methylguanine-DNA Methyltransferase Research Articles

DeepDepth: Prediction of O(6)-methylguanine-DNA methyltransferase genotype in glioblastoma patients using multimodal representation learning based on deep feature fusion

DeepDepth: Prediction of O(6)-methylguanine-DNA methyltransferase genotype in glioblastoma patients using multimodal representation learning based on deep feature fusion

Abstract CT019: Biological mechanisms underlying objective responses in recurrent GBM patients treated with sequential bortezomib and temozolomide: An interim analysis of NCT03643549 Phase IB/II trial

Abstract Background: Glioblastoma (GBM) has dismal prognosis, where median survival is approximately 12 months for patients harboring unmethylated O6−methylguanine DNA methyltransferase (MGMT) promoter (uMGMT) due to temozolomide (TMZ) chemotherapy resistance. In preclinical studies, we showed that sequential administration of bortezomib (BTZ) prior to TMZ depleted MGMT protein, abrogated autophagic flux and sensitized uMGMT GBM cells to TMZ. Thus, a phase I/II was launched to investigate clinical benefit. An interim analysis based on Simon´s MinMax design (where at least 2 patients should show clinical benefit amongst the first 15 evaluable patients) would allow the study to continue to full recruitment. Clinical benefit, was defined by progression free survival and or objective radiological complete (CR), partial (PR) responses or stable disease (SD) based on RANO criteria at 6 months and 1-year follow-up. This study aimed to identify the biological mechanisms underlying the objective responses in the initial 15 recurrent GBM patients treated in this trial. Methods: Adult recurrent GBM patients with uMGMT promoter, progressing ≥12 weeks after radiotherapy, Karnofsky performance status (KPS) ≥70 and with measurable lesions were enrolled. They received BTZ 1.3mg/m2 IV on days 1,4,7, during each 4-week cycle starting on day 3 with per oral TMZ at 200mg/m2 5 days/week. The sample size was powered for n=63 patients. Quantitative LC-MS/MS was used to identify novel biomarkers that correlate with objective treatment responses by determining proteomic changes in plasma collected on days 1,4,7,11,15 and 22 during first cycle of treatment. Targeted sequencing of 360 cancer genes and whole exome sequencing (WES) of tumor DNA were conducted to identify associated molecular genetic changes. Results: The 15 patients had median age 52 yrs (range 25-62 yrs), 10 male and 5 female treated at Haukeland University Hospital in Norway. Median KPS was 90 (70-100) and median NANO score was 1 (0-7). 27% (n=4/15) of patients obtained objective radiological responses, where 2/4 (50%) obtained PR and 2/4 (50%) had SD. LC-MS/MS revealed significantly increased (p<0.05) levels of proteins important for regulation of cell death and apoptosis (ADAMTS13, HPR, HBD, CLU and APOE) in objective responders compared to the rest of the patients. Sequential BTZ+ TMZ therapy was safe, tolerated and platelet nadirs consistently normalized by day 22 of each cycle. Proteins associated with platelet activation, aggregation and degranulation (ACTN1, ITGB3, PLEK, PPBP, THBS1, TF, TAGLN2, TLN1, PFN1, VCL and FERMT3) were significantly upregulated (1.6-4.8 fold, p<0.05) on day 15 and 22 compared to baseline in patient plasma. Preliminary analysis of sequencing data identified EGFR gain-of-function mutation in 3 of the 4 responder patients; potentially distinguishing this as a molecular biomarker for the objective treatment responders. Conclusion: Sequential BTZ+TMZ therapy is safe and effective as indicated by objective radiological response. Activation of tumor cell death and apoptosis pathways was observed specifically in objective responders. The interim criteria were fulfilled as 4 amongst the first 15 patients showed clinical benefit. The study is currently recruiting. Citation Format: Mohummad Aminur Rahman, Dorota Goplen, Andreas Waha, Leif Oltedal, Judit Haasz, Surendra Kumar, Even Birkeland, Hrvoje Miletic, Frode Selheim, Martha Chekenya. Biological mechanisms underlying objective responses in recurrent GBM patients treated with sequential bortezomib and temozolomide: An interim analysis of NCT03643549 Phase IB/II trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT019.

USP19 regulates DNA methylation damage repair and confers temozolomide resistance through MGMT stabilization.

To elucidate the relationship between USP19 and O(6)-methylguanine-DNA methyltransferase (MGMT) after temozolomide treatment in glioblastoma (GBM) patients with chemotherapy resistance. Screening the deubiquitinase pannel and identifying the deubiquitinase directly interacts with and deubiquitination MGMT. Deubiquitination assay to confirm USP19 deubiquitinates MGMT. The colony formation and tumor growth study in xenograft assess USP19 affects the GBM sensitive to TMZ was performed by T98G, LN18, U251, and U87 cell lines. Immunohistochemistry staining and survival analysis were performed to explore how USP19 is correlated to MGMT in GBM clinical management. USP19 removes the ubiquitination of MGMT to facilitate the DNA methylation damage repair. Depletion of USP19 results in the glioblastoma cell sensitivity to temozolomide, which can be rescued by overexpressing MGMT. USP19 is overexpressed in glioblastoma patient samples, which positively correlates with the level of MGMT protein and poor prognosis in these patients. The regulation of MGMT ubiquitination by USP19 plays a critical role in DNA methylation damage repair and GBM patients' temozolomide chemotherapy response.

