Diffuse gliomas to date and beyond 2016 WHO Classification of Tumours of the Central Nervous System

T2-FLAIR mismatch sign, an imaging biomarker for CDKN2A-intact in non-enhancing astrocytoma, IDH-mutant

INTRODUCTION

The WHO classification of central nervous system tumors (5th edition) classified astrocytoma, IDH-mutant accompanied with CDKN2A/B homozygous deletion as WHO grade 4. Loss of immunohistochemical (IHC) staining for methylthioadenosine phosphorylase (MTAP) was developed as a surrogate marker for CDKN2A-HD. Identification of imaging biomarkers for CDKN2A status is of immense clinical relevance. In this study, we explored the association between radiological characteristics of non-enhancing astrocytoma, IDH-mutant to the CDKN2A/B status.

METHODS

Thirty-one cases of astrocytoma, IDH-mutant with MTAP results by IHC were included in this study. The status of CDKN2A was diagnosed by IHC staining for MTAP in all cases, which was further confirmed by comprehensive genomic analysis in 12 cases. The T2-FLAIR mismatch sign, cystic component, calcification, and intratumoral microbleeding were evaluated. The relationship between the radiological features and molecular pathological diagnosis was analyzed.

RESULTS

Twenty-six cases were identified as CDKN2A-intact while 5 cases were CDKN2A-HD. The presence of > 33% and > 50% T2-FLAIR mismatch was observed in 23 cases (74.2%) and 14 cases (45.2%), respectively, and was associated with CDKN2A-intact astrocytoma (p = 0.0001, 0.0482). None of the astrocytoma, IDH-mutant with CDKN2A-HD showed T2-FLAIR mismatch sign. Cystic component, calcification, and intratumoral microbleeding were not associated with CDKN2A status.

CONCLUSION

In patients with non-enhancing astrocytoma, IDH-mutant, the T2-FLAIR mismatch sign is a potential imaging biomarker for the CDKN2A-intact subtype. This imaging biomarker may enable preoperative prediction of CDKN2A status among astrocytoma, IDH-mutant.

Integrative analysis of bulk RNA-seq and scRNA-seq data indicates the prognostic and immunologic values of SERPINH1 in glioma

BACKGROUND

SERPINH1 is abnormally expressed in multiple cancers and is associated with malignant progression. However, few reports detail its role in the etiopathogenesis of glioma. Hence, the aim of this article was to investigate the potential value of SERPINH1 in glioma using an integrative analysis.

METHODS

Data of RNA-seq and scRNA-seq was obtained and evaluated using online databases. The expression of SERPINH1 was confirmed by qRT-PCR and immunohistochemistry. The prognostic value of SERPINH1 was evaluated using univariate and multivariate Cox regression analyses. SERPINH1-related signaling pathways and the interaction of SERPINH1 with immunity were also investigated.

RESULTS

SERPINH1 exhibited a markedly elevated expression in glioma compared to normal brain tissues in the online databases. Similar results were confirmed by qRT-PCR and immunohistochemistry. SERPINH1 was found to be an independent prognosis factor, and high expression of SERPINH1 indicated poor survival. Moreover, a nomogram was constructed to predict prognosis more accurately and intuitively. GSEA analysis showed that SERPINH1 was involved in seven signaling pathways, including JAK-STAT pathway. Further analysis indicated SERPINH1 was significantly associated with immunity, especially in low-grade glioma. Additionally, an examination of scRNA-seq data revealed that SERPINH1 was primarily expressed in T cells of the CD4+ and CD8+ subsets.

CONCLUSIONS

SERPINH1 is a key biomarker of glioma prognosis and is immunologically relevant, which provides additional options for targeted therapy of glioma.

The spectrum of microvascular patterns in adult diffuse glioma and their correlation with tumor grade

BACKGROUND

Primary brain tumors constitute the leading cause of cancer-related mortality. Among them, adult diffuse gliomas are the most common type, affecting the cerebral hemispheres and displaying a diffuse infiltrative pattern of growth in the surrounding neuropil that accounts for about 80% of all primary intracranial tumors. The hallmark feature of gliomas is blood vessel proliferation, which plays an important role in tumor growth, tumor biological behavior, and disease outcome. High-grade gliomas exhibit increased vascularity, the worst prognosis, and lower survival rates. Several angiogenic receptors and factors are upregulated in glioblastomas and stimulate angiogenesis signaling pathways by means of activating oncogenes and/or down-regulating tumor-suppressor genes. Existing literature has emphasized that different microvascular patterns (MVPs) are displayed in different subtypes of adult diffuse gliomas.

