IDH-wildtype Gliomas Research Articles

A multicenter retrospective study of the duration of adjuvant temozolomide in IDH-mutant gliomas.

e14048 Background: Gliomas with isocitrate dehydrogenase (IDH) mutations have improved prognosis and are more treatment responsive compared to IDH wild-type gliomas. For glioblastoma (IDH wild-type glioma), Stupp protocol has demonstrated superiority with 6 cycles of adjuvant temozolomide (TMZ). However, recommended duration of TMZ for IDH mutant gliomas is not well-defined, with studies such as RTOG 0424, CATNON, and CODEL extending treatment up to 12 cycles. Prolonged TMZ duration following radiation therapy (RT) is associated with increased toxicity including both financial (cost of drug, lab work, and visits) and drug side effects including cytopenias. We aimed to evaluate for any differences in survival between patients treated with more than 6 cycles of TMZ and those treated with 6 or fewer. Methods: We conducted a multicenter retrospective study of patients treated at the University of Washington and Stanford Medical Center for oligodendrogliomas (oligo) and IDH mutated astrocytomas (astro) using World Health Organization 2016 molecular diagnostic criteria including IDH mutation. Other inclusion criteria were grades 2 and 3, as well as treatment with RT (with or without concurrent TMZ) followed by adjuvant TMZ monotherapy with number of cycles documented. Survival probability, mean overall survival (mOS) and mean progression-free survival (mPFS), were calculated using Kaplan-Meier method with distributions compared using log-rank test in Prism GraphPad comparing >6 cycles of adjuvant TMZ and ≤6 cycles. Results: Of 153 patients treated with both XRT and adjuvant TMZ, 88 were treated with between 1 and 6 cycles of adjuvant TMZ, while 91 were treated with >6 cycles Treatment duration ranged from 1-12 cycles for oligos, 4-12 cycles for grade 2 astros, and 1-14 cycles for grade 3 astros. mOS of oligos was undefined for those treated with 1-6 cycles and 84 months (m) for those treated with >6 cycles (p=0.1448). mOS of grade 2 astros was 154m for those treated with 1-6 cycles and 162.9m for those treated with >6 cycles (p=0.8864). mOS of grade 3 astros was undefined for those treated with 1-6 cycles and 117m for those treated with >6 cycles (p=0.8003). mPFS of oligos was 93m for those treated with 1-6 cycles and undefined for those treated with >6 cycles (p=0.584). mPFS of grade 2 astros was 79.6m for those treated with 1-6 cycles and 144.56m for those treated with >6 cycles (p=0.610). mPFS of grade 3 astros was 72m for those treated with 1-6 cycles and 79.4m for those treated with >6 cycles (p=0.9596). Conclusions: While this study is limited by power, there was no difference in mOS or mPFS with greater than 6 cycles of TMZ among patients with oligodendrogliomas and IDH mutant astrocytomas. More data is needed to evaluate the optimal treatment duration to maximize survival without over-exposing these patients to toxicities.[Table: see text]

Phase II trial of combination pembrolizumab, olaparib, and temozolomide for patients with recurrent glioma.

TPS2087 Background: Diffuse gliomas are primary brain tumors characterized by substantial morbidity and mortality. Standard treatment includes maximal safe surgical resection followed by combination radiation and chemotherapy. Despite aggressive treatment, diffuse gliomas inevitably recur. Alkylating agents, and in particular temozolomide, play an important role in the treatment of gliomas, resulting in single-strand DNA breakages which require PARP activity for detection and repair. Gliomas with mutations in isocitrate dehydrogenase ( IDH) 1 or 2 have an accumulation of 2-hydroxyglutarate (2HG) which results in a BRCA-like state of homologous recombination deficiency (HRD). When PARP is inhibited in the setting of HRD, single-strand DNA damage progresses to double-strand breaks resulting in synthetic lethality. PARP inhibition has also been shown to increase mutational burden and neoantigen expression (“immune-priming”) and increases tumor-infiltrating lymphocytes and expression of PD-L1. Here, we present an ongoing clinical trial combining the checkpoint inhibitor pembrolizumab, the PARP inhibitor olaparib, and temozolomide for treatment of recurrent gliomas with HRD. Methods: This is an open-label, non-randomized phase II trial of combination pembrolizumab, olaparib, and temozolomide for patients with recurrent glioma. The main study cohort (A) will consist of 52 patients with recurrent enhancing grade 2 or 3 IDH-mutant gliomas. An exploratory cohort (B) will consist of 5 patients with recurrent IDH-wildtype gliomas and mutations associated HRD. Study intervention is administered in 21-day cycles and includes pembrolizumab (200mg IV q3 weeks day 1), olaparib (200mg bid orally days 8-14) and temozolomide (50mg/m2 orally days 8-14). The primary outcome is overall response rate (ORR) in cohort A. Secondary objectives include safety and toxicity of triplet therapy, overall and progression-free survival, and best radiographic response. Exploratory objectives will describe outcomes in the IDH-wildtype cohort and associate response to tumor markers obtained through archival tissue and cell free DNA of cerebrospinal fluid. The trial includes a 6-patient safety lead-in to assess tolerability of triplet therapy. Cohort A patients must have grade 2 or 3 IDH-mutant glioma without known CDKN2A/B loss. Patients in Cohort B must have IDH-wildtype glioma with an alternate deleterious mutation involved in homologous recombination. Additional inclusion criteria include age ≥ 18, ECOG 0-1, and glioma recurrent after prior therapy with measurable disease by RANO. Patients must be on a stable dose of corticosteroids not to exceed 2mg/day. There are no restrictions regarding number of recurrences or prior therapies if an appropriate washout has been completed. To date, seven of 57 patients have enrolled. The safety-lead in was completed without dose-limiting toxicities. Clinical trial information: NCT05188508 .