A systematic review of high impact CpG sites and regions for MGMT methylation in glioblastoma [A systematic review of MGMT methylation in GBM

BackgroundMGMT (O 6 -methylguanine-DNA methyltransferase) promoter methylation is a commonly assessed prognostic marker in glioblastoma (GBM). Epigenetic silencing of the MGMT gene by promoter methylation is associated with greater overall and progression free survival with alkylating agent regimens. To date, there is marked heterogeneity in how MGMT promoter methylation is tested and which CpG sites are interrogated.MethodsTo further elucidate which MGMT promoter CpG sites are of greatest interest, we performed comprehensive searches in PubMed, Web of Science, and Embase and reviewed 2,925 article abstracts. We followed the GRADE scoring system to assess risk of bias and the quality of the studies we included.ResultsWe included articles on adult glioblastoma that examined significant sites or regions within MGMT promoter for the outcomes: overall survival, progression free survival, and/or MGMT expression. We excluded systemic reviews and articles on lower grade glioma. fifteen articles met inclusion criteria with variable overlap in laboratory and statistical methods employed, as well as CpG sites interrogated. Pyrosequencing or BeadChip arrays were the most popular methods utilized, and CpG sites between CpG’s 70–90 were most frequently investigated. Overall, there was moderate concordance between the CpG sites that the studies reported to be highly predictive of prognosis. Combinations or means of sites between CpG’s 73–89 were associated with improved OS and PFS. Six studies identified CpG sites associated with prognosis that were closer to the transcription start site: CpG’s 8, 19, 22, 25, 27, 32,38, and CpG sites 21–37, as well as low methylation level of the enhancer regions.ConclusionThe following systematic review details a comprehensive investigation of the current literature and highlights several potential key CpG sites that demonstrate significant association with OS, PFS, and MGMT expression. However, the relationship between extent of MGMT promoter methylation and survival may be non-linear and could be influenced by potential CpG hotspots, the extent of methylation at each CpG site, and MGMT enhancer methylation status. There were several limitations within the studies such as smaller sample sizes, variance between methylation testing methods, and differences in the various statistical methods to test for association to outcome. Further studies of high impact CpG sites in MGMT methylation is warranted.

Patterns of care and survival in patients with multifocal glioblastoma: A Danish cohort study

Abstract Background This Danish cohort study aims to (1) compare patterns of care (POC) and survival of patients with multifocal glioblastoma (mGBM) to those with unifocal glioblastoma (uGBM), and (2) explore the association of patient-related factors with treatment assignment and prognosis, respectively, in the subgroup of mGBM patients. Methods Data on all adults with newly diagnosed, pathology-confirmed GBM between 2015 and 2019 were extracted from the Danish Neuro-Oncology Registry. To compare POC and survival of mGBM to uGBM, we applied multivariable logistic and Cox regression analysis, respectively. To analyze the association of patient-related factors with treatment assignment and prognosis, we established multivariable logistic and Cox regression models, respectively. Results In this cohort of 1343 patients, 231 had mGBM. Of those, 42% underwent tumor resection and 41% were assigned to long-course chemoradiotherapy. Compared to uGBM, mGBM patients less often underwent a partial (odds ratio [OR] 0.4, 95% confidence interval [CI] 0.2–0.6), near-total (OR 0.1, 95% CI 0.07–0.2), and complete resection (OR 0.1, 95% CI 0.07–0.2) versus biopsy. mGBM patients were furthermore less often assigned to long-course chemoradiotherapy (OR 0.6, 95% CI 0.4–0.97). Median overall survival was 7.0 (95% CI 5.7–8.3) months for mGBM patients, and multifocality was an independent poor prognostic factor for survival (hazard ratio 1.3, 95% CI 1.1–1.5). In mGBM patients, initial performance, O[6]-methylguanine-DNA methyltransferase promotor methylation status, and extent of resection were significantly associated with survival. Conclusions Patients with mGBM were treated with an overall less intensive approach. Multifocality was a poor prognostic factor for survival with a moderate effect. Prognostic factors for patients with mGBM were identified.

Molecular GBM versus Histopathological GBM: Radiology-Pathology-Genetic Correlation and the New WHO 2021 Definition of Glioblastoma.

