Malignant brainstem gliomas in adults: clinicopathological characteristics and prognostic factors

Clinical characteristics and prognostic factors of adult brainstem gliomas: A retrospective analysis of histologically-proven 40 cases

To illustrate the clinical characteristics and prognostic factors of adult patients pathologically confirmed with brainstem gliomas (BSGs). Clinical data of 40 adult patients pathologically diagnosed with BSGs admitted to Beijing Shijitan Hospital from 2009 to 2022 were recorded and retrospectively analyzed. The primary parameters included relevant symptoms, duration of symptoms, Karnofsky performance status (KPS), tumor location, type of surgical resection, diagnosis, treatment, and survival. Univariate and multivariate analyses were evaluated by Cox regression models. The gliomas were located in the midbrain of 9 patients, in the pons of 14 cases, in the medulla of 5 cases, in the midbrain and pons of 6 cases and invading the medulla and pons of 6 cases, respectively. The proportion of patients with low-grade BSGs was 42.5%. Relevant symptoms consisted of visual disturbance, facial paralysis, dizziness, extremity weakness, ataxia, paresthesia, headache, bucking, dysphagia, dysacousia, nausea, dysphasia, dysosmia, hypomnesia and nystagmus. 23 (57.5%) patients accepted stereotactic biopsy, 17 (42.5%) patients underwent surgical resection. 39 patients received radiotherapy and 34 cases were treated with temozolomide. The median overall survival (OS) of all patients was 26.2 months and 21.5 months for the median progression-free survival (PFS). Both duration of symptoms (P = .007) and tumor grading (P = .002) were the influencing factors for OS, and tumor grading was significantly associated with PFS (P = .001). Duration of symptoms for more than 2 months and low-grade are favorable prognostic factors for adult patients with BSGs.

Decoding the puzzle: A multidisciplinary systematic review of adult brainstem glioma

Adult brainstem gliomas (BSGs) are a group of rare central nervous system tumors with varying prognoses and controversial standard treatment strategies. To provide an overview of current trends, a systematic review using the PRISMA guidelines, Class of evidence (CE) and strength of recommendation (SR), was conducted. The review identified 27 studies. Surgery was found to have a positive impact on survival, particularly for focal lesions with CE II SR C. Stereotactic image-guided biopsy was recommended when resective surgery was not feasible with CE II and SR B. The role of systemic treatments remains unclear. Eight studies provided molecular biology data. This review gathers crucial literature on diagnosis and management of adult BSGs. It provides evidence-based guidance with updated recommendations for diagnosing and treating, taking into account recent molecular and genetic advancements. The importance of brain biopsy is emphasized to optimize treatment using emerging genetic-molecular findings and explore potential targeted therapies.

NTMS based tractography and segmental diffusion analysis in patients with brainstem gliomas: Risk stratification and clinical potential

Introduction

Surgery on the brainstem level is associated with a high-risk of postoperative morbidity. Recently, we have introduced the combination of navigated transcranial magnetic stimulation (nTMS) and diffusion tensor imaging (DTI) tractography to define functionally relevant motor fibers tracts on the brainstem level to support operative planning and risk stratification in brainstem cavernomas.

Research question

Evaluate this method and assess it's clinical impact for the surgery of brainstem gliomas.

Material and methods

Patients with brainstem gliomas were examined preoperatively with motor nTMS and DTI tractography. A fractional anisotropy (FA) value of 75% of the individual FA threshold (FAT) was used to track descending corticospinal (CST) and -bulbar tracts (CBT). The distance between the tumor and the somatotopic tracts (hand, leg, face) was measured and diffusion parameters were correlated to the patients' outcome.

Results

12 patients were enrolled in this study, of which 6 underwent surgical resection, 5 received a stereotactic biopsy and 1 patient received conservative treatment. In all patients nTMS mapping and somatotopic tractography were performed successfully. Low FA values correlated with clinical symptoms revealing tract alteration by the tumor (p = 0.049). A tumor-tract distance (TTD) above 2 mm was the critical limit to achieve a safe complete tumor resection.