METHODS

We examined the distribution and biological characteristics of different MVPs in 50 patients with adult diffuse gliomas. Haematoxylin and eosin staining results, along with periodic acid-Schiff and CD34 dual-stained sections, were examined to assess the vascular patterns and correlate with different grades of diffuse glioma.

RESULTS

The present observational study on adult diffuse glioma evaluated tumor grade and MVPs. Microvascular sprouting was the most common pattern, while a bizarre pattern (type 2) was associated with the presence of a high-grade glioma. Vascular mimicry was observed in 6% of cases, all of which were grade 4 gliomas.

CONCLUSIONS

This study supplements the role of neo-angiogenesis and aberrant vasculature patterns in the grading and progression of adult diffuse gliomas, which can be future targets for planning treatment strategies.

Targeting the Endocannabinoid System Present in the Glioblastoma Tumour Microenvironment as a Potential Anti-Cancer Strategy

The highly aggressive and invasive glioblastoma (GBM) tumour is the most malignant lesion among adult-type diffuse gliomas, representing the most common primary brain tumour in the neuro-oncology practice of adults. With a poor overall prognosis and strong resistance to treatment, this nervous system tumour requires new innovative treatment. GBM is a polymorphic tumour consisting of an array of stromal cells and various malignant cells contributing to tumour initiation, progression, and treatment response. Cannabinoids possess anti-cancer potencies against glioma cell lines and in animal models. To improve existing treatment, cannabinoids as functionalised ligands on nanocarriers were investigated as potential anti-cancer agents. The GBM tumour microenvironment is a multifaceted system consisting of resident or recruited immune cells, extracellular matrix components, tissue-resident cells, and soluble factors. The immune microenvironment accounts for a substantial volume of GBM tumours. The barriers to the treatment of glioblastoma with cannabinoids, such as crossing the blood-brain barrier and psychoactive and off-target side effects, can be alleviated with the use of nanocarrier drug delivery systems and functionalised ligands for improved specificity and targeting of pharmacological receptors and anti-cancer signalling pathways. This review has shown the presence of endocannabinoid receptors in the tumour microenvironment, which can be used as a potential unique target for specific drug delivery. Existing cannabinoid agents, studied previously, show anti-cancer potencies via signalling pathways associated with the hallmarks of cancer. The results of the review can be used to provide guidance in the design of future drug therapy for glioblastoma tumours.

An In Vitro Model of Glioma Development

Gliomas are the prevalent forms of brain cancer and derive from glial cells. Among them, astrocytomas are the most frequent. Astrocytes are fundamental for most brain functions, as they contribute to neuronal metabolism and neurotransmission. When they acquire cancer properties, their functions are altered, and, in addition, they start invading the brain parenchyma. Thus, a better knowledge of transformed astrocyte molecular properties is essential. With this aim, we previously developed rat astrocyte clones with increasing cancer properties. In this study, we used proteomic analysis to compare the most transformed clone (A-FC6) with normal primary astrocytes. We found that 154 proteins are downregulated and 101 upregulated in the clone. Moreover, 46 proteins are only expressed in the clone and 82 only in the normal cells. Notably, only 11 upregulated/unique proteins are encoded in the duplicated q arm of isochromosome 8 (i(8q)), which cytogenetically characterizes the clone. Since both normal and transformed brain cells release extracellular vesicles (EVs), which might induce epigenetic modifications in the neighboring cells, we also compared EVs released from transformed and normal astrocytes. Interestingly, we found that the clone releases EVs containing proteins, such as matrix metalloproteinase 3 (MMP3), that can modify the extracellular matrix, thus allowing invasion.

ECM2, a prognostic biomarker for lower grade glioma, serves as a potential novel target for immunotherapy

