Pre­operative mean platelet volume is associated with overall survival in patients with IDH­wildtype glioblastoma undergoing maximal safe resection.

Glioblastoma (GBM) is the most common, fast-growing, and aggressive malignant primary CNS tumor, with a survival time of ~15 months despite the use of surgery and adjuvant treatments. In recent years, there has been a growing interest in exploring the potential contribution of hemostasis and platelet activation in GBM biology. The present study assessed the association between the pre-operative coagulation profile [as indicated by prothrombin time (PT) ratio and activated partial thromboplastin time (aPTT) ratio], overall platelets (PLT) count and the mean platelet volume (MPV) with tumoral characteristics and overall survival in patients with isocitrate dehydrogenase-wildtype (IDH-wt) GBM.

Profiling hypoxia signaling reveals a lncRNA signature contributing to immunosuppression in high-grade glioma.

Background: Hypoxic conditions in glioma are linked to tumor aggressiveness, poor prognosis, and treatment resistance. Long non-coding RNAs (lncRNAs) play key roles in the hypoxic and immune microenvironment of cancers, but their link to hypoxia-induced immunosuppression in high-grade glioma (HGG) is not well-studied. Methods: Gene expression profiles from TCGA and CGGA, along with clinical and genomic data, were analyzed. Bioinformatics methods including Consensus Clustering, Pearson correlation, and Cox regression analyses were used. Cell proliferation was assessed using cell counting kit-8 and colony formation assays. Glioma-macrophage interactions were evaluated using a co-culture model. Results: Hypoxia subtype clustering showed hypoxic stress correlates with worse HGG prognosis. Eight hypoxia-related lncRNAs (AP000695.4, OSMR-AS1, AC078883.3, RP11-545E17.3, LINC01057, LINC01503, TP73-AS1, and LINC00672) with prognostic value were identified, forming a risk signature that separated patients into distinct prognostic groups. Multivariate Cox regression confirmed the signature as an independent prognostic factor. High-risk patients had greater hypoxia, leading to an immunosuppressive environment and immunotherapy resistance via tumor-associated macrophages (TAMs). TP73-AS1 significantly influenced hypoxia-induced TAM infiltration and M2 polarization. Conclusions: We profiled hypoxic stress in HGG and developed an 8-lncRNA hypoxia-related signature predicting patient survival and immunotherapy response, emphasizing its role in hypoxia-induced immunosuppression.

Review of Novel Surgical, Radiation, and Systemic Therapies and Clinical Trials in Glioblastoma.

Glioblastoma (GBM) is the most common malignant primary brain tumor in adults. Despite an established standard of care including surgical resection, radiation therapy, and chemotherapy, GBM unfortunately is associated with a dismal prognosis. Therefore, researchers are extensively evaluating avenues to expand GBM therapy and improve outcomes in patients with GBM. In this review, we provide a broad overview of novel GBM therapies that have recently completed or are actively undergoing study in clinical trials. These therapies expand across medical, surgical, and radiation clinical trials. We additionally review methods for improving clinical trial design in GBM.

Fotemustine in recurrent high­grade glioma: MRI neuro­radiological findings.