Prevalence and characteristics analysis of CDKN2A/B deletion in glioma.

e14026 Background: Glioma is the most common type of brain malignancy in adults. The 5th edition of the World Health Organization (WHO) highlighted the homozygous deletion of the CDKN2A/2B as a clinically important molecular alteration in IDH-mutant glioma. In the study, we reported the prevalence and characteristics analysis of CDKN2A/B deletion in glioma. Methods: This study retrospectively analyzed the genomic alteration of 2390 Chinese glioma patients during 2019-2022. Next-generation sequencing (NGS) of 131-gene profiling was performed to detect gene mutations in tumors of the patients. Patients were divided into two groups for copy number (CN) variation set, as heterozygous deletion (CN> 0.5, HET-del) or homozygous deletion (CN≤ 0.5, HOM-del) group. Results: A total of 743 (31%) cases were detected with CDKN2A/B deletion, 21 cases were children (< 18 years old), and 722 cases were adults, with a mean age of 53 years (0-85 years). CDKN2A/B deletion showed a higher frequency in the subgroup of IDH-wildtype glioma compared with IDH-mutant glioma in adults (39% vs. 15%, p<0.005). The age showed no significant difference between CDKN2A/B HET-del (n=420) and HOM-del (n=323) patients (average age: 53, p = 0.74). In both of the two groups, the most frequently somatic mutated genes were TERT, EGFR, PTEN. However, NF1 mutations were significantly enriched in the HET-del group (21% vs. 12%，p<0.005). Conclusions: Taken together, CDKN2A/B deletion were found in 31% glioma patients and showed higher frequency in IDH-wildtype glioma. NF1 mutations were significantly enriched in the HET-del group, which may reveal distinct prognosis and pathogenic mechanisms in glioma.

Reduced YAP1 and FOLR1 in gliomas predict better response to chemotherapeutics

Gliomas harbouring mutations in IDH1 (isocitrate dehydrogenase 1) are characterized by greater sensitivity to chemotherapeutics. These mutants also exhibit diminished levels of transcriptional coactivator YAP1 (yes-associated protein 1). Enhanced DNA damage in IDH1 mutant cells, as evidenced by γH2AX formation (phosphorylation of histone variant H2A.X) and ATM (serine/threonine kinase; ataxia telangiectasia mutated) phosphorylation, was accompanied by reduced FOLR1 (folate receptor 1) expression. Diminished FOLR1, concomitant with heightened γH2AX levels, was also observed in patient-derived IDH1 mutant glioma tissues. Chromatin immunoprecipitation, overexpression of mutant YAP1, and treatment with YAP1-TEAD (TEA domain transcription factors) complex inhibitor verteporfin demonstrated regulation of FOLR1 expression by YAP1 and its partner transcription factor TEAD2. TCGA (The Cancer Genome Atlas) data analysis demonstrated better patient survival with reduced FOLR1 expression. Depletion of FOLR1 rendered IDH1 wild-type gliomas more susceptible to temozolomide-mediated death. Despite heightened DNA damage, IDH1 mutants exhibited reduced levels of IL6 (interleukin 6) and IL8 (interleukin 8) – pro-inflammatory cytokines known to be associated with persistent DNA damage. While both FOLR1 and YAP1 influenced DNA damage, only YAP1 was involved in regulating IL6 and IL8. ESTIMATE and CIBERSORTx analyses revealed the association between YAP1 expression and immune cell infiltration in gliomas. By identifying the influence of YAP1-FOLR1 link in DNA damage, our findings suggest that simultaneous depletion of both could amplify the potency of DNA damaging agents, while concomitantly reducing the release of inflammatory mediators and potentially affecting immune modulation. This study also highlights the novel role of FOLR1 as a probable prognostic marker in gliomas, predicting responsiveness to temozolomide and other DNA damaging agents.