Extracellular matrix protein 2 (ECM2), which regulates cell proliferation and differentiation, has recently been reported as a prognostic indicator for multiple cancers, but its value in lower grade glioma (LGG) remains unknown. In this study, LGG transcriptomic data of 503 cases in The Cancer Genome Atlas (TCGA) database and 403 cases in The Chinese Glioma Genome Atlas (CGGA) database were collected to analyze ECM2 expression patterns and the relationship with clinical characteristics, prognosis, enriched signaling pathways, and immune-related markers. In addition, a total of 12 laboratory samples were used for experimental validation. Wilcoxon or Kruskal-Wallis tests demonstrated highly expressed ECM2 in LGG was positively associated with malignant histological features and molecular features such as recurrent LGG and isocitrate dehydrogenase (IDH) wild-type. Also, Kaplan-Meier (KM) curves proved high ECM2 expression could predict shorter overall survival in LGG patients, as multivariate analysis and meta-analysis claimed ECM2 was a deleterious factor for LGG prognosis. In addition, the enrichment of immune-related pathways for ECM2, for instance JAK-STAT pathway, was obtained by Gene Set Enrichment Analysis (GSEA) analysis. Furthermore, positive relationships between ECM2 expression with immune cells infiltration and cancer-associated fibroblasts (CAFs), iconic markers (CD163), and immune checkpoints (CD274, encoding PD-L1) were proved by Pearson correlation analysis. Finally, laboratory experiments of RT-qPCR and immunohistochemistry showed high expression of ECM2, as well as CD163 and PD-L1 in LGG samples. This study identifies ECM2, for the first time, as a subtype marker and prognostic indicator for LGG. ECM2 could also provide a reliable guarantee for further personalized therapy, synergizing with tumor immunity, to break through the current limitations and thus reinvigorating immunotherapy for LGG. AVAILABILITY OF DATA AND MATERIALS: Raw data from all public databases involved in this study are stored in the online repository (chengMD2022/ECM2 (github.com)).

Events in CNS Tumor Pathology Post-2016 WHO CNS: cIMPACT-NOW Updates and Other Advancements: A Comprehensive Review Plus a Summary of the Salient Features of 2021 WHO CNS 5

Introduction

The 2016 World Health Organization Classification (WHO) of Tumors of the Central Nervous System (CNS) represented a major change. It recommended an "integrated diagnosis" comprising histologic and molecular information facilitating a more precise diagnosis of specific CNS tumors. Its goal was to provide greater diagnostic precision and reproducibility resulting in more clinical relevance and predictive value, ultimately leading to better patient care. Advances in molecular classification, mostly resulting from DNA methylation array profiling of CNS tumors, were occurring at a very rapid pace and required more rapid integration into clinical practice.

Methods

cIMPACT-NOW updates and other recent papers plus salient features of 2021 WHO CNS5 in this comprehensive write-up were reviewed.

Results

CNS tumor classification needs to be updated at a rapid pace and mechanisms put into place to guide diagnosticians and clinicians in the interim period if major changes in the classification of tumor types came to light. Recognizing the need to integrate these into clinical practice more rapidly and without inordinate delay, the International Society of Neuropathology (ISN) 2016 sponsored an initiative called cIMPACT-NOW.

Discussion and/or Conclusion

Goal of cIMPACT-NOW was to provide clarification regarding contentious issues arising in the wake of the 2016 WHO CNS update as well as report new advancements in molecular classification of CNS tumors and new tumor entities emerging as a result of these advancements. cIMPACT-NOW updates: It thus laid the foundation for the 5th edition of the WHO Classification of CNS tumors (2021 WHO CNS 5). We have discussed cIMPACT updates in detail in this review. In addition, molecular diagnostics including DNA methylation-based classification of CNS tumors and the practical use of molecular classification in the prognostication and treatment of CNS tumors is discussed. Finally, the salient features of the new CNS tumor classification are summarized.

Enhanced delivery to brain using sonosensitive liposome and microbubble with focused ultrasound

Glioblastoma is considered one of the most aggressive and dangerous brain tumors. However, treatment of GBM has been still challenged due to blood-brain barrier (BBB). BBB prevents that the chemotherapeutic molecules are extravasated to brain. In this study, sonosensitive liposome encapsulating doxorubicin (DOX) was developed for enhancement of GBM penetration in combination with focused ultrasound (FUS) and microbubbles. Upon ultrasound (US) irradiation, microbubbles induce cavitation resulting in the tight junction of BBB endothelium to temporarily open. In addition, the composition of sonosensitive liposome was optimized by comparison of sonosensitivity and intracellular uptake to U87MG cells. The optimal sonosensitive liposome, IMP301-DC, resulted 123.9 ± 38.2 nm in size distribution and 98.2 % in loading efficiency. Related to sonosensitivity of IMP301-DC, US-triggered release ratio of doxorubicin was 69.2 ± 12.3 % at 92 W/cm² of US intensity for 1 min. In the in vivo experiments, the accumulation of DiD fluorescence probe labeled IMP301-DC-shell in the brain through the BBB opening was increased more than two-fold compared to that of Doxil-shell, non-sonosensitive liposome. US exposure significantly increased GBM cytotoxicity of IMP301-DC. In conclusion, this study demonstrated that IMP301-DC could serve as an alternative solution to enhance the penetration to GBM treatment via BBB opening by non-invasive FUS combined with microbubbles.

