OS ((HR = 2.78; 95% CI: 0.58, 13.22, P = 0.20). Grade 3+ adverse events occurred in 25%, 42%, and 33% of patients (arms A, B, and C). There were no differences between arms in neurocognitive decline comparing baseline to 3 months.

CONCLUSIONS

TMZ-alone patients experienced significantly shorter PFS than patients treated on the RT arms. The ongoing CODEL trial has been redesigned to compare RT + PCV versus RT + TMZ.

Diagnostic Utility of the Immunohistochemical Expression of Serine and Arginine Rich Splicing Factor 1 (SRSF1) in the Differential Diagnosis of Adult Gliomas

Simple Summary

Gliomas represent a wide group of central nervous system neoplasms, arising from the glial component of the central nervous system. They are generally sub-classified into astrocytomas, oligodendrogliomas, ependymomas and other rarer subtypes. Apart from morphological and molecular features, there are currently no specific markers for this heterogeneous group of tumors: thus, there is a need to identify more specific and useful markers to distinguish each histological subtype from the others. SRSF1 has been recently characterized as being functionally involved in gliomagenesis and it has been found that SRSF1 is increased in glioma tissues and its increased immunohistochemical expression among adult diffuse astrocytomas is positively correlated with histological grade. The aim of this study is to evaluate the immunohistochemical expression of the SRSF1 protein in a series of astrocytic and non-astrocytic adult gliomas, emphasizing its potential use in the differential diagnosis of these neuropathological entities.

Abstract

Background: The aim of this study was to investigate the immunohistochemical expression and distribution of serine and arginine rich splicing factor 1 (SRSF1) in a series of 102 cases of both diffuse and circumscribed adult gliomas to establish the potential diagnostic role of this protein in the differential diagnosis of brain tumors. Methods: This retrospective immunohistochemical study included 42 glioblastoma cases, 21 oligodendrogliomas, 15 ependymomas, 15 pilocytic astrocytomas, 5 sub-ependymal giant cell astrocytoma and 4 pleomorphic xanthoastrocytomas. Results: Most glioblastoma (81%), oligodendroglioma (71%), sub-ependymal giant cell astrocytoma (80%) and pleomorphic xanthoastrocytoma (75%) cases showed strong SRSF1 immunoexpression, while no detectable staining was found in the majority of ependymomas (87% of cases) and pilocytic astrocytomas (67% of cases). Conclusions: The immunohistochemical expression of SRSF1 may be a promising diagnostic marker of astrocytomas and oligodendrogliomas and its increased expression might allow for excluding entities that often enter into differential diagnosis, such as ependymomas and pilocytic astrocytomas.

TEMOBIC: Phase II Trial of Neoadjuvant Chemotherapy for Unresectable Anaplastic Gliomas: An ANOCEF Study

LESSONS LEARNED

Treatment with temozolomide and BCNU was associated with substantial response and survival rates for patients with unresectable anaplastic glioma, suggesting potential therapeutic alternative for these patients. The optimal treatment for unresectable large anaplastic gliomas remains debated.

BACKGROUND

The optimal treatment for unresectable large anaplastic gliomas remains debated.

METHODS

Adult patients with histologically proven unresectable anaplastic oligodendroglioma or mixed gliomas (World Health Organization [WHO] 2007) were eligible. Treatment consisted of BCNU (150 mg/m² ) and temozolomide (110 mg/m² for 5 days) every 6 weeks for six cycles before radiotherapy.

RESULTS

Between December 2005 and December 2009, 55 patients (median age of 53.1 years; range, 20.5-70.2) were included. Forty percent of patients presented with wild-type IDH1 gliomas, and 30% presented with methylated MGMT promoter. Median progression-free survival (PFS), centralized PFS, and overall survival (OS) were 16.6 (95% confidence interval [CI], 12.8-20.3), 15.4 (95% CI, 10.0-20.8), and 25.4 (95% CI, 17.5-33.2) months, respectively. Complete and partial responses under chemotherapy were observed for 28.3% and 17% of patients, respectively. Radiotherapy completion was achieved for 75% of patients. Preservation of functional status and self-care capability (Karnofsky performance status [KPS] ≥70) were preserved until disease progression for 69% of patients. Grade ≥ 3 toxicities were reported for 52% of patients, and three deaths were related to treatment. By multivariate analyses including age and KPS, IDH mutation was associated with better prognostic for both PFS and OS, whereas MGMT promoter methylation was associated with better OS.

CONCLUSION

The association of BCNU and temozolomide upfront is active for patients with unresectable anaplastic gliomas, but toxicity limits its use.