The use of fotemustine (FTM) has been authorized in certain countries for the treatment of recurrent high-grade gliomas (HGG) after Stupp therapy. However, to the best of our knowledge, no studies have assessed changes in magnetic resonance imaging (MRI) during treatment with FTM monotherapy. The aim of the present study was to assess the neuroradiological findings in a cohort of patients with recurrent HGG treated with FTM monotherapy. Patients with HGG already undergoing the Stupp protocol were retrospectively included. MRIs (pre- and post-FTM treatment) were analyzed by two neuroradiologists in consensus: Volume and diffusion values of the contrast-enhanced component were measured on T1-weighted volumetric sequences after gadolinium injection and on apparent diffusion coefficient (ADC) maps, respectively. A total of 19 patients [median age, 49 years; interquartile range (IQR), 43-57 years] were included, 17 of whom had glioblastoma and 2 had astrocytoma isocitrate dehydrogenase-mutated grade 4. The median duration of FTM therapy was 4 months (IQR, 2-6 months). The median tumor volume measured on the contrast-enhanced component was 2,216 mm3 (IQR, 768-13,169 mm3) at baseline and 9,217 mm3 (IQR, 3,455-16,697 mm3) at the end of treatment, with a median change of +38% (IQR, -45-+574%). A total of seven patients showed a volume decrease. ADC value analysis of the enhancement area demonstrated no significant difference between the pre- and the post-FTM treatment periods (P=0.36); however, in three patients, the decreases in ADC levels were particularly marked. In conclusion, the present study described a series of patients with recurrent HGG treated with FTM in monotherapy, demonstrating a prevalent increase in lesion enhancement and three cases of marked restrictions on diffusion-weighted imaging. Further prospective studies are required to corroborate such preliminary results.

Microglia and monocyte-derived macrophages drive progression of pediatric high-grade gliomas and are transcriptionally shaped by histone mutations.

Pediatric high-grade gliomas (pHGGs), including hemispheric pHGGs and diffuse midline gliomas (DMGs), harbor mutually exclusive tumor location-specific histone mutations. Using immunocompetent de novo mouse models of pHGGs, we demonstrated that myeloid cells were the predominant infiltrating non-neoplastic cell population. Single-cell RNA sequencing (scRNA-seq), flow cytometry, and immunohistochemistry illustrated the presence of heterogeneous myeloid cell populations shaped by histone mutations and tumor location. Disease-associated myeloid (DAM) cell phenotypes demonstrating immune permissive characteristics were identified in murine and human pHGG samples. H3.3K27M DMGs, the most aggressive DMG, demonstrated enrichment of DAMs. Genetic ablation of chemokines Ccl8 and Ccl12 resulted in a reduction of DAMs and an increase in lymphocyte infiltration, leading to increased survival of tumor-bearing mice. Pharmacologic inhibition of chemokine receptors CCR1 and CCR5 resulted in extended survival and decreased myeloid cell infiltration. This work establishes the tumor-promoting role of myeloid cells in DMG and the potential therapeutic opportunities for targeting them.

3D ultrasound-augmented image guidance for surgery of high-grade gliomas - A quantitative analysis focused on the extent of resection.

Background: We have retrospectively reviewed our series of brain tumor patients operated on using 3D IntraOperative UltraSound (IOUS) to report technical advantages and areas of improvement. Methods: Clinical and radiological data of patients with a diagnosis of high-grade glioma IV operated with and without IOUS were retrieved and analyzed. Results: We have found 391 patients operated using IOUS coupled with neuronavigation and 257 using neuronavigation standalone. We have selected a pool of 60 patients with a diagnosis of GlioBlastoma (GB), comparing two equally sized groups operated with and without IOUS, respectively. The average extent of resection (EOR) in the IOUS group was 93%, while in the control group, it was 80%. IOUS was significantly associated with improved EOR (P < 0.0004), even when accounting for other factors affecting EOR. The average overall survival (OS) was 13.4 months, and the average progression-free survival (PFS) was 7.4 months. The Cox proportional hazard model showed an advantage in OS on patients operated using the IOUS. No statistically significant effect was observed on PFS. Conclusion: Intraoperative ultrasound coupled with image guidance is associated with an improved EOR and possibly an improved OS. While we are aware of several limitations related to the present analysis, these data support the routine use of IOUS as a safe and reliable technology. Larger, prospective series with updated IOUS technology are desirable to verify the accuracy of these results.

Recent updates in pediatric diffuse glioma classification: insights and conclusions from the WHO 5th edition.

