IDH-mutant Tumors Research Articles

HGG-15. HIGH-GRADE GLIOMAS OCCURRING IN TEENAGERS AND YOUNG ADULT PATIENTS COMPRISE NOVEL MOLECULAR SUBGROUPS

Abstract High-grade gliomas (HGG) arise in any central nervous system location, in adults and children, with a poor prognosis. HGGs in teenagers and young adults (TYA) are understudied; this project aimed to characterise these tumours and identify potential therapeutic targets. HGG samples (n=195, FFPE/FF, 13-30 years) were collected, excluding well-characterised entities (histone/IDH-mutant). DNA methylation profiling (Illumina EPIC BeadArrays, brain tumour classifier (MNP v12.5 R package), n=195) classified cases against a reference cohort. Calibrated scores guided workflows to characterise mutational landscapes including RNA-based ArcherDx fusion panel (n=112), whole exome sequencing (n=84), and histological reviews in parallel. Well-characterised entities (n=50, including IDH-mutant tumours (n=18), PXA (n=12)) were excluded. Of the cases scoring >0.6, 64% classified as paediatric-type subgroups (pedHGG-RTK1A/B/C (30%), pedHGG-MYCN (10%), pedHGG-A/B (7%), pedHGG-RTK2A (6%)). 29% classified as subgroups more frequently seen in adults (GBM-MES (12%), GBM-RTK1/2 (3%)). 54% classified with a score <0.6. 38% cases were assigned to novel, recently identified, poorly-characterised subgroups with distinct methylation profiles and molecular features (HGG-B, HGG-E, ANTCON, GBM-CBM). Frequency comparisons to publicly available methylation data showed GBM-MES-ATYP tumours are TYA age-specific, in contrast to adult age-specific GBM-MES-TYP. Copy number profiling identified frequent changes across the cohort, including chromosomal gains (chr1q (54%), chr2 (22%), chr7 (41%)) and losses (chr10 (40%), chr13 (64%)). Focal amplifications included PDGFRA (12%), CDK4 (7%), MYCN/ID2 (3%), MYC (2%) and EGFR (0.7%) and the most common focal deletion was CDKN2A/p16 (12%). The most frequent glioma-associated somatic variants included TP53, PDGFRA, EGFR, and NF1. BCOR alterations were enriched compared to adult and paediatric reference cohorts. 10% cases showed a hypermutator phenotype, enriched in HGG-E. CDK4 amplifications were recurrent in GBM-RTK1 and GBM-CBM. Histology showed variable cytological and architectural features within novel subgroups. TYA HGG comprise novel subgroups with distinct methylation profiles and molecular characteristics, representing opportunities to refine future treatment.

Intra-operative desorption-electrospray ionization mass-spectrometry for real-time diagnosis, margin assessment, and maximization of brain cancer resection.

2071 Background: Despite advances in our understanding of brain cancer, the ability to discern between infiltrated and non-infiltrated tissue with current adjuncts, remains elusive. Isocitrate dehydrogenase (IDH) mutation is unique to IDH-mut glioma cells and can be used as a surrogate for tumor infiltration. Further, emerging evidence has shown unique signatures in brain cancer lipidomic profiling, with lipid metabolism playing a key role in brain cancer biology. Here, we aimed to evaluate the impact of desorption electrospray ionization-mass spectrometry (DESI-MS) as a near real-time method to determine infiltration status and the use of DESI-MS to perform intra-operative histological diagnosis. Methods: This is a prospective multi-institution cohort study using intra-operative DESI-MS on freshly obtained tumor samples to evaluate 2-hydroxyglutarate (2HG), with post-hoc validation by review by a board-certified neuropathologist. For tumor cell estimation and tissue diagnosis, high-throughput DESI-MS was used for rapid analysis of high-density arrays using lipidomic profiling. Analysis of the data was performed using a pre-written algorithm employing a combination of Python- and MATLAB-based custom software allowing results in less than a second per sample. Results: A total of 496 tumor biopsies from 72 patients have been analyzed. Earlier iterations focused on absolute quantitation of 2HG in 247 biopsies from 49 patients to determine IDH genotype yielding sensitivity, specificity, and accuracy values of 89, 100, and 94% for core biopsies (71). Improvement in accuracy was obtained with relative measurement of 2HG in comparison to glutamate allowing for detection of IDH-mut infiltration at the margin, resulting in 93% sensitivity, 100% specificity, and 98% accuracy with turnover times averaging 3 minutes in 183 biopsies from 23 patients. Margin assessment beyond the limits of neuro-navigation and surgeon assessment showed tumor infiltration in 88% of margin biopsies from IDH mutant tumors (30 of 34 biopsies) with 100% accuracy. Intra-operative tissue diagnosis was pursued in 66 unique tumor samples using DESI-MS lipidomic profiling, including samples of normal brain parenchyma, gliomas, meningiomas and pituitary adenomas, split into two microarray sets (36 and 40 samples). Using estimated principal components as input features, high accuracy ( > 90%; ROC AUCs ≥ 0.89) was obtained for supervised tissue classification using simple machine learning algorithms. Conclusions: We present a novel system for intra-operative evaluation of tumor infiltration at the margin in gliomas and for intra-operative tissue diagnosis of brain cancer. Our method identified tumor infiltration beyond the surgical margins and serves as a foundation for future uses employing DESI-MS to allow for molecularly guided surgery in IDH-mut gliomas.