Given the recent advances in molecular pathogenesis of tumors, with better correlation with tumor behavior and prognosis, major changes were made to the new 2021 WHO (CNS5) classification of CNS tumors, including updated criteria for diagnosis of glioblastoma. Diagnosis of GBM now requires absence of isocitrate dehydrogenase and histone 3 mutations (IDH-wildtype and H3-wildtype) as the basic cornerstone, with elimination of the IDH-mutated category. The requirements for diagnosis were conventionally histopathological, based on the presence of pathognomonic features such as microvascular proliferation and necrosis. However, even if these histological features are absent, many lower grade (WHO grade 2/3) diffuse astrocytic gliomas behave clinically similar to GBM (grade 4). The 2021 WHO classification introduced new molecular criteria that can be used to upgrade the diagnosis of such histologically lower-grade, IDH-wildtype, astrocytomas to GBM. The three molecular criteria include: concurrent gain of whole chromosome 7 and loss of whole chromosome 10 (+7/-10); TERT promoter mutation; epidermal growth factor receptor (EGFR) amplification. Given these changes, it is now strongly recommended to have molecular analysis of WHO grade 2/3 diffuse astrocytic, IDH-wildtype, gliomas in adult patients, as identification of any of the above mutations allows for upgrading the tumor to WHO grade 4 ("molecular GBM") with important prognostic implications. Despite at an early stage, there is active ongoing research on the unique MRI features of molecular GBM. This paper highlights the differences between "molecular" and "histopathological" GBM, with the aim of providing a basic understanding about these changes.ABBREVIATIONS: GBM=Glioblastoma; TERT=telomerase reverse transcriptase; EGFR=epidermal growth factor receptor; MGMT= methylguanine-DNA methyltransferase; NGS= next-generation sequencing; IDH= isocitrate dehydrogenase.

MGMT promoter methylation prediction based on multiparametric MRI via vision graph neural network.

Glioblastoma (GBM) is aggressive and malignant. The methylation status of the -methylguanine-DNA methyltransferase (MGMT) promoter in GBM tissue is considered an important biomarker for developing the most effective treatment plan. Although the standard method for assessing the MGMT promoter methylation status is via bisulfite modification and deoxyribonucleic acid (DNA) sequencing of biopsy or surgical specimens, a secondary automated method based on medical imaging may improve the efficiency and accuracy of those tests. We propose a deep vision graph neural network (ViG) using multiparametric magnetic resonance imaging (MRI) to predict the MGMT promoter methylation status noninvasively. Our model was compared to the RSNA radiogenomic classification winners. The dataset includes 583 usable patient cases. Combinations of MRI sequences were compared. Our multi-sequence fusion strategy was compared with those using single MR sequences. Our best model [Fluid Attenuated Inversion Recovery (FLAIR), T1-weighted pre-contrast (T1w), T2-weighted (T2)] outperformed the winning models with a test area under the curve (AUC) of 0.628, an accuracy of 0.632, a precision of 0.646, a recall of 0.677, a specificity of 0.581, and an F1 score of 0.661. Compared to the winning models with single MR sequences, our ViG utilizing fused-MRI showed a significant improvement statistically in AUC scores, which are FLAIR (), T1w (), T1wCE (), and T2 (). Our model is superior to challenge champions. A graph representation of the medical images enabled good handling of complexity and irregularity. Our work provides an automatic secondary check pipeline to ensure the correctness of MGMT methylation status prediction.

Clinical Relevance and Interplay between miRNAs in Influencing Glioblastoma Multiforme Prognosis.

Glioblastoma multiforme (GBM) is usually treated with surgery followed by adjuvant partial radiotherapy combined with temozolomide (TMZ) chemotherapy. Recent studies demonstrated a better survival and good response to TMZ in methylguanine-DNA methyltransferase (MGMT)-methylated GBM cases. However, approximately 20% of patients with MGMT-unmethylated GBM display an unexpectedly favorable outcome. Therefore, additional mechanisms related to the TMZ response need to be investigated. As such, we decided to investigate the clinical relevance of six miRNAs involved in brain tumorigenesis (miR-181c, miR-181d, miR-21, miR-195, miR-196b, miR-648) as additional markers of response and survival in patients receiving TMZ for GBM. We evaluated miRNA expression and the interplay between miRNAs in 112 IDH wt GBMs by applying commercial assays. Then, we correlated the miRNA expression with patients' clinical outcomes. Upon bivariate analyses, we found a significant association between the expression levels of the miRNAs analyzed, but, more interestingly, the OS curves show that the combination of low miR-648 and miR-181c or miR-181d expressions is associated with a worse prognosis than cases with other low-expression miRNA pairs. To conclude, we found how specific miRNA pairs can influence survival in GBM cases treated with TMZ.

Allyl isothiocyanate induces DNA damage and inhibits DNA repair-associated proteins in a human gastric cancer cells in vitro.

