Adult infiltrating gliomas with WHO 2016 integrated diagnosis: additional prognostic roles of ATRX and TERT

Potential Diagnostic and Clinical Significance of Selected Genetic Alterations in Glioblastoma

Glioblastoma is currently considered the most common and, unfortunately, also the most aggressive primary brain tumor, with the highest morbidity and mortality rates. The average survival of patients diagnosed with glioblastoma is 14 months, and only 2% of patients survive 3 years after surgery. Based on our clinical experience and knowledge from extensive clinical studies, survival is mainly related to the molecular biological properties of glioblastoma, which are of interest to the general medical community. Our study examined a total of 71 retrospective studies published from 2016 through 2022 and available on PubMed that deal with mutations of selected genes in the pathophysiology of GBM. In conclusion, we can find other mutations within a given gene group that have different effects on the prognosis and quality of survival of a patient with glioblastoma. These mutations, together with the associated mutations of other genes, as well as intratumoral heterogeneity itself, offer enormous potential for further clinical research and possible application in therapeutic practice.

Can quantifying the extent of 'high grade' features help explain prognostic variability in anaplastic astrocytoma?

PURPOSE

Both phenotypic and genotypic variations now underpin glioma classification, thus helping to more accurately guide their clinical management. However, WHO Grade III anaplastic astrocytoma (AA) remains an unpredictable, heterogeneous entity; displaying a variable prognosis, clinical course and treatment response. This study aims to examine whether additional tumour characteristics influence either overall survival (OS) or 3-year survival in AA.

MATERIALS AND METHODS

Data were collected on all newly diagnosed cases of AA between 2003 and 2014, followed up for a minimum of 3 years. Molecular information was obtained from case records and if missing, was re-analysed. Histological slides were independently examined for Ki-67 proliferation index, cellularity and number of mitotic figures. Kaplan-Meier and Cox regression analyses were used to assess OS.

RESULTS

In total, 50 cases were included with a median OS of 14.5 months (range: 1-150 months). Cumulative 3-year survival was 31.5%. Median age was 50 years (range: 24 - 77). Age, IDH1 mutation status, lobar location, oncological therapy and surgical resection were significant independent prognostic indicators for OS. In cases demonstrating an OS ≥ 3 years (n = 15), Ki-67 index, number of mitotic figures and percentage areas of 'high cellularity' were significantly reduced, i.e. more characteristic of lower-grade/WHO Grade II glioma.

CONCLUSIONS

IDH1 status, age, treatment and location remain the most significant prognostic indicators for patients with AA. However, Ki-67 index, mitotic figures and cellularity may help identify AA cases more likely to survive < 3 years, i.e. AA cases more similar to glioblastoma and those cases more likely to survive > 3 years, i.e. more similar to a low-grade glioma.

A custom next-generation sequencing panel for 1p/19q codeletion and mutational analysis in gliomas

The World Health Organization has updated their classification system for the diagnosis of gliomas, combining histological features with molecular data including isocitrate dehydrogenase 1 and codeletion of chromosomal arms 1p and 19q. 1p/19q codeletion analysis is commonly performed by fluorescence in situ hybridization (FISH). In this study, we developed a 57-gene targeted next-generation sequencing (NGS) panel including 1p/19q codeletion detection mainly to assess diagnosis and potential treatment response in melanoma, gastrointestinal stromal tumor, and glioma patients. Loss of heterozygosity analysis was performed using the NGS method on 37 formalin-fixed paraffin-embedded glioma tissues that showed 1p and/or 19q loss determined by FISH. Conventional methods were applied for the validation of some glioma-related gene mutations. In 81.1% (30 of 37) and 94.6% (35 of 37) of cases, 1p and 19q were found to be in agreement whereas concordance for 1p/19q codeletion and no 1p/19q codeletion was found in 94.7% (18 of 19) and 94.4% (17 of 18) of cases, respectively. Overall, comparing NGS results with those of conventional methods showed high concordance. In conclusion, the NGS panel allows reliable analysis of 1p/19q codeletion and mutation at the same time.

Genome-wide Polygenic Risk Scores Predict Risk of Glioma and Molecular Subtypes

Background

Polygenic risk scores (PRS) aggregate the contribution of many risk variants to provide a personalized genetic susceptibility profile. Since sample sizes of glioma genome-wide association studies (GWAS) remain modest, there is a need to find efficient ways of capturing genetic risk factors using available germline data.

Methods

We developed a novel PRS (PRS-CS) that uses continuous shrinkage priors to model the joint effects of over 1 million polymorphisms on disease risk and compared it to an approach (PRS-CT) that selects a limited set of independent variants that reach genome-wide significance (P<5×10-8). PRS models were trained using GWAS results stratified by histological (10,346 cases, 14,687 controls) and molecular subtype (2,632 cases, 2,445 controls), and validated in two independent cohorts.

Results

PRS-CS was consistently more predictive than PRS-CT across glioma subtypes with an average increase in explained variance (R2) of 21%. Improvements were particularly pronounced for glioblastoma tumors, with PRS-CS yielding larger effect sizes (odds ratio (OR)=1.93, P=2.0×10-54 vs. OR=1.83, P=9.4×10-50) and higher explained variance (R2=2.82% vs. R2=2.56%). Individuals in the 95th percentile of the PRS-CS distribution had a 3-fold higher lifetime absolute risk of IDH mutant (0.63%) and IDH wildtype (0.76%) glioma relative to individuals with average PRS. PRS-CS also showed high classification accuracy for IDH mutation status among cases (AUC=0.895).

Conclusions

Our novel genome-wide PRS may improve the identification of high-risk individuals and help distinguish between prognostic glioma subtypes, increasing the potential clinical utility of germline genetics in glioma patient management.

Epidemiology and survival of adult-type diffuse glioma in Belgium during the molecular era

BACKGROUND

Survival data of diffuse adult-type glioma is mostly based on prospective clinical trials or small retrospective cohort studies. Real-world data with large patient cohorts is currently lacking.

METHODS

Using the nationwide, population-based Belgian Cancer Registry, all known histological reports of patients diagnosed with an adult-type diffuse glioma in Belgium between 2017 and 2019 were reviewed. The ICD-O-3 morphology codes were matched with the histological diagnosis. The gathered data were transformed into the 2021 World Health Organization classification of CNS tumors using the IDH- and 1p/19q-mutation status.

RESULTS

Between 2017 and 2019, 2233 diffuse adult-type gliomas were diagnosed in Belgium. Full molecular status was available in 67.1% of identified cases. The age-standardized incidence rate of diffuse adult-type glioma in Belgium was estimated at 8.55 per 100 000 person-years and 6.72 per 100 000 person-years for grade 4 lesions. Median overall survival time in IDH-wild-type glioblastoma was 9.3 months, significantly shorter compared to grade 4 IDH-mutant astrocytoma (median survival time: 25.9 months). The 3-year survival probability was 86.0% and 75.7% for grades 2 and 3 IDH-mutated astrocytoma. IDH-wild-type astrocytoma has a worse prognosis with a 3-year survival probability of 31.6% for grade 2 and 5.7% for grade 3 lesions.

CONCLUSIONS

This registry-based study presents a large cohort of adult-type diffuse glioma with known molecular status and uses real-world survival data. It adds to the current literature which is mainly based on historical landmark trials and smaller retrospective cohort studies.

TERT promoter mutations and the outcome of patients with advanced urothelial carcinoma treated by platinum-based chemotherapy or pembrolizumab

BACKGROUND

TERT promoter mutation is one of the most common genomic alterations in urothelial carcinoma (UC). Its prognostic role on patients' outcomes is still not clear.

METHODS

We performed a single-center retrospective analysis on patients with advanced UC treated with platinum-based chemotherapy or immunotherapy to assess the presence of somatic TERT-124[C>T] and TERT-146[C>T] mutations and their association with clinicopathologic factors and survival outcomes. Patients were assessed for Overall Survival (OS), Progression-Free Survival (PFS), and Overall Response Rate (ORR).

RESULTS

We analyzed 45 UC tumors; 38 of them received first-line chemotherapy and 21 second-line pembrolizumab; 6 patients (13%) harbored -146 C > T TERTp mutation and 25 patients (56%)-124 C > T. The presence of TERT promoter mutations was associated with a higher rate of lower tract UC and a lower rate of synchronous or lymph node metastases. TERT wild-type patients showed higher 12- and 24-months OS-rates in the chemotherapy subgroup and 6-, 12- and 24-months OS rates in the pembrolizumab subgroup. The presence of TERT promoter mutations was also associated with a lower 6 months-PFS rate in patients receiving chemotherapy and in all the three time points in those treated by pembrolizumab. The ORRs of pembrolizumab were 21% and 71% in patients with or without TERT promoter mutations, respectively (p < 0.001).

CONCLUSIONS

Our analysis suggests that the presence of TERT promoter mutations could negatively affect the outcome of UC patients treated by chemotherapy or pembrolizumab. This hypothesis should be further evaluated in wider cohorts.

Identification of telomere-associated gene signatures to predict prognosis and drug sensitivity in glioma

OBJECTIVE

Gliomas are a heterogeneous group of brain tumors with distinct biological and clinical properties, leading to significant mortality and morbidity. Emerging evidence shows telomere maintenance has implicated in glioma susceptibility and prognosis. In this study, we comprehensively analyzed gene signatures related to telomere maintenance in glioma and their predictive values for predicting the prognosis and drug sensitivity in glioma.

