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Background and Aim: Glioblastoma (GBM) is the most common and aggressive form of primary malignant brain tumors. Phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit delta (PIK3CD), which is overexpressed in GBM, is involved in GBM pathogenesis and drug resistance. However, the molecular mechanism by which PIK3CD drives its transcriptional program toward GBM favors remains elusive. Materials and Methods: Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) and CRISPR-associated 9 technology was used to knock-out (KO) PIK3CD gene, and comprehensive RNAseq analysis was performed to investigate the underlying role of PIK3CD in GBM. Results: To minimize the off-target effects, two KO cell clones were used, and our data showed that PIK3CD KO altered the expression 306 genes in both KO cell clones compared with the parent U87 cell line. Gene set enrichment analysis revealed that genes involved in epithelial-mesenchymal (MES) transition-related biological processes were highly depressed in both KO cell clones in a similar fashion, suggesting PIK3CD's involvement in MES transformation/transition in GBM. Comprehensive pathway analysis by three different platforms confirmed that PIK3CD exerted its oncogenic function in GBM through phosphatidylinositol 3-kinase (PI3K)-Akt signaling pathway. In addition, other signaling pathways (integrin, cadherin, Wnt, and inflammation mediated by chemokine and cytokine signaling pathways) were found decreased in the KO cell clones. Further, The Cancer Genomic Atlas (TCGA) analysis of our PI3K-Akt pathway-related genes showed a similar pattern of expression. Conclusion: PIK3CD is involved in GBM pathogenesis, and this action probably mediated through the PI3K-Akt signaling pathway.

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Recent advances in genetic and molecular characterization of telomere maintenance mechanisms (TMMs) highlighted their strong relationship with cancer pathogenesis; neoplastic cells rely on two mechanisms to maintain telomere length and escape from replicative senescence: (a) reactivation of telomerase expression and (b) activation of alternative lengthening of telomere (ALT). Our aims are to describe the role of telomere maintenance in the context of recently published literature regarding pediatric brain cancers and to discuss the emerging therapeutic strategies to target telomerase-positive and ALT-positive tumors. In this review, we illustrate the incidence of TMM via telomerase or ALT and discuss the importance of analyzing telomere length and ALT-associated genetic alterations in certain histological/molecular subtypes of pediatric brain tumors, as potential therapeutic biomarkers. Telomerase-dependent TMM is a common mechanism in SHH-medulloblastomas and ependymomas, which could potentially benefit from antitelomerase therapies, while ALT-dependent TMM is more frequently activated in α-thalassemia/mental retardation syndrome X-linked/H3.3-mutated pediatric high-grade gliomas, metastatic medulloblastomas, and choroid plexus tumors, which could potentially be treated with ALT-targeted drugs. Conversely, pediatric low-grade gliomas lack both mechanisms of telomere maintenance, and anti-TMM therapies do not appear to be a promising strategy for these tumors.

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As theories evolve, the mechanism of glioma origination remains poorly understood. Understanding this mechanism promotes the clinical research on glioma therapeutic strategy and then improves the prognosis of patients with glioma. However, the overall survival of these patients is unsatisfactory. In the recent decade, a few novel therapies, such as tumor-treating fields and immunotherapy, have been introduced in clinic. Before they can be widely used, many key factors, including efficacy, safety, and benefit ratio, should be fully evaluated. Therefore, more clinical trials are required to corroborate the results and conclusions of basic research and improve the current treatment strategies. In this article, we searched relevant literature published in the past 5 years in PubMed and China National Knowledge Infrastructure and reviewed the advancements of clinical therapeutic research on glioma.

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Diffuse low-grade gliomas are a diverse category of neuroepithelial neoplasms, which are characterized by a low proliferation index and an indolent course with a long-term survival in comparison with high-grade gliomas. It is convinced that maximal safe resection can significantly increase survival. Multiple intraoperative techniques help neurosurgeons to maximize the resection with a safe range; however, the tumors involving motor areas are still intractable for many surgeons who believe that these tumors are unresectable. We searched on PubMed database and summarized studies and reviews about diffuse low-grade gliomas within/near motor areas. Moreover, studies about anatomy about motor area were also reviewed. In this article, we discussed the anatomy of the central lobe and supplementary motor area, including the cortex, subcortical fibers, and relevant vessels, as well as the technical details of awake craniotomy and direct electrical stimulation. At last, combined with some cases, we try to demonstrate that tumors within/near motor areas are resectable, which may cause only mild neurological deficits using awake craniotomy with intraoperative monitoring by cortical/subcortical mapping, and, furthermore, it provides a longer and better survival for those young patients.

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We reported a case of awake surgery for the left frontal low-grade glioma and reviewed the literature on the strategy of awake surgical resection for glioma. The eloquent cerebral areas that are involved in motor, language, memory, and visuospatial functions, which have to be preserved during surgery, is identified through intraoperative use of brain mapping techniques. This technique of combining intraoperative ultrasound and neuronavigation enabled extension of the surgical indications and improved the extent of resection, while minimizing postoperative morbidity and safeguarding the patient's quality of life. This work was approved by the Institutional Review Board of Tangdu Hospital, Fourth Military Medical University, China.

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Medulloblastoma is one of the most common pediatric malignant brain tumors. Its understanding and treatment have advanced rapidly over the decade, with the identification of four distinct molecular groups. In contrast, adult medulloblastoma is a rare entity that accounts for <1% of adult central nervous system tumors, and is understudied in both its genetic landscape and clinical management. Adult medulloblastomas demonstrate many differences from pediatric medulloblastomas that are relevant to clinicians and biologists. Unlike its pediatric counterpart, adult medulloblastomas are typically located laterally in the cerebellum, are seldom metastatic, and commonly relapse beyond 5 years. The distribution and survival outcomes of molecular groups in adult medulloblastoma differ from those in pediatric medulloblastoma, with the sonic hedgehog-activated group being the predominant and most well-studied group in adults. Adult medulloblastomas also exhibit cytogenetic and mutational characteristics unique to this age group, such as the high frequency of telomerase reverse transcriptase promoter mutations and the paucity of MYC and MYCN amplifications. Clinical trials for adult medulloblastoma need to take into account the clinical and biological differences between adult and pediatric medulloblastomas, for example through the use of smoothened inhibitors in adult SHH medulloblastomas to lower the toxicities resulting from direct adoption of pediatric chemotherapeutic regimens. This review summarizes the clinical characteristics, molecular groups, genetic features, and treatment of adult medulloblastoma, with a focus on its differences from pediatric medulloblastoma.

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Hypoxia is a powerful driver of the malignant phenotype in solid tumors including gliomas. A major, though not sole, driver of this effect is the hypoxia-inducible factors (HIF) which promote the expression of hundreds of downstream genes through binding with hypoxia-responsive elements in the promoter regions of targeted genes. HIF-2α drives the cancer stem cell phenotype that has been shown to promote chemo- and radioresistance. HIF-1α drives the transcription of a number of genes, the most prolific and important of which appears to be that of CAIX, but also drives the transcription of VEGF and a number of glycolytic enzymes, thus participating in driving the Warburg effect. This brief review introduces how the localization of CAIX by immunohistochemistry has, though still in its early phases, allowed the identification of gliomas with worse prognosis, an application of significant importance in diagnostic neuropathology. The future of hypoxia research will manipulate these downstream pathways to provide further biomarkers through which the presence of hypoxia and its effects can be established, analyzed, and exploited.

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