The World Health Organization (WHO) Central Nervous System (CNS) Tumors Classification 5th edition (2021) integrates both molecular and histopathological criteria for diagnosing glial tumors. This updated classification highlights significant differences between pediatric and adult gliomas in terms of molecular characteristics and prognostic implications. The 5th edition comprises a new category of pediatric-type diffuse low-grade glioma (PDLGG) and pediatric-type diffuse high-grade glioma (PDHGG), classified mainly based on genetic alterations and histopathological features. We reviewed the microscopy, diagnostic molecular pathology, and prognosis of various tumors under the categories PDLGG and PDHGG. The review also addresses the need for clarification concerning overlapping diagnostic features. PDLGG are characterized by diffuse growth, low-grade morphology, and MYB/MYBL1(MYB Proto-Oncogene Like 1) gene fusion or mitogen-activated protein kinase (MAPK) pathway alterations. In contrast, PDHGG is described by diffuse growth, high-grade morphology, and increased mitosis and often shows alterations of histone gene resulting in epigenetic alterations, which contrasts with common isocitrate dehydrogenase (IDH) mutation and epidermal growth factor receptor (EGFR) amplification seen in adult-type high-grade glioma.

Is Carmustine Wafer Implantation in Progressive High-Grade Gliomas a Relevant Therapeutic Option? Complication Rate, Predictors of Complications and Onco-Functional Outcomes in a Series of 53 Cases.

Background/Objectives: The aim was to determine the complication rate and the predictors of complications and survival in high-grade glioma surgically managed at progression with implantation of Carmustine wafers. Methods: A retrospective series of 53 consecutive patients operated on between 2017 and 2022 was built. Results: The median age was 55 ± 10.9 years. The rates of global and infectious complications were 35.8% and 18.9%, respectively. In multivariate analysis, patients with a preoperative neurological deficit were more prone to develop a postoperative complication (HR = 5.35 95% CI 1.49-19.26, p = 0.01). No predictor of infectious complication was identified. In the grade 4 glioma subgroup (n = 44), progression-free and overall survival (calculated starting from the reresection) reached 3.95 months, 95% CI 2.92-5.21 and 11.51 months, 95% CI 9.11-17.18, respectively. Preoperative KPS > 80% (HR = 0.97 95% CI 0.93-0.99, p = 0.04), Gross Total Resection (HR = 0.38 95% CI 0.18-0.80, p = 0.01), and 3-month postoperative KPS > 80% (HR = 0.35 95% CI 0.17-0.72, p = 0.004) were predictors of prolonged overall survival. Conclusions: Surgical resection is a relevant option in high-grade gliomas at progression, especially in patients with a preoperative KPS > 80%, without preoperative neurological deficit, and amenable to complete resection. In patients elected for surgery, Carmustine wafer implantation is associated with a high rate of complications. It is consequently critical to closely monitor the patients for whom this option is chosen.

Intracranial administration of anti-PD-1 and anti-CTLA-4 immune checkpoint-blocking monoclonal antibodies in patients with recurrent high-grade glioma.