Incidence of non-canonical IDH mutations and IDH co-mutations in a multicenter prospective study of patients with glioma.

e14033 Background: IDH-mutant tumors are a distinct disease entity accounting for one third of gliomas with a more favourable prognosis despite still harboring high morbidity and mortality rates. Most IDH mutations (muts) in gliomas group at R132/R172 hotspots in IDH1/IDH2, respectively. Our aim was to study IDH non-canonical muts and IDH co-mutations (co-muts) since the evidence is still limited. Methods: Prospective study of patients (pts) with gliomas at 4 third-level hospitals in Spain (Hospital Clinico Universitario San Carlos, Hospital Universitario La Paz, Hospital Universitario de Canarias, Hospital Universitario Nuestra Señora de la Candelaria). High throughput next generation sequencing (NGS) using a customized gene panel ((Illumina, Inc) including IDH1 and IDH2 was used in FFPE and/or fresh tumor samples, and run in an Illumina MiSeq instrument (Illumina, Inc). Only pathogenic mutations were considered as valid. Clonal IDH (cIDH) muts were defined as those with a MAF ≥ 1% and subclonal IDH (scIDH) muts as those with a MAF < 1%. Results: Between February 2017 and February 2021, 49 glioma pts enrolled and sequenced for IDH1/IDH2 tumor muts. Median age 51 (Min-max: 20-78). WHO 5th Ed (n = 42): IDH-MUT astrocytoma (n = 14), IDH-MUT oligodendroglioma (n = 7), IDH-WT glioblastoma (n = 21). 37/49 pts (75.5%) presented cIDH and/or scIDH muts, of which 21 pts (43%) harbored cIDH muts in IDH1 (R132H (n = 17), R132C (n = 1), R132G (n = 1), R100Q (n = 1), G161R (n = 1)) and in IDH2 (R140W (n = 1), R140Q (n = 1)). In 17/21 pts (81%) cIDH-mut MAF ≥ 10%. Of 21 cIDH-mutant pts, there were IDH co-muts in 11 pts (52%). Of these 11 pts, IDH co-muts were scIDH in 91%: #2 (IDH1 R100Q/G161R), #3 (IDH1 R132H/R119Q/G161R), #4 (IDH1 R132H/R132C; IDH2 R172G/R140Q), #11 (IDH1 R132H/R132C), #21 (IDH1 R132H/G161R; IDH2 R140Q), #23 (IDH1 R132H/R132C), #31 (IDH1 R132H/G161R; IDH2 R140Q/P162L), #32 (IDH1 R132H/R100Q), #33 (IDH1 R132H/R100Afs*29/I130V), #37 (IDH1 R132H; IDH2 R159H), #40 (IDH1 R132H; IDH2 R172G). Median overall survival (OS) longer in cIDH-mut vs IDH-wt (159 vs 16 months, P = 0.000). No difference in OS in: cIDH vs cIDH + scIDH (NR vs 67 m, P = 0.437), in scIDH vs cIDH (79 vs 159 m, P = 0.111), and scIDH vs IDH-wt (79 vs 12 m, P = 0.229). Conclusions: Subclonal (defined as MAF < 1%) canonical and non-canonical IDH-mutations and co-mutations occur frequently in gliomas. This may have implications for the design of future clinical trials and in the development of IDH inhibitors including the anticipation of potential resistance mechanisms.

Phase I study of the mutant IDH1 inhibitor ivosidenib: Long-term safety and clinical activity in patients with conventional chondrosarcoma.