Tumor-related molecular determinants of neurocognitive deficits in patients with diffuse glioma

BACKGROUND

Cognitive impairment is a common and debilitating symptom in patients with diffuse glioma, and is the result of multiple factors. We hypothesized that molecular tumor characteristics influence neurocognitive functioning (NCF), and aimed to identify tumor-related markers of NCF in diffuse glioma patients.

METHODS

We examined the relation between cognitive performance (executive function, memory, and psychomotor speed) and intratumoral expression levels of molecular markers in treatment-naive patients with diffuse glioma. We performed a single-center study in a consecutive cohort, through a two-step design: (1) hypothesis-free differential expression and gene set enrichment analysis to identify candidate oncogenetic markers for cognitive impairment. Nineteen molecular markers of interest were derived from this set of genes, as well as from prior knowledge; (2) correlation of cognitive performance to intratumoral expression levels of these nineteen molecular markers, measured with immunohistochemistry.

RESULTS

From 708 included patients with immunohistochemical data, we performed an in-depth analysis of neuropsychological data in 197, and differential expression analysis in 65 patients. After correcting for tumor volume and location, we found significant associations between expression levels of CD3 and IDH-1 and psychomotor speed; between IDH-1, ATRX, NLGN3, BDNF, CK2Beta, EAAT1, GAT-3, SRF, and memory performance; and between IDH-1, P-STAT5b, NLGN3, CK2Beta, and executive functioning. P-STAT5b, CD163, CD3, and Semaphorin-3A were independently associated after further correction for histopathological grade.

CONCLUSION

Molecular characteristics of glioma can be independent determinants of patients' cognitive functioning. This suggests that besides tumor volume, location, and histological grade, variations in glioma biology influence cognitive performance through mechanisms that include perturbation of neuronal communication. These results pave the way towards targeted cognition improving therapies in neuro-oncology.

Dynamic Intercell Communication between Glioblastoma and Microenvironment through Extracellular Vesicles

Glioblastoma is simultaneously the most common and most aggressive primary brain tumor in the central nervous system, with poor patient survival and scarce treatment options. Most primary glioblastomas reoccur and evolve radio- and chemoresistant properties which make them resistant to further treatments. Based on gene mutations and expression profiles, glioblastoma is relatively well classified; however, research shows that there is more to glioblastoma biology than that defined solely by its genetic component. Specifically, the overall malignancy of the tumor is also influenced by the dynamic communication to its immediate and distant environment, as important messengers to neighboring cells in the tumor microenvironment extracellular vesicles (EVs) have been identified. EVs and their cargo can modulate the immune microenvironment and other physiological processes, and can interact with the host immune system. They are involved in tumor cell survival and metabolism, tumor initiation, progression, and therapy resistance. However, on the other hand EVs are thought to become an effective treatment alternative, since they can cross the blood-brain barrier, are able of specific cell-targeting and can be loaded with various therapeutic molecules.

Case Report: Five Adult Cases of H3K27-Altered Diffuse Midline Glioma in the Spinal Cord

Background

Diffuse midline glioma with H3K27-altered (DMG-H3K27a) is a novel tumor entity of the pediatric-type diffuse high-grade tumor in the latest WHO CNS 5. It mostly affects children and is only rarely found in adults. The tumor has a high level of aggressiveness, with a rapid progression and bad prognosis. In adults, the spinal cord is the most common site of DMG-H3K27a. Rare adult cases of primary DMG-H3K27a in the spinal cord were reported in this study, together with clinico-histopathologico-radiographic data.

Methods

From January 2016 to December 2020, we conducted a retrospective study of five adults with primary DMG-H3K27a in the spinal cord, analyzing their clinical, pathohistological, and radiographic datasets from the first diagnosis to follow-up.

Results

All five patients were diagnosed for the first time and were given full treatment. In three of the five patients, post-operative follow-up revealed tumor recurrence. The longest survival of the five patients was 45 months at the time of report submission, while the longest progression-free survival (PFS) following surgery was 20 months. Immunohistochemical studies showed the tumors featured aggressive behavior (grade 4) and were positive for the H3K27M mutation. The radiographic appearances were varied, but they were all initially mistaken as benign. DMG-H3K27a in the spinal cord was characterized by isointense/hyperintense on T1WI and isointense/hyperintense on T2WI, as well as cystic necrosis and peripheral spinal cord edema, as well as central canal enlargement and other types of enhancement.

Conclusion

This is the first case report focusing on adult DMG-H3K27a of the pediatric-type diffuses high-grade gliomas in the spinal cord. In our cases, we discovered the following: 1) adults had a better prognosis with a longer PFS compared with prior pediatric reports; 2) despite aggressive behavior under the microscope, radiographic appearances of the tumors were less aggressive; and 3) adjuvant treatment, including TCM, may have played a role in the prognosis.