BACKGROUND: Recurrent high-grade glioma (rHGG) lacks effective life-prolonging treatments and the efficacy of systemic PD-1 and CTLA-4 immune checkpoint inhibitors is limited. The multi-cohort Glitipni phase I trial investigates the safety and feasibility of intraoperative intracerebral (iCer) and postoperative intracavitary (iCav) nivolumab (NIVO) ± ipilimumab (IPI) treatment following maximal safe resection (MSR) in rHGG. MATERIALS AND METHODS: Patients received 10 mg IV NIVO within 24 h before surgery, followed by MSR, iCer 5 mg IPI and 10 mg NIVO, and Ommaya catheter placement in the resection cavity. Biweekly postoperative iCav administrations of 1-5-10 mg NIVO (cohort 4) or 10 mg NIVO plus 1-5-10 mg IPI (cohort 7) were combined with 10 mg IV NIVO for 11 cycles. RESULTS: 42 rHGG patients underwent MSR with iCer NIVO + IPI. 16 pts were treated in cohort 4 (postoperative iCav NIVO at escalating doses) while 28 patients were treated in cohort 7 (intra and postoperative iCav NIVO and escalating doses of IPI). The most common TRAE was fatigue; no grade 5 AE occurred. Dose-limiting toxicity was grade 3 neutrophilic pleocytosis (4 pts) receiving iCav NIVO plus 5 or 10 mg IPI. PFS and OS did not significantly differ between cohorts (median OS: 42 [95% CI 26-57] vs. 35 [29-40] weeks; 1-year OS rate: 37% vs. 29%). Baseline B7-H3 expression significantly correlated with worse survival. OS compared favorably to a historical pooled cohort (n = 469) of Belgian rHGG pts treated with anti-VEGF therapies (log-rank P = .015). CONCLUSION: Intraoperative iCer IPI + NIVO with postoperative iCav NIVO ± IPI up to biweekly doses of 1 mg IPI + 10 mg NIVO is feasible and safe, showing encouraging OS in rHGG patients. ClinicalTrials.gov registration: NCT03233152.

AB005. Development of tumour specific therapy for treatment of diffuse intrinsic pontine glioma (DIPG).

BACKGROUND: Diffuse intrinsic pontine glioma (DIPG), is an aggressive form of paediatric high-grade glioma (pHGG) that affects children below the age of 10 months. The survival period for a child suffering from DIPG has not changed in decades (approximately 10 months). This pattern is similar for most pHGG; even though the survival period is more extended, tumour recurrence and death are almost inevitable. This is primarily due to the presence of the blood-brain barrier (BBB), which blocks the entry of most therapeutics into the brain, and also due to tumour heterogeneity associated with central nervous system (CNS) tumours that blunt the efficacy of targeted therapy. The development of a meaningful cure for paediatric brain cancer hinges on discovering chemotherapy agents that (I) can cross the BBB; (II) accumulates explicitly in tumour tissues; and (III) can block pathways leading to the escape of cancer stem cells, promoting recurrence. METHODS: This project aims to develop therapeutics that can cross the BBB, a significant hindrance to delivering medicines across the brain, and specifically target cancer cells without affecting normal brain cells. We will accomplish this by attaching novel dyes possessing tumour specificity to various classes of chemotherapy agents. The compounds will be tested on patient-derived paediatric brain cancer cell lines and the most potent compounds will be progressed to an animal model of DIPG. RESULTS: Several drug-dye conjugates were designed and synthesized to target various aberrant pathways involved in disease initiation and progression of DIPG. These were tested first in patient-derived DIPG cell lines. Several of these drug-dye conjugates showed potent antiproliferative effect in various DIPG cell lines. One of these conjugates is currently undergoing maximum tolerated dose study in an animal model of DIPG. CONCLUSIONS: The present work details an effort to develop BBB crossing tumour specific therapeutic agents for the treatment of DIPG. The work has resulted in several promising drug-dye conjugates showing antiproliferative activity in various patient-derived DIPG cell lines, enabling the progression of such conjugates into animal models of DIPG. Such studies will inform the utility of such drug-dye conjugates for application in difficult to treat pHGGs such as DIPG.

AB014. The accurate classification of high-grade glioma, IDH-wildtype, is based on methylation profiling: a case report.