Discussion and conclusion

nTMS based DTI tractography combined with local diffusion analysis is a valuable tool for preoperative visualization and functional assessment of relevant motor fiber tracts, improving planning of safe entry corridors and perioperative risk stratification in brainstem gliomas tumors. This technique allows for customized treatment strategy to maximize patients' safety.

Surgical Management of Adult Brainstem Gliomas: A Systematic Review and Meta-Analysis

The present review aims to investigate the survival and functional outcomes in adult high-grade brainstem gliomas (BGSs) by comparing data from resective surgery and biopsy. MEDLINE, EMBASE and Cochrane Library were screened to conduct a systematic review of the literature, according to the PRISMA statement. Analysis was limited to articles including patients older than 18 years of age and those published from 1990 to September 2022. Case reports, review articles, meta-analyses, abstracts, reports of aggregated data, and reports on multimodal therapy where surgery was not the primary treatment were excluded. The ROBINS-I tool was applied to evaluate the risk of bias. Six studies were ultimately considered for the meta-analysis. The resective group was composed of 213 subjects and the bioptic group comprised 125. The analysis demonstrated a survival benefit in those patients in which an extensive resection was possible (STR HR 0.59 (95% CI 0.42, 0.82)) (GTR HR 0.63 (95% CI 0.43, 0.92)). Although surgical resection is associated with increased survival, the significantly higher complication rate makes it difficult to recommend surgery instead of biopsy for BSGs. Future investigations combining volumetric data and molecular profiles could add important data to better define the proper indication between resection and biopsy.

Adult Brainstem Astroblastoma: Unusual Presentation of a Rare Tumor

Astroblastoma is a rare tumor, which is mostly found in pediatric population. Due to scarcity of literature, the data about treatment is lacking. We are reporting case of brainstem astroblastoma in an adult female. A 45-year-old lady presented with complaint of headache, vertigo, vomiting, and nasal regurgitation for 3 months. On examination, she had weak gag, left hemiparesis. Magnetic resonance imaging brain reported medulla oblongata mass, dorsally exophytic. She underwent suboccipital craniotomy and decompression of mass. Histopathology confirmed diagnosis of astroblastoma. She underwent radiotherapy and recovered well. Brainstem astroblastoma is an extremely rare entity. The surgical resection is possible due to well-defined plane. For best outcome, maximum resection and radiation are indicated.

The location of estrogen receptor variant ER-α36 is associated with the invasion of glioblastoma

Glioblastoma (GBM) is the most common central nervous system tumor and is associated with poor outcomes. There have been no significant improvements in GBM mortality in recent decades. ER-α36 is a variant of ER-α66 that may be involved in carcinoma growth and proliferation via genomic and nongenomic mechanisms. This variant might play an essential role in tamoxifen resistance of several tumors. Previously, our laboratory found that ER-α36 is expressed in GBM and participates in proliferation; nevertheless, the role of ER-α36 in GBM invasion remains unknown. This study aimed to determine the effects of the ER-α36 modulator SNG162 on GBM growth and invasion. U251 cells, U87cells, and U87-36KD cells with knockdown of ER-α36 expression were cultured under the two-dimensional and the three-dimensional (3D) environments. GBM cells growth was examined by cell counting, flow cytometry, western blot, and MTT assays. Invasiveness was measured using confocal microscopy in the 3D environment. Growth of U87 cells with downregulated EGFR and ER-α36 expression was significantly reduced after treatment with 1 µM, 3 µM, and 5 µM of SNG162; growth inhibition in U251 cells was more potent than in U87 cells, although the expression level of ER-α36 in U251 cells was lower than in U87 cells. We found that 1 μM SNG162 suppressed E₂-induced MAPK/ERK pathway activation in U87 cells. We also showed that SNG162 inhibited U87 cells invasion; however, it did not significantly affect U251 and U87-36KD cells invasion using the 3D culture method. Finally, we determined that ER-α36 was expressed in the nucleus of invading GBM cells, and SNG162 significantly inhibited the expression of ER-α36 in these cells. SNG162 inhibited the expression of EGFR on cell membranes of non-invasive GBM cells. These results suggest that SNG162 could be a therapeutic agent for GBM by targeting ER-α36.