Immunohistochemical expression of HIF-1α, IDH1 and TP53: Prognostic profile of Moroccan patients with diffuse glioma

Diffuse gliomas are growing brain tumors that occur in adult life. This study was designed to determine whether the immunohistochemical analysis of IDH1, HIF-1alpha, or TP53 can provide useful biomarkers of clinical severity and progression of diffuse gliomas. Also, it is hypothesized that the expression of IDH1 mutant induces HIF-1alpha. Immunohistochemical staining for HIF-1alpha, IDH1, and TP 53 was performed in biopsy or resection (sub-total or gross-total) tissue from diffuse gliomas in a clinical series of 32 patients. Associations of the HIF-1alpha, IDH1, and TP53 with clinical characteristics were evaluated and the co-expression of two biomarkers (HIF-1alpha and IDH1) was tested. Our data revealed that each biomarker is expressed in a subset of gliomas (IDH1 was positive in 56% cases, HIF-1alpha was positive in 50% cases and TP53 was positive in 44% cases). While no associations were found between clinical characteristics and the expression of HIF-1alpha, and TP53, IDH1 expression was associated with less severe clinical presentation (Karnofsky Performance Status) and disease progression and was more often expressed in females than males. In addition, there was no clear association between IDH1 and HIF-1alpha expression (21.9% of patients co-expressed IDH1 and HIF-1alpha). The current series provides clinical and immunohistochemical findings that can be useful for the clinical management of patients with diffused gliomas.

Proliferating CD8+ T Cell Infiltrates Are Associated with Improved Survival in Glioblastoma

Background: tumor-infiltrating lymphocytes are prognostic in many human cancers. However, the prognostic value of lymphocytes infiltrating glioblastoma (GBM), and roles in tumor control or progression are unclear. We hypothesized that B and T cell density, and markers of their activity, proliferation, differentiation, or function, would have favorable prognostic significance for patients with GBM. Methods: initial resection specimens from 77 patients with IDH1/2 wild type GBM who received standard-of-care treatment were evaluated with multiplex immunofluorescence histology (mIFH), for the distribution, density, differentiation, and proliferation of T cells and B cells, as well as for the presence of tertiary lymphoid structures (TLS), and IFNγ expression. Immune infiltrates were evaluated for associations with overall survival (OS) by univariate and multivariate Cox proportional hazards modeling. Results: in univariate analyses, improved OS was associated with high densities of proliferating (Ki67⁺) CD8⁺ cells (HR 0.36, p = 0.001) and CD20⁺ cells (HR 0.51, p = 0.008), as well as CD8⁺Tbet⁺ cells (HR 0.46, p = 0.004), and RORγt⁺ cells (HR 0.56, p = 0.04). Conversely, IFNγ intensity was associated with diminished OS (HR 0.59, p = 0.036). In multivariable analyses, adjusting for clinical variables, including age, resection extent, Karnofsky Performance Status (KPS), and MGMT methylation status, improved OS was associated with high densities of proliferating (Ki67⁺) CD8⁺ cells (HR 0.15, p < 0.001), and higher ratios of CD8⁺ cells to CD4⁺ cells (HR 0.31, p = 0.005). Diminished OS was associated with increases in patient age (HR 1.21, p = 0.005) and higher mean intensities of IFNγ (HR 2.13, p = 0.027). Conclusions: intratumoral densities of proliferating CD8 T cells and higher CD8/CD4 ratios are independent predictors of OS in patients with GBM. Paradoxically, higher mean intensities of IFNγ in the tumors were associated with shorter OS. These findings suggest that survival may be enhanced by increasing proliferation of tumor-reactive CD8⁺ T cells and that approaches may be needed to promote CD8⁺ T cell dominance in GBM, and to interfere with the immunoregulatory effects of IFNγ in the tumor microenvironment.

Radiologic-pathologic association of tumor-like lesions with inflammation in cerebral white matter: Comparison of two cases with distinct clinical outcomes