11532 Background: Chondrosarcomas (CS) are rare primary bone malignancies for which there are no approved systemic therapies. 85% of CS are the conventional subtype. Mutations in the isocitrate dehydrogenase 1 ( IDH1) gene occur in ~50% of conventional CS. In a phase 1 study in patients (pts) with IDH1-mutated advanced solid tumors, ivosidenib (IVO), an oral potent inhibitor of mutant IDH1, demonstrated manageable toxicity (without dose-limiting toxicities), suppression of the oncometabolite 2-hydroxyglutarate at dose levels ≥300 mg/day, and disease control in pts with conventional CS. We report long-term safety, tolerability and efficacy of IVO in pts with conventional CS. Methods: In this phase I multicenter open-label dose-escalation and expansion study, IVO was administered orally (100 mg twice/day [BID] to 1200 mg once/day [QD]) in continuous 28-day cycles. Primary outcome was safety and tolerability; secondary outcomes included clinical activity (objective response rates [ORR, defined as complete response (CR) + partial response (PR)], stable disease [SD] and progression-free survival [PFS]). Adverse events (AEs) were assessed every visit and reported per the Common Terminology Criteria for Adverse Events (CTCAE version 4.03). Responses were assessed every other cycle using Response Evaluation Criteria in Solid Tumors (RECIST version 1.1). Results: 13 pts with advanced conventional CS were included in this analysis (data cut off 15 September 2022; women, n = 4; median age 54.0; AJCC tumor grade I [n = 2], II [n = 8], III [n = 1], unknown [n = 2]; 6 had received prior systemic therapy; received 100 mg IVO BID [n = 1], 400 mg QD [n = 1], 500 mg QD [n = 7], 800 mg QD [n = 2], and 1200 mg QD [n = 2]). Median treatment duration was 11.3 months (range: 0.5-92.6 months). Four pts (30.8%) have continued therapy for > 6 years (two of which were treated for > 7 years). Median relative dose intensity was 100%. The most frequent treatment emergent AEs (in > 4 pts; mostly grade 1/2) were diarrhea (n = 5) and nausea (n = 5). Six pts experienced grade ≥3 AEs. Three pts experienced serious AEs (none considered related to treatment). There were no discontinuations, dose reductions or deaths due to AEs. The ORR was 23.1%. Median duration of response was 42.5 months (range: 25.8-51.8 months). One pt with a base of the skull lesion achieved a CR (1200 mg IVO QD); two achieved PR (one 500 mg and one 1200 mg IVO QD); seven had SD (five received ≥500 mg IVO QD) and two had PD (both received ≥500 mg IVO QD). All responses occurred after > 2 years on treatment. Median PFS was 7.4 months (95% CI: 2.0-61.3). Conclusions: In pts with IDH1 mutated advanced conventional CS, IVO demonstrates manageable toxicity and durable disease control including long-term responses, extending several years for a proportion of pts. Future studies are warranted to better understand the efficacy of IVO in pts with advanced conventional CS. Clinical trial information: NCT02073994 .

Feasibility and utility of the custom RNA-seq for the identification of therapeutic targets and diagnostic biomarkers in glioma.

e14029 Background: The detection of novel therapeutic targets is increasingly important in oncology. The Todai OncoPanel (TOP) RNA panel is a custom target RNA-seq using the junction capture method to maximize the sensitivity in detecting of known 456 fusion gene transcripts, which is scheduled to be approved for clinical application in Japan in April 2023. Above, TOP RNA panel interrogates aberrantly spliced transcripts and analyzes the expression profiles of 1,390 genes. Malignant brain tumors, including gliomas, require various molecular profiles to be classified based on the latest WHO classification criteria, while their poor prognosis also necessitates new therapeutic targets. In this study, we aimed to classify gliomas and identify the molecular targets by TOP RNA panel. Methods: Among 131 frozen tumor samples of malignant gliomas, 124 samples passed quality control for further validation and were subjected to TOP RNA panel to classify based on the molecular profiles and to identify the molecular targets. Fusion detection and RNA expression analysis were conducted with the original pipeline. Cluster analysis and Gene Set Enrichment Analysis (GSEA) were performed to identify gene sets specific for individual subtypes. Copy numbers of tyrosine kinase genes, MDM2 and CDK4 were evaluated by digital droplet PCR (ddPCR). Results: Among 58 cases of glioblastoma, gene fusions were detected in 11 cases (19.0%) including novel MET fusions, and overexpression of seven tyrosine kinase genes were observed in 21 cases (36.2%). Of the 34 overexpressed genes, gene amplification was observed in 17 genes (50%) by ddPCR. In contrast to IDH-wildtype glioblastoma, IDH-mutant tumors including astrocytomas and oligodendrogliomas hardly harbored fusion genes or gene overexpression. GSEA to compare astrocytomas and oligodendrogliomas identified that the gene sets related to 1p36 and 19q were relatively enriched in astrocytoma, suggesting that regional genomic DNA copy number alterations can be evaluated by gene expression analysis. Conclusions: TOP RNA panel is utilized not only for the detection of molecular targets but also for the molecular classification of glioma, both of which is essential for providing treatments optimized for the individual patients.

The clinical value of proneural, classical and mesenchymal protein signatures in WHO 2021 adult-type diffuse lower-grade gliomas.