Adult diffuse intrinsic pontine glioma: clinical, radiological, pathological, molecular features, and treatments of 96 patients

OBJECTIVE

Unlike its pediatric counterpart, adult diffuse intrinsic pontine glioma (DIPG) remains largely unelucidated. In this study, the authors examined the clinical, radiological, pathological, molecular, and clinical aspects of 96 adult DIPGs.

METHODS

The National Brain Tumor Registry of China (April 2013-December 2019) was used to collect data on radiologically diagnosed adult DIPG patients. Survival analysis was conducted using Kaplan-Meier curves and univariate and multivariate Cox regression. The chi-square test/Wilcoxon rank-sum test and multivariable logistic regression were used to examine the clinical and radiological characteristics of patients with long-term survival (LTS). Interaction analyses between clinical factors were also conducted.

RESULTS

The median age at symptom onset was 33.5 years, and the median duration of symptoms was 4.5 months. The frequencies of H3K27M and IDH1 mutations were 37.2% and 26.5%, respectively. All adult DIPG patients had a median overall survival (OS) of 19.5 months, with 1-, 2-, and 3-year survival rates of 67.0%, 42.8%, and 36.0%, respectively. The median OS of 40 patients who did not undergo treatment was 13.4 months. Patients with H3K27M-mutant tumors had a poorer prognosis than those with IDH-mutant tumors (p < 0.001) and H3K27M(-)/IDH-wild-type tumors (p = 0.002), with a median OS of 11.4 months. The median OSs of patients with H3K27M-mutant tumors who received treatment and those who did not were 13.8 months and 7.5 months, respectively (p = 0.016). Among patients with and without a pathological diagnosis, H3K27M mutation (p < 0.001) and contrast enhancement on MRI (p = 0.003), respectively, imparted a worse prognosis. Treatments were the predictive factor for patients with H3K27M-mutant tumors (p = 0.038), whereas contrast enhancement on MRI was the prognostic factor for the H3K27M(-) group (p = 0.038). In addition, H3K27M mutation and treatment were significant predictors for patients with symptom duration ≤ 4 months (H3K27M, p = 0.020; treatment, p = 0.014) and tumors with no contrast enhancement (H3K27M, p = 0.003; treatment, p = 0.042). Patients with LTS were less likely to have cranial nerve palsy (p = 0.002) and contrast enhancement on MRI at diagnosis (p = 0.022).

CONCLUSIONS

It is recommended that all adult DIPG patients undergo genomic testing for H3K27M and IDH mutations. Despite the low prevalence, additional study is needed to better characterize the efficacy of various treatment modalities in adults with DIPG.

Prognostic factors in adult brainstem glioma: a tertiary care center analysis and review of the literature

Introduction

Adult brainstem gliomas (BSGs) are rare central nervous system tumours characterized by a highly heterogeneous clinical course. Median survival times range from 11 to 84 months. Beyond surgery, no treatment standard has been established. We investigated clinical and radiological data to assess prognostic features providing support for treatment decisions.

Methods

34 BSG patients treated between 2000 and 2019 and aged ≥ 18 years at the time of diagnosis were retrospectively identified from the databases of the two largest Austrian Neuro-Oncology centres. Clinical data including baseline characteristics, clinical disease course, applied therapies, the outcome as well as neuroradiological and neuropathological findings were gathered and analysed. The tumour apparent diffusion coefficient (ADC), volumetry of contrast-enhancing and non-contrast-enhancing lesions were determined on magnetic resonance imaging scans performed at diagnosis.