METHODS

We initially identified telomere-related genes differentially expressed between low-grade glioma (LGG) and glioblastoma (GBM) and accordingly developed a risk model by univariate and multivariate Cox analysis to assess the expressions of telomere-related genes across the risk groups. Finally, to assess these genes in immune function the anti-tumor medications often used in the clinical treatment of glioma, we computed immune cell infiltration analysis and drug sensitivity analysis.

RESULTS

The consensus clustering analysis identified 20 telomere-related genes which split LGG patients into two distinct subtypes. The patient survival, the expressions of key telomere-related DEGs, and immune cell infiltration significantly differed between Cluster 1 and Cluster 2. The LASSO risk model [riskScore=(0.086)*HOXA7+(0.242)*WEE1+(0.247)*IGF2BP3+(0.052)*DUSP10] showed significant differences regarding the 1-, 3-, 5-year overall survival, immune cell infiltration, and drug sensitivity between high- and low-risk groups. The predictive nomogram constructed to quantify the survival probability of each sample at 1, 3, and 5 years was consistent with the actual patient survival.

CONCLUSION

Our comprehensive characterization of telomere-associated gene signatures in glioma reveals their possible roles in the development, tumor microenvironment, and prognosis. The study provides some suggestive relationships between four telomere-related genes (HOXA7, WEE1, IGF2BP3, and DUSP10) and glioma prognosis.

The Biological and Clinical Role of the Telomerase Reverse Transcriptase Gene in Glioblastoma: A Potential Therapeutic Target?

Glioblastoma IDH-wildtype represents the most lethal and frequent primary tumor of the central nervous system. Thanks to important scientific efforts, we can now investigate its deep genomic assessment, elucidating mutated genes and altered biological mechanisms in addition to its clinical aggressiveness. The telomerase reverse transcriptase gene (TERT) is the most frequently altered gene in solid tumors, including brain tumors and GBM IDH-wildtype. In particular, it can be observed in approximately 80-90% of GBM IDH-wildtype cases. Its clonal distribution on almost all cancer cells makes this gene an optimal target. However, the research of effective TERT inhibitors is complicated by several biological and clinical obstacles which can be only partially surmounted. Very recently, novel immunological approaches leading to TERT inhibition have been investigated, offering the potential to develop an effective target for this altered protein. Here, we perform a narrative review investigating the biological role of TERT alterations on glioblastoma and the principal obstacles associated with TERT inhibitions in this population. Moreover, we discuss possible combination treatment strategies to overcome these limitations.

ATRX is a predictive marker for endocrinotherapy and chemotherapy resistance in HER2-/HR+ breast cancer through the regulation of the AR, GLI3 and GATA2 transcriptional network

Drug resistance in breast cancer (BC) is a clinical challenge. Exploring the mechanism and identifying a precise predictive biomarker for the drug resistance in BC is critical. Three first-line drug (paclitaxel, doxorubicin and tamoxifen) resistance datasets in BC from GEO were merged to obtain 1,461 differentially expressed genes for weighted correlation network analysis, resulting in identifying ATRX as the hub gene. ATRX is a chromatin remodelling protein, therefore, ATRX-associated transcription factors were explored, thereby identifying the network of AR, GLI3 and GATA2. GO and KEGG analyses revealed immunity, transcriptional regulation and endocrinotherapy/chemotherapy resistance were enriched. Moreover, CIBERSORT revealed immunity regulation was inhibited in the resistance group. ssGSEA showed a significantly lower immune status in the ATRX-Low group compared to the ATRX-High group. Furthermore, the peaks of H3K9me3 ChIP-seq on the four genes were higher in normal tissues than in BC tissues. Notably, the frequency of ATRX mutation was higher than BRCA in BC. Moreover, depressed ATRX revealed worse overall survival and disease-free survival in the human epidermal growth factor receptor 2 (HER2)-/hormone receptor (HR)+ BC. Additionally, depressed ATRX predicted poor results for patients who underwent endocrinotherapy or chemotherapy in the HER2-/HR+ BC subgroup. A nomogram based on ATRX, TILs and ER exhibited a significantly accurate survival prediction ability. Importantly, overexpression of ATRX significantly inhibited the IC50 of the three first-line drugs on MCF-7 cell. Thus, ATRX is an efficient predictive biomarker for endocrinotherapy and chemotherapy resistance in HER2-/HR+ BC and acts by suppressing the AR, GLI3 and GATA2 transcriptional network.

Potential of pre-operative MRI features in glioblastoma to predict for molecular stem cell subtype and patient overall survival

AIM OF THE STUDY

A molecular signature based on 10 mRNA abundances that characterizes the mesenchymal-to-proneural phenotype of glioblastoma stem(like) cells (GSCs) enriched in primary culture has been previously established. As this phenotype has been proposed to be prognostic for disease outcome the present study aims to identify features of the preoperative MR imaging that may predict the GSC phenotype of individual tumors.

MATERIAL/METHODS

Molecular mesenchymal-to-proneural mRNA signatures and intrinsic radioresistance (SF4, survival fraction at 4 Gy) of primary GSC-enriched cultures were associated with survival data and pre-operative MR imaging of the corresponding glioblastoma patients of a prospective cohort (n = 24). The analyzed imaging parameters comprised linear vectors derived from tumor volume, necrotic volume and edema as contoured manually.

RESULTS

A necrosis/tumor vector ratio and to a weaker extent the product of this ratio and the edema vector were identified to correlate with the mesenchymal-to-proneural mRNA signature and the SF4 of the patient-derived GSC cultures. Importantly, both parameter combinations were predictive for overall survival of the whole patient cohort. Moreover, the combination of necrosis/tumor vector ratio and edema vector differed significantly between uni- and multifocally recurring tumors.

CONCLUSION

Features of the preoperative MR images may reflect the molecular signature of the GSC population and might be used in the future as a prognostic factor and for treatment stratification especially in the MGMT promotor-unmethylated sub-cohort of glioblastoma patients.

Concordance analysis of cerebrospinal fluid with the tumor tissue for integrated diagnosis in gliomas based on next-generation sequencing

Purpose: The driver mutations of gliomas have been identified in cerebrospinal fluid (CSF). Here we compared the concordance between CSF and tumor tissue for integrated diagnosis in gliomas using next-generation sequencing (NGS) to evaluate the feasibility of CSF detection in gliomas. Patients and methods: 27 paired CSF/tumor tissues of glioma patients were sequenced by a customized gene panel based on NGS. All CSF samples were collected through lumbar puncture before surgery. Integrated diagnosis was made by analysis of histology and tumor DNA molecular pathology according to the 2021 WHO classification of the central nervous system tumors. Results: A total of 24 patients had detectable circulating tumor DNA (ctDNA) and 22 had at least one somatic mutation or chromosome alteration in CSF. The ctDNA levels varied significantly across different ages, Ki-67 index, magnetic resonance imaging signal and glioma subtypes (p < 0.05). The concordance between integrated ctDNA diagnosis and the final diagnosis came up to 91.6% (Kappa, 0.800). We reclassified the clinical diagnosis of 3 patients based on the results of CSF ctDNA sequencing, and 4 patients were reassessed depending on tumor DNA. Interestingly, a rare IDH1 R132C was identified in CSF ctDNA, but not in the corresponding tumor sample. Conclusion: This study demonstrates a high concordance between integrated ctDNA diagnosis and the final diagnosis of gliomas, highlighting the practicability of NGS based detection of mutations of CSF in assisting integrated diagnosis of gliomas, especially glioblastoma.

The combined signatures of telomere and immune cell landscape provide a prognostic and therapeutic biomarker in glioma

Background

Gliomas, the most prevalent primary malignant tumors of the central nervous system in adults, exhibit slow growth in lower-grade gliomas (LGG). However, the majority of LGG cases progress to high-grade gliomas, posing challenges for prognostication. The tumor microenvironment (TME), characterized by telomere-related genes and immune cell infiltration, strongly influences glioma growth and therapeutic response. Therefore, our objective was to develop a Telomere-TME (TM-TME) classifier that integrates telomere-related genes and immune cell landscape to assess prognosis and therapeutic response in glioma.

Methods

This study encompassed LGG patients from the TCGA and CCGA databases. TM score and TME score were derived from the expression signatures of telomere-related genes and the presence of immune cells in LGG, respectively. The TM-TME classifier was established by combining TM and TME scores to effectively predict prognosis. Subsequently, we conducted Kaplan-Meier survival estimation, univariate Cox regression analysis, and receiver operating characteristic curves to validate the prognostic prediction capacity of the TM-TME classifier across multiple cohorts. Gene Ontology (GO) analysis, biological processes, and proteomaps were performed to annotate the functional aspects of each subgroup and visualize the cellular signaling pathways.

Results

The TM_low+TME_high subgroup exhibited superior prognosis and therapeutic response compared to other subgroups (P<0.001). This finding could be attributed to distinct tumor somatic mutations and cancer cellular signaling pathways. GO analysis indicated that the TM_low+TME_high subgroup is associated with the neuronal system and modulation of chemical synaptic transmission. Conversely, the TM_high+TME_low subgroup showed a strong association with cell cycle and DNA metabolic processes. Furthermore, the classifier significantly differentiated overall survival in the TCGA LGG cohort and served as an independent prognostic factor for LGG patients in both the TCGA cohort (P<0.001) and the CGGA cohort (P<0.001).