PERK-Mediated Cholesterol Excretion from IDH Mutant Glioma Determines Anti-Tumoral Polarization of Microglia.

Isocitrate dehydrogenase (IDH) mutation, a known pathologic classifier, initiates metabolic reprogramming in glioma cells and has been linked to the reaction status of glioma-associated microglia/macrophages (GAMs). However, it remains unclear how IDH genotypes contribute to GAM phenotypes. Here, it is demonstrated that gliomas expressing mutant IDH determine M1-like polarization of GAMs, while archetypal IDH induces M2-like polarization. Intriguingly, IDH-mutant gliomas secrete excess cholesterol, resulting in cholesterol-rich, pro-inflammatory GAMs without altering their cholesterol biosynthesis, and simultaneously exhibiting low levels of tumoral cholesterol due to expression remodeling of cholesterol transport molecules, particularly upregulation of ABCA1 and downregulation of LDLR. Mechanistically, a miR-19a/LDLR axis-mediated novel post-transcriptional regulation of cholesterol uptake is identified, modulated by IDH mutation, and influencing tumor cell proliferation and invasion. IDH mutation-induced PERK activation enhances cholesterol export from glioma cells via the miR-19a/LDLR axis and ABCA1/APOE upregulation. Further, a synthetic PERK activator, CCT020312 is introduced, which markedly stimulates cholesterol efflux from IDH wild-type glioma cells, induces M1-like polarization of GAMs, and consequently suppresses glioma cell invasion. The findings reveal an essential role of the PERK/miR-19a/LDLR signaling pathway in orchestrating gliomal cholesterol transport and the subsequent phenotypes of GAMs, thereby highlighting a novel potential target pathway for glioma therapy.

Does the distance to the cancer center affect psycho-oncological care and emergency visits of patients with IDH wild-type gliomas? A retrospective study.

Malignant isocitrate dehydrogenase wild-type (IDHwt) gliomas impose a high symptomatic and psychological burden. Wide distances from patients' homes to cancer centers may affect the delivery of psycho-oncological care. Here, we investigated, in a large brain tumor center with a rural outreach, the initiation of psycho-oncological care depending on spatial distance and impact of psycho-oncological care on emergency visits. Electronic patient charts, the regional tumor registry, and interviews with the primary care physicians were used to investigate clinical data, psycho-oncological care, and emergency unit visits. Interrelations with socio-demographic, clinical, and treatment aspects were investigated using univariable and multivariable binary logistic regression analysis and the Pearson's Chi-square test. Of 491, 229 adult patients of this retrospective cohort fulfilled the inclusion criteria for analysis. During the last three months of their lives, 48.9% received at least one psycho-oncological consultation, and 37.1% visited the emergency unit at least once. The distance from the cancer center did neither affect the initiation of psycho-oncological care nor the rate of emergency unit visits. Receiving psycho-oncological care did not correlate with the frequency of emergency unit visits in the last three months of life. We conclude that the distance of IDHwt glioma patients' homes from their cancer center, even in a rural area, does not significantly influence the rate of psycho-oncological care.

GALNT2 sustains glioma stem cells by promoting CD44 expression

Glioblastoma (GBM) is the most prevalent and malignant brain tumor and is highly resistant to currently available treatment. In this study, we reveal that polypeptide N-acetylgalactosaminyltransferase 5 (GALNT2) expression level was elevated in GBM, IDH1 wildtype glioma, and GBM stem cells (GSCs). GALNT2 increased expression correlated with GBM patients' unfavorable clinical outcomes. Functionally, targeting GALNT2 blocks GSCs cell proliferation, self-renewal, and malignant invasion through repressing CD44 expression. Most importantly, we first provide evidence suggesting that STAT3 activates GALNT2 expression at the transcriptional level by directly binding to the GALNT2 promoter. Through a rational screening, we found a GALNT2 inhibitor that dramatically suppresses GSCs self-maintenance in vitro and in vivo. Collectively, we uncovered the critical function of GALNT2 in promoting GSCs self-maintenance and GBM progression and may provide a new potential drug for GBM clinical therapy.

Glutamine metabolism-related genes predict prognosis and reshape tumor microenvironment immune characteristics in diffuse gliomas.

