Is the voltage-gated sodium channel ß3 subunit (SCN3B) a biomarker for glioma?

Recent studies suggest a need for reliable biomarkers enhancing prognosis prediction and treatment strategies in cancer. Here, we performed a data analysis bearing on the expression of SCN3B, voltage-gated sodium channel (VGSC) ß3 subunit, as a possible candidate for the development of a glioma biomarker for the first time. This extends our previous review article that mentioned the potential of SCN3B as a prognostic biomarker for glioma survival, further examining its association with existing indicators and immune responses. We utilized clinical and genomic data from multiple glioma cohorts. These include the Cancer Genome Atlas (TCGA) and the Chinese Glioma Genome Atlas (CGGA). We employed analytical techniques including time-dependent receiver operating characteristic (ROC) analysis, decision curves analysis (DCA), and correlation studies with immune checkpoint markers. Our findings indicate a differential SCN3B expression between glioma grades, and that this significantly correlates with patient survival, particularly in oligodendroglioma subtypes. The DCA curves suggested that the inclusion of SCN3B in the prognostic model would improve decision-making in these subtypes. Moreover, SCN3B expression positively correlated with the presence of key immune cells and negatively correlated with several immune checkpoint inhibitors. This suggests potential roles in modulating immune responses in glioma. Thus, SCN3B emerges as a promising potential prognostic biomarker for glioma, especially for oligodendroglioma. Its dual correlations with prognosis and immune regulation present a compelling case for further experimental and clinical investigations to establish its utility in enhancing glioma management strategies. These findings underscore the importance of integrating novel biomarkers with traditional prognostic models to refine treatment paradigms and improve patient outcomes.

Determinants of long-term survival in patients with IDH-mutant gliomas.

BACKGROUND: Survival times of patients with IDH-mutant gliomas are variable and can extend to decades. Many studies provide progression-free rather than overall survival times and prognostic factors remain ill-defined. Here we explored characteristics of short- and long-term survivors within a cohort of patients with extended follow-up. METHODS: This single-center, case-control study included 86 patients diagnosed between 1998 and 2023 who either died within 6 years after diagnosis or survived at least 15 years. Patient characteristics and prognostic factors were stratified by short- (< 6 years) versus long-term (≥ 15 years) survival. RESULTS: Forty-seven patients (55%) diagnosed with astrocytoma and 39 patients (45%) with oligodendroglioma were included retrospectively. Median follow-up of the survivors was 16.6 years (range 15-28.9). Thirty-four deaths (40%) had been reported at database closure. Long-term survival was associated with CNS WHO grade 2 (p < 0.01), smaller tumor volumes (p = 0.01), lack of contrast enhancement (p < 0.01), wait-and-scan strategies (p < 0.01) and female sex (p = 0.04). In multivariate analyses for oligodendroglioma, larger T2 tumor volumes were associated with shorter survival (HR 1.02; 95% CI 1.01-1.05; p = 0.04). In patients with astrocytoma, lack of contrast enhancement (HR 0.38; 95% CI 0.15-0.94; p = 0.04) and wait-and-scan strategies (HR 5.75; 95% CI 1.66-26.61; p = 0.01) were associated with longer survival. CONCLUSION: Large T2 tumor volume and contrast enhancement may be important risk factors for shorter survival, while age might be of lesser importance. Wait-and-scan strategies may yield excellent long-term survival in some patients with astrocytoma.

Newly emerged T2 high-signal intensity area mimicking oligodendroglioma expansion on intraoperative magnetic resonance imaging: A case report.