Conclusion

Overall, our findings underscore the significance of the TM-TME classifier in predicting prognosis and immune therapeutic response in glioma, shedding light on the complex immune landscape within each subgroup. Additionally, our results suggest the potential of integrating risk stratification with precision therapy for LGG.

The application of decision tree model based on clinicopathological risk factors and pre-operative MRI radiomics for predicting short-term recurrence of glioblastoma after total resection: a retrospective cohort study

To develop a decision tree model based on clinical information, molecular genetics information and pre-operative magnetic resonance imaging (MRI) radiomics-score (Rad-score) to investigate its predictive value for the risk of recurrence of glioblastoma (GBM) within one year after total resection. Patients with pathologically confirmed GBM at Huashan Hospital, Fudan University between November 2017 and June 2020 were retrospectively analyzed, and the enrolled patients were randomly divided into training and test sets according to the ratio of 3:1. The relevant clinical and MRI data of patients before, after surgery and follow-up were collected, and after feature extraction on preoperative MRI, the LASSO filter was used to filter the features and establish the Rad-score. Using the training set, a decision tree model for predicting recurrence of GBM within one year after total resection was established by the C5.0 algorithm, and scatter plots were generated to evaluate the prediction accuracy of the decision tree during model testing. The prediction performance of the model was also evaluated by calculating area under the receiver operating characteristic (ROC) curve (AUC), ACC, Sensitivity (SEN), Specificity (SPE) and other indicators. Besides, two external validation datasets from Wuhan union hospital and the second affiliated hospital of Xuzhou Medical University were used to verify the reliability and accuracy of the prediction model. According to the inclusion and exclusion criteria, 134 patients with GBM were finally identified for inclusion in the study, and 53 patients recurred within one year after total resection, with a mean recurrence time of 5.6 months. According to the importance of the predictor variables, a decision tree model for predicting recurrence based on five important factors, including patient age, Rad-score, O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation, pre-operative Karnofsky Performance Status (KPS) and Telomerase reverse transcriptase (TERT) promoter mutation, was developed. The AUCs of the model in the training and test sets were 0.850 and 0.719, respectively, and the scatter plot showed excellent consistency. In addition, the prediction model achieved AUCs of 0.810 and 0.702 in two external validation datasets from Wuhan union hospital and the second affiliated hospital of Xuzhou Medical University, respectively. The decision tree model based on clinicopathological risk factors and preoperative MRI Rad-score can accurately predict the risk of recurrence of GBM within one year after total resection, which can further guide the clinical optimization of patient treatment decisions, as well as refine the clinical management of patients and improve their prognoses to a certain extent.

Machine learning for cryosection pathology predicts the 2021 WHO classification of glioma

BACKGROUND

Timely and accurate intraoperative cryosection evaluations remain the gold standard for guiding surgical treatments for gliomas. However, the tissue-freezing process often generates artifacts that make histologic interpretation difficult. In addition, the 2021 WHO Classification of Tumors of the Central Nervous System incorporates molecular profiles in the diagnostic categories, so standard visual evaluation of cryosections alone cannot completely inform diagnoses based on the new classification system.

METHODS

To address these challenges, we develop the context-aware Cryosection Histopathology Assessment and Review Machine (CHARM) using samples from 1,524 glioma patients from three different patient populations to systematically analyze cryosection slides.

FINDINGS

Our CHARM models successfully identified malignant cells (AUROC = 0.98 ± 0.01 in the independent validation cohort), distinguished isocitrate dehydrogenase (IDH)-mutant tumors from wild type (AUROC = 0.79-0.82), classified three major types of molecularly defined gliomas (AUROC = 0.88-0.93), and identified the most prevalent subtypes of IDH-mutant tumors (AUROC = 0.89-0.97). CHARM further predicts clinically important genetic alterations in low-grade glioma, including ATRX, TP53, and CIC mutations, CDKN2A/B homozygous deletion, and 1p/19q codeletion via cryosection images.

CONCLUSIONS

Our approaches accommodate the evolving diagnostic criteria informed by molecular studies, provide real-time clinical decision support, and will democratize accurate cryosection diagnoses.

FUNDING

Supported in part by the National Institute of General Medical Sciences grant R35GM142879, the Google Research Scholar Award, the Blavatnik Center for Computational Biomedicine Award, the Partners' Innovation Discovery Grant, and the Schlager Family Award for Early Stage Digital Health Innovations.

Understanding the molecular profiling of diffuse gliomas classification: A brief overview

Background

Gliomas represent almost 30% of all primary brain tumors and account for 80% of malignant primary ones. In the last two decades, significant progress has been made in understanding gliomas' molecular origin and development. These advancements have demonstrated a remarkable improvement in classification systems based on mutational markers, which contribute paramount information in addition to traditional histology-based classification.

Methods

We performed a narrative review of the literature including each molecular marker described for adult diffuse gliomas used in the World Health Organization (WHO) central nervous system 5.

Results

The 2021 WHO classification of diffuse gliomas encompasses many molecular aspects considered in the latest proposed hallmarks of cancer. The outcome of patients with diffuse gliomas relies on their molecular behavior and consequently, to determine clinical outcomes for these patients, molecular profiling should be mandatory. At least, the following molecular markers are necessary for the current most accurate classification of these tumors: (1) isocitrate dehydrogenase (IDH) IDH-1 mutation, (2) 1p/19q codeletion, (3) cyclin-dependent kinase inhibitor 2A/B deletion, (4) telomerase reverse transcriptase promoter mutation, (5) α-thalassemia/ mental retardation syndrome X-linked loss, (6) epidermal growth factor receptor amplification, and (7) tumor protein P53 mutation. These molecular markers have allowed the differentiation of multiple variations of the same disease, including the differentiation of distinct molecular Grade 4 gliomas. This could imply different clinical outcomes and possibly impact targeted therapies in the years to come.

Conclusion

Physicians face different challenging scenarios according to the clinical features of patients with gliomas. In addition to the current advances in clinical decision-making, including radiological and surgical techniques, understanding the disease's molecular pathogenesis is paramount to improving the benefits of its clinical treatments. This review aims to describe straightforwardly the most remarkable aspects of the molecular pathogenesis of diffuse gliomas.

CDKN2A/B Homozygous Deletions in Astrocytomas: A Literature Review

Genomic alterations of CDKN2A and CDKN2B in astrocytomas have been an evolving area of study for decades. Most recently, there has been considerable interest in the effect of CDKN2A and/or CDKN2B (CDKN2A/B) homozygous deletions (HD) on the prognosis of isocitrate dehydrogenase (IDH)-mutant astrocytomas. This is highlighted by the adoption of CDKN2A/B HD as an essential criterion for astrocytoma and IDH-mutant central nervous system (CNS) WHO grade 4 in the fifth edition of the World Health Organisation (WHO) Classification of Central Nervous System Tumours (2021). The CDKN2A and CDKN2B genes are located on the short arm of chromosome 9. CDKN2A encodes for two proteins, p14 and p16, and CDKN2B encodes for p15. These proteins regulate cell growth and angiogenesis. Interpreting the impact of CDKN2A/B alterations on astrocytoma prognosis is complicated by recent changes in tumour classification and a lack of uniform standards for testing CDKN2A/B. While the prognostic impact of CDKN2A/B HD is established, the role of different CDKN2A/B alterations-heterozygous deletions (HeD), point mutations, and promoter methylation-is less clear. Consequently, how these alternations should be incorporated into patient management remains controversial. To this end, we reviewed the literature on different CDKN2A/B alterations in IDH-mutant astrocytomas and their impact on diagnosis and management. We also provided a historical review of the changing impact of CDKN2A/B alterations as glioma classification has evolved over time. Through this historical context, we demonstrate that CDKN2A/B HD is an important negative prognostic marker in IDH-mutant astrocytomas; however, the historical data is challenging to interpret given changes in tumour classification over time, variation in the quality of evidence, and variations in the techniques used to identify CDKN2A/B deletions. Therefore, future prospective studies using uniform classification and detection techniques are required to improve the clinical interpretation of this molecular marker.

IDH wild-type lower-grade gliomas with glioblastoma molecular features: a systematic review and meta-analysis

The WHO 2021 classification defines IDH wild type (IDHw) histologically lower-grade glioma (hLGG) as molecular glioblastoma (mGBM) if TERT promoter mutation (pTERTm), EGFR amplification or chromosome seven gain and ten loss aberrations are indicated. We systematically reviewed articles of IDHw hLGGs studies (49 studies, N = 3748) and meta-analyzed mGBM prevalence and overall survival (OS) according to the PRISMA statement. mGBM rates in IDHw hLGG were significantly lower in Asian regions (43.7%, 95% confidence interval [CI: 35.8-52.0]) when compared to non-Asian regions (65.0%, [CI: 52.9-75.4]) (P = 0.005) and were significantly lower in fresh-frozen specimen when compared to formalin-fixed paraffin-embedded samples (P = 0.015). IDHw hLGGs without pTERTm rarely expressed other molecular markers in Asian studies when compared to non-Asian studies. Patients with mGBM had significantly longer OS times when compared to histological GBM (hGBM) (pooled hazard ratio (pHR) 0.824, [CI: 0.694-0.98], P = 0.03)). In patients with mGBM, histological grade was a significant prognostic factor (pHR 1.633, [CI: 1.09-2.447], P = 0.018), as was age (P = 0.001) and surgical extent (P = 0.018). Although bias risk across studies was moderate, mGBM with grade II histology showed better OS rates when compared to hGBM.