SNP-based detection of allelic imbalance: A novel approach for identifying KIAA1549-BRAF fusion in pilocytic astrocytoma using DNA sequencing

Pilocytic astrocytoma (PA) is the most common glioma subtype found in children, and it is a non-malignant tumor type. The majority of PAs is caused by an approximately 2 Mb tandem duplication within 7q34 which creates an in-frame KIAA1549-BRAF fusion gene. The kinase domain of BRAF is fused to the N-terminal of KIAA1549, whereby BRAF is constitutively activated. We here present a novel approach for identifying KIAA1549-BRAF fusion based on single nucleotide polymorphism (SNP) analysis and next generation sequencing (NGS). Highly polymorphic SNPs in the duplicated area and in adjacent areas were selected and a custom targeted amplicon based NGS panel was designed. The panel was tested on DNA extracted from formalin fixed and paraffin embedded tissue from a retrospective cohort, consisting of biopsies from patients with PA, anaplastic astrocytoma, oligodendroglioma and glioblastoma as well as two non-tumor biopsies. The panel could distinguish chromosome 7 gain from BRAF fusion and correctly identified 8/9 PA samples with KIAA1549-BRAF fusion confirmed by RNA sequencing. The one biopsy where no fusion was detected was fresh frozen and from the RNA sequencing expected to have very low tumor content. No allelic imbalance was detected in either oligodendroglioma or in the non-tumor biopsies.

IDH-Mutant Low-grade Glioma: Advances in Molecular Diagnosis, Management, and Future Directions

PURPOSE OF REVIEW

IDH-mutant low-grade gliomas (LGG) have emerged as a distinct clinical and molecular entity with unique treatment considerations. Here, we review updates in IDH-mutant LGG diagnosis and classification, imaging biomarkers, therapies, and neurocognitive and patient-reported outcomes.

RECENT FINDINGS

CDKN2A/B homozygous deletion in IDH-mutant astrocytoma is associated with shorter survival, similar to WHO grade 4. The T2-FLAIR mismatch, a highly specific but insensitive sign, is diagnostic of IDH-mutant astrocytoma. Maximal safe resection is currently indicated in all LGG cases. Radiotherapy with subsequent PCV (procarbazine, lomustine, vincristine) provides longer overall survival compared to radiotherapy alone. Temozolomide in place of PCV is reasonable, but high-level evidence is still lacking. LGG adjuvant treatment has important quality of life and neurocognitive side effects that should be considered. Although incurable, IDH-mutant LGG have a favorable survival compared to IDH-WT glioma. Recent advances in molecular-based classification, imaging, and targeted therapies will hopefully improve survival and quality of life.

A basic review on systemic treatment options in WHO grade II-III gliomas

WHO grade II-III gliomas are rare primary brain tumors occurring at a median age of about 35-55 years. Median survival is longer in WHO grade II-III glioma compared with WHO grade IV glioblastoma as survival times of up to 10 years and longer can be observed. Maximal safe resection and adjuvant therapies including chemotherapy and radiotherapy are the mainstay of treatment. Clinical trials in WHO grade II-III tumors are challenging due to the rarity and the long follow up times. The 2016 WHO Classification of Central Nervous Tumours introduced a new diagnostic framework relying on molecular characteristics, providing the definition of prognostically more homogenous subgroups compared to the histopathological analysis. Most available evidence on the adjuvant treatment of WHO II-III gliomas was generated in the pre-molecular era, challenging the interpretation of study results. The present review therefore summarizes the available data from prospective trials on systemic treatment options in WHO grade II-III glioma, considering molecular markers, recently published results and future outlooks in the field.

lncRNA CTBP1-AS2 promotes proliferation and migration of glioma by modulating miR-370-3p-Wnt7a-mediated epithelial-mesenchymal transition

Glioma is one of the most common and aggressive malignant primary brain tumors, with a poor 5-year survival rate. The long noncoding RNA (lncRNA) CTBP1-AS2 has been shown to be correlated with the prognosis of cancer, but the role of CTBP1-AS2 in glioma and its concrete mechanism is fully unknown. The clinical data and tissues of glioma patients were analyzed. Cell viability and migration assays were performed. Western blotting and qRT-PCR were adopted for investigation of target protein expressions. Double luciferase assay was used to investigate the interaction between different elements. The lncRNA CTBP1-AS2 had increased expression profiles in tumor tissues, which is associated with poor prognosis. In detail, CTBP1-AS2 knockdown decreased proliferation and migration phenotypes in both U87-MG and LN229 cells. Moreover, CTBP1-AS2 knockdown suppressed the key epithelial-mesenchymal transition (EMT) markers by downregulating Wnt7a-mediated signaling. Furthermore, miR-370-3p functioned as a link that could be absorbed by CTBP1-AS2, thus regulating Wnt7a expression. Lastly, the CTBP1-AS2-miR-370-3p-Wnt7a axis modulated EMT in glioma cells in vitro and in vivo. This study provides new insights that a novel lncRNA, CTBP1-AS2, regulates EMT of glioma by modulating the miR-370-3p-Wnt7a axis.