Here, we report two cases showing tumor-like white matter lesions; one case was diagnosed as having inflammatory disease, and the other was diagnosed as having astrocytoma. Their outcomes were completely distinct despite similar pathology. Prior to biopsy, perfusion computed tomography (CT) and magnetic resonance imaging (MRI) were conducted. The two mass-forming lesions were distinct in edema level and vascularity patterns on CT and MRI. However, pathological examination of brain biopsy specimens revealed commonalities, including (1) proliferation of glial cells, (2) perivascular lymphocytic infiltration, and (3) appearance of numerous macrophages. Although atypical astrocytes proliferated in both cases, nuclear atypia was more distinct in case 2 than in case 1. The immunohistochemical results were the same for both cases: isocitrate dehydrogenase 1 (IDH1) R132H mutation was negative, and alpha thalassaemia mental retardation X-linked (ATRX) was retained. Faint immunoreactivity for p53 was observed in a few glial cells, and Ki-67 immunoreactive cells were markedly reduced in numbers (< 1%). Inflammatory reactions were evident in both cases: T cells dominantly infiltrated over B cells in the perivascular area in case 1, whereas both T and B cells infiltrated in case 2. Molecular analysis revealed wild-type IDH1 and IDH2 in both cases. However, a telomerase reverse transcriptase (TERT) sequence mutation was detected in case 2 but not in case 1. Eventually, case 1 was diagnosed as having inflammatory lesions, whereas case 2 was diagnosed as having diffuse astrocytoma associated with inflammatory reactions. The prognosis was favorable for case 1, whereas case 2 died 10 months following biopsy. These data indicated the diagnostic value of molecular analysis, for example, a TERT mutation, in association with the radiological findings. Although in case 2, histopathological evidence did not suggest high-grade glioma, the case met the new diagnostic criteria: "diffuse astrocytic glioma, IDH wild-type, with molecular features of glioblastoma, World Health Organization (WHO) grade IV," according to cIMPACT-NOW, update 3. Thus, interdisciplinary approaches are essential for accurate diagnosis of newly categorized white matter diseases.

Choline Kinase Alpha Promoted Glioma Development by Activating PI3K/AKT Signaling Pathway

Objective: The most commonly reported primary brain tumor in adults is glioma. Choline kinase alpha (CHKA) has been proved to play important roles in glioma. However, the mechanism of CHKA involved remains unclear. Therefore, this study aims to explore the mechanism of CHKA in glioma development. Methods: Immunohistochemistry, qRT-PCR, and Western blot were used to detect the expression of CHKA. Flow cytometry, Cell Counting Kit-8 (CCK-8), transwell, and wound healing assays were performed to evaluate cell apoptosis, proliferation, invasion, and migration, respectively. RNA sequencing was used to explore the differentially expressed genes affected by CHKA. The enrichment analysis of gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) helped to detect the signaling pathways CHKA affected. Tumor-bearing mice were established and evaluated by TUNEL assay, Ki-67 immunohistochemistry. and hematoxylin and eosin staining. Results: CHKA increased in glioma tissues and promoted cell proliferation, invasion, and migration, while inhibiting the glioma cell apoptosis. It was also showed that CHKA promoted glioma development in vivo. GO and KEGG analysis indicated that PI3K/AKT was significantly enriched in CHKA knockdown U251 cells. And CHKA promoted glioma development by activating PI3K/AKT signaling pathway. Conclusions: The authors demonstrated that CHKA was significantly elevated in glioma tissues. Mechanism analysis indicated that CHKA could promote glioma development by activating PI3K/AKT signaling pathway, suggesting that CHKA is promising to be a biomarker and therapeutic strategy for prognostic prediction of patients with glioma.

Targeted Delivery of Liposomal Temozolomide Enhanced Anti-Glioblastoma Efficacy through Ultrasound-Mediated Blood-Brain Barrier Opening

Glioblastoma (GBM) is the commonest form of primary brain tumor in the central nervous system, with median survival below 15 months and only a 25% two-year survival rate for patients. One of the major clinical challenges in treating GBM is the presence of the blood-brain barrier (BBB), which greatly limits the availability of therapeutic drugs to the tumor. Ultrasound-mediated BBB opening provides a promising approach to help deliver drugs to brain tumors. The use of temozolomide (TMZ) in the clinical treatment of GBM has been shown to be able to increase survival in patients with GBM, but this improvement is still trivial. In this study, we developed a liposomal temozolomide formulation (TMZ-lipo) and locally delivered these nanoparticles into GBM through ultrasound-mediated BBB opening technology, significantly suppressing tumor growth and prolonging tumor-bearing animal survival. No significant side effects were observed in comparison with control rats. Our study provides a novel strategy to improve the efficacy of TMZ against GBM.

Molecular Alterations and Their Correlation With the Survival of Glioblastoma Patients With Corpus Callosum Involvement

Purpose: To explore molecular alterations and their correlation with the survival of patients with glioblastoma (GBM) with corpus callosum (CC) involvement (ccGBM).