Interdependencies of the Neuronal, Immune and Tumor Microenvironment in Gliomas

Gliomas are the most common primary brain malignancy and are universally fatal. Despite significant breakthrough in understanding tumor biology, treatment breakthroughs have been limited. There is a growing appreciation that major limitations on effective treatment are related to the unique and highly complex glioma tumor microenvironment (TME). The TME consists of multiple different cell types, broadly categorized into tumoral, immune and non-tumoral, non-immune cells. Each group provides significant influence on the others, generating a pro-tumor dynamic with significant immunosuppression. In addition, glioma cells are highly heterogenous with various molecular distinctions on the cellular level. These variations, in turn, lead to their own unique influence on the TME. To develop future treatments, an understanding of this complex TME interplay is needed. To this end, we describe the TME in adult gliomas through interactions between its various components and through various glioma molecular phenotypes.

Expression of IL-13Rα2 and FUS in glioma: clinicopathological and prognostic correlation

BACKGROUND

IL-13Rα2 is one of the most widely studied tumor-associated antigens in glioma research. Fused in sarcoma (FUS) is a DNA/RNA binding protein that is dysfunctional in various malignant tumors. However, the expression of IL-13Rα2 and FUS, their relationship with clinicopathological parameters and their prognostic value in glioma remain unclear.

METHODS

In the present study, the expression of IL-13Rα2 and FUS was measured in a glioma tissue array by immunohistochemistry. Pearson's X² test was used to determine the correlation between immunohistochemical expressions and clinicopathological parameters. Pearson's or Spearman's correlation test was used to determine the association between these two proteins expression. The Kaplan-Meier analysis was used to investigate the effect of these proteins on prognosis.

RESULTS

The expressions of IL-13Rα2 were significantly higher in high-grade gliomas (HGG) than that in low-grade gliomas (LGG) and was associated with IDH mutation status, whereas FUS location demonstrated no significant correlation with clinicopathological parameters. Moreover, a positive relationship was found between nuclear and cytoplasmic co-localization FUS and IL-13Rα2 expression. Kaplan-Meier analysis revealed that patients with IDH wide type or IL-13Rα2 had worst overall survival (OS) compared to other biomarkers. In HGG, IL-13Rα2 combined with nuclear and cytoplasmic co-localization of FUS was associated with worse OS. Multivariate analysis showed that tumor grade, Ki-67, P53 and IL-13Rα2 could be the independent prognostic factors for OS.

CONCLUSION

IL-13Rα2 expression was significantly associated with cytoplasmic distribution of FUS in human glioma samples and could be the independent prognostic factors for OS, while the prognostic value of its co-expression with cytoplasmic FUS in glioma need to be addressed in the future studies.

The Chromatin Remodeler ATRX: Role and Mechanism in Biology and Cancer

The alpha-thalassemia mental retardation X-linked (ATRX) syndrome protein is a chromatin remodeling protein that primarily promotes the deposit of H3.3 histone variants in the telomere area. ATRX mutations not only cause ATRX syndrome but also influence development and promote cancer. The primary molecular characteristics of ATRX, including its molecular structures and normal and malignant biological roles, are reviewed in this article. We discuss the role of ATRX in its interactions with the histone variant H3.3, chromatin remodeling, DNA damage response, replication stress, and cancers, particularly gliomas, neuroblastomas, and pancreatic neuroendocrine tumors. ATRX is implicated in several important cellular processes and serves a crucial function in regulating gene expression and genomic integrity throughout embryogenesis. However, the nature of its involvement in the growth and development of cancer remains unknown. As mechanistic and molecular investigations on ATRX disclose its essential functions in cancer, customized therapies targeting ATRX will become accessible.

Imaging biomarkers for clinical applications in neuro-oncology: current status and future perspectives

Biomarker discovery and development are popular for detecting the subtle diseases. However, biomarkers are needed to be validated and approved, and even fewer are ever used clinically. Imaging biomarkers have a crucial role in the treatment of cancer patients because they provide objective information on tumor biology, the tumor's habitat, and the tumor's signature in the environment. Tumor changes in response to an intervention complement molecular and genomic translational diagnosis as well as quantitative information. Neuro-oncology has become more prominent in diagnostics and targeted therapies. The classification of tumors has been actively updated, and drug discovery, and delivery in nanoimmunotherapies are advancing in the field of target therapy research. It is important that biomarkers and diagnostic implements be developed and used to assess the prognosis or late effects of long-term survivors. An improved realization of cancer biology has transformed its management with an increasing emphasis on a personalized approach in precision medicine. In the first part, we discuss the biomarker categories in relation to the courses of a disease and specific clinical contexts, including that patients and specimens should both directly reflect the target population and intended use. In the second part, we present the CT perfusion approach that provides quantitative and qualitative data that has been successfully applied to the clinical diagnosis, treatment and application. Furthermore, the novel and promising multiparametric MR imageing approach will provide deeper insights regarding the tumor microenvironment in the immune response. Additionally, we briefly remark new tactics based on MRI and PET for converging on imaging biomarkers combined with applications of bioinformatics in artificial intelligence. In the third part, we briefly address new approaches based on theranostics in precision medicine. These sophisticated techniques merge achievable standardizations into an applicatory apparatus for primarily a diagnostic implementation and tracking radioactive drugs to identify and to deliver therapies in an individualized medicine paradigm. In this article, we describe the critical principles for imaging biomarker characterization and discuss the current status of CT, MRI and PET in finiding imaging biomarkers of early disease.

Characterization of an IDH1 R132H Rabbit Monoclonal Antibody, MRQ-67, and Its Applications in the Identification of Diffuse Gliomas

The current diagnosis of diffuse glioma involves isocitrate dehydrogenase (IDH) mutation testing. Most IDH mutant gliomas carry a G-to-A mutation at IDH1 position 395, resulting in the R132H mutant. R132H immunohistochemistry (IHC), therefore, is used to screen for the IDH1 mutation. In this study, the performance of MRQ-67, a recently generated IDH1 R132H antibody, was characterized in comparison with H09, a frequently used clone. Selective binding was demonstrated by an enzyme-linked immunosorbent assay for MRQ-67 to the R132H mutant, with an affinity higher than that for H09. By Western and dot immunoassays, MRQ-67 was found to bind specifically to the IDH1 R1322H, with a higher capacity than H09. IHC testing with MRQ-67 demonstrated a positive signal in most diffuse astrocytomas (16/22), oligodendrogliomas (9/15), and secondary glioblastomas tested (3/3), but not in primary glioblastomas (0/24). While both clones demonstrated a positive signal with similar patterns and equivalent intensities, H09 exhibited a background stain more frequently. DNA sequencing on 18 samples showed the R132H mutation in all IHC positive cases (5/5), but not in negative cases (0/13). These results demonstrate that MRQ-67 is a high-affinity antibody suitable for specific detection of the IDH1 R132H mutant by IHC and with less background as compared with H09.

Multicenter clinical radiomics-integrated model based on [18F]FDG PET and multi-modal MRI predict ATRX mutation status in IDH-mutant lower-grade gliomas

OBJECTIVES

To develop a clinical radiomics-integrated model based on ¹⁸ F-fluorodeoxyglucose positron emission tomography ([¹⁸F]FDG PET) and multi-modal MRI for predicting alpha thalassemia/mental retardation X-linked (ATRX) mutation status of IDH-mutant lower-grade gliomas (LGGs).

METHODS

One hundred and two patients (47 ATRX mutant-type, 55 ATRX wild-type) diagnosed with IDH-mutant LGGs (CNS WHO grades 1 and 2) were retrospectively enrolled. A total of 5540 radiomics features were extracted from structural MR (sMR) images (contrast-enhanced T1-weighted imaging, CE-T1WI; T2-weighted imaging, and T2WI), functional MR (fMR) images (apparent diffusion coefficient, ADC; cerebral blood volume, CBV), and metabolic PET images ([¹⁸F]FDG PET). The random forest algorithm was used to establish a clinical radiomics-integrated model, integrating the optimal multi-modal radiomics model with three clinical parameters. The predictive effectiveness of the models was evaluated by receiver operating characteristic (ROC) and decision curve analysis (DCA).

RESULTS

The optimal multi-modal model incorporated sMR (CE-T1WI), fMR (ADC), and metabolic ([¹⁸F]FDG) images ([¹⁸F]FDG PET+ADC+ CE-T1WI) with the area under curves (AUCs) in the training and test groups of 0.971 and 0.962, respectively. The clinical radiomics-integrated model, incorporating [¹⁸F]FDG PET+ADC+CE-T1WI, three clinical parameters (KPS, SFSD, and ATGR), showed the best predictive effectiveness in the training and test groups (0.987 and 0.975, respectively).