BACKGROUND: The 2021 World Health Organization (WHO) classification has significantly enhanced the molecular diagnostics of diffuse gliomas, emphasizing the role of molecular features alongside histology. However, accurate classification remains challenging, particularly for high-grade gliomas, IDH-wildtype. DNA methylation profiling provides an unbiased diagnostic approach, offering valuable insights into tumor classification. Here, we present a case of a high-grade glioma, initially diagnosed as glioblastoma, IDH-wildtype based on histological and genetic analysis, but later reclassified as a diffuse pediatric-type high-grade glioma, H3-wildtype and IDH-wildtype (RTK2 subtype) through methylation profiling. CASE DESCRIPTION: A 7-year-old boy presenting with seizures was admitted to our hospital, where brain magnetic resonance imaging revealed a tumor in the right temporal lobe. Intraoperative histology indicated a high-grade glioma, prompting maximal resection. Diagnosis according to the 2021 WHO classification involved histological analysis, immunohistochemistry, testing for specific genetic alterations, and DNA methylation profiling. Histological and immunohistochemical assessment initially identified the tumor as a high-grade astrocytoma, IDH-wildtype. Specific genetic testing revealed IDH1-wildtype, IDH2-wildtype, and TERT promoter mutation, consistent with a diagnosis of glioblastoma, IDH-wildtype. However, methylation profiling yielded a classifier score of 0.99 for a diffuse pediatric-type high-grade glioma, H3-wildtype and IDH-wildtype (RTK2 subtype). CONCLUSIONS: Our case illustrated that conventional histological and genetic analysis classification can be reclassified according to the DNA methylation analysis, demonstrating that methylation profiling is useful to accurately classify high-grade gliomas, particularly those of the IDH-wildtype subtype.

AB048. Evidence of effectiveness of neoadjuvant camrelizumab and apatinib in patients with recurrent high-grade gliomas.

BACKGROUND: Recurrent high-grade glioma (HGG) is a challenge with limited treatment options and a poor prognosis. We conducted an open-label phase II study: neoadjuvant camrelizumab and apatinib in patients with recurrent high-grade gliomas (NCT04588987), and interim analysis showed very promising results. We are further searching for evidence of the effectiveness of this strategy. METHODS: Patients with recurrent HGG received neoadjuvant treatment with camrelizumab (intravenous injection 200 mg on day 1) and apatinib (oral 250 mg per day on days 1-7), and 14 days later received surgery for recurrent tumor resection. Sequential therapy began 2 weeks after surgery with the biweekly camrelizumab (200 mg) and 4 weeks after surgery with the daily apatinib (250 mg) until investigator assessed progressive disease or unable to tolerate toxicity. The primary endpoint was overall survival (OS). When patients suspected progress during per-protocol treatment, re-surgery for resection of lesion was done, and the tissue was further examined. RESULTS: Between October 9, 2020, and March 30, 2024, 24 patients were enrolled [19 glioblastomas, one World Health Organization (WHO) grade 4 diffuse astrocytoma, three anaplastic astrocytoma, and one anaplastic oligodendroglioma]. Nineteen patients with interim analysis data, and showed the median progression-free survival (PFS) was 4.8 months [95% confidence interval (CI): 4.4-5.2], the median OS was 12.9 months (95% CI: 9.3-16.4) respectively, with a median follow-up time of 17.5 months (95% CI: 9.0-26.1). There were two patients who suspected progress and received second surgery. One patient showed real tumor progression with active tumor cells. While another patient the histology revealed mainly necrosis with inflammatory cells. Five patients initially showed increased enhancement on magnetic resonance imaging (MRI) but without increased symptoms, and showed continuous improvement when receiving further treatment. CONCLUSIONS: This immuno-target combination neoadjuvant therapy in recurrent HGG demonstrated encouraging efficacy and revealed some evidence of efficacy, and worth to further investigate.

AB055. Infantile high-grade glioma (IHG)-a case series of Hong Kong experience.