Allyl isothiocyanate (AITC) is abundant in cruciferous vegetables and it present pharmacological activity including anticancer activity in many types of human cancer cells in vitro and in vivo. Currently, no available information to show AITC affecting DNA damage and repair-associated protein expression in human gastric cancer cells. Therefore, in the present studies, we investigated AITC-induced cytotoxic effects on human gastric cancer in AGS and SNU-1 cells whether or not via the induction of DNA damage and affected DNA damage and repair associated poteins expressions in vitro. Cell viability and morphological changes were assayed by flow cytometer and phase contrast microscopy, respectively, the results indicated AITC induced cell morphological changes and decreased total viable cells in AGS and SNU-1 cells in a dose-dependently. AITC induced DNA condensation and damage in a dose-dependently which based on the cell nuclei was stained by 4', 6-diamidino-2-phenylindole present in AGS and SNU-1 cells. DNA damage and repair associated proteins expression in AGS and SNU-1 cells were measured by Western blotting. The results indicated AITC decreased nuclear factor erythroid 2-related factor 2 (NRF2), heme oxygenase-1 (HO-1), glutathione, and catalase, but increased superoxide dismutase (SOD (Cu/Zn)), and nitric oxide synthase (iNOS) in AGS cells, however, in SNU-1 cells are increased HO-1. AITC increased DNA-dependent protein kinase (DNA-PK), phosphorylation of gamma H2A histone family member X on Ser139 (γH2AXpSer139 ), and heat shock protein 90 (HSP90) in AGS cells. AITC increased DNA-PK, mediator of DNA damage checkpoint protein 1 (MDC1), γH2AXpSer139 , topoisomerase II alpha (TOPIIα), topoisomerase II beta (TOPIIβ), HSP90, and heat shock protein 70 (HSP70) in SNU-1 cells. AITC increased p53, p53pSer15 , and p21 but decreased murine double minute 2 (MDM2)pSer166 and O6 -methylguanine-DNA methyltransferase (MGMT) in AGS cells; however, it has a similar effect of AITC except increased ataxia telangiectasia and Rad3 -related protein (ATR)pSer428 , checkpoint kinase 1 (CHK1), and checkpoint kinase 2 (CHK2) in SNU-1 cells. Apparently, both cell responses to AITC are different, nonetheless, all of these observations suggest that AITC inhibits the growth of gastric cancer cells may through induction off DNA damage in vitro.

An Insight into Emerging Phytocompounds for Glioblastoma Multiforme Therapy.

Despite intense research in the field of glioblastoma multiforme (GBM) therapeutics, the resistance against approved therapy remains an issue of concern. The resistance against the therapy is widely reported due to factors like clonal selection, involvement of multiple developmental pathways, and majorly defective mismatch repair (MMR) mediated by O6- methylguanine DNA methyltransferase (MGMT). Phytotherapy is one of the most effective alternatives to overcome resistance. It involves plant-based compounds, divided into several classes: alkaloids; phenols; terpenes; organosulfur compounds. The phytocompounds comprised in these classes are extracted or processed from certain plant sources. They can target various proteins of molecular pathways associated with the progression and survival of GBM. Phytocompounds have also shown promise as immunomodulatory agents and are being explored for immune checkpoint inhibition. Therefore, research and innovations are required to understand the mechanism of action of such phytocompounds against GBM to develop efficacious treatments for the same. This review gives insight into the potential of phytochemical-based therapeutic options for GBM treatment.

EPID-15. SEX-SPECIFIC DIFFERENCES IN GLIOBLASTOMA IN THE RESPOND CONSORTIUM

Abstract AIM The goal of this study was to understand sex-specific differences in the molecular, clinical and radiological tumor parameters and survival outcomes of Glioblastoma (GBM) patients within the international GBM dataset, known as the ReSPOND (Radiomic Signatures for PrecisiON Diagnostics) consortium. METHODS Sex-based differences were retrospectively studied in 1922 GBM patients from the ReSPOND consortium which includes information from over 14 institutions across 3 continents. The parameters include age, Methylguanine-DNA Methyltransferase (MGMT) promoter methylation status, isocitrate dehydrogenase 1 (IDH1) mutation status, Karnofsky performance status (KPS), extent of resection (EOR), tumor epicenter, volumes, laterality and spatial extent. Non-parametric tests, log-rank test and cox-proportional hazard analysis were performed to understand sex-based differences in tumor parameters, survival rates and hazard ratios. Spatial atlases were generated to understand radiological parameters such as tumor spatial extent. RESULTS GBM in was diagnosed at a median age of 62.6 years in females compared to 61 years in males (p = 0.001). Additionally, 44% females compared to 37% males (p = 0.04) had methylated MGMT and 79% females compared to 73% males (p = 0.004) had IDH1 wildtype. The tumor volumes were smaller in females (necrotic core, edema, and enhancing tumor) compared to males. Females exhibited a higher prevalence of right hemisphere (39.6%) and right temporal lobe tumors (19.7%), while males showed a higher prevalence of left hemisphere (40.3%) left temporal lobe tumors (23.7%). No significant sex-based differences in OS and PFS was observed in overall sample, although longer PFS was observed in elderly (above 60 years) female patients. CONCLUSION This is a first international large cohort study looking at sex-based differences in GBM patients using the ReSPOND consortium data. Several sex-specific differences in the distribution of various tumor phenotypes were noted, however sex was not a contributing factor in OS and PFS.