Magnetic resonance imaging (MRI) is an indispensable tool in neurosurgery, though it sometimes faces challenges such as "tumor mimicry." While intraoperative MRI (iMRI) is widely recognized for its usefulness in achieving maximal safe resection during glioma surgery, instances of tumor mimicry still occur on iMRI. Moreover, reports on tumor mimics observed through iMRI, particularly in low-grade gliomas, remain scarce. In this article, we present a case of oligodendroglioma, where a newly emerged T2 high-signal intensity region on iMRI necessitated differentiation from tumor expansion. A 23-year-old man presented with a newly diagnosed brain tumor and underwent surgical removal. An iMRI taken after tumor removal revealed a newly emerged T2 hyperintense area without diffusion restriction around the resection cavity, which was not observed in the preoperative MRI. Suspecting residual tumor, we performed additional resection. An MRI on the following day confirmed that the T2 hyperintense area identified on the iMRI had been completely resected but also revealed an enlarged T2 high-signal area over a wider region. Histopathology found no tumor cells in the additionally resected area, indicating that the iMRI finding was a tumor mimic. Six months later, the T2 high-signal area around the resection cavity had disappeared on MRI without any additional treatment. This case highlights the challenge of distinguishing between T2 hyperintense mimicry and tumor enlargement during glioma surgery seen on iMRI. Despite the significant value of iMRI, our report underscores the need for careful interpretation in neurosurgical practice, particularly with non-contrast-enhancing tumors.

AB027. Distinguishing oligodendroglioma from astrocytoma: a radiological case report.

BACKGROUND: Oligodendroglioma, the third most common glioma, accounts for 5% of primary brain tumors and around 20% of all glial neoplasms. It is a rare brain tumor that develops from glial cells called oligodendrocytes, which cover nerve cells. Oligodendroglioma is classified as an adult diffuse glioma in the fifth edition of the World Health Organization (WHO) Classification of Tumors of the Central Nervous System (CNS). Patients may present with cognitive impairment, aphasia, behavioral changes, and seizures. The symptoms at presentation are often related to the anatomic location of the tumor. CASE DESCRIPTION: A 55-year-old female presented with episodes of facial seizure with drooping on the right side of her face 4 months before coming to our hospital. Her seizures lasted around one minute, causing her to be unable to speak during the seizure. She also complained of chronic headaches in the last 1 year. She initially underwent a non-contrast computed tomography (CT) scan of the brain. The scans showed an isodense calcified mass on the perifalcine anterior left lobe with surrounding peritumoral edema. Magnetic resonance imaging (MRI) brain confirmed the presence of an intraaxial white matter mass involving the left frontal lobe. This tumor did not demonstrate any contrast enhancement. MRI findings were suggestive of a low-grade astrocytoma. Histopathological examination following craniotomy and tumor removal surgery confirmed the diagnosis of oligodendroglioma not otherwise specified (NOS) CNS WHO grade II. Molecular analysis revealed to be isocitrate dehydrogenase (IDH) wildtype, inconsistent with the classic molecular profile of oligodendroglioma. The patient underwent adjuvant radiotherapy following surgery. Subsequent follow-up assessments demonstrated stable disease with improvement in symptoms. CONCLUSIONS: Differentiating between oligodendroglioma and astrocytoma poses a significant challenge due to their overlapping clinical and radiological features, yet understanding their key differences is crucial for accurate diagnosis. On MRI, calcification strongly favors oligodendrogliomas, while T2/fluid-attenuated inversion recovery (FLAIR) mismatch sign favors astrocytoma. Only 50% of oligodendrogliomas appear to be contrast-enhanced. While oligodendrogliomas and astrocytomas share some similarities, careful consideration is essential for accurate differentiation, even though histopathological and molecular findings are the final determinants of diagnosis.

AB061. Oligodendroglioma in a 10-year-old girl with history of mediastinal mass and radiotherapy: a case report.

BACKGROUND: Oligodendroglioma is a part of diffusely infiltrating gliomas with poorly understood pathological aspect often manifesting histologic overlap among other intracranial tumors, though it only consisted 5% in total. Its occurrences among pediatric is a rare finding, constituted <1% of total brain tumors in the population, but with molecularly distinct properties to its adult version. Metachronous pediatric oligodendroglioma plus mediastinal mass is even more uncommon, as history of double primary tumor serves as a groundbreaking point in understanding individual pathology. This study reports a rare case of pediatric oligodendroglioma with history of mediastinal mass. CASE DESCRIPTION: This study reports a rare case of pediatric oligodendroglioma with history of mediastinal mass. A 10-year-old female presented to our emergency department with altered consciousness level in the past couple of weeks, and progressively worsening for 3 days. Moreover, she withstands a yearlong headache, plus continuously worsens weakness on the left side of the extremities for 6 months, right sided weakness of face and visual disturbances appeared at least 4 months prior presentation; no seizures were observed. History of pericardial effusion due to mediastinal mass was also recorded in 3 years before with history of pericardial tapping, with cytology showed malignant lesion; with history of 5 times radiotherapy cycle for treatment purpose, and patient discontinued therapy due to loss of follow up. Non-contrast head computed tomography (CT)-scan observed a mix-density lesion on the frontotemporoparietal region with calcification. On magnetic resonance imaging (MRI), mix-intensity lesion was found suggesting a glioma lesion. Patient underwent removal of tumor, with gross tumor removal was achieved. Histopathology result of oligodendroglioma was found. CONCLUSIONS: The management of pediatric oligodendroglioma in our case involves wide range of discipline to elaborate its interaction with prior metachronous mediastinal mass, and findings of double primary tumor should raise any suspicion for any tumor-related genetic mutations.