Diffuse gliomas possess a kind of malignant brain tumor with high mortality. Glutamine represents the most abundant and versatile amino acid in the body. Glutamine not only plays an important role in cell metabolism but also involves in cell survival and malignancies progression. Recent studies indicate that glutamine could also affect the metabolism of immune cells in the tumor microenvironment (TME). The transcriptome data and clinicopathological information of patients with glioma were acquired from TCGA, CGGA, and West China Hospital (WCH). The glutamine metabolism-related genes (GMRGs) were retrieved from the Molecular Signature Database. Consensus clustering analysis was used to discover expression patterns of GMRGs, and glutamine metabolism risk scores (GMRSs) were established to model tumor aggressiveness-related GMRG expression signature. ESTIMATE and CIBERSORTx were applied to depict the TME immune landscape. The tumor immunological phenotype analysis and TIDE were utilized for predicting the therapeutic response of immunotherapy. A total of 106 GMRGs were retrieved. Two distinct clusters were established by consensus clustering analysis, which showed a close association with the IDH mutational status of gliomas. In both IDH-mutant and IDH-wildtype gliomas, cluster 2 had significantly shorter overall survival compared with cluster 1, and the differentially expressed genes between the two clusters enriched in pathways related to malignant transformation as well as immunity. In silico TME analysis of the two IDH subtypes revealed not only significantly different immune cell infiltrations and immune phenotypes between the GMRG expression clusters but also different predicted responses to immunotherapy. After the screening, a total of 10 GMRGs were selected to build the GMRS. Survival analysis demonstrated the independent prognostic role of GMRS. Prognostic nomograms were established to predict 1-, 2-, and 3-year survival rates in the four cohorts. Different subtypes of glutamine metabolism could affect the aggressiveness and TME immune features of diffuse glioma, despite their IDH mutational status. The expression signature of GMRGs could not only predict the outcome of patients with glioma but also be combined into an accurate prognostic nomogram.

Urinary 8-hydroxy-2′-deoxyguanosine levels are elevated in patients with IDH1-wildtype glioblastoma and are associated with tumor recurrence in gliomas

2021 World Health Organization (WHO) Central Nervous System (CNS) Tumor Classification includes molecular diagnostic parameters such as isocitrate dehydrogenase (IDH) mutation or 1p19q codeletion status, in addition to the classical histological classification. Several studies have revealed that patients with IDH1 mutation have a longer survival rate compared to wildtype individuals. In glioma cells, increased oxidative stress has been identified. However, till now, the relation between oxidative stress levels and IDH1 mutation status in those patients was not examined. Therefore, the aim of this study was to investigate the urinary levels of oxidatively induced DNA damage products, 8-hydroxy-2′- deoxyguanosine (8-OH-dG), (5′R) and (5′S)-8,5′-cyclo-2′-deoxyadenosines (R-cdA and S-cdA) as reliable oxidative stress markers in patients with IDH1-wildtype (n = 20) and IDH1-mutant (n = 22) glioma. Absolute quantification of 8-OH-dG, R-cdA and S-cdA was achieved by liquid chromatography-tandem mass spectrometry with isotope dilution. The levels of 8-OH-dG were significantly greater in IDH1-wildtype glioma patients than those in IDH1-mutant ones (p = 0.017). No statistically significant difference was observed for R-cdA and S-cdA levels. 8-OH-dG levels were positively correlated with patients’ tumor recurrence in all patients (r = 0.382, p = 0.014). The mutation status of glioma is well correlated with oxidative stress. Examination of noninvasively measured oxidative DNA damage products along with IDH1 mutation status in glioma patients, might be particularly important in terms of evaluating and monitoring the effectiveness of treatment.

Impact of GAP-43, Cx43 and actin expression on the outcome and overall survival in diffuse and anaplastic gliomas

Distant intercellular communication in gliomas is based on the expansion of tumor microtubuli, where actin forms cytoskeleton and GAP-43 mediates the axonal conus growth. We aimed to investigate the impact of GAP-43 and actin expression on overall survival (OS) as well as crucial prognostic factors. FFPE tissue of adult patients with diffuse and anaplastic gliomas, who underwent first surgery in our center between 2010 and 2019, were selected. GAP-43, Cx43 and actin expression was analyzed using immunohistochemistry and semi-quantitatively ranked. 118 patients with a median age of 46 years (IqR: 35–57) were evaluated. 48 (41%) presented with a diffuse glioma and 70 (59%) revealed anaplasia. Tumors with higher expression of GAP-43 (p = 0.024, HR = 1.71/rank) and actin (p < 0.001, HR = 2.28/rank) showed significantly reduced OS. IDH1 wildtype glioma demonstrated significantly more expression of all proteins: GAP-43 (p = 0.009), Cx43 (p = 0.003) and actin (p < 0.001). The same was confirmed for anaplasia (GAP-43 p = 0.028, actin p = 0.029), higher proliferation rate (GAP-43 p = 0.016, actin p = 0.038), contrast-enhancement in MRI (GAP-43 p = 0.023, actin p = 0.037) and age (GAP-43 p = 0.004, actin p < 0.001; Cx43 n.s. in all groups). The intercellular distant communication network in diffuse and anaplastic gliomas formed by actin and GAP-43 is associated with a negative impact on overall survival and with unfavorable prognostic features. Cx43 did not show relevant impact on OS.