Results

The median age at diagnosis was 38.5 years (range 18–71 years). Tumour progression occurred in 26/34 (76.5%) patients after a median follow up time of 19 months (range 0.9–236.2). Median overall survival (OS) and progression-free survival (PFS) was 24.1 months (range 0.9–236.2; 95% CI 18.1–30.1) and 14.5 months (range 0.7–178.5; 95% CI 5.1–23.9), respectively. Low-performance status, high body mass index (BMI) at diagnosis and WHO grading were associated with shorter PFS and OS at univariate analysis (p < 0.05, log rank test, respectively). ADC values below the median were significantly associated with shorter OS (14.9 vs 44.2 months, p = 0.018).

Conclusion

ECOG, BMI, WHO grade and ADC values were associated with the survival prognosis of BSG patients and should be included in the prognostic assessment.

The many faces of glioblastoma: Pictorial review of atypical imaging features

Glioblastoma is an aggressive primary central nervous system tumour that usually has a poor prognosis. Generally, the typical imaging features are easily recognisable, but the behaviour of glioblastoma multiforme (GBM) can often be unusual. Several variations and heterogeneity in GBM appearance have been known to occur. In this pictorial essay, we present cases of pathologically confirmed GBM that illustrate unusual locations and atypical features on neuroimaging, and review the relevant literature. Even innocuous-looking foci, cystic lesions, meningeal-based pathology, intraventricular and infra-tentorial masses, multifocal/multicentric lesions and spinal cord abnormalities may represent GBM. We aim to highlight the atypical characteristics of glioblastoma, clarify their importance and list the potential mimickers. Although a definitive diagnosis in these rare cases of GBM warrants histopathological confirmation, an overview of the many imaging aspects may help make an early diagnosis.

Clinical and Genetic Features of Brainstem Glioma in Adults: A Report of 50 Cases in a Single Center

Background and Purpose

Brainstem gliomas (BSGs) in adults are rare brain tumors with dismal outcomes. The aim of this study was to determine the clinical and genetic features in a series of BSGs and their association with the prognosis.

Methods

Fifty patients who underwent a stereotactic biopsy between January 2016 and April 2018 at a single institution were collected. Data on clinicopathological characteristics were analyzed and factors associated with patient survival were identified using a Cox regression model.

Results

The median age at diagnosis was 55.5 years, and 62% of the patients were male. Glioblastoma (44%) accounted for the largest proportion of BSGs, and oligodendroglioma (2 of 50) was rarely encountered. The IDH mutation (6 of 44) occurred infrequently in astrocytomas, and IDH-mutant tumors harbored both ATRX loss and MGMT promoter methylation at a relatively low level. Wild-type IDH astrocytomas were identified as having high rates of 1p/19q codeletion (5 of 38) and loss of heterozygosity 1p (8 of 38) or 19q (8 of 38) only. In diffuse midline glioma H3K27M mutant, MGMT promoter methylation occurred in three of four cases. Patients were offered radiotherapy and/or concurrent/adjuvant temozolomide chemotherapy, and their median survival time was 13 months. Multivariate analysis revealed that a low tumor grade, absence of tumor enhancement, duration of symptoms ≥3 months, Karnofsky performance status ≥70, and ATRX loss conferred a survival advantage.

Conclusions

Adult BSGs showed different molecular genetic characteristics, but also resembled supratentorial gliomas in their clinical features associated with oncological outcomes.

The Surgical Resection of Brainstem Glioma: Outcomes and Prognostic Factors

BACKGROUND

The management of brainstem glioma remains controversial, with increasing evidence supporting surgical resection as the primary treatment for a select subgroup of tumors. However, there remains no consensus on the specific benefits and risks, the selection of surgical candidates, and prognostic factors that may further refine surgical indications.