Accumulating evidence shows that mesenchymal transition of glioblastomas is associated with a more aggressive course of disease and therapy resistance. In WHO2021-defined adult-type diffuse gliomas of lower grade (dLGG), the transition of the tumor phenotype over time, has not been studied. Most efforts to correlate proneural, classical or mesenchymal phenotype with outcome in dLGG were made prior to the WHO 2021 classification. Here, we set out to investigate if phenotype predicted survival and tumor recurrence in a clinical cohort of dLGGs, re-classified according to the 2021 WHO criteria. Using a TMA-based approach with five immunohistochemical markers (EGFR, p53, MERTK, CD44 and OLIG2), we investigated 183 primary and 49 recurrent tumors derived from patients with previously diagnosed dLGG. Of the 49 relapses, nine tumors recurred a second time, and one a third time. In total, 71.0% of all tumors could be subtyped. Proneural was most dominant in IDH-mut tumors (78.5%), mesenchymal more common among IDH-wt tumors (63.6%). There was a significant difference in survival between classical, proneural and mesenchymal phenotypes in the total cohort (p<0.001), but not after molecular stratification (IDH-mut: p = 0.220, IDH-wt: p = 0.623). Upon recurrence, proneural was retained in 66.7% of the proneural IDH-mut dLGGs (n = 21), whereas IDH-wt tumors (n = 10) mainly retained or gained mesenchymal phenotype. No significant difference in survival was found between IDH-mut gliomas remaining proneural and those shifting to mesenchymal phenotype (p = 0.347). Subtyping into classical, proneural and mesenchymal phenotypes by five immunohistochemical markers, was possible for the majority of tumors, but protein signatures did not correlate with patient survival in our WHO2021-stratified cohort. At recurrence, IDH-mut tumors mainly retained proneural, while IDH-wt tumors mostly retained or gained mesenchymal signatures. This phenotypic shift, associated with increased aggressiveness in glioblastoma, did not affect survival. Group sizes were, however, too small to draw any firm conclusions.

RYK Gene Expression Associated with Drug Response Variation of Temozolomide and Clinical Outcomes in Glioma Patients.

Temozolomide (TMZ) chemotherapy is an important tool in the treatment of glioma brain tumors. However, variable patient response and chemo-resistance remain exceptionally challenging. Our previous genome-wide association study (GWAS) identified a suggestively significant association of SNP rs4470517 in the RYK (receptor-like kinase) gene with TMZ drug response. Functional validation of RYK using lymphocytes and glioma cell lines resulted in gene expression analysis indicating differences in expression status between genotypes of the cell lines and TMZ dose response. We conducted univariate and multivariate Cox regression analyses using publicly available TCGA and GEO datasets to investigate the impact of RYK gene expression status on glioma patient overall (OS) and progression-free survival (PFS). Our results indicated that in IDH mutant gliomas, RYK expression and tumor grade were significant predictors of survival. In IDH wildtype glioblastomas (GBM), MGMT status was the only significant predictor. Despite this result, we revealed a potential benefit of RYK expression in IDH wildtype GBM patients. We found that a combination of RYK expression and MGMT status could serve as an additional biomarker for improved survival. Overall, our findings suggest that RYK expression may serve as an important prognostic or predictor of TMZ response and survival for glioma patients.

GESTALT (GammaTile Enhanced Stupp Alternative): Feasibility Study of Resection and GammaTile® Followed by Concomitant External Beam Radiation Therapy (EBRT)/Temozolomide (TMZ) and Adjuvant TMZ in Newly Diagnosed Glioblastoma (GBM) (P13-13.001)