HOXD12 defines an age-related aggressive subtype of oligodendroglioma.

Oligodendroglioma, IDH-mutant and 1p/19q-codeleted has highly variable outcomes that are strongly influenced by patient age. The distribution of oligodendroglioma age is non-Gaussian and reportedly bimodal, which motivated our investigation of age-associated molecular alterations that may drive poorer outcomes. We found that elevated HOXD12 expression was associated with both older patient age and shorter survival in the TCGA (FDR < 0.01, FDR = 1e-5) and the CGGA (p = 0.03, p < 1e-3). HOXD12 gene body hypermethylation was associated with older age, higher WHO grade, and shorter survival in the TCGA (p < 1e-6, p < 0.001, p < 1e-3) and with older age and higher WHO grade in Capper et al. (p < 0.002, p = 0.014). In the TCGA, HOXD12 gene body hypermethylation and elevated expression were independently prognostic of NOTCH1 and PIK3CA mutations, loss of 15q, MYC activation, and standard histopathological features. Single-nucleus RNA and ATAC sequencing data showed that HOXD12 activity was elevated in neoplastic tissue, particularly within cycling and OPC-like cells, and was associated with a stem-like phenotype. A pan-HOX DNA methylation analysis revealed an age and survival-associated HOX-high signature that was tightly associated with HOXD12 gene body methylation. Overall, HOXD12 expression and gene body hypermethylation were associated with an older, atypically aggressive subtype of oligodendroglioma.

Multimodal imaging for the diagnosis of oligodendroglioma associated with arteriovenous malformation: A case report.

BACKGROUND: The rare co-occurrence of oligodendroglioma and arteriovenous malformation (AVM) in the same intracranial location. CASE SUMMARY: In a 61-year-old man presenting with progressive headaches, is described in this case study. Preoperative multimodal imaging techniques (computed tomography, magnetic resonance imaging, magnetic resonance spectroscopy, digital subtraction angiography, and computed tomography angiography) were employed to detect hemorrhage, cystic and solid lesions, and arteriovenous shunting in the right temporal lobe. The patient underwent right temporal craniotomy for lesion removal, and postoperative pathological analysis confirmed the presence of oligodendroglioma (World Health Organization grade II, not otherwise specified) and AVM. CONCLUSION: The preoperative utilization of multimodal imaging examination can help clinicians reduce the likelihood of misdiagnosis or oversight of these conditions, and provides important information for subsequent treatment. This case supports the feasibility of craniotomy for the removal of glioma with AVM.

Oligodendroglioma patient survival is associated with circulating B-cells and age.

Background: Variations in survival among patients with oligodendroglioma are unexplained by known prognostic factors. To assess the impact of peripheral immune profiles on prognosis, we applied immunomethylomics analyses-DNA methylation of archived whole blood samples, to characterize immune cells. Methods: We compared the proportions of immune cells from patients with oligodendroglioma to other glioma subtypes and controls. We used recursive partitioning analysis (RPA) within the oligodendrogliomas to correlate with survival. Results: Patients with oligodendrogliomas (141) were median age at diagnosis of 44 years; 57% male; 75% White; 60% prior chemotherapy; and 25% on dexamethasone at sample collection. Patients with oligodendrogliomas had immune profiles more similar to controls than other glioma subtypes, though with notably lower B-cells. RPA of patients with oligodendrogliomas delineated 2 survival groups based on an interaction between age and B-naïve cells. Patients with longer survival (median 24.2 years) were ≤42 years of age with higher B-naïve cells versus worse survival (median 16.9 years) who were ≤42 years of age with lower B-naïve cells or >42 years of age (P = .00032). Patients with worse survival also had lower CD4- and CD8-naïve T-cells. Similar immune profiles were observed in an independent cohort of oligodendroglioma patients prior to surgery. Conclusions: Peripheral blood immune profiles in oligodendroglioma suggested that younger patients with lower B-naïve cells experienced shorter survival. Though our findings lack of validation cohort and use a heterogenous patient population, they suggest peripheral blood immune profiles may be prognostic for patients with glioma and warrant further investigation.