CONCLUSIONS

The clinical radiomics-integrated model with metabolic, structural, and functional information based on [¹⁸F]FDG PET and multi-modal MRI achieved promising performance for predicting the ATRX mutation status of IDH-mutant LGGs.

KEY POINTS

• The clinical radiomics-integrated model based on [¹⁸F]FDG PET and multi-modal MRI achieved promising performance for predicting ATRX mutation status in LGGs. • The study investigated the value of multicenter clinical radiomics-integrated model based on [¹⁸F]FDG PET and multi-modal MRI in LGGs regarding ATRX mutation status prediction. • The integrated model provided structural, functional, and metabolic information simultaneously and demonstrated with satisfactory calibration and discrimination in the training and test groups (0.987 and 0.975, respectively).

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.

The TERT Promoter: A Key Player in the Fight for Cancer Cell Immortality

The review describes the role of telomeres and telomerase in tumor progression, as well as various mechanisms of the activation of telomerase reverse transcriptase (TERT) expression in CNS tumors and other cancers. The main mechanism of TERT activation involves acquisition of somatic mutations by the TERT gene promoter (TERTp). The article presents information on the TERTp structure and transcription factors directly interacting with TERTp and regulating its transcription. The prospects of using the mutational status of TERTp as a prognostic marker of CNS malignancies and other tumors with a common profile of TERTp mutations are discussed.

Molecular Characterization of Adult Tumors Diagnosed as Cerebellar Glioblastomas Identifies Subgroups Associated With Prognosis

Adult tumors diagnosed as cerebellar glioblastoma (cGBM) are rare and their optimal classification remains to be determined. The aim of this study was to identify subgroups of cGBM based on targeted molecular analysis. cGBM diagnosed between 2003 and 2017 were identified from the French Brain Tumor Database and reviewed according to the WHO 2021 classification. The following molecular alterations were studied: IDH1/2 , H3F3A , FGFR1 , BRAF , TERT promoter mutations, EGFR amplification, MGMT promoter methylation, and alternative lengthening of telomere status. DNA methylation profile was assessed in a subset of cases. Eighty-three cGBM were included and could be classified into 6 mutually exclusive subgroups associated with median age at diagnosis (MA) and prognosis: TERT -mutant and/or EGFR -amplified tumors (n=22, 26.5%, MA=62 y, median overall survival [OS]=4 mo), H3K27M-mutant tumors (n=15, 18.1%, MA=48 y, median OS=8 mo), mitogen-activated protein kinases (MAPK) pathway-activated tumors ( FGFR1 , BRAF mutation, or occurring in neurofibromatosis type I patients, n=15, 18.1%, MA=48 y, median OS=57 mo), radiation-associated tumors (n=5, 6%, MA=47 y, median OS=5 mo), IDH-mutant tumors (n=1), and unclassified tumors (n=25, 30.1%, MA=63 y, median OS=17 mo). Most MAPK pathway-activated tumors corresponded to high-grade astrocytomas with piloid features based on DNA methylation profiling. In multivariate analysis, MAPK pathway-activating alterations, ATRX loss of expression, and alternative lengthening of telomere positivity were independently associated with a better outcome and TERT / EGFR alterations with a worse outcome. cGBM display an important intertumoral heterogeneity. Targeted molecular analysis enables to classify the majority of tumors diagnosed as cGBM into mutually exclusive and clinically relevant subgroups. The presence of MAPK pathway alterations is associated with a much better prognosis.

Distinct gene mutation profiles among multiple and single primary lung adenocarcinoma

With the development of technologies, multiple primary lung cancer (MPLC) has been detected more frequently. Although large-scale genomics studies have made significant progress, the aberrant gene mutation in MPLC is largely unclear. In this study, 141 and 44 lesions from single and multiple primary lung adenocarcinoma (SP- and MP-LUAD) were analyzed. DNA and RNA were extracted from formalin-fixed, paraffin-embedded tumor tissue and sequenced by using the next-generation sequencing-based YuanSu450TM gene panel. We systematically analyzed the clinical features and gene mutations of these lesions, and found that there were six genes differently mutated in MP-LUAD and SP-LUAD lesions, including RBM10, CDK4, ATRX, NTRK1, PREX2, SS18. Data from the cBioPortal database indicated that mutation of these genes was related to some clinical characteristics, such as TMB, tumor type, et al. Besides, heterogeneity analysis suggested that different lesions could be tracked back to monophyletic relationships. We compared the mutation landscape of MP-LUAD and SP-LUAD and identified six differentially mutated genes (RBM10, CDK4, ATRX, NTRK1, PREX2, SS18), and certain SNV loci in TP53 and EGFR which might play key roles in lineage decomposition in multifocal samples. These findings may provide insight into personalized prognosis prediction and new therapies for MP-LUAD patients.

Implications of TERT promoter mutations and telomerase activity in solid tumors with a focus on genitourinary cancers

INTRODUCTION

The reactivation of telomerase represents a key moment in the carcinogenesis process. Mutations in the central promoter region of the telomerase reverse transcriptase (TERT) gene cause telomerase reactivation in approximately 90% of solid tumors. In some of these, its prognostic and predictive role in response to treatments has already been demonstrated, in others (such as tumors of the genitourinary tract like urothelial carcinoma) data are controversial and the research is still ongoing. In the future, TERT promoter mutations and telomerase activity could have diagnostic, prognostic, and therapeutic applications in many types of cancer.

AREAS COVERED

We performed a review the literature with the aim of describing the current evidence on the prognostic and predictive role of TERT promoter mutations. In some tumor types, TERT promoter mutations have been associated with a worse prognosis and could have a potential value as biomarkers to guide therapeutic decisions. Mutations in TERT promoter seems to make the tumor particularly immunogenic and more responsive to immunotherapy, although data is controversial.

EXPERT OPINION

We described the role of TERT promoter mutations in solid tumors with a particular focus in genitourinary cancers, considering their frequency in this tract.

Epidemiological characteristics and genetic alterations in adult diffuse glioma in East Asian populations

Understanding the racial specificities of diseases-such as adult diffuse glioma, the most common primary malignant tumor of the central nervous system-is a critical step toward precision medicine. Here, we comprehensively review studies of gliomas in East Asian populations and other ancestry groups to clarify the racial differences in terms of epidemiology and genomic characteristics. Overall, we observed a lower glioma incidence in East Asians than in Whites; notably, patients with glioblastoma had significantly younger ages of onset and longer overall survival than the Whites. Multiple genome-wide association studies of various cohorts have revealed single nucleotide polymorphisms associated with overall and subtype-specific glioma susceptibility. Notably, only 3 risk loci-5p15.33, 11q23.3, and 20q13.33-were shared between patients with East Asian and White ancestry, whereas other loci predominated only in particular populations. For instance, risk loci 12p11.23, 15q15-21.1, and 19p13.12 were reported in East Asians, whereas risk loci 8q24.21, 1p31.3, and 1q32.1 were reported in studies in White patients. Although the somatic mutational profiles of gliomas between East Asians and non-East Asians were broadly consistent, a lower incidence of EGFR amplification in glioblastoma and a higher incidence of 1p19q-IDH-TERT triple-negative low-grade glioma were observed in East Asian cohorts. By summarizing large-scale disease surveillance, germline, and somatic genomic studies, this review reveals the unique characteristics of adult diffuse glioma among East Asians, to guide clinical management and policy design focused on patients with East Asian ancestry.

ATRX status in patients with gliomas: Radiomics analysis

MATERIAL AND METHODS

A cohort of 123 patients diagnosed with gliomas (World Health Organization grades II-IV) who underwent surgery and was treated at our center between January 2016 and July 2020, was enrolled in this retrospective study. Radiomics features were extracted from MR T1WI, T2WI, T2FLAIR, CE-T1WI, and ADC images. Patients were randomly split into training and validation sets at a ratio of 4:1. A radiomics signature was constructed using the least absolute shrinkage and selection operator (LASSO) to train the SVM model using the training set. The prediction accuracy and area under curve and other evaluation indexes were used to explore the performance of the model established in this study for predicting the ATRX mutation state.

RESULTS

Fifteen radiomic features were selected to generate an ATRX-associated radiomic signature using the LASSO logistic regression model. The area under curve for ATRX mutation (ATRX(-)) on training set was 0.93 (95% confidence interval [CI]: 0.87-1.0), with the sensitivity, specificity and accuracy being 0.91, 0.82 and 0.88, while on the validation set were 0.84 (95% CI: 0.63-0.91), with the sensitivity, specificity and accuracy of 0.73, 0.86, and 0.79, respectively.

CONCLUSIONS

These results indicate that radiomic features derived from preoperative MRI facilitat efficient prediction of ATRX status in gliomas, thus providing a novel evaluation method for noninvasive imaging biomarkers.

H3K27M-Altered Diffuse Midline Gliomas Among Adult Patients: A Systematic Review of Clinical Features and Survival Analysis

OBJECTIVE

The objective of the study was to summarize the clinical characteristics, histo-genomic profiles, management strategies, and survival outcomes of H3K27M-altered adult diffuse midline gliomas (aDMGs).

METHODS

PubMed, Scopus, and Cochrane databases were used to identify relevant articles. Papers including H3K27M-altered aDMGs with sufficient clinical outcome data were included. Descriptive clinical characteristics and survival analysis were also conducted.