<h3>Objective:</h3> To evaluate the safety and feasibility of combining resection with immediate initiation of radiation and subsequent Stupp protocol in newly diagnosed GBM. <h3>Background:</h3> GBM is highly proliferative, with rapid early local progression (REP) after surgical resection, prior to the initiation of concurrent EBRT/TZM documented in 25–50% of patients. This high rate of REP supports initiation of an effective postoperative treatment as early as safely possible. FDA cleared GammaTiles (GT)(GT Medical Technologies, Inc, Tempe, AZ) consist of Cesium-131 radiation sources precisely imbedded in bio-resorbable collagen tiles. Intraoperatively tiles are permanently placed to line the at-risk areas of the resection bed achieving an immediate initiation of surgically targeted radiation therapy (STaRT). <h3>Design/Methods:</h3> GESTALT is a single arm 61 patient multi-center trial. Adults with suspected or confirmed GBM consented pre-operatively undergo a maximum safe resection and GT placement. Subjects with confirmed molecular GBM (WHO 2021 criteria) start concurrent EBRT/TMZ beginning 25±4 days post-surgery. Subsequent EBRT (20 fractions, 4 weeks) to low and high-risk PTV takes GT dose into account to a combined biologically equivalent dose of 46 and 60 Gy delivered in 2Gy/fraction, respectively. Adjuvant TMZ (6 cycles) begins 28±7 days after EBRT/TMZ; TTF is allowed. IDH-mutated tumors will be followed for safety. Outcomes include feasibility of incorporating GT without delay of Stupp protocol, consent/attrition rates, safety, OS, progression free survival, local control, functional decline (ECOG-PS) and immune competence (absolute lymphocyte counts). <h3>Results:</h3> The trial opened for enrollment in August of 2022 at 3 sites with 12 additional sites pending (NCT05342883). Clinical results to-date will be presented. <h3>Conclusions:</h3> This is the first trial in newly diagnosed GBM patients combining resection, GT, and the Stupp protocol, and attempts to reduce REP. The outcomes of this trial, if suggestive, will be used as the basis for a subsequent randomized trial. <b>Disclosure:</b> Dr. Dunbar has nothing to disclose. Dr. McCracken has received personal compensation for serving as an employee of GT Medical. Dr. McCracken has received personal compensation in the range of $500-$4,999 for serving as a Consultant for GT Medical. Dr. McCracken has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for GT Medical. Dr. Nowlan has received personal compensation for serving as an employee of GT Medical. Dr. Nowlan has received personal compensation in the range of $500-$4,999 for serving as a Consultant for GT Medical. Kathryn Dusenbery has nothing to disclose. Dr. Ferreira has nothing to disclose. Dr. Lee has received personal compensation in the range of $500-$4,999 for serving as a Consultant for GT Medical. Dr. Lee has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Novocure. Dr. Lee has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for GT Medical. Dr. Lee has received personal compensation in the range of $500-$4,999 for serving as an Expert Witness for Huff Powell Bailey Law Firm. An immediate family member of Dr. Lee has stock in Remedy Pharmaceuticals. An immediate family member of Dr. Lee has stock in Martin Pharmaceuticals. An immediate family member of Dr. Lee has stock in Critical Diagnostics. An immediate family member of Dr. Lee has stock in Woolsey Pharmaceuticals. An immediate family member of Dr. Lee has stock in Monogram Orthopaedics. An immediate family member of Dr. Lee has stock in Cytonics. An immediate family member of Dr. Lee has stock in 20-20 Gene Systems. Dr. Peach has nothing to disclose. Dr. Corns has nothing to disclose. Clark Chen has nothing to disclose.

Predictive role of magnetic resonance imaging in the distinction of isocitrate dehydrogenase (IDH) mutant grade 4 astrocytomas versus glioblastomas.

Isocitrate dehydrogenase (IDH) mutation status is a crucial prognostic factor in high-grade glial tumors. To investigate whether magnetic resonance imaging (MRI) features can display a diagnostic performance in the determination of IDH mutation in high-grade gliomas. A total of 170 patients including 24 IDH mutant grade 4 astrocytomas and 146 glioblastomas (GBM) were retrospectively examined via contrast-enhanced (CE) MRI before surgery. Immunohistochemistry and genomic sequence analyses were performed on specimen materials for the determination of IDH mutational status. Certain morphological and diffusion-weighted imaging (DWI) parameters were utilized to see if they could play a role to be non-invasive potential imaging predictors in the discrimination of IDH mutant versus wild-type (WT) high-grade gliomas. On histopathological examination, IDH mutation was detected in 24 patients with high-grade glioma and 146 of the patients were found to be WT. Certain morphological criteria of tumor location and involvement, tumor margins, visual detection of diffusion restriction on DWI, and quantitative apparent diffusion coefficient (ADC) parameters consisting of ADCmean, ADCmin, and ADCr could be used as imaging predictors in the discrimination of high-grade IDH mutant versus WT tumors. Certain MRI morphologic features and visual detection of diffusion restriction on DWI and quantitative ADC parameters consisting of ADCmean, ADCmin, and ADCr can be considered non-invasive, significant independent imaging predictors in the discrimination and can obviate invasive procedures for histopathological diagnosis.

Conventional chondrosarcoma of the rib cage and sternum: clinicopathological and molecular analysis of 27 patients treated at a single institution