Forecasting Molecular Features in IDH-Wildtype Gliomas: The State of the Art of Radiomics Applied to Neurosurgery.

The fifth edition of the WHO Classification of Tumors of the Central Nervous System (CNS), published in 2021, marks a step forward the future diagnostic approach to these neoplasms. Alongside this, radiomics has experienced rapid evolution over the last several years, allowing us to correlate tumor imaging heterogeneity with a wide range of tumor molecular and subcellular features. Radiomics is a translational field focused on decoding conventional imaging data to extrapolate the molecular and prognostic features of tumors such as gliomas. We herein analyze the state-of-the-art of radiomics applied to glioblastoma, with the goal to estimate its current clinical impact and potential perspectives in relation to well-rounded patient management, including the end-of-life stage. A literature review was performed on the PubMed, MEDLINE and Scopus databases using the following search items: "radiomics and glioma", "radiomics and glioblastoma", "radiomics and glioma and IDH", "radiomics and glioma and TERT promoter", "radiomics and glioma and EGFR", "radiomics and glioma and chromosome". A total of 719 articles were screened. Further quantitative and qualitative analysis allowed us to finally include 11 papers. This analysis shows that radiomics is rapidly evolving towards a reliable tool. Further studies are necessary to adjust radiomics' potential to the newest molecular requirements pointed out by the 2021 WHO classification of CNS tumors. At a glance, its application in the clinical routine could be beneficial to achieve a timely diagnosis, especially for those patients not eligible for surgery and/or adjuvant therapies but still deserving palliative and supportive care.

Elevated ratio of C-type lectin-like receptor 2 level and platelet count (C2PAC) aids in the diagnosis of post-operative venous thromboembolism in IDH-wildtype gliomas

IntroductionPodoplanin (PDPN) is known to induce platelet aggregation via interacting with the C-type lectin-like receptor-2 on platelets and is involved in postoperative venous thromboembolism (VTE) formation. In this study, we investigate the correlation between soluble C-type lectin-like receptor (sCLEC-2) levels and PDPN expression in patients with high grade gliomas and the relationship between sCLEC-2 levels and the occurrence of VTE. Materials and methodsForty-four patients harboring high grade gliomas, treated surgically at the Department of Neurosurgery, Niigata University from April 2018 to August 2020, were included. Patients with high grade gliomas were divided into isocitrate dehydrogenase (IDH)- wildtype and mutant groups, and the presence or absence of VTE and the intensity of PDPN by immunohistochemistry were confirmed. Platelet counts, as well as plasma sCLEC-2 and PDPN were measured in these patients. Furthermore, the levels of sCLEC-2 concentration were divided by the platelet count (C2PAC index) for comparison. ResultsIDH-wildtype glioma patients highly expressed PDPN (P < 0.001) compared to IDH-mutant glioma patients. In total, 9 (20.5 %) patients were diagnosed with VTE during the follow-up period, of which 8 patients harbored IDH-wildtype gliomas, and one patient an IDH-mutant glioma. Mean sCLEC-2 levels and C2PAC index in patients with IDH-wildtype gliomas were significantly higher than that of low or no PDPN expression group, which included patients with IDH-mutant gliomas (P = 0.0004, P = 0.0002). In patients with IDH-wildtype gliomas, the C2PAC index in patients with VTE was significantly higher than in patients without VTE (P = 0.0492). The optimal cutoff point of C2PAC for predicting VTE in IDH-wildtype glioma patients was 3.7 with a sensitivity of 87.5 % and specificity of 51.9 %. ConclusionPlatelet activation is strongly involved in the development of VTE in patients with IDH-wildtype high grade gliomas, and C2PAC index is a potential marker to detect VTE formation after surgery.

Apparent Diffusion Coefficient as Imaging Biomarker for Identifying IDH Mutation, 1p19q Codeletion, and MGMT Promoter Methylation Status in Patients With Glioma.