Central Nervous System Cancers, Version 3.2020, NCCN Clinical Practice Guidelines in Oncology

The NCCN Guidelines for Central Nervous System (CNS) Cancers focus on management of adult CNS cancers ranging from noninvasive and surgically curable pilocytic astrocytomas to metastatic brain disease. The involvement of an interdisciplinary team, including neurosurgeons, radiation therapists, oncologists, neurologists, and neuroradiologists, is a key factor in the appropriate management of CNS cancers. Integrated histopathologic and molecular characterization of brain tumors such as gliomas should be standard practice. This article describes NCCN Guidelines recommendations for WHO grade I, II, III, and IV gliomas. Treatment of brain metastases, the most common intracranial tumors in adults, is also described.

The interaction between TERT promoter mutation and MGMT promoter methylation on overall survival of glioma patients: a meta-analysis

Background

There are controversial results concerning the prognostic implication of TERT promoter mutation in glioma patients concerning MGMT status. In this meta-analysis, we investigated whether there are any interactions of these two genetic markers on the overall survival (OS) of glioma patients.

Methods

Electronic databases including PubMed and Web of Science were searched for relevant studies. Hazard ratio (HR) and its 95% confidence interval (CI) for OS adjusted for selected covariates were calculated from the individual patient data (IPD), Kaplan-Meier curve (KMC), or directly obtained from the included studies.

Results

A total of nine studies comprising 2819 glioma patients were included for meta-analysis. Our results showed that TERT promoter mutation was associated with a superior outcome in MGMT-methylated gliomas (HR = 0.73; 95% CI = 0.55–0.98; p-value = 0.04), whereas this mutation was associated with poorer survival in gliomas without MGMT methylation (HR = 1.86; 95% CI = 1.54–2.26; p-value < 0.001). TERT-mutated glioblastoma (GBM) patients with MGMT methylation benefited from temozolomide (TMZ) treatment (HR = 0.33; 95% CI = 0.23–0.47; p-value < 0.001). MGMT methylation was not related with any improvement in OS in TERT-wild type GBMs (HR = 0.80; 95% CI = 0.56–1.15; p-value = 0.23).

Conclusions

The prognostic value of TERT promoter mutation may be modulated by MGMT methylation status. Not all MGMT-methylated GBM patients may benefit from TMZ; it is possible that only TERT-mutated GBM with MGMT methylation, in particular, may respond.

CeRNA Network Analysis Representing Characteristics of Different Tumor Environments Based on 1p/19q Codeletion in Oligodendrogliomas

Simple Summary

Oligodendroglioma (OD) is a subtype of glioma occurring in the central nervous system. The 1p/19q codeletion is a prognostic marker of OD with an isocitrate dehydrogenase (IDH) mutation and is associated with a clinically favorable overall survival (OS). The long non-coding RNAs (lncRNAs) protects the mRNA from degradation by binding with the same miRNA by acting as a competitive endogenous RNA (ceRNA). Recently, although there is an increasing interest in lncRNAs on glioma studies, however, studies regarding their effects on OD and the 1p/19q codeletion remain limited. In our study, we performed in silico analyses using low-grade gliomas from datasets obtained from The Cancer Genome Atlas to investigate the effects of ceRNA with 1p/19q codeletion on ODs. We constructed 16 coding RNA–miRNA–lncRNA networks and the ceRNA network participated in ion channel activity, insulin secretion, and collagen network and extracellular matrix (ECM) changes. In conclusion, our results can provide insights into the possibility in the different tumor microenvironments and OS following 1p/19q codeletion through changes in the ceRNA network.

Abstract

Oligodendroglioma (OD) is a subtype of glioma occurring in the central nervous system. The 1p/19q codeletion is a prognostic marker of OD with an isocitrate dehydrogenase (IDH) mutation and is associated with a clinically favorable overall survival (OS); however, the exact underlying mechanism remains unclear. Long non-coding RNAs (lncRNAs) have recently been suggested to regulate carcinogenesis and prognosis in cancer patients. Here, we performed in silico analyses using low-grade gliomas from datasets obtained from The Cancer Genome Atlas to investigate the effects of ceRNA with 1p/19q codeletion on ODs. Thus, we selected modules of differentially expressed genes that were closely related to 1p/19q codeletion traits using weighted gene co-expression network analysis and constructed 16 coding RNA–miRNA–lncRNA networks. The ceRNA network participated in ion channel activity, insulin secretion, and collagen network and extracellular matrix (ECM) changes. In conclusion, ceRNAs with a 1p/19q codeletion can create different tumor microenvironments via potassium ion channels and ECM composition changes; furthermore, differences in OS may occur. Moreover, if extrapolated to gliomas, our results can provide insights into the consequences of identical gene expression, indicating the possibility of tracking different biological processes in different subtypes of glioma.