Conventional chondrosarcoma of the chest wall is rare, accounting for 15% of cases. Our purpose was to document clinicopathological, imaging and outcome results from a novel set of chest wall chondrosarcomas, and to analyze for IDH mutations and novel molecular alterations. Gross and microscopic pathology, imaging and clinical charts were reviewed. Targeted next-generation sequencing was performed to identify somatic mutations and copy number alterations. The cohort consisted of 27 patients: 16 men and 11 women (mean age 51 years; range 23-76). Palpable mass was the most common presentation. Five were discovered incidentally. Among 20 tumors with complete imaging, 15 arose from a rib and 5 from the sternum. Seven rib tumors were central/intramedullary, 5 were periosteal, 2 were secondary peripheral chondrosarcomas, and one was indeterminate. Among sternal tumors, 4 were central/intramedullary and one was periosteal. Half the periosteal tumors arose from the costochondral junctional cartilage (CCJ). Periosteal chondrosarcomas were sometimes mistaken for extraskeletal masses on initial clinical or radiological examinations. Fifty-nine percent of all tumors were grade 1 and 41% were grade 2. None were dedifferentiated chondrosarcomas. Heterozygous IDH1 mutation was detected in one tumor and heterozygous RAD50 mutation in another. Local recurrence(s) happened in 41% and metastasis in 41%. Grade had strong association with local recurrence (25% grade 1 vs. 64% grade 2 [P=.0447]), metastatic recurrence (19% grade 1 vs. 73% grade 2 [P=.0058]), and survival. Although chest wall chondrosarcomas share morphologic and molecular features with other chondrosarcomas, there is a much higher incidence of periosteal chondrosarcomas. IDH mutant tumors are uncommon. Early diagnosis and margin-negative resection is treatment of choice since chondrosarcomas are chemo- and radioresistant.

212 Intra-Operative Near Real-Time Detection of Tumor Infiltration in IDH-Mutant Gliomas Using Desorption Electrospray Ionization-Mass Spectrometry (DESI-MS)

INTRODUCTION: Surgery remains the mainstay of treatment in gliomas. However, distinction between tumor infiltrated and non-infiltrated tissues remains a challenge with current surgical adjuncts, particularly at the margin. Isocitrate dehydrogenase (IDH) mutation is unique to IDH mutant glioma cells and can be used as a potential surrogate for tumor infiltration. METHODS: We conducted a prospective study, using intraoperative DESI-MS analysis on freshly obtained tissue samples to evaluate the presence of 2-hydroxyglutarate (2HG) by relative quantitation in comparison with an internal control (glutamate), with subsequent review of each smear by board-certified neuropathologist. RESULTS: Earlier iterations of our DESI-MS allowed for genotyping of the tumor with a total of 247 biopsies from a 49-patient study yielding sensitivity, specificity, and accuracy values of 89, 100, and 94% for core biopsies (n = 71). Subsequent improvement of DESI-MS, from absolute quantitation to relative measurement in comparison to glutamate (GLU) allowed for detection of IDH-mut infiltration at the margin. We have collected 183 biopsies (116 core and 67 margin) from 23 patients. Preliminary results of IDH mutation assessments of core biopsies indicate 93% sensitivity, 100% specificity, and 98% accuracy and margin biopsies indicate 88% sensitivity, 100% specificity, 94% accuracy, with turnover times averaging 3 minutes per patient. Tumor infiltration at the margin after surgical resection was detected in 88% of margin biopsies from IDH mutant tumors (30 of 34 biopsies). CONCLUSIONS: We present a novel system to allow intraoperative evaluation of tumor infiltration at the margin in IDH-mutant gliomas. Our method and its validation identified tumor infiltration beyond the surgical margins and serves as a foundation for future uses employing DESI-MS to allow for molecularly guided surgery in IDH-mut gliomas.

Imaging 2-hydroxyglutarate and other brain oncometabolites pertinent to critical genomic alterations in brain tumors.

The 2021 World Health Organization (WHO) Classification of Tumors of the Central Nervous System (CNS) and recent smaller annual updates have shown that alterations in tumor genetics are essential to determining tumor diagnosis, biological activity, and potential treatment options. This review summarizes the most important mutations and oncometabolites, with a focus on the central role played by 2-hydroxyglutarate in isocitrate dehydrogenase mutant tumors, as well as their corresponding imaging counterparts using standard and advanced imaging techniques.

Cognitive issues in patients with IDH mutant gliomas: from neuroscience to clinical neuropsychology.

The understanding of cognitive symptoms in patients with IDH-Mutant gliomas (IDH-Mut) is rapidly developing. In this article, we summarize the neuroscientific knowledge base regarding the influence of IDH-Mut tumors and their treatment on cognition and provide guidance regarding the management of these symptoms in patients. We performed a review of peer reviewed publications relevant to IDH-Mut glioma and cognitive outcomes and provide an overview of the literature as well as a case example to clarify management strategies. At the time of presentation, patients with IDH-Mut gliomas have a favorable cognitive profile as compared with those with IDH-wild type (WT) tumors. The relatively low cognitive burden may reflect the slower growth rate of IDH-Mut tumors, which is less disruptive to both local and widespread neural networks. Human connectomic research using a variety of modalities has demonstrated relatively preserved network efficiency in patients with IDH-Mut gliomas as compared with IDH-WT tumors. Risk of cognitive decline from surgery can potentially be mitigated by careful integration of intra-operative mapping. Longer term cognitive risks of tumor treatment, including chemotherapy and radiation, are best managed by instituting neuropsychological assessment as part of the long-term care of patients with IDH-Mutant glioma. A specific timeline for such integrative care is provided. Given the relative recency of the IDH-mutation based classification of gliomas, as well as the long time course of this disease, a thoughtful and comprehensive strategy to studying patient outcomes and devising methods of cognitive risk reduction is required.