Assessment of The Utility of The Sarcoma DNA Methylation Classifier In Surgical Pathology.

Diagnostic classification of soft tissue tumors is based on histology, immunohistochemistry, genetic findings, and radiologic and clinical correlations. Recently, a sarcoma DNA methylation classifier was developed, covering 62 soft tissue and bone tumor entities. The classifier is based on large-scale analysis of methylation sites across the genome. It includes DNA copy number analysis and determines O 6 methylguanine DNA methyl-transferase methylation status. In this study, we evaluated 619 well-studied soft tissue and bone tumors with the sarcoma classifier. Problem cases and typical examples of different entities were included. The classifier had high sensitivity and specificity for fusion sarcomas: Ewing, synovial, CIC -rearranged, and BCOR -rearranged. It also performed well for leiomyosarcoma, malignant peripheral nerve sheath tumors (MPNST), and malignant vascular tumors. There was low sensitivity for diagnoses of desmoid fibromatosis, neurofibroma, and schwannoma. Low specificity of matches was observed for angiomatoid fibrous histiocytoma, inflammatory myofibroblastic tumor, Langerhans histiocytosis, schwannoma, undifferentiated sarcoma, and well-differentiated/dedifferentiated liposarcoma. Diagnosis of lipomatous tumors was greatly assisted by the detection of MDM2 amplification and RB1 loss in the copy plot. The classifier helped to establish diagnoses for KIT-negative gastrointestinal stromal tumors, MPNSTs with unusual immunophenotypes, and undifferentiated melanomas. O 6 methylguanine DNA methyl-transferase methylation was infrequent and most common in melanomas (35%), MPNSTs (11%), and undifferentiated sarcomas (11%). The Sarcoma Methylation Classifier will likely evolve with the addition of new entities and refinement of the present methylation classes. The classifier may also help to define new entities and give new insight into the interrelationships of sarcomas.

Proteomic and metabolomic analyses illustrate the mechanisms of expression of the O6 -methylguanine-DNA methyltransferase gene in glioblastoma.

Glioblastoma (GBM) has been reported to be the most common high-grade primary malignant brain tumor in clinical practice and has a poor prognosis. O6 -methylguanine-DNA methyltransferase (MGMT) promoter methylation has been related to prolonged overall survival (OS) in GBM patients after temozolomide treatment. Proteomics and metabolomics were combined to explore the dysregulated metabolites and possible protein expression alterations in white matter (control group), MGMT promoter unmethylated GBM (GBM group) or MGMT promoter methylation positive GBM (MGMT group). In total, 2745 upregulated and 969 downregulated proteins were identified in the GBM group compared to the control group, and 131 upregulated and 299 downregulated proteins were identified in the MGMT group compared to the GBM group. Furthermore, 131 upregulated and 299 downregulated metabolites were identified in the GBM group compared to the control group, and 187 upregulated and 147 downregulated metabolites were identified in the MGMT group compared to the GBM group. The results showed that 94 upregulated and 19 downregulated proteins and 20 upregulated and 16 downregulated metabolites in the MGMT group were associated with DNA repair. KEGG pathway enrichment analysis illustrated that the dysregulated proteins and metabolites were involved in multiple metabolic pathways, including the synthesis and degradation of ketone bodies, amino sugar and nucleotide sugar metabolism. Moreover, integrated metabolomics and proteomics analysis was performed, and six key proteins were identified in the MGMT group and GBM group. Three key pathways were recognized as potential biomarkers for recognizing MGMT promoter unmethylated GBM and MGMT promoter methylation positive GBM from GBM patient samples, with areas under the curve of 0.7895, 0.7326 and 0.7026, respectively. This study provides novel mechanisms to understand methylation in GBM and identifies some biomarkers for the prognosis of two different GBM types, MGMT promoter unmethylated or methylated GBM, by using metabolomics and proteomics analyses.

Outcomes of Fluorescence-Guided vs White Light Resection of Glioblastoma in a Single Institution.