BACKGROUND: Infantile high-grade glioma (IHG) is diagnosed in patients less than 12 months of age. Studies have shown that it displays a more stable genome and is usually single mutation-driven. The most identifiable mutations are receptor tyrosine kinase (RTK) fusion, such as neurotrophic tyrosine receptor kinase (NTRK) family, reactive oxygen species (ROS1), anaplastic lymphoma kinase (ALK), and mesenchymal-epithelial transition (MET) factor. The current principal treatment remains to be surgery, but it is challenging for a complete resection due to hemispheric involvement. Use of chemotherapeutic drugs for IHG is still under debate, with targeted therapy showing efficacy in promoting tumor shrinkage. Despite being a challenging central nervous system (CNS) tumor, the overall survival of IHG is superior to other high-grade gliomas. CASE DESCRIPTION: This is a retrospective review of local IHG patients and their outcome. Up till the end of 2022, we identified eight IHG patients in our local data. Mean age of diagnosis was 3 months. There were four males and four females. Seven patients had histological diagnosis of glioblastoma and one patient had a diagnosis of anaplastic astrocytoma. One patient had her tumor located in the infratentorial region. Four patients had multilobar involvement. NTRK fusion was found in four patients (ETV6-NTRK3 fusion and TPR-NTRK1 fusion). ALK fusion was found in one patient (HMBOX1-ALK). ROS1 fusion was found in one patient (ZCCHZ8-ROS1). All patients underwent chemotherapy, with four patients switched to NTRK inhibitors and one patient to ROS1 inhibitors afterward. Surgery was performed at various time points for these patients. Two patients passed away, at 22 and 35 months of age at submission of this abstract. CONCLUSIONS: Infantile high-grade glioma should be regarded as a unique tumor entity and a multidisciplinary approach is paramount in improving survival for this group of patients.

AB071. Predictive value of plasma microRNA-10b and microRNA-21 on chemotherapy toxicity, recurrence, and overall survival in high-grade glioma patients treated with temozolomide.

BACKGROUND: The low level of median survival rate after complete therapy (i.e., surgery and concomitant chemotherapy and radiotherapy) in high-grade glioma (HGG) patients reflects the needs for a better understanding about HGG pathogenesis, including the role of epigenetic in glioma. MicroRNA (miRNA), a small chain non-coding RNA, has been increasingly utilized in the management of other oncology cases and might possess an immense potential in HGG. The expression of miRNA-10b and miRNA-21 (i.e., two miRNAs that are frequently studied due to its involvement in glioma) are higher in HGG patients and their role in regulatory mechanism of glioma has been established. However, the influence of those miRNAs in toxicity, recurrence, and overall survival of HGG patients is still unclear. We aim to assess the predictive value of plasma miRNA-10b and miRNA-21 in the chemotherapy toxicity, recurrence, and overall survival of HGG patients. METHODS: This is an observational analytic study using hospital-based mixed cohort approach. The study is conducted in RSUP Dr. Sardjito, Yogyakarta, from January 2021 to December 2024. We prospectively assess the plasma miRNA level from HGG patients who met the inclusive and exclusive criteria. The consecutive sampling is used until the sample size is met. Statistical analysis will be conducted for temozolomide toxicity using Spearman's rank correlation, for recurrence using logistical regression, and for overall survival test. RESULTS: In this ongoing study, we plan to collect samples from 155 HGG patients. As of April 2024, we managed to collect 96 samples (median age of 49 years and 55% of male patients). Most of the patients were diagnosed with World Health Organization (WHO) grade IV tumors (69.3%), with the most common diagnosis was glioblastoma (62%). Most of the patients had unmethylated O6-methylguanine-DNA methyltransferase (MGMT) and wild-type isocitrate dehydrogenase (IDH) status (62% and 57%, respectively). There was no difference in miRNA-21 expression based on MGMT status (methylated or unmethylated), nor IDH status (wild type or mutant), with P=0.39 and P=0.25, respectively. Moreover, we found no significant difference in miRNA-10b expression in both MGMT status and both IDH status (P=0.19 and P=0.09). As for the data regarding toxicity, recurrence, and overall survival was still on the process of data collection. CONCLUSIONS: MiRNA is a promising epigenetic modulator that might be utilized in HGG management. A better understanding on the role of miRNA in HGG patients might be able to improve clinical outcome.

AB001. Development of tumour-targeted therapy for the treatment of adult and paediatric high-grade gliomas.