Methods: Electronic medical records were reviewed for glioma patients tested for molecular alterations and treated at our hospital between January 2016 and July 2020. ccGBM was compared to GBM without CC involvement (non-ccGBM) to identify differences in molecular alterations. Clinical outcomes and survival were compared between ccGBM and non-ccGBM patients, as well as among patients with ccGBM with different molecular alteration statuses. ccGBM was also compared to diffuse midline glioma (DMG) to clarify their correlation in molecular alterations, the progression-free survival (PFS), and overall survival (OS).

Results: Thirty ccGBM and 88 non-ccGBM patients were included. PDGFRA amplification (PDGFRAamp, 33.3 vs. 9.1%, P = 0.004) and missense mutation (PDGFRAmut, 20.0 vs. 3.4%, P = 0.011) both had higher incidences in ccGBM than in non-ccGBM. PDGFRA alteration was associated with the occurrence of ccGBM (OR = 4.91 [95% CI: 1.55–15.52], P = 0.007). ccGBM with PDGFRAamp resulted in a shorter median PFS (8.6 vs. 13.5 months, P = 0.025) and OS (12.4 vs. 17.9 months, P = 0.022) than non-ccGBM with PDGFRAnon-amp. ccGBM with PDGFRAamp combined with PDGFRAmut (PDGFRAamp-mut) had a shorter median PFS (7.6 vs. 8.9 months, P = 0.022) and OS (9.6 vs. 17.8 months, P = 0.006) than non-ccGBM with wild-type PDGFRA and no amplification (PDGFRA-w, non-amp). Compared to ccGBM with PDGFRA-w, non-amp, ccGBM with PDGFRAamp and PDGFRAamp-mut both had a shorter median PFS and OS (P < 0.05). The hazard ratios (HRs) of PDGFRAamp for PFS and OS in ccGBM were 3.08 (95% CI: 1.02–9.35, P = 0.047) and 5.07 (1.52–16.89, P = 0.008), respectively, and the HRs of PDGFRAamp-mut for PFS and OS were 13.16 (95% CI: 3.19–54.40, P < 0.001) and 16.36 (2.66–100.70, P = 0.003). ccGBM may have similar incidences of PDGFRAamp or mut (PDGFRAamp/mut) as DMG, and they also had similar median PFS (10.9 vs. 9.0 months, P = 0.558) and OS (16.8 vs. 11.5 months, P = 0.510).

Conclusion:PDGFRA alterations are significantly associated with the occurrence and poor prognosis of ccGBM. ccGBM with PDGFRAamp/mut may be classified as a single subtype of GBM that has a similar survival rate to DMG. PDGFR inhibitors may be a promising treatment method for ccGBM.

Diagnostic Utility of Oncomine Comprehensive Assay v3 in Differentiating Between Isocitrate Dehydrogenase (IDH)-mutated Grade II-III Astrocytoma and Oligodendroglioma

BACKGROUND/AIM

The application of Oncomine Comprehensive Assay v3 (OCAv3) panel in diffuse gliomas (DGs) remains unknown. We investigated the utility of OCAv3-based next-generation sequencing (NGS) in isocitrate dehydrogenase (IDH)-mutated grade II-III DGs.

PATIENTS AND METHODS

We collected 20 tissue samples obtained from IDH-mutated grade II-III DG patients and performed OCAv3-based NGS.

RESULTS

By conventional molecular methods, the 20 DGs were classified into seven astrocytomas and 13 oligodendrogliomas. OCAv3 detected all mutations identified in these samples using the conventional methods. The results were highly corroborated by the known mutations in each group. Clustered copy number loss of genes located at the 1p and 19q loci was detected in all 13 oligodendroglioma cases, which harbor the 1p/19q codeletion.

CONCLUSION

The application of OCAv3-based NGS will improve diagnostic accuracy in DG, with the most beneficial aspects expected in detecting copy number alterations to identify the 1p/19q codeletion correctly.

Comprehensive Molecular Characterization of Chinese Patients with Glioma by Extensive Next-Generation Sequencing Panel Analysis

Background

Tremendous efforts have been made to explore biomarkers for classifying and grading glioma. However, the majority of the current understanding is based on public databases that might not accurately reflect the Asian population. Here, we investigated the genetic landscape of Chinese glioma patients using a validated multigene next-generation sequencing (NGS) panel to provide a strong rationale for the future classification and prognosis of glioma in this population.

Methods

We analyzed 83 samples, consisting of 71 initial treatments and 12 recurrent surgical tumors, from 81 Chinese patients with gliomas by performing multigene NGS with an Acornmed panel targeting 808 cancer-related hotspot genes, including genes related to glioma (hotspots, selected exons or complete coding sequences) and full-length SNPs located on chromosomes 1 and 19.