Glioma genotypes are of importance for clinical decision-making. This data can only be acquired through histopathological analysis based on resection or biopsy. Consequently, there is a need for alternative biomarkers that noninvasively provide reliable information for preoperatively identifying molecular characteristics. To investigate apparent diffusion coefficient (ADC) as imaging biomarker for preoperatively identifying glioma genotypes based on the 2021 World Health Organization (WHO) classification of central nervous system (CNS) tumors. Retrospective. One hundred and fifty-nine patients (47.6 ± 14.4 years) diagnosed with WHO grade 2-4 glioma including 93 males and 66 females. A 3 T/spin echo echo planner imaging. The ADC measurements were assessed by two neuroradiologists (both with 6 years of experience). Three different lowest portions inside the tumors without overlap were manually drawn on the ADC maps as regions of interest (ROIs). The mean ADC value of the three ROIs was defined as the minimum ADC value (ADCmin ). An ROI was placed in the contralateral normal appearing white matter (NAWM) to obtain the ADC value (ADCNAWM ). The ADCmin to ADCNAWM ratio (ADCratio ) was calculated. Genetics results were retrospectively recorded from pathologic and genetic test reports. Two-sample independent t-tests, receiver operating characteristic curve analysis, and intraclass correlation coefficient analysis were used. Statistical significance was set at P < 0.05. Isocitrate dehydrogenase (IDH)-mutated glioma showed higher ADCmin and ADCratio than IDH wild-type glioma. Among IDH-mutated glioma, higher ADCmin and ADCratio were found in 1p19q intact glioma than in 1p19q codeletion glioma. ADC parameters enabled differentiation of IDH mutation status with area under the curve (AUC) of 0.84 and 0.86. ADC has potential discriminative value for IDH mutation and 1p19q codeletion status. 3. Stage 2.

Characterization, Potential Prognostic Value, and Immune Heterogeneity of Cathepsin C in Diffuse Glioma

Aims: Diffuse glioma is the most frequent intracranial tumor and remains universally lethal. Prognostic biomarkers have remained a focus in diffuse glioma during the last decades. More reliable predictors to adequately characterize the prognosis of diffuse glioma are essential. Cathepsin C (CTSC), a lysosomal cysteine protease, is an essential component of the lysosomal hydrolase family, with their potential roles in diffuse glioma remaining to be characterized Objective: We aimed to investigate the performance of CTSC in predicting prognosis and therapeutic targets in diffuse glioma. Method: The expression profile of CTSC in multiple tumors and more than 2000 glioma samples with corresponding clinical data were collected through authoritative public databases. The expression level of CTSC was evaluated by qPCR and IHC. The prognostic value of CTSC was assessed using the univariate and multivariate cox regression analysis. The ESTIMATE R package was used to evaluate the immune and stromal scores based on the gene expression profile. The CIBERSORT was applied to evaluate the relative levels of 22 immune cell subtypes by using the R package 'CIBERSORT' to define the cell composition of tumor tissues. In addition, the MCP counter was used to assess the absolute abundance of neutrophils. Result: CTSC was aberrantly expressed and significantly correlated with clinical outcomes in multiple tumors. CTSC was heterogeneously expressed across histologic types and tumor grades for diffuse glioma and highly enriched in IDH or IDH1-wildtype glioma. CTSC was positively associated with immune and stromal scores and infiltrating levels of M2 macrophages and neutrophils and negatively associated with infiltrating levels of NK cells. Additionally, CTSC was closely correlated with some immune checkpoint molecules, including CD276, CD80, CD86 and PD-L2. Conclusion: Conclusion: CTSC was involved in shaping the immunosuppressive microenvironment and acted as an independent indicator of a poor prognosis in diffuse glioma. Targeting CTSC for glioma therapies might provide promising prospects.

Elevated Fras1-related extracellular matrix 3 in isocitrate dehydrogenase 1-mutant astrocytoma World Health Organization grade 4 predicts favorable prognosis in glioma: A bioinformatic and experimental analysis