Histone Acetyl Transferase 1 Is Overexpressed in Poor Prognosis, High-grade Meningeal and Glial Brain Cancers: Immunohistochemical and Aptahistochemical Study.

Primary malignancies of the central nervous system account for 2% of all cancers in adults and almost 15% in children under 15 years of age. The prognosis of brain anaplastic cancers and glioblastomas remains extremely poor, with devastating survival expectative, and new molecular markers and therapeutic targets are essential. Epigenetic changes constitute an extensive field for the development of new diagnostic and therapeutic strategies. Histone acetyl transferase-1 (HAT1) has merged as a potential prognostic marker and therapy target for different malignancies. Data repository analysis showed HAT1 mRNA overexpression in gliomas and has been described its alternative splicing in glioblastomas. Using immunohistochemical and aptahistochemical methods, we analyzed the expression of HAT1 in meningiomas, oligodendrogliomas, and astroglial cancers. We observed that HAT1 overexpression is associated with the most aggressive tumor types and the worse prognosis, as well as with a higher probability of early relapse in meningiomas. Its cytosolic localization correlates with tumor progression and prognosis. Aptamers, synthetic oligonucleotides capable to bind and inhibit a wide variety of targets, are considered as promising diagnostic and therapeutic tools. Aptahistochemistry using the aptamer apHAT610 offered superior results in comparison with the antibody used, as a good example of the potential of aptamers as diagnostic tools for histopathology.

Unveiling hierarchy and spatial distribution of O6-methylguanine-DNA methyltransferase promoter methylation in World Health Organization grade 2-3 gliomas.

This study investigated the role of O6-methylguanine-DNA methyltransferase promoter (MGMTp) methylation hierarchy and heterogeneity in grade 2-3 gliomas, focusing on variations in chemotherapy benefits and resection dependency. A cohort of 668 newly diagnosed grade 2-3 gliomas, with comprehensive clinical, radiological, and molecular data, formed the basis of this analysis. The extent of resection was categorized into gross total resection (GTR ≥100%), subtotal resection (STR >90%), and partial resection (PR ≤90%). MGMTp methylation levels were examined using quantitative pyrosequencing. Our findings highlighted the critical role of GTR in improving the prognosis for astrocytomas (IDH1/2-mutant and 1p/19q non-codeleted), contrasting with its lesser significance for oligodendrogliomas (IDH1/2 mutation and 1p/19q codeletion). Oligodendrogliomas demonstrated the highest average MGMTp methylation levels (median: 28%), with a predominant percentage of methylated cases (average methylation levels >20%). Astrocytomas were more common in the low-methylated group (10%-20%), while IDH wild-type gliomas were mostly unmethylated (<10%). Spatial distribution analysis revealed a decrement in frontal lobe involvement from methylated, low-methylated to unmethylated cases (72.8%, 59.3%, and 47.8%, respectively). In contrast, low-methylated and unmethylated cases were more likely to invade the temporal-insular region (19.7%, 34.3%, and 40.4%, respectively). Astrocytomas with intermediate MGMTp methylation were notably associated with temporal-insular involvement, potentially indicating a moderate response to temozolomide and underscoring the importance of aggressive resection strategies. In conclusion, our study elucidates the complex interplay of MGMTp methylation hierarchy and heterogeneity among grade 2-3 gliomas, providing insights into why astrocytomas and IDH wild-type lower-grade glioma might derive less benefit from chemotherapy.

Current challenges in the treatment of gliomas: The molecular era.