Background Glioblastoma (GBM) is the most common malignant primary brain tumour and confers a very poor prognosis. Maximal safe resection of tumour is the goal of neurosurgical intervention and may be more easily achieved through the use of surgical adjuncts such as fluorescence-guided surgery (FGS). 5-Aminolevulinic acid (5-ALA) accumulates in GBM tissue and fluorescered, distinguishing tumour cells from the surrounding tissue and therefore making resection easier. 5-ALA-guided resection in GBM has been shown to increase resection rates and prolongprogression-free survival without impacting post-operative morbidity. Radiotherapy and concomitant chemotherapy also improve survival in GBM. Other factors such as patient age and molecular status of the tumour also impact prognosis. Aims The aim of this study was to compare the outcomes of 5-ALA vs white light-guided resection for glioblastoma in the west of Scotland. Methods This was a retrospective analysis of baseline characteristics (age, sex, tumour molecular markers, radiotherapy, chemotherapy, anatomical location of tumour and treatment group) and outcomes (mortality, survival, degree of resection and performance status) of 239 patients who underwent primary resection of glioblastoma over a four-year period (2017-2020). A variety of statistical methods were used to analyse the relationship between each variable and surgical technique; multivariate Cox regression and the Kaplan-Meier method were used in survival analysis. Results 5-ALA-guided resection substantiallyimproved resection rates (74.0% vs 40.2%). Mortality at 15 months was 5.1% lower in the 5-ALA group (52.0% vs 57.1%, p = 0.53), and patients lived an average of 68 days longer compared to the white light group (444 days vs 376 days, p = 0.21). There were negligible differences between treatment groups in terms of post-operative performance status (PS) and post-operative complications. In our multivariate Cox regression model, six factors were statistically significant at a level of p ≤ 0.05: age, radiotherapy, chemotherapy, O(6)-methylguanine-DNA methyltransferase (MGMT) methylation, anatomical location and >90% resection. Receiving chemotherapy and radiotherapy, MGMT methylation and undergoing >90% resection conferred a survival benefit at 15 months. Older age and multi-focal disease were related to a worsened mortality rate. Undergoing radiotherapy and maximal resection were the two greatest predictors of improved survival, reducing mortality risk by 58% and 51%, respectively. Conclusion 5-ALA-guided resection improved resection rates without impacting post-operative morbidity. 5-ALA-guided resection was associated with improved survival and lower mortality rate, but this was not statistically significant. Receiving chemoradiotherapy, MGMT methylation and undergoing maximal resection conferred a survival benefit, whilst older age and multi-focal disease were associated with a poorer prognosis.

Outcomes and Treatment Algorithm in Glioblastoma Patients 80 Years and Older

The current standard of care for patients with glioblastoma (GBM) is maximal safe resection followed by adjuvant radiation therapy with concurrent temozolomide chemotherapy. Previous studies that identified this treatment regimen focused on younger patients with GBM. The proportion of patients with GBM over the age of 80 years is increasing. We investigate whether elderly patients benefit from the current standard of care with additional maximal safe resection. Clinical, operative, radiographic, demographic, genetic, and outcomes data were retrospectively collected for patients treated for histologically confirmed World Health Organization grade 4 GBM at University of Pittsburgh Medical Center from 2009 to 2020. Only patients 80 years and older were included (n= 123). Statistically significant values were set at P < 0.05. A univariate Cox proportional hazards analysis of GBM patients aged >80 years identified the use of temozolomide, radiation, Karnofsky Performance Status (KPS) > 70, and methylguanine DNA methyltransferase methylation with increased overall survival (OS). Further multivariate Cox proportional hazards model analysis showed that the variables identified in the univariate analysis passed multicollinearity testing, and that use of temozolomide, KPS >70, and gross total resection were shown to significantly impact survival. Survival analysis showed that patients with biopsy alone had a shorter median OS compared with patients who received resection, temozolomide, and radiation (P < 0.0001, median OS 1.6 vs. 7.5 months). Additionally, patients who underwent biopsy and then received temozolomide and radiation had a shorter median OS when compared with patients who received resection, temozolomide, and radiation (P= 0.0047, median OS 3.6 vs. 7.5 months). For elderly patients with KPS >70, GTR followed by radiation and temozolomide is associated with maximum OS.

Molecular imaging of gliomas.

Molecular characterization has become a key diagnostic tool for the classification and grading of primary brain tumors. Molecular markers, such as isocitrate dehydrogenase (IDH) mutation status, 1p/19q codeletion, methylation of the O(6)-methylguanine-DNA methyltransferase (MGMT) promoter, or CDKN2A/B homozygous deletion discriminate different tumor entities and grades, and play a crucial role for treatment response and prognosis. In recent years, magnetic resonance imaging (MRI), whose main functions has been to detect a tumor, to provide spatial information for neurosurgical and radiotherapy planning, and to monitor treatment response, has shown potential in assessing molecular features of gliomas from image-based biomarkers. As an outstanding example, numerous studies have proven that the T2/FLAIR mismatch sign can identify IDH-mutant, 1p/19q non-codeleted astrocytomas with a specificity of up to 100%. For other purposes, multiparametric MRI, often coupled with machine learning methods, seems to achieve the highest accuracy in predicting molecular markers. Relevant future applications might be anticipating changes in the molecular composition of gliomas and providing useful information about the cellular and genetic heterogeneity of gliomas, especially in the non-resected tumor parts.

BORTEM-17: A phase IB/II single arm, multicentre study investigating the efficacy of sequential bortezomib and temozolomide in recurrent GBM with unmethylated MGMT promoter—The results of an interim analysis.