RESULTS

Twenty studies describing 135 patients were included. The median age at diagnosis was 42 years, and there was a slight male predominance (N = 60, 54%). In our cohort, 15 (11%) patients experienced headache, 10 had nausea and vomiting (7%), and 10 had ataxia (7%). Within this cohort, histopathologic diagnoses included glioblastoma (N = 22, 40%) and anaplastic astrocytoma (N = 21, 38%), while genetic alterations included ATRX mutation (N = 22, 16%), PTPN11 mutation (N = 9, 7%), and MGMT promoter methylation (N = 9, 7%). Among histo-genetic alterations, only ATRX mutation was associated with survival and correlated with worse prognosis (log-rank test, P = 0.04). Neither surgical resection versus biopsy nor greater extent of resection demonstrated survival benefit in our cohort. Chemotherapy was administered in 98 (73%) cases with radiotherapy administered in 71 (53%) cases. Unlike chemotherapy, radiotherapy demonstrated a significant survival benefit (log-rank test, P = 0.019). The median overall survival and progression-free survival within our patient cohort were 10 and 7 months, respectively.

CONCLUSIONS

H3K27M-altered aDMGs were associated with relatively poor survival. ATRX gene mutation was significantly associated with survival disadvantage, while radiotherapy was associated with survival benefit. Large, prospective studies are needed to establish a standard management strategy and provide reliable prognostic conclusions.

The telomere maintenance mechanism spectrum and its dynamics in gliomas

Background

The activation of the telomere maintenance mechanism (TMM) is one of the critical drivers of cancer cell immortality. In gliomas, TERT expression and TERT promoter mutation are considered to reliably indicate telomerase activation, while ATRX mutation and/or loss indicates an alternative lengthening of telomeres (ALT). However, these relationships have not been extensively validated in tumor tissues.

Methods

Telomerase repeated amplification protocol (TRAP) and C-circle assays were used to profile and characterize the TMM cross-sectionally (n = 412) and temporally (n = 133) across glioma samples. WES, RNA-seq, and NanoString analyses were performed to identify and validate the genetic characteristics of the TMM groups.

Results

We show through the direct measurement of telomerase activity and ALT in a large set of glioma samples that the TMM in glioma cannot be defined solely by the combination of telomerase activity and ALT, regardless of TERT expression, TERT promoter mutation, and ATRX loss. Moreover, we observed that a considerable proportion of gliomas lacked both telomerase activity and ALT. This telomerase activation-negative and ALT negative group exhibited evidence of slow growth potential. By analyzing a set of longitudinal samples from a separate cohort of glioma patients, we discovered that the TMM is not fixed and can change with glioma progression.

Conclusions

This study suggests that the TMM is dynamic and reflects the plasticity and oncogenicity of tumor cells. Direct measurement of telomerase enzyme activity and evidence of ALT should be considered when defining TMM. An accurate understanding of the TMM in glioma is expected to provide important information for establishing cancer management strategies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13073-022-01095-x.

Radiological Prediction of Isocitrate Dehydrogenase (IDH) Mutational Status and Pathological Verification for Lower-Grade Astrocytomas

Background and objective

The isocitrate dehydrogenase (IDH) status of patients with World Health Organization (WHO) grade II or III astrocytoma is essential for understanding its biological features and determining therapeutic strategies. This study aimed to use radiological analysis to predict the IDH status of patients with lower-grade astrocytomas and to verify the pathological implications.

Methods

In this study, 47 patients with grade II (17 cases) or III astrocytomas (30 cases), based on 2016 WHO Classification, underwent methionine (MET) positron emission tomography (PET) and magnetic resonance spectroscopy (MRS) on the same day between January 2013 and June 2020. The patients were retrospectively assessed. Immunohistochemistry showed 23 cases of IDH-mutant and 24 of IDH-wildtype. Based on fluid-attenuated recovery inversion (FLAIR)/T2 imaging, three doctors blinded to clinical data independently allocated 18 patients to the clear boundary group between the tumor and the normal brain and 29 to the unclear boundary group. The peak ratios of N-acetylaspartate (NAA)/creatine (Cr), choline (Cho)/Cr, and Cho/NAA and the tumor-to-normal region (T/N) ratio for maximum accumulation in MET-PET were calculated. For statistical analysis, Fisher’s exact test was used to assess associations between two variables, and the Mann-Whitney U test to compare the values between the IDH-wildtype and IDH-mutant groups. The optimal cut-off values of MET T/N ratio and MRS parameters for discriminating IDH-wildtype from IDH-mutant were obtained using receiver operating characteristics curves.

Results

The unclear boundary group had significantly more IDH-wildtype cases than the clear boundary group (P<0.001). The IDH-wildtype group had significantly lower Cho/Cr (<1.84) and Cho/NAA (<1.62) ratios (P=0.02 and P=0.047, respectively) and a higher MET T/N ratio (>1.44, P=0.02) than the IDH-mutant group. The odds for the IDH-wildtype were 0.22 for patients who fulfilled none of the four criteria, including boundary status and three ratios, and 0.9 for all four criteria.

Conclusions

These results suggest that the combination of MRI, MRS, and MET-PET examination could be helpful for the prediction of IDH status in WHO grade II/III gliomas.

Molecular landscape of IDH-wild type, pTERT-wild type adult glioblastomas

Telomerase reverse transcriptase (TERT) promoter (pTERT) mutation has often been described as a late event in gliomagenesis and it has been suggested as a prognostic biomarker in gliomas other than 1p19q codeleted tumors. However, the characteristics of isocitrate dehydrogenase (IDH) wild type (wt) (IDHwt), pTERTwt glioblastomas are not well known. We recruited 72 adult IDHwt, pTERTwt glioblastomas and performed methylation profiling, targeted sequencing, and fluorescence in situ hybridization (FISH) for TERT structural rearrangement and ALT (alternative lengthening of telomeres). There was no significant difference in overall survival (OS) between our cohort and a the Cancer Genome Atlas (TCGA) cohort of IDHwt, pTERT mutant (mut) glioblastomas, suggesting that pTERT mutation on its own is not a prognostic factor among IDHwt glioblastomas. Epigenetically, the tumors clustered into classic‐like (11%), mesenchymal‐like (32%), and LGm6‐glioblastoma (GBM) (57%), the latter far exceeding the corresponding proportion seen in the TCGA cohort of IDHwt, pTERTmut glioblastomas. LGm6‐GBM‐clustered tumors were enriched for platelet derived growth factor receptor alpha (PDGFRA) amplification or mutation (p = 0.008), and contained far fewer epidermal growth factor receptor (EGFR) amplification (p < 0.01), 10p loss (p = 0.001) and 10q loss (p < 0.001) compared with cases not clustered to this group. LGm6‐GBM cases predominantly showed ALT (p = 0.038). In the whole cohort, only 35% cases showed EGFR amplification and no case showed combined chromosome +7/−10. Since the cases were already pTERTwt, so the three molecular properties of EGFR amplification, +7/−10, and pTERT mutation may not cover all IDHwt glioblastomas. Instead, EGFR and PDGFRA amplifications covered 67% and together with their mutations covered 71% of cases of this cohort. Homozygous deletion of cyclin dependent kinase inhibitor 2A (CDKN2A)/B was associated with a worse OS (p = 0.031) and was an independent prognosticator in multivariate analysis (p = 0.032). In conclusion, adult IDHwt, pTERTwt glioblastomas show epigenetic clustering different from IDHwt, pTERTmut glioblastomas, and IDHwt glioblastomas which are pTERTwt may however not show EGFR amplification or +7/−10 in a significant proportion of cases. CDKN2A/B deletion is a poor prognostic biomarker in this group.

Tumor-Associated Microenvironment of Adult Gliomas: A Review

The glioma-associated tumor microenvironment involves a multitude of different cells ranging from immune cells to endothelial, glial, and neuronal cells surrounding the primary tumor. The interactions between these cells and glioblastoma (GBM) have been deeply investigated while very little data are available on patients with lower-grade gliomas. In these tumors, it has been demonstrated that the composition of the microenvironment differs according to the isocitrate dehydrogenase status (mutated/wild type), the presence/absence of codeletion, and the expression of specific alterations including H3K27 and/or other gene mutations. In addition, mechanisms by which the tumor microenvironment sustains the growth and proliferation of glioma cells are still partially unknown. Nonetheless, a better knowledge of the tumor-associated microenvironment can be a key issue in the optic of novel therapeutic drug development.

Molecular and Circulating Biomarkers in Patients with Glioblastoma

Glioblastoma is the most aggressive malignant tumor of the central nervous system with a low survival rate. The difficulty of obtaining this tumor material represents a major limitation, making the real-time monitoring of tumor progression difficult, especially in the events of recurrence or resistance to treatment. The identification of characteristic biomarkers is indispensable for an accurate diagnosis, the rigorous follow-up of patients, and the development of new personalized treatments. Liquid biopsy, as a minimally invasive procedure, holds promise in this regard. The purpose of this paper is to summarize the current literature regarding the identification of molecular and circulating glioblastoma biomarkers and the importance of their integration as a valuable tool to improve patient care.