Background and Aim: World Health Organization (WHO) grade 4 glioma is a malignancy of the central nervous system characterized by refractoriness to treatment and a high mortality rate. Isocitrate dehydrogenase (IDH) mutation is a crucial molecular event for the classification of glioma and associated with prognosis and exploring genetic and molecular differences between IDH mutant and wildtype glioma is crucial. The aim of this study was to investigate the prognostic gene between IDH mutant and wildtype WHO grade 4 glioma and its functional significance. Materials and Methods: The mRNA expression profile data of WHO grade 4 glioma were downloaded from the Gene Expression Omnibus and Chinese Glioma Genome Atlas databases. Bioinformatic analysis was performed to identify the differentially expressed genes between IDH1-mutant and wildtype WHO grade 4 glioma. Survival analysis, functional enrichment analysis, immune cell infiltration evaluation, and in vitro experimental validation were conducted to evaluate the prognostic and functional significance of Fras1-related extracellular matrix 3 (FREM3). This study was approved by the Institutional Ethics Committee of Xinqiao Hospital, Third Military Medical University (approval No. 2021-Y068-01). Results: Elevated expression of FREM3 in IDH1-mutant WHO grade 4 astrocytoma predicted favorable prognosis in glioma. FREM3 was negatively associated with epithelial–mesenchymal transition (EMT), angiogenesis, and hypoxia; notably, low expression of FREM3 was associated with a higher degree of immune cell infiltration. In vitro experiments demonstrated that high FREM3 expression might attenuate the process of EMT and cellular proliferation in glioma. Conclusions: The gene FREM3 plays a major role in IDH1-mutant WHO grade 4 glioma and elevated FREM3 predicts a favorable prognosis of glioma. Further investigation on FREM3 is warranted to elucidate the mechanisms underlying the malignant evolution of glioma.

Proteomics separates adult-type diffuse high-grade gliomas in metabolic subgroups independent of 1p/19q codeletion and across IDH mutational status

High-grade adult-type diffuse gliomas are malignant neuroepithelial tumors with poor survival rates in combined chemoradiotherapy. The current WHO classification is based on IDH1/2 mutational and 1p/19q codeletion status. Glioma proteome alterations remain undercharacterized despite their promise for a better molecular patient stratification and therapeutic target identification. Here, we use mass spectrometry to characterize 42 formalin-fixed, paraffin-embedded (FFPE) samples from IDH-wild-type (IDHwt) gliomas, IDH-mutant (IDHmut) gliomas with and without 1p/19q codeletion, and non-neoplastic controls. Based on more than 5,500 quantified proteins and 5,000 phosphosites, gliomas separate by IDH1/2 mutational status but not by 1p/19q status. Instead, IDHmut gliomas split into two proteomic subtypes with widespread perturbations, including aerobic/anaerobic energy metabolism. Validations with three independent glioma proteome datasets confirm these subgroups and link the IDHmut subtypes to the established proneural and classic/mesenchymal subtypes in IDHwt glioma. This demonstrates common phenotypic subtypes across the IDH status with potential therapeutic implications for patients with IDHmut gliomas.

Feasibility of evaluating the histologic and genetic subtypes of WHO grade II-IV gliomas by diffusion-weighted imaging

BackgroundTo explore the feasibility of diffusion-weighted imaging (DWI) metrics to predict the histologic subtypes and genetic status of gliomas (e.g., IDH, MGMT, and TERT) noninvasively.MethodsOne hundred and eleven patients with pathologically confirmed WHO grade II-IV gliomas were recruited retrospectively. Apparent diffusion coefficient (ADC) values were measured in solid parts of gliomas on co-registered T2-weighted images and were compared with each other in terms of WHO grading and genotypes using t-tests. Receiver operating characteristic analysis was performed to assess the diagnostic performances of ADC. Subsequently, multiple linear regression was used to find independent variables, which can directly affect ADC values.ResultsThe values of overall mean ADC (omADC) and normalized ADC (nADC) of high grade gliomas and IDH wildtype gliomas were lower than low grade gliomas and IDH mutated gliomas (P < 0.05). nADC values showed better diagnostic performance than omADC in identifying tumor grade (AUC: 0.787 vs. 0.750) and IDH status (AUC: 0.836 vs. 0.777). ADC values had limited abilities in distinguishing TERT status (AUC = 0.607 for nADC and 0.617 for omADC) and MGMT status (AUC = 0.651 for nADC). Only tumor grade and IDH status were tightly associated with ADC values.ConclusionDWI metrics can predict glioma grading and IDH mutation noninvasively, but have limited use in detecting TERT mutation and MGMT methylation.