Gliomas originate from glial cells in the central nervous system. Approximately 80%-85% of malignant brain tumors in adults are gliomas. The most common central nervous system tumor in children is low-grade pediatric glioma. Diagnosis was determined by histological features until 2016 when the World Health Organization classification integrated molecular data with anatomopathological information to achieve a more integral diagnosis. Molecular characterization has led to better diagnostic and prognostic staging, which in turn has increased the precision of treatment. Current efforts are focused on more effective therapies to prolong survival and improve the quality of life of adult and pediatric patients with glioma. However, improvements in survival have been modest. Currently, clinical guidelines, as well as the article by Mohamed et al accompanying this editorial piece, are adapting treatment recommendations (surgery, chemotherapy, and radiotherapy) according to diagnosis and prognosis guided by molecular biomarkers. Furthermore, this paves the way for the design of clinical trials with new therapies, which is especially important in pediatric gliomas.

Contemporary Prognostic Signatures and Refined Risk Stratification of Gliomas: An Analysis of 4,400 Tumors.

BACKGROUND: With the significant shift in the classification, risk stratification, and standards of care for gliomas, we sought to understand how the overall survival of patients with these tumors is impacted by molecular features, clinical metrics, and treatment received. METHODS: We assembled a cohort of patients with a histopathologically diagnosed glioma from The Cancer Genome Atlas, Project Genomics Evidence Neoplasia Information Exchange, and Dana-Farber Cancer Institute/Brigham and Women's Hospital. This incorporated retrospective clinical, histological, and molecular data alongside prospective assessment of patient survival. RESULTS: 4,400 gliomas were identified: 2,195 glioblastoma, 1,198 IDH1/2-mutant astrocytoma, 531 oligodendroglioma, 271 other IDH1/2-wildtype glioma, and 205 pediatric-type glioma. Molecular classification updated 27.2% of gliomas from their original histopathologic diagnosis. Examining the distribution of molecular alterations across glioma subtypes revealed mutually exclusive alterations within tumorigenic pathways. Non-TCGA patients had significantly improved overall survival compared to TCGA patients, with 26.7%, 55.6%, and 127.8% longer survival for glioblastoma, IDH1/2-mutant astrocytoma, and oligodendroglioma respectively (all p<0.01). Several prognostic features were characterized, including NF1 alteration and 21q loss in glioblastoma, and EGFR amplification and 22q loss in IDH1/2-mutant astrocytoma. Leveraging the size of this cohort, nomograms were generated to assess the probability of overall survival based on patient age, the molecular features of a tumor, and the treatment received. CONCLUSIONS: By applying modern molecular criteria, we characterize the genomic diversity across glioma subtypes, identify clinically applicable prognostic features, and provide a contemporary update on patient survival to serve as a reference for ongoing investigations.

Histopathological Spectrum of Gliomas and Its Immunohistochemical Correlation in a Tertiary Care Setup.

Introduction Central nervous system (CNS) tumors pose significant diagnostic challenges due to their varied morphological and differentiating characteristics. Modern advancements in immunohistochemistry (IHC) and molecular pathology have greatly enhanced prognostication, screening, and therapeutic management. Gliomas, a type of tumor originating from glial cells in the CNS, can develop from astrocytes, oligodendrocytes, or ependymal cells. According to the 2021 update, the classification of diffuse gliomas is primarily based on the presence or absence of isocitrate dehydrogenase (IDH1/2) mutations. IDH-wildtype gliomas (glioblastomas) have a significantly poorer prognosis compared to IDH-mutant gliomas (astrocytomas and oligodendrogliomas). Gliomas are highly infiltrative and resistant to treatment, making them largely incurable regardless of their grade and prognosis. Objective This study aimed to determine the histopathological diversity of gliomas and its correlation with protein expressions of IDH, ATRX gene (α-thalassemia/mental retardation syndrome X-linked), Ki-67, and p53 mutations (tumor suppressor gene-53), according to the 2021 World Health Organization (WHO) Classification of CNS Tumors, Fifth Edition. Methods This descriptive cross-sectional study was carried out in the Department of Pathology at a tertiary care center, focusing on various types of gliomas received over a two-year period. A total of 54 specimens of gliomas received from the Department of Neurosurgery were subjected to histopathological examination. Sections were stained using hematoxylin and eosin (H&E), and IHC was performed using four markers (IDH, ATRX, p53, Ki-67) in each case. Results were analyzed according to the 2021 WHO Classification of CNS Tumors, Fifth Edition. Results The majority of individuals were between the age group of 40 and 60 years, showing a male predominance (65%). The most common site was the frontal lobe. Glioblastoma constituted the largest proportion (46.2%) of the total cases, followed by astrocytoma (20.3%), oligodendroglioma (18.5%), pilocytic astrocytoma (7.4%), and ependymoma (7.4%). All 11 cases of astrocytoma exhibited IDH mutation and ATRX loss, with p53 positive in the majority of cases. Strong nuclear p53 immunohistochemical positivity in >10% of tumor nuclei correlates with TP53 mutations. Among 25 cases of glioblastoma, IDH was negative, ATRX was retained in all cases, and 11 cases were positive for p53 mutation. For oligodendroglioma, out of 10 cases, IDH mutation was positive, and ATRX was retained in all cases. p53 mutation was not seen in any case. All cases of pilocytic astrocytoma were negative for IDH and p53 mutations, with ATRX retained in all cases. In all cases of ependymoma, IDH and p53 mutations were negative, and ATRX was retained in all cases. Glioblastomas exhibited the highest Ki-67 expression. Conclusion The 2021 WHO Classification of CNS Tumors, Fifth Edition, was updated, building on previously established concepts and continuing to evolve. The final diagnosis of gliomas relies on a comprehensive combination of clinical evaluation, neuroimaging, pathological examination, and molecular analysis. Nonetheless, histopathological examination, along with IHC, remains the cornerstone of diagnosis.