BACKGROUND: Brain cancer patients, especially those suffering from high-grade gliomas (HGGs) face a bleak future with very dismal long-term disease-free survival outcomes due to the limited treatment options currently available. Therefore, there is an unmet need for new therapeutic intervention that extends patients' progress-free survival and improves their quality of life. A significant hurdle is the inability of current chemotherapy agents to cross the blood-brain barrier (BBB). BBB acts as a protective shield that filters the blood to ensure nothing harmful makes it to the brain. This protection is usually good, but it becomes a problem if you want to deliver therapeutic cancer drugs through it. This barrier blocks 98% of drugs from entering the brain. Even the ones that cross BBB are unevenly distributed in the normal brain and tumour tissue, resulting in mediocre treatment and severe side effects. METHODS: We are developing drug delivery systems that can cross the BBB and facilitate the specific accumulation of drugs in the tumour tissue. This will significantly improve the efficacy of anticancer drugs in treating various brain cancers and reduce systemic toxicity. Our group has explored and developed BBB crossing and tumour targeting near infra-red dyes, which can be covalently attached to Food and Drug Administration (FDA)-approved chemotherapy agents (drug-dye conjugates), thereby delivering it to the tumour tissue. RESULTS: We synthesized such drug-dye conjugates to target various aberrant pathways in HGG and tested these conjugates against patient-derived HGG cell lines. One such conjugate was tested on a mouse model of glioblastoma, an aggressive form of HGG, and shown to cross the BBB and specifically accumulate in tumour tissue, bringing forth tumour burden reduction. CONCLUSIONS: The results obtained from this work serve as proof of principle that enables tumour-specific drug delivery to treat HGG. This work also paves the way for treating other brain cancers and central nervous system (CNS) disorders like Parkinson's and Alzheimer's disease, for which no adequate therapy exists.

Value of 11C-Methionine PET Imaging in High-Grade Gliomas: A Narrative Review.

11C-Methionine (MET) is a widely utilized amino acid tracer in positron emission tomography (PET) imaging of primary brain tumors. 11C-MET PET offers valuable insights for tumor classification, facilitates treatment planning, and aids in monitoring therapeutic response. Its tracer properties allow better delineation of the active tumor volume, even in regions that show no contrast enhancement on conventional magnetic resonance imaging (MRI). This review focuses on the role of MET-PET in brain glioma imaging. The introduction provides a brief clinical overview of the problems of high-grade and recurrent gliomas. It discusses glioma management, radiotherapy planning, and the difficulties of imaging after chemoradiotherapy (pseudoprogression or radionecrosis). The mechanism of MET-PET is described. Additionally, the review encompasses the application of MET-PET in the context of primary gliomas, addressing its diagnostic precision, utility in tumor classification, prognostic value, and role in guiding biopsy procedures and radiotherapy planning.

A High-Grade Glioma, Not Elsewhere Classified in an Older Adult with Discordant Genetic and Epigenetic Analyses.

The World Health Organization's (WHO) classification of central nervous system (CNS) tumors is continually being refined to improve the existing diagnostic criteria for high-grade gliomas (HGGs), including glioblastoma. In 2021, advances in molecular analyses and DNA methylation profiling were incorporated to expand upon the diagnostic criteria for HGG, including the introduction of high-grade astrocytoma with piloid features (HGAP), a new tumor entity for which a match to the HGAP class in DNA methylation profiling is an essential criterion. We present an equivocal case of a 72-year-old male with an HGG exhibiting features of both HGAP and glioblastoma, but which did not conform to any existing 2021 WHO classification of CNS tumor entities. This "no match" in DNA methylation profiling resulted in a final diagnosis of HGG not elsewhere classified (NEC), for which standard treatment options do not exist.

Cell and gene therapy in neuro-oncology.