Results

A total of 76 (91.57%) glioma samples had at least one somatic mutation. The most commonly mutated genes were TP53, TERT, IDH1, PTEN, ATRX, and EGFR. Approximately one-third of cases exhibited more than one copy number variation. Of note, this study identified the amplification of genes, such as EGFR and PDGFRA, which were significantly associated with glioblastoma but had not been previously used for clinical classification (P<0.05). Significant differences in genomic profiles between different pathological subtypes and WHO grade were observed. Compared to the MSKCC database primarily comprised of Caucasians, H3F3A mutations and MET amplifications exhibited higher mutation rates, whereas TERT mutations and EGFR and CDKN2A/B copy number variations presented a lower mutation rate in Chinese patients with glioma (P<0.05).

Conclusion

Our multigene NGS in the simultaneous evaluation of multiple relevant markers revealed several novel genetic alterations in Chinese patients with glioma. NGS-based molecular analysis is a reliable and effective method for diagnosing brain tumors, assisting clinicians in evaluating additional potential therapeutic options, such as targeted therapy, for glioma patients in different racial/ethnic groups.

The Strange Case of Jekyll and Hyde: Parallels Between Neural Stem Cells and Glioblastoma-Initiating Cells

During embryonic development, radial glial precursor cells give rise to neural lineages, and a small proportion persist in the adult mammalian brain to contribute to long-term neuroplasticity. Neural stem cells (NSCs) reside in two neurogenic niches of the adult brain, the hippocampus and the subventricular zone (SVZ). NSCs in the SVZ are endowed with the defining stem cell properties of self-renewal and multipotent differentiation, which are maintained by intrinsic cellular programs, and extrinsic cellular and niche-specific interactions. In glioblastoma, the most aggressive primary malignant brain cancer, a subpopulation of cells termed glioblastoma stem cells (GSCs) exhibit similar stem-like properties. While there is an extensive overlap between NSCs and GSCs in function, distinct genetic profiles, transcriptional programs, and external environmental cues influence their divergent behavior. This review highlights the similarities and differences between GSCs and SVZ NSCs in terms of their gene expression, regulatory molecular pathways, niche organization, metabolic programs, and current therapies designed to exploit these differences.

Establishment and Preliminary Characterization of Three Astrocytic Cells Lines Obtained from Primary Rat Astrocytes by Sub-Cloning

Gliomas are complex and heterogeneous tumors that originate from the glial cells of the brain. The malignant cells undergo deep modifications of their metabolism, and acquire the capacity to invade the brain parenchyma and to induce epigenetic modifications in the other brain cell types. In spite of the efforts made to define the pathology at the molecular level, and to set novel approaches to reach the infiltrating cells, gliomas are still fatal. In order to gain a better knowledge of the cellular events that accompany astrocyte transformation, we developed three increasingly transformed astrocyte cell lines, starting from primary rat cortical astrocytes, and analyzed them at the cytogenetic and epigenetic level. In parallel, we also studied the expression of the differentiation-related H1.0 linker histone variant to evaluate its possible modification in relation with transformation. We found that the most modified astrocytes (A-FC6) have epigenetic and chromosomal alterations typical of cancer, and that the other two clones (A-GS1 and A-VV5) have intermediate properties. Surprisingly, the differentiation-specific somatic histone H1.0 steadily increases from the normal astrocytes to the most transformed ones. As a whole, our results suggest that these three cell lines, together with the starting primary cells, constitute a potential model for studying glioma development.

Beyond IDH-Mutation: Emerging Molecular Diagnostic and Prognostic Features in Adult Diffuse Gliomas

Diffuse gliomas are among the most common adult central nervous system tumors with an annual incidence of more than 16,000 cases in the United States. Until very recently, the diagnosis of these tumors was based solely on morphologic features, however, with the publication of the WHO Classification of Tumours of the Central Nervous System, revised 4th edition in 2016, certain molecular features are now included in the official diagnostic and grading system. One of the most significant of these changes has been the division of adult astrocytomas into IDH-wildtype and IDH-mutant categories in addition to histologic grade as part of the main-line diagnosis, although a great deal of heterogeneity in the clinical outcome still remains to be explained within these categories. Since then, numerous groups have been working to identify additional biomarkers and prognostic factors in diffuse gliomas to help further stratify these tumors in hopes of producing a more complete grading system, as well as understanding the underlying biology that results in differing outcomes. The field of neuro-oncology is currently in the midst of a "molecular revolution" in which increasing emphasis is being placed on genetic and epigenetic features driving current diagnostic, prognostic, and predictive considerations. In this review, we focus on recent advances in adult diffuse glioma biomarkers and prognostic factors and summarize the state of the field.