Intra-axial Cortical-Based Tumour Presented as Homonymous Hemianopia in a Young Patient: A Diagnostic Dilemma.

Intra-axial cortical-based tumours are rare tumours affecting children and young adults. These tumours can be classified as either low-grade or high-grade, depending on their aggressiveness and rate of growth. We report a case of homonymous hemianopia secondary to an intra-axial cortical-based tumour in a young patient. A 26-year-old lady presented with bilateral blurring of vision for three weeks associated with a headache. Visual acuity was 6/6 in both eyes. Bilateral optic nerve functions were normal. The Humphrey visual field test showed left-homonymous hemianopia. A CT scan and MRI of the brain revealed an intra-axial cortical-based tumor. Differential diagnoses include pleomorphic xanthoastrocytoma (PXA), ganglioglioma, oligodendroglioma, and dysembryoplastic neuroepithelial tumour (DNET). The patient was treated conservatively and closely monitored through clinic follow-up.

Targeted radionuclide therapy for gliomas: emerging clinical trial landscape.

According to the new WHO classification of 2021, gliomas are a heterogeneous group of tumors with very different histology, molecular genetics and prognoses. In addition to glioblastomas, the most common gliomas, there are also numerous less common gliomas, some of which have a very favorable prognosis. Targeted radionuclide therapy is a therapeutic option that can be attractive if a tumor can be targeted based on its molecular characteristics. It is particularly useful when tumors cannot be completely resected or when conventional imaging does not fully capture the extent of the tumor. Numerous approaches to radionuclide therapy for gliomas are in early development. The most advanced approaches for patients with gliomas in the clinic employ L-type amino acid transporter 1 as an uptake mechanism for radiolabeled amino acids or target somatostatin receptor 2 or gastrin-releasing peptide receptor. Here, we discuss the various target structures of radionuclide therapy in gliomas and provide an outlook for which glioma entities radionuclide therapy could most likely provide a therapeutic alternative.

Insights into brain tumor diagnosis: exploring in situ hybridization techniques.