Molecular Characterization of IDH Wild-type Diffuse Astrocytomas: The Potential of cIMPACT-NOW Guidelines

IDH wild-type (wt) grade 2/3 astrocytomas are a heterogenous group of tumors with disparate clinical and molecular profiles. cIMPACT-NOW recommendations incorporated in the new 2021 World Health Organization (WHO) Classification of Central Nervous System (CNS) Tumors urge minimal molecular criteria to identify a subset that has an aggressive clinical course similar to IDH -wt glioblastomas (GBMs). This paper describes the use of a panel of molecular markers to reclassify IDH -wt grade 2/3 diffuse astrocytic gliomas (DAGs) and study median overall survival concerning for to IDH -wt GBMs in the Indian cohort. IDH -wt astrocytic gliomas (grades 2, 3, and 4) confirmed by IDHR132H immunohistochemistry and IDH1/2 gene sequencing, 1p/19q non-codeleted with no H3F3A mutations were included. TERT promoter mutation by Sanger sequencing, epidermal growth factor receptor amplification, and whole chromosome 7 gain and chromosome 10 loss by fluorescence in situ hybridization was assessed and findings correlated with clinical and demographic profiles. The molecular profile of 53 IDH -wt DAGs (grade 2: 31, grade 3: 22) was analyzed. Eleven cases (grade 2: 8, grade 3: 3) (20.75%) were reclassified as IDH -wt GBMs, WHO grade 4 ( TERT promoter mutation in 17%, epidermal growth factor receptor amplification in 5.5%, and whole chromosome 7 gain and chromosome 10 loss in 2%). Molecular GBMs were predominantly frontal (54.5%) with a mean age of 36 years and median overall survival equivalent to IDH -wt GBMs (18 vs. 19 mo; P =0.235). Among grade 2/3 DAGs not harboring these alterations, significantly better survival was observed for grade 2 versus grade 3 DAGs (25 vs. 16 mo; P =0.002). Through the incorporation of a panel of molecular markers, a subset of IDH -wt grade 2 DAGs can be stratified into molecular grade 4 tumors with prognostic and therapeutic implications. However, IDH -wt grade 3 DAGs behave like GBMs irrespective of molecular profile.

Immune Infiltration of Ulcerative Colitis and Detection of the m6A Subtype

Ulcerative colitis (UC) is an inflammatory bowel disease characterized by persistent colon inflammation. N6-methyladenosine (m6A) methylation is one of the most prevalent RNA modifications with key roles in both normal and illness, but m6A methylation in ulcerative colitis is unknown. This research investigated m6A methylation in UC. We examined the expression of known m6A RNA methylation regulators in UC using the Gene Expression Omnibus database (GEO database). First, we used m6A regulators to examine m6A change in UC samples. These two patient groups were created by clustering three m6A gene expression datasets. These genes were then utilized to build an m6A gene network using WGCNA and PPI. These networks were built using differentially expressed genes. The 12 m6A regulators were found to be dispersed throughout the chromosome. The study’s data were then connected, revealing positive or negative relationships between genes or signaling pathways. Then, PCA of the 12 m6A-regulated genes indicated that the two patient groups could be discriminated in both PC1 and PC2 dimensions. The ssGSEA algorithm found that immune invading cells could be easily distinguished across diverse patient groups. Both groups had varied levels of popular cytokines. The differential gene analysis of the two samples yielded 517 genes like FTO and RFX7. It found 9 hub genes among 121 genes in the blue module, compared their expression in two groups of samples, and found that the differences in expression of these 9 genes were highly significant. The identification of 9 possible m6A methylation-dependent gene regulatory networks suggests that m6A methylation is involved in UC pathogenesis. Nine candidate genes have been identified as possible markers for assessing UC severity and developing innovative UC targeted therapeutic approaches.

Signaling pathways and therapeutic approaches in glioblastoma multiforme (Review)

Glioblastoma multiforme (GBM) is the most aggressive type of primary brain tumor and is associated with a poor clinical prognosis. Despite the progress in the understanding of the molecular and genetic changes that promote tumorigenesis, effective treatment options are limited. The present review intended to identify and summarize major signaling pathways and genetic abnormalities involved in the pathogenesis of GBM, as well as therapies that target these pathways. Glioblastoma remains a difficult to treat tumor; however, in the last two decades, significant improvements in the understanding of GBM biology have enabled advances in available therapeutics. Significant genomic events and signaling pathway disruptions (NF‑κB, Wnt, PI3K/AKT/mTOR) involved in the formation of GBM were discussed. Current therapeutic options may only marginally prolong survival and the current standard of therapy cures only a small fraction of patients. As a result, there is an unmet requirement for further study into the processes of glioblastoma pathogenesis and the discovery of novel therapeutic targets in novel signaling pathways implicated in the evolution of glioblastoma.

A Potential New Treatment for High-Grade Glioma: A Study Assessing Repurposed Drug Combinations against Patient-Derived High-Grade Glioma Cells

Repurposed drugs have demonstrated in vitro success against high-grade gliomas; however, their clinical success has been limited due to the in vitro model not truly representing the clinical scenario. In this study, we used two distinct patient-derived tumour fragments (tumour core (TC) and tumour margin (TM)) to generate a heterogeneous, clinically relevant in vitro model to assess if a combination of repurposed drugs (irinotecan, pitavastatin, disulfiram, copper gluconate, captopril, celecoxib, itraconazole and ticlopidine), each targeting a different growth promoting pathway, could successfully treat high-grade gliomas. To ensure the clinical relevance of our data, TC and TM samples from 11 different patients were utilized. Our data demonstrate that, at a concentration of 100µm or lower, all drug combinations achieved lower LogIC₅₀ values than temozolomide, with one of the combinations almost eradicating the cancer by achieving cell viabilities below 4% in five of the TM samples 6 days after treatment. Temozolomide was unable to stop tumour growth over the 14-day assay, while combination 1 stopped tumour growth, with combinations 2, 3 and 4 slowing down tumour growth at higher doses. To validate the cytotoxicity data, we used two distinct assays, end point MTT and real-time IncuCyte life analysis, to evaluate the cytotoxicity of the combinations on the TC fragment from patient 3, with the cell viabilities comparable across both assays. The local administration of combinations of repurposed drugs that target different growth promoting pathways of high-grade gliomas have the potential to be translated into the clinic as a novel treatment strategy for high-grade gliomas.

Combinations of Single-Gene Biomarkers Can Precisely Stratify 1,028 Adult Gliomas for Prognostication

Advanced genomic techniques have now been incorporated into diagnostic practice in neuro-oncology in the literature. However, these assays are expensive and time-consuming and demand bioinformatics expertise for data interpretation. In contrast, single-gene tests can be run much more cheaply, with a short turnaround time, and are available in general pathology laboratories. The objective of this study was to establish a molecular grading scheme for adult gliomas using combinations of commonly available single-gene tests. We retrospectively evaluated molecular diagnostic data of 1,275 cases of adult diffuse gliomas from three institutions where we were testing for IDH1/2 mutation, TERTp mutation, 1p19q codeletion, EGFR amplification, 10q deletion, BRAF V600E, and H3 mutations liberally in our regular diagnostic workup. We found that a molecular grading scheme of Group 1 (1p19q codeleted, IDH mutant), Group 2 (IDH mutant, 1p19q non-deleted, TERT mutant), Group 3 (IDH mutant, 1p19q non-deleted, TERT wild type), Group 4 (IDH wild type, BRAF mutant), Group 5 (IDH wild type, BRAF wild type and not possessing the criteria of Group 6), and Group 6 (IDH wild type, and any one of TERT mutant, EGFR amplification, 10q deletion, or H3 mutant) could significantly stratify this large cohort of gliomas for risk. A total of 1,028 (80.6%) cases were thus classifiable with sufficient molecular data. There were 270 cases of molecular Group 1, 59 cases of molecular Group 2, 248 cases of molecular Group 3, 27 cases of molecular Group 4, 117 cases of molecular Group 5, and 307 cases of molecular Group 6. The molecular groups were independent prognosticators by multivariate analyses and in specific instances, superseded conventional histological grades. We were also able to validate the usefulness of the Groups with a cohort retrieved from The Cancer Genome Atlas (TCGA) where similar molecular tests were liberally available. We conclude that a single-gene molecular stratification system, useful for fine prognostication, is feasible and can be adopted by a general pathology laboratory.

ATRX-dependent SVCT2 mediates macrophage infiltration in the glioblastoma xenograft model

Alpha thalassemia/mental retardation syndrome X-linked (ATRX) mutation impairs DNA damage repair in glioblastoma (GBM), making these cells more susceptible to treatment, which may contribute to the survival advantage in GBM patients containing ATRX mutations. To better understand the role of ATRX in GBM, genes correlated with ATRX expression were screened in the Cancer Genome Atlas (702 cases) and Chinese Glioma Genome Atlas (325 cases) databases. Sodium-vitamin C cotransporter 2 (SVCT2) was the most positively correlated gene with ATRX expression. ATRX (about 1.99-fold) and SVCT2 (about 2.25-fold) were upregulated in GBM tissues from 40 patients compared to normal brain tissues from 23 subjects. ShSVCT2 transfection did not alter the in vitro viability of GL261 cells. At the same time, it could inhibit the proliferation of GL261 cells in the orthotopic transplantation model with diminished infiltrating macrophages (CD45^highCD11b⁺), down-regulated chemokine (C-C motif) ligand 2 (Ccl2), Ccl4, C-X-C motif chemokine ligand 1 (Cxcl1), and Cxcl15 expression, and decreased p-IκBα and p-c-Jun expression. Effect of ShSVCT2 transfection could be reversed by overexpression of SVCT2. siRNA interference of ATRX-dependent SVCT2 signal with shSVCT2 could inhibit tumor cell proliferation in Glu261-LuNeo xenograft tumor model with more survival advantage, probably by the inhibited macrophage chemotaxis. These results indicate that ATRX-dependent SVCT2-mediated chemokine-induced macrophage infiltration is regulated by the NF-κB pathway, which could be considered as treatment targets.