ET-6 EFFICACY OF NEAR-INFRARED PHOTOIMMUNOTHERAPY TARGETING PODOPLANIN IN MALIGNANT GLIOMAS

Abstract Background Near-infrared photoimmunotherapy (NIR-PIT) is a new cancer treatment based on a conjugate of photosensitizer IR700 and an antibody which selectively binds to the surface antigen of cancer cells. Upon exposure to near infrared light, which does not harm normal tissues, cancer cells are selectively killed. Clinical application for EGFR amplified head and neck cancer has already been realized but is still in the preclinical stages of research for brain tumors. Finding a surface antigen which is selective to cancer cells is key to the effective application of NIR-PIT. In IDH-wildtype gliomas, we found that podoplanin (PDPN) is a promising candidate. PDPN is a transmembrane sialoglycoprotein highly expressed in IDH-wildtype gliomas and other cancers. Methods Three PDPN-positive (NGT-11, NGT-41, LN319) and three PDPN-negative (T98G, U87MG, U251MG) glioblastoma cell lines were treated with PDPN-IR700 conjugate and exposed to near infrared light. Cytotoxicity was assessed by cell viability assays. Next, we treated subcutaneous mouse xenografts by NIR-PIT. Results Cytotoxicity was only observed after NIR-PIT using PDPN-conjugate in cell lines expressing PDPN. This cytotoxicity was dose-dependent to near infrared light exposure, and most pronounced in LN319 cell line, which expressed the highest levels of PDPN. Time lapse videos revealed instantaneous expanding, followed by rounding of dead cells after treatment. NIR-PIT treated subcutaneous xenografts showed significantly smaller tumor sizes compared to control, and pathological investigation revealed selective and extensive necrosis of tumor tissue. Discussion/conclusion PDPN is highly expressed in IDH-wildtype gliomas, and we found that NIR-PIT was highly effective in treating PDPN expressing glioblastoma cell lines. NIR-PIT is anticipated to be more selective and cytotoxic than photodynamic therapy and is a promising new treatment strategy for IDH-wildtype gliomas.

High levels of TIMP1 are associated with increased extracellular matrix stiffness in isocitrate dehydrogenase 1-wild type gliomas

Glioma progression is accompanied with increased tumor tissue stiffness, yet the underlying mechanisms are unclear. Herein, we employed atomic force microscopy analysis to show that tissue stiffness was higher in isocitrate dehydrogenase (IDH)-wild type gliomas than IDH-mutant gliomas. Bioinformatic analyses revealed that tissue inhibitor of metalloproteinase-1 (TIMP1) was one of the preferentially upregulated genes in IDH-wild type gliomas as compared to IDH-mutant gliomas, and its higher expression indicated worse prognosis of glioma patients. TIMP1 intensity determined by immunofluorescence staining on glioma tissues positively correlated with glioma tissue stiffness. Mechanistically, TIMP1 expression was positively correlated with the gene expression of two predominant extracellular matrix components, tenascin C and fibronectin, both of which were also highly expressed in IDH-wild type gliomas. By introducing IDH1-R132H-containing vectors into human IDH1-wild type glioma cells to obtain an IDH1-mutant cell line, we found that IDH1 mutation increased the TIMP1 promoter methylation through methylation-specific PCR. More importantly, IDH1-R132H mutation decreased both the expression of TIMP1, fibronectin, tenascin C, and the tumor tissue stiffness in IDH1-mutant glioma xenografts in contrast to IDH1-wild type counterparts. Moreover, TIMP1 knockdown in IDH-wild type glioma cells inhibited the expression of tenascin C and fibronectin, and decreased tissue stiffness in intracranial glioma xenografts. Conclusively, we revealed an IDH mutation status-mediated mechanism in regulating glioma tissue stiffness through modulating TIMP1 and downstream extracellular matrix components.The authors identified tissue inhibitor of metalloproteinase-1 (TIMP1) as an important regulator of tissue stiffness in isocitrate dehydrogenase (IDH)-wild type (WT) gliomas. TIMP1 knockdown decreases tissue stiffness, inhibited the expression of tenascin C and fibronectin, and suppressed tumor progression. These results suggest that TIMP1 could be a potential therapeutic target for IDH-WT gliomas.

PDPN contributes to constructing immunosuppressive microenvironment in IDH wildtype glioma

The tumor immunosuppressive microenvironment (IME) significantly affects tumor occurrence, progression, and prognosis, but the underlying molecular mechanisms remain to make known. We investigated the prognostic significance of PDPN and its role in IME in glioma. Weighted gene co-expression network analysis (WGCNA) found PDPN closely related to IDH wildtype status and higher immune score. Correlation analysis suggested PDPN was highly positively relevant to immune checkpoints expression and immune checkpoints block responding status. Correlation analysis together with verification in vitro suggested PDPN highly positively relevant tumor-associated neutrophils (TANs) and tumor-associated macrophages (TAMs). Least absolute shrinkage and selection operator (LASSO) regression employed to develop the prediction model with TANs and TAMs markers showed that high risk scores predicted worse prognosis. We highlight that PDPN overexpression is an independent prognostic indicator, and promotes macrophage M2 polarization and neutrophil degranulation, ultimately devotes to the formation of an immunosuppressive tumor microenvironment. Our findings contribute to re-recognizing the role of PDPN in IDH wildtype gliomas and implicate promising target therapy combined with immunotherapy for this highly malignant tumor.