Objectives: Diagnosing brain tumors is critical due to their complex nature. This review explores the potential of in situ hybridization for diagnosing brain neoplasms, examining their attributes and applications in neurology and oncology. Methods: The review surveys literature and cross-references findings with the OMIM database, examining 513 records. It pinpoints mutations suitable for in situ hybridization and identifies common chromosomal and gene anomalies in brain tumors. Emphasis is placed on mutations' clinical implications, including prognosis and drug sensitivity. Results: Amplifications in EGFR, MDM2, and MDM4, along with Y chromosome loss, chromosome 7 polysomy, and deletions of PTEN, CDKN2/p16, TP53, and DMBT1, correlate with poor prognosis in glioma patients. Protective genetic changes in glioma include increased expression of ADGRB3/1, IL12B, DYRKA1, VEGFC, LRRC4, and BMP4. Elevated MMP24 expression worsens prognosis in glioma, oligodendroglioma, and meningioma patients. Meningioma exhibits common chromosomal anomalies like loss of chromosomes 1, 9, 17, and 22, with specific genes implicated in their development. Main occurrences in medulloblastoma include the formation of isochromosome 17q and SHH signaling pathway disruption. Increased expression of BARHL1 is associated with prolonged survival. Adenomas mutations were reviewed with a focus on adenoma-carcinoma transition and different subtypes, with MMP9 identified as the main metalloprotease implicated in tumor progression. Discussion: Molecular-genetic diagnostics for common brain tumors involve diverse genetic anomalies. In situ hybridization shows promise for diagnosing and prognosticating tumors. Detecting tumor-specific alterations is vital for prognosis and treatment. However, many mutations require other methods, hindering in situ hybridization from becoming the primary diagnostic method.

Extracranial metastatic oligodendroglioma with molecular progression, case presentation.

BACKGROUND: Extraneural metastasis of central nervous system tumors is generally rare and most often reported in glioblastomas and medulloblastomas, whereas oligodendrogliomas seem to have the lowest risk of extracranial metastasis. Given its infrequent occurrence, both the diagnosis and therapy of metastatic oligodendroglioma is often challenging. CASE PRESENTATION: This case study presents an oligodendroglioma, the isocitrate dehydrogenase 1 (IDH1) mutant, 1p/19q-codeleted tumor with bone marrow metastasis. The significance of this case lies in the comprehensive molecular analysis conducted for both the primary tumor and the metastasis. Chromosome 7 trisomy and chromosome 10 monosomy (+ 7/-10) were detected in the metastasis indicating molecular progression, which, to the best of our knowledge, has not been previously documented in metastatic oligodendroglioma. CONCLUSIONS: This case study serves additional information for better understanding of the metastatic capabilities of CNS tumors.

Immunohistochemical Expression of PTEN in Canine Gliomas.

Phosphatase and tensin homolog (PTEN) is a critical tumor suppressor gene with a vital role in regulating cell proliferation, migration, and survival. The loss of PTEN function, either by genetic alterations or decreased protein expression, is frequent in human gliomas and has been correlated with tumor progression, grade, therapeutic resistance, and decreased overall survival in patients with glioma. While different genetic mutations in PTEN gene have been occasionally reported in canine gliomas, no alterations in protein expression have been reported. This study investigates the immunohistochemical expression of PTEN in canine gliomas to evaluate possible alterations, as those reported in human gliomas. Immunohistochemical PTEN expression and pattern distribution were analyzed in 37 spontaneous canine gliomas. Among gliomas, 52.6% cases showed high PTEN expression and 48.6% displayed reduced (13.5%) or highly reduced (35.1%) immunopositivity. Most oligodendrogliomas showed high expression (73.7%), while the majority of astrocytomas (69.2%) showed a reduced or highly reduced expression. A reduced PTEN expression was mostly associated with a heterogeneous loss of PTEN immunopositivity. These observations are in line with those reported in human gliomas and provide a rationale for future studies regarding abnormalities in PTEN expression and PI3K/Akt/mTor pathway in canine gliomas, to evaluate its prognostic and therapeutic implications.

Favorable Radiographic Response in a Patient With an Oligodendroglioma Treated With Azacitidine and Venetoclax for Acute Myeloid Leukemia.

The standard chemotherapy for treating oligodendrogliomas consists of a combination of procarbazine, lomustine, and vincristine (PCV). The combination of hypomethylating agents like azacitidine and BCL2 inhibitors like venetoclax has not been formally studied in the treatment of glial tumors. The combination of these two drugs is commonly used to treat acute myeloid leukemia (AML), with IDH-mutant disease being a particularly sensitive subtype. The use of azacitidine for the treatment of IDH-mutant gliomas has been reported in the literature, with mixed results that might suggest at least some benefits in a subtype of patients. It is also reported in the literature that the BCL2 gene is associated with treatment resistance and tumor recurrence in gliomas. Here, we present a patient with an oligodendroglioma who was treated with a conventional chemotherapy regimen for AML and, at the same time, had a favorable radiographic response to his brain tumor.