The majority of primary brain tumors are gliomas, among which glioblastoma multiforme (GBM) is the most common malignant brain tumor in adults. GBM has a median survival of 18-24 months, and despite extensive research it remains incurable, thus novel therapies are urgently needed. The current standard of care is a combination of surgery, radiation, and chemotherapy, but still remains ineffective due to the invasive nature and high recurrence of gliomas. Gene therapy is a versatile treatment strategy investigated for multiple tumor types including GBM. In gene therapy, a variety of vectors are employed to deliver genes designed for different antitumoral effects. Also, over the past decades, stem cell biology has provided a new approach to cancer therapies. Stem cells can be used as regenerative medicine, therapeutic carriers, drug targeting, and generation of immune cells. Stem cell-based therapy allows targeted therapy that spares healthy brain tissue as well as establishes a long-term antitumor response by stimulating the immune system and delivering prodrug, metabolizing genes, or even oncolytic viruses. This chapter describes the latest developments and the current trends in gene and cell-based therapy against GBM from both preclinical and clinical perspectives, including different gene therapy delivery systems, molecular targets, and stem cell therapies.

Emerging and Biological Concepts in Pediatric High-Grade Gliomas.

Primary central nervous system tumors are the most frequent solid tumors in children, accounting for over 40% of all childhood brain tumor deaths, specifically high-grade gliomas. Compared with pediatric low-grade gliomas (pLGGs), pediatric high-grade gliomas (pHGGs) have an abysmal survival rate. The WHO CNS classification identifies four subtypes of pHGGs, including Grade 4 Diffuse midline glioma H3K27-altered, Grade 4 Diffuse hemispheric gliomas H3-G34-mutant, Grade 4 pediatric-type high-grade glioma H3-wildtype and IDH-wildtype, and infant-type hemispheric gliomas. In recent years, we have seen promising advancements in treatment strategies for pediatric high-grade gliomas, including immunotherapy, CAR-T cell therapy, and vaccine approaches, which are currently undergoing clinical trials. These therapies are underscored by the integration of molecular features that further stratify HGG subtypes. Herein, we will discuss the molecular features of pediatric high-grade gliomas and the evolving landscape for treating these challenging tumors.

Intraoperative Comparison Between Strain Elastography and Preoperative Magnetic Resonance Imaging Features in High-Grade Gliomas Using Fusion Imaging: A Pilot Study.

OBJECTIVE: To compare the elastographic patterns of high-grade gliomas (HGGs) solid portions and those of adjacent healthy brain parenchyma, on intraoperative ultrasound, with magnetic resonance image (MRI) characteristics. METHODS: Clinical records and images of HGGs patients, operated between June and December 2018, were retrospectively reviewed. Fusion images were used to compare preoperative gadolinium-enhanced T1-weighted MRI/fluid-attenuated inversion recovery images (Gd-T1 MRI/FLAIR) to intraoperative strain elastography (SE). FLAIR/Gd-T1 MRI images were used to define enhancement patterns (absent/whole lesion/peripheral) and lesions' characteristics (primary and secondary pattern, further subdivided in solid/necrotic/cystic/infiltrating). HGGs SE patterns were categorized as homogeneous/inhomogeneous, while lesions' primary and secondary patterns as stiff/intermediate/elastic. The SE motive of neighboring healthy brain parenchyma was defined similarly. RESULTS: Eighteen patients (M:F, 11:7; mean age: 53 years) harboring 14 glioblastomas (77.8%) and 4 anaplastic astrocytomas (22.2%) were compared. Glioblastomas typically enhanced peripherally and had a primary necrotic pattern (78.6% and 64.3%, respectively), while anaplastic astrocytomas did not enhance and were solid (75% both) at T1-Gd MRI and FLAIR images. At SE anaplastic astrocytomas had a homogeneous stiff primary pattern, whereas the majority of glioblastomas primary patterns were heterogeneous (85.7%) and intermediate (78.6%). CONCLUSIONS: Three major SE patterns defined HGGs and adjacent healthy brain parenchyma. SE patterns varied according to HGG histotypes and Gd-T1 MRI/FLAIR characteristics.