2019 Background: Glioblastoma (GBM) is the most frequent, lethal primary brain tumor in adults. Patients harboring tumors with functional O6 methylguanine DNA methyltransferase ( MGMT) DNA enzyme gain limited benefit from temozolomide therapy. As shown in preclinical studies, bortezomib depletes the MGMT enzyme, restoring the tumor ́s susceptibility to temozolomide, if administered in a precise schedule when the MGMT enzyme is depleted. We hypothesized that recurrent GBM patients with unmethylated MGMT promoter may obtain clinical benefit from sequential BTZ and TMZ treatment. Methods: BORTEM-17 is a multicenter, open label, single arm, non-randomized phase IB/II trial to investigate potential survival benefit for recurrent glioblastoma patients administered bortezomib 48hrs prior to temozolomide. Sample size is calculated to 63 patients, of whom 10 included in phase IB. The doses of bortezomib is 1.3mg/m2 intravenously days 1, 4, and 7 during 4-week cycle, and temozolomide 200mg/m2 days 5-7. The control group is a retrospective cohort of 467 patients treated at 2 referral hospitals in Norway from January 2015 to December 2017. For the survival analysis, the patients included in BORTEM-17 (n=44) were compared with MGMT unmethylated control, age matched patients (n=116). The pre-defined interim analysis was performed after inclusion of 15 patients and as more than 2 of 15 patients had clinical benefit, the study was continued. Results: Until January 2023, 44 patients with median age 55 years (range 25-69), 30 males and 14 females were treated. Median KPS was 90 (70-100) and median NANO score 1 (0-7). The interim analysis was performed after inclusion of 15 patients in the phase IB and II and clinical benefit was observed in 5 patients. Two of them had tumor volume reduction and three experienced stable disease. The study proceeded to the next step. No treatment related deaths were observed. The most common adverse effects included hematological toxicity, gastrointestinal symptoms, muscle weakness, lower back pain and fatigue. Patients that progressed during the BORTEM-17 trial and were fit for further therapy received treatment at their physician’s discretion. The preliminary data analysis after 44 of planned 63 patients were treated indicate prolonged median survival for BORTEM-17 patients 19.0 months vs 12.2 months of control MGMT unmethylated age matched patients. Median survival after recruitment is 5.5 months (1.0-23.8). Conclusions: The sequential BTZ+TMZ therapy is safe, feasible and effective as indicated by preliminary data when 70% of planned MGMT unmethylated patients have been included. Preliminary data indicate that the combination of BTZ and TMZ may offer an additional line of treatment with limited toxicity to the group of patients with particularly dismal prognosis. Clinical trial information: NCT03643549 .

Alliance A021804: A prospective, multi-institutional phase II trial evaluating temozolomide versus temozolomide and olaparib for advanced pheochromocytoma and paraganglioma.

TPS4191 Background: Pheochromocytomas (PHEOs) and paragangliomas (PGLs) are rare neuroendocrine tumors (NETs) that arise from chromaffin cells. Few antitumor therapies have been developed for patients (pts) with advanced PHEO/PGLs (APP). Potent poly (ADP-ribose) polymerase (PARP) is activated after DNA damage and regulates base excision repair, homologous recombination and non-homologous end joining. Inhibition of PARP enzymatic activity blocks PARP-mediated DNA repair, therefore PARP inhibitors can be directly cytotoxic to tumor cells which then permits synergy with agents that increase prevalence of single-strand breaks in tumor models. Temozolomide (TMZ) is an alkylating agent that induces single-strand DNA breaks and therefore is an optimal therapeutic pair with a PARP inhibitor. We are conducting a phase II multi-institutional study to evaluate the antitumor activity of TMZ and olaparib [OLA (a PARP inhibitor)] in patients with APP. Methods: Patients with APP with radiographic evidence of disease progression by RECIST v1.1 in the 12 months prior to registration can be enrolled in this phase II randomized study. Patients will be randomized in a 2:1 allocation with more patients to Arm 1. Arm 1 will receive TMZ 75 mg/m2 daily and OLA 200 mg twice daily on days 1-7 of a 21-day cycle. Arm 2 will receive TMZ 200 mg/m2 daily on days 1-5 of a 28-day cycle. Treatment on Arm 1 will continue for 13 cycles, followed by OLA maintenance until disease progression. Treatment on Arm 2 will continue for 13 cycles or until disease progression. The primary objective is to compare the progression-free survival between the two arms with a planned interim analysis for futility. Secondary endpoints include safety, response rate, and overall survival. Correlative endpoints include biochemical response and biomolecular markers (germline succinyl dehydrogenase mutations and tumor status of the repair enzyme methylguanine-DNA methyltransferase). We anticipate a null PFS median of approximately 5.4 months. We plan to accrue a total of 76 patients (randomized at a rate of 2:1 with more patients enrolled to the TMZ+OLA arm) in 38 months with a minimum follow-up of 2.5 months to achieve 56 PFS events. This design includes one interim analysis for futility using Rho Family spending functions (Rho = 2.5) and will yield 89% power to detect a hazard ratio (HR) of 0.5 (median PFS of 5.4 vs. 10.8 months) assuming exponential survival and using a one-sided log-rank test with type I error rate of 0.11. Clinical trial information: NCT04394858 .