Code-free machine learning for classification of central nervous system histopathology images.

Machine learning (ML), an application of artificial intelligence, is currently transforming the analysis of biomedical data and specifically of biomedical images including histopathology. The promises of this technology contrast, however, with its currently limited application in routine clinical practice. This discrepancy is in part due to the extent of informatics expertise typically required for implementation of ML. Therefore, we assessed the suitability of 2 publicly accessible code-free ML platforms (Microsoft Custom Vision and Google AutoML), for classification of histopathological images of diagnostic central nervous system tissue samples. When trained with typically 100 to more than 1000 images, both systems were able to perform nontrivial classifications (glioma vs brain metastasis; astrocytoma vs astrocytosis, prediction of 1p/19q co-deletion in IDH-mutant tumors) based on hematoxylin and eosin-stained images with high accuracy (from ∼80% to nearly 100%). External validation of the predicted accuracy and negative control experiments were found to be crucial for verification of the accuracy predicted by the algorithms. Furthermore, we propose a possible diagnostic workflow for pathologists to implement classification of histopathological images based on code-free machine platforms.

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

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

PRMT1 driven PTX3 regulates ferritinophagy in glioma

ABSTRACT Mutations in the Krebs cycle enzyme IDH1 (isocitrate dehydrogenase (NADP(+)) 1) are associated with better prognosis in gliomas. Though IDH1 mutant (IDH1R132H) tumors are characterized by their antiproliferative signatures maintained through hypermethylation of DNA and chromatin, mechanisms affecting cell death pathways in these tumors are not well elucidated. On investigating the crosstalk between the IDH1 mutant epigenome, ferritinophagy and inflammation, diminished expression of PRMT1 (protein arginine methyltransferase 1) and its associated asymmetric dimethyl epigenetic mark H4R3me2a was observed in IDH1R132H gliomas. Reduced expression of PRMT1 was concurrent with diminished levels of PTX3, a key secretory factor involved in cancer-related inflammation. Lack of PRMT1 H4R3me2a in IDH1 mutant glioma failed to epigenetically activate the expression of PTX3 with a reduction in YY1 (YY1 transcription factor) binding on its promoter. Transcriptional activation and subsequent secretion of PTX3 from cells was required for maintaining macroautophagic/autophagic balance as pharmacological or genetic ablation of PTX3 secretion in wild-type IDH1 significantly increased autophagic flux. Additionally, PTX3-deficient IDH1 mutant gliomas exhibited heightened autophagic signatures. Furthermore, we demonstrate that the PRMT1-PTX3 axis is important in regulating the levels of ferritin genes/iron storage and inhibition of this axis triggered ferritinophagic flux. This study highlights the conserved role of IDH1 mutants in augmenting ferritinophagic flux in gliomas irrespective of genetic landscape through inhibition of the PRMT1-PTX3 axis. This is the first study describing ferritinophagy in IDH1 mutant gliomas with mechanistic details. Of clinical importance, our study suggests that the PRMT1-PTX3 ferritinophagy regulatory circuit could be exploited for therapeutic gains. Abbreviations: 2-HG: D-2-hydroxyglutarate; BafA1: bafilomycin A1; ChIP: chromatin immunoprecipitation; FTH1: ferritin heavy chain 1; FTL: ferritin light chain; GBM: glioblastoma; HMOX1/HO-1: heme oxygenase 1; IHC: immunohistochemistry; IDH1: isocitrate dehydrogenase(NADP(+))1; MDC: monodansylcadaverine; NCOA4: nuclear receptor coactivator 4; NFE2L2/Nrf2: NFE2 like bZIP transcription factor 2; PTX3/TSG-14: pentraxin 3; PRMT: protein arginine methyltransferase; SLC40A1: solute carrier family 40 member 1; Tan IIA: tanshinone IIA; TCA: trichloroacetic acid; TEM: transmission electron microscopy; TNF: tumor necrosis factor

Clinical significance of histopathological features of paired recurrent gliomas: a cohort study from a single cancer center