Development and validation of a novel survival prediction model for newly diagnosed lower-grade gliomas

OBJECTIVE

Diffuse gliomas are the most common primary gliomas with a poor prognosis. This study aimed to develop and validate prognostic models for predicting the survival probability in newly diagnosed lower-grade glioma (LGG) patients.

METHODS

Detailed data were obtained for newly diagnosed LGG from The Cancer Genome Atlas (TCGA) and the Chinese Glioma Genome Atlas (CGGA) cohorts. Survival was assessed using Cox proportional hazards regression with adjustment for known prognostic factors. The model was established using the TCGA cohort, and independently validated using the CGGA cohort, to predict the 3-, 5-, and 10-year survival probabilities of patients.

RESULTS

Data from 293 patients with newly diagnosed LGG from the TCGA cohort were used to establish a prognostic model, and from 232 patients with primary LGG in the CGGA cohort to validate the model. Age, tumor grade, molecular subtype, tumor resection, and preoperative neurological deficits were included in the prediction model. The Cox regression model had a satisfactory corrected concordance index of 0.8508, 0.8510, and 0.8516 in the internal bootstrap validation at 3, 5, and 10 years, respectively. The calibration plots demonstrated high consistency of the predicted and observed outcomes. The CGGA cohort was used for external validation and showed satisfactory discrimination of 0.7776, 0.7682, and 0.7051 at 3, 5, and 10 years, respectively. The calibration plots demonstrated an acceptable calibration capability in the external validation.

CONCLUSIONS

This study established and validated a prognostic model to predict the survival probability of patients with newly diagnosed LGG. The model performed well in discrimination and calibration with ease of use, speed, accessibility, interpretability, and generalizability. An easily used nomogram based on the Cox model was established for clinical application. Moreover, a free, easy-to-use software interface based on the nomogram is provided online.

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.

Differences in stem cell marker and osteopontin expression in primary and recurrent glioblastoma

Background

Despite of a multimodal approach, recurrences can hardly be prevented in glioblastoma. This may be in part due to so called glioma stem cells. However, there is no established marker to identify these stem cells.

Methods

Paired samples from glioma patients were analyzed by immunohistochemistry for expression of the following stem cell markers: CD133, Musashi, Nanog, Nestin, octamer-binding transcription factor 4 (Oct4), and sex determining region Y-box 2 (Sox2). In addition, the expression of osteopontin (OPN) was investigated. The relative number of positively stained cells was determined. By means of Kaplan–Meier analysis, a possible association with overall survival by marker expression was investigated.

Results

Sixty tissue samples from 30 patients (17 male, 13 female) were available for analysis. For Nestin, Musashi and OPN a significant increase was seen. There was also an increase (not significant) for CD133 and Oct4. Patients with mutated Isocitrate Dehydrogenase-1/2 (IDH-1/2) status had a reduced expression for CD133 and Nestin in their recurrent tumors. Significant correlations were seen for CD133 and Nanog between OPN in the primary and recurrent tumor and between CD133 and Nestin in recurrent tumors. By confocal imaging we could demonstrate a co-expression of CD133 and Nestin within recurrent glioma cells. Patients with high CD133 expression had a worse prognosis (22.6 vs 41.1 months, p = 0.013). A similar trend was seen for elevated Nestin levels (24.9 vs 41.1 months, p = 0.08).

Conclusions

Most of the evaluated markers showed an increased expression in their recurrent tumor. CD133 and Nestin were associated with survival and are candidate markers for further clinical investigation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-022-02510-4.

Newly Diagnosed Glioblastoma in Elderly Patients

Purpose of Review

Elderly patients with newly diagnosed glioblastoma (eGBM) carry a worse prognosis compared with their younger counterparts. eGBM garners special attention due to the unique challenges, including increased treatment-associated toxicity, less relative benefit from aggressive therapy, medical comorbidities, and immunosuppression. The pivotal GBM trials excluded patients > 70 years old and the optimal treatment approach remains unsettled for eGBM. In this review, we analyze the historical evidence-based data for treating eGBM and discuss the future direction for managing this vulnerable population.

Recent Findings

Treatment for eGBM continues to evolve. Therapy choice is guided by performance status and presence of O6-methylguanine-DNA-methyltransferase (MGMT) promoter methylation. For eGBM with good performance status, combinatorial hypofractionated radiation therapy (hRT) and temozolomide should be recommended. For those with poor performance status, further stratification based on MGMT promoter methylation test result is recommended. Single-agent temozolomide is a viable treatment option for MGMT methylated tumors (mMGMT); in particular, those classified with receptor tyrosine kinase II methylation. hRT alone can be considered in MGMT unmethylated (uMGMT) eGBM patients. As precision oncology continues to advance, effective targeted and immunotherapy may emerge as new treatment options for eGBM.

Summary

Management of elderly patients with newly diagnosed GBM carries a unique set of challenges. Progress has been made in defining the optimal therapeutic approach for these patients, but many questions remain to be answered.

WHO Grade Loses Its Prognostic Value in Molecularly Defined Diffuse Lower-Grade Gliomas

BACKGROUND

While molecular insights to diffuse lower-grade glioma (dLGG) have improved the basis for prognostication, most established clinical prognostic factors come from the pre-molecular era. For instance, WHO grade as a predictor for survival in dLGG with isocitrate dehydrogenase (IDH) mutation has recently been questioned. We studied the prognostic role of WHO grade in molecularly defined subgroups and evaluated earlier used prognostic factors in the current molecular setting.

MATERIAL AND METHODS

A total of 253 adults with morphological dLGG, consecutively included between 2007 and 2018, were assessed. IDH mutations, codeletion of chromosomal arms 1p/19q, and cyclin-dependent kinase inhibitor 2A/B (CDKN2A/B) deletions were analyzed.

RESULTS

There was no survival benefit for patients with WHO grade 2 over grade 3 IDH-mut dLGG after exclusion of tumors with known CDKN2A/B homozygous deletion (n=157) (log-rank p=0.97). This was true also after stratification for oncological postoperative treatment and when astrocytomas and oligodendrogliomas were analyzed separately. In IDH-mut astrocytomas, residual tumor volume after surgery was an independent prognostic factor for survival (HR 1.02; 95% CI 1.01-1.03; p=0.003), but not in oligodendrogliomas (HR 1.02; 95% CI 1.00-1.03; p=0.15). Preoperative tumor size was an independent predictor in both astrocytomas (HR 1.03; 95% CI 1.00-1.05; p=0.02) and oligodendrogliomas (HR 1.05; 95% CI 1.01-1.09; p=0.01). Age was not a significant prognostic factor in multivariable analyses (astrocytomas p=0.64, oligodendrogliomas p=0.08).

CONCLUSION

Our findings suggest that WHO grade is not a robust prognostic factor in molecularly well-defined dLGG. Preoperative tumor size remained a prognostic factor in both IDH-mut astrocytomas and oligodendrogliomas in our cohort, whereas residual tumor volume predicted prognosis in IDH-mut astrocytomas only. The age cutoffs for determining high risk in patients with IDH-mut dLGG from the pre-molecular era are not supported by our results.

TERT expression increases with tumor grade in a cohort of IDH-mutant gliomas

The molecular mechanisms underlying progression from astrocytoma to secondary glioblastoma are poorly understood. Telomerase reverse transcriptase (TERT), a gene encoding for the catalytic subunit of telomerase, is upregulated in various cancers. Upregulation of TERT is a likely mechanism by which malignant cells delay senescence and evade cell death. TERT activity is also the primary mechanism by which malignant cells replenish telomeres, with the other means of telomere replacement being the alternative lengthening of the telomeres (ALT) system. The ALT system is known to be upregulated in tumors harboring loss of function mutations in ATRX. This study analyzed aggregate data on TERT and ATRX expression in astrocytoma, anaplastic astrocytoma, and secondary glioblastoma and then supplemented the data with our findings. In data obtained from Oncomine, significantly higher TERT expression is seen in astrocytomas and secondary glioblastomas compared to normal brain tissue. Additionally, The Cancer Genome Atlas data shows that TERT expression is a significant predictor of overall survival in low-grade gliomas. However, studies comparing the expression of TERT across all grades of astrocytomas had not been performed to date. Using immunohistochemical staining, we showed that controlling for ATRX and IDH mutational status, TERT expression increased with tumor grade in a cohort of patient-derived astrocytoma, anaplastic astrocytoma, and secondary glioblastoma samples. These findings indicate that TERT expression increases as astrocytomas become more aggressive tumors, and probably plays a role in their progression.