Researchers engineer a universal receptor system for cell immunotherapies

Chimeric antigen receptor (CAR) T-cell therapy is a promising immunotherapy against cancer. The idea is to fortify a person’s immune system to fight its own battle by boosting T cells with the ability to ferret out tumor-associated antigens. But engineering CAR-T cells is an arduous process, and they are usually customized to recognize only one antigen. In a new paper, one research group reports broadening the versatility of engineered CAR-T cells by bringing into the fold functionalized antibodies that act as universal adapters between the CAR-T cell and various tumor antigens ( Nat. Commun. 2023, DOI: 10.1038/s41467-023-37863-5 ). “An antibody is . . . easier to chemically modify than an entire cell,” says Alexander Deiters, a University of Pittsburgh chemist and a coauthor of the study. The researchers engineered CAR-T cells with receptors that carry a SNAPtag label, a modified O 6 -methylguanine-DNA methyltransferase. This SNAPtag can covalently bind with

Clinical characteristics associated with the development of preoperative and postoperative seizures in patients with glioblastoma (P3-1.002)

<h3>Objective:</h3> To determine the factors which predict the occurrence of preoperative seizures (PRS) and post-operative seizures (POS) among patients with glioblastoma (GBM). <h3>Background:</h3> Seizures have been well described in patients with GBM, albeit at a lower frequency than low grade gliomas. Although recent studies suggest epileptogenesis has more to do with genetic molecular markers in low grade glioma-related seizure, information on factors that influence the development of of GBM-related PRS and POS is lacking. <h3>Design/Methods:</h3> We performed a single-center retrospective cohort study of patients with GBM evaluated at Mayo Clinic Florida, between 2018 and 2022. Clinical factors including, tumor molecular markers, neurophysiological and imaging findings were analyzed according to the status of PRS and POS. <h3>Results:</h3> One hundred thirty-two adult patients (median age=61.5 years), 79 (59.85%) females) were included. The most common locations were the temporal (n=50, 42.02%) and frontal (n=47, 39.50%) lobes. All patients underwent GBM resection, with 17.1% undergoing total resection (n=22). Sixty-two patients (46.27%) underwent intra-operative electrocorticography during GBM resection. Isocitrate dehydrogenase 1 (IDH1) wildtype was present in 121 patients (90.3%), 61 patients had O⁶-methylguanine-DNA methyltransferase (<i>MGMT</i>)-methylated GBM (46.21%). Forty patients (33.9%) had PRS, and 39 patients (38.24%) had POS (median follow-up=17.27 months; IQR=10.6–30.1). IDH1 wildtype and MGMT methylation status were not associated with PRS or POS. Patients with PRS were younger (59 years vs. 64 years, <b><i>p=0.021</i></b>) and experienced a longer survival time (16.1 months vs. 8.3 months, <b><i>p=0.044</i></b>) compared to patients without PRS. Occipital lobe GBM was associated with a lower likelihood of PRS (<b><i>p=0.043</i></b>) and POS (<b><i>p=0.001</i></b>). <h3>Conclusions:</h3> PRS is associated with younger age and longer survival time. PRS and POS are less likely to occur with occipital lobe tumors. Further studies are needed to confirm our findings and elucidate the influence of other tumor molecular markers in the development of PRS and POS in patients with GBM. <b>Disclosure:</b> Dr. Sánchez Boluarte has nothing to disclose. Dr. Garcia has nothing to disclose. Dr. Gunasekera has nothing to disclose. Dr. Tatum has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Bioserenity. Dr. Tatum has received personal compensation in the range of $500-$4,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for Elsevier. Dr. Tatum has received personal compensation in the range of $500-$4,999 for serving as an Expert Witness for Defense Law Firm on behalf of a patient with epilepsy with funds donated to the Epilepsy Foundation of America. The institution of Dr. Tatum has received research support from Esai. The institution of Dr. Tatum has received research support from Mayo Clinic. The institution of Dr. Tatum has received research support from Liva Nova. The institution of Dr. Tatum has received research support from Engage Pharmaceuticals. The institution of Dr. Tatum has received research support from Xenon. Dr. Tatum has received publishing royalties from a publication relating to health care. Dr. Tatum has received publishing royalties from a publication relating to health care. Dr. Sirven has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for UCB. Dr. Sirven has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Medtronic. Dr. Sirven has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Neurelis. Dr. Sirven has received personal compensation in the range of $5,000-$9,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Medtronic. Dr. Sirven has received personal compensation in the range of $10,000-$49,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for AAN. Dr. Sirven has stock in Doximity. Dr. Sirven has received publishing royalties from a publication relating to health care. Dr. Sirven has a non-compensated relationship as a Host with WJCT Public Media/ NPR that is relevant to AAN interests or activities. Dr. Freund has nothing to disclose. The institution of Dr. Ritaccio has received research support from NIH. Dr. Ritaccio has received intellectual property interests from a discovery or technology relating to health care. Kaisorn Chaichana has nothing to disclose. Alfredo Quiñones-Hinojosa has nothing to disclose. Dr. Feyissa has nothing to disclose.