ObjectiveTo explore the histopathological characteristics of paired recurrent gliomas and their clinical significance.MethodsGlioma patients who received both primary surgery and reoperation when recurrence at Sun Yat-sen University Cancer Center from June 2001 to June 2019 were enrolled. Clinical and pathological characteristics were analyzed retrospectively, and histopathology of reoperation specimens was divided into three categories according to tumor cell activity and the degree of necrosis: active group, low-activity group, and necrosis group.ResultsA total of 89 patients were included in this study. The 2016 WHO grade of the first operation pathology and IDH1 status were related to survival time after the first operation, but there was no significant association with survival time after reoperation. The time interval between primary and reoperation was shorter for primary high-grade glioma and/or IDH1 wild-type tumor patients than for low-grade glioma and/or IDH1 mutant tumor patients (P < 0.001). Histopathological types of recurrent gliomas were analyzed, and 67 cases (75.3%) were classified into the active group, 14 (15.8%) into the low-activity group, and 8 (8.9%) into the necrosis group. The low-activity or necrosis group was associated with a higher radiotherapy dose and shorter operation interval. Further univariate and multivariate Cox survival analyses showed the histopathological patterns of recurrent gliomas to be related to survival time after reoperation.ConclusionPrimary WHO low grade or IDH1 mutant gliomas appeared survival benefit mainly on later recurrence, but was not a prognostic predictor following recurrence. Histopathological feature of recurrent glioma is related to previous treatment, including radiotherapy dosage and chemotherapy treatment, and is also an important independent prognostic factor for patients after reoperation.

Astrocytoma with 1p19q codeletion

Using the example of a recurrent tumor with a 10-year follow-up, the authors show that mutation of the IDH1/2 genes in astrocytomas is not always an early event in the pathogenesis of glioma, that in rare cases a 1p19q codeletion can be found in astrocytomas, and that IDH-mutant tumors can occur in childhood.

The effect of chemotherapies on the crosstalk interaction between CD8 cytotoxic T-cells and MHC-I peptides in the microenvironment of WHO grade 4 astrocytoma.

CD8 + T-cells and MHC-I have been detected in brain gliomas with a significant outcome. The effect of chemotherapies on the crosstalk interaction between CD8 + T-cells and MHC-I has never been explored. The protein expression profiling of CD8 cytotoxic T-cells and the gene expression assay of MHC-I in 35 patients diagnosed with WHO grade 4 astrocytoma were performed. The impact of these two factors on tumor recurrence was analyzed. IDH was wildtype in 13 tumors. MHC-I protein expression was absent or low in 34 tumors and dense in a single case. MHC-I gene expression was upregulated in 10 tumors and 25 tumors showed MHC-I gene downregulation. Temozolomide (TMZ) was given to 24 patients and 11 patients received TMZ plus other chemotherapies. No statistically significant association was observed between IDH mutation and CD8 + T-cells ( p = 0.383). However, this association was significant in recurrence-free interval (RFI) ( p = 0.012). IDH-wildtype tumors with highly infiltrated CD8 + T-cells or IDH-mutant tumors with low CD8 + T-cells showed late tumor recurrence. There was a statistically significant difference in RFI between tumors with different MHC-I expression and CD8 + T-cell counts after treatment with TMZ or TMZ plus ( p = 0.026). No association between IDH mutation and CD8+ cytotoxic T-cell was found. IDH is directly linked to tumor recurrence regardless of CD8 + T-cells infiltration. TMZ plus other adjuvants is proved to be more effective in improving patient survival and delaying tumor recurrence, as compared to using TMZ alone. Nonetheless, none-TMZ adjuvants may increase tumor sensitization to cytotoxic T-cells more than TMZ.

Predicting methylation class from diffusely infiltrating adult gliomas using multimodality MRI data.

Radiogenomic studies of adult-type diffuse gliomas have used magnetic resonance imaging (MRI) data to infer tumor attributes, including abnormalities such as IDH-mutation status and 1p19q deletion. This approach is effective but does not generalize to tumor types that lack highly recurrent alterations. Tumors have intrinsic DNA methylation patterns and can be grouped into stable methylation classes even when lacking recurrent mutations or copy number changes. The purpose of this study was to prove the principle that a tumor's DNA-methylation class could be used as a predictive feature for radiogenomic modeling. Using a custom DNA methylation-based classification model, molecular classes were assigned to diffuse gliomas in The Cancer Genome Atlas (TCGA) dataset. We then constructed and validated machine learning models to predict a tumor's methylation family or subclass from matched multisequence MRI data using either extracted radiomic features or directly from MRI images. For models using extracted radiomic features, we demonstrated top accuracies above 90% for predicting IDH-glioma and GBM-IDHwt methylation families, IDH-mutant tumor methylation subclasses, or GBM-IDHwt molecular subclasses. Classification models utilizing MRI images directly demonstrated average accuracies of 80.6% for predicting methylation families, compared to 87.2% and 89.0% for differentiating IDH-mutated astrocytomas from oligodendrogliomas and glioblastoma molecular subclasses, respectively. These findings demonstrate that MRI-based machine learning models can effectively predict the methylation class of brain tumors. Given appropriate datasets, this approach could generalize to most brain tumor types, expanding the number and types of tumors that could be used to develop radiomic or radiogenomic models.