METHODS

A retrospective single-surgeon chart review was performed for all patients who underwent surgical treatment for radiographically suspected brainstem glioma between 2000 and 2017. Preoperative and postoperative radiographic evaluations on magnetic resonance imaging were conducted. Survival outcomes were collected, and machine-learning techniques were used for multivariate analysis.

RESULTS

Seventy-seven patients with surgical treatment of brainstem glioma were identified, with a median age of 9 years (range, 0-58 years). The cohort included 64% low-grade (I and II) and 36% high-grade (III and IV) tumors. For all patients, the 1-year and 5-year overall survival were 76.4% and 62.3%, respectively. Transient neurologic deficit was present in 34% of cases, and permanent deficit in a further 29%.

CONCLUSIONS

The radical surgical resection of brainstem gliomas can be performed with acceptable risk in well-selected cases and likely confers survival advantage for what is otherwise a rapidly and universally fatal disease. Various radiographic features are useful during patient selection and may guide treatment selection.

Knockdown of DEPDC1B inhibits the development of glioblastoma

Background

Glioblastoma (GBM) is the most common primary malignant brain tumor in adults with a poor prognosis. DEPDC1B (DEP domain-containing protein 1B) has been shown to be associated with some types of malignancies. However, the role and underlying regulatory mechanisms of DEPDC1B in GBM remain elusive.

Methods

In this research, the expression level of DEPDC1B in GBM tissues was detected by IHC. The DEPDC1B knockdown cell line was constructed, identified by qRT-PCR and western blot and used to construct the xenotransplantation mice model and intracranial xenograft model. MTT assay, colony formation assay, flow cytometry, and Transwell assay were used to detected cell proliferation, apoptosis and migration.

Results

The results proved that DEPDC1B was significantly upregulated in tumor tissues, and silencing DEPDC1B could inhibit proliferation, migration and promote apoptosis of GBM cell. In addition, human apoptosis antibody array detection showed that after DEPDC1B knockdown, the expression of apoptosis-related proteins was downregulated, such as IGFBP-2, Survivin, N-cadherin, Vimentin and Snail. Finally, we indicated that knockdown of DEPDC1B significantly inhibited tumor growth in vivo.

Conclusions

In summary, DEPDC1B was involved in the development and progression of GBM, which may be a potential therapeutic target and bring a breakthrough in the treatment.

Long intergenic non-coding LINC00657 regulates tumorigenesis of glioblastoma by acting as a molecular sponge of miR-190a-3p

To detect the aberrantly expressed long non-coding RNAs in glioblastoma, two pairs of glioblastoma and adjacent normal tissues were firstly analyzed by RNA sequencing. Long intergenic non-coding RNA LINC00657 was considered to play a vital role in glioblastoma based on the results of RNA sequencing. Hence, we aimed to investigate the mechanisms by which LINC00657 regulated the tumorigenesis of glioblastoma. The level of LINC00657 in 40 glioblastoma samples and glioblastoma cell lines was detected by RT-qPCR. LINC00657 was significantly decreased in patients with glioblastoma compared with adjacent normal tissues. Overexpression of LINC00657 inhibited proliferation, colony formation, invasion and migration in glioma cells via inducing apoptosis. Dual luciferase report assay indicated LINC00657 was the target of miR-190a-3p. Overexpression of LINC00657 greatly inhibited the relative amount of miR-190a-3p. Besides, miR-190a-3p was found to be a negative regulator of PTEN. Additionally, active-caspase 3 was increased in cells transfected with pcDNA3.1-LINC00657. Finally, in vitro results were further confirmed by in vivo studies using nude mice bearing with glioblastoma tumors. In conclusion, LINC00657 was effective in inhibiting glioblastoma by acting as a molecular sponge of miR-190a-3p to regulate PTEN expression. Therefore, targeting LINC00657 may serve as a potential strategy for the treatment of patients with glioblastoma.

Association between extent of resection on survival in adult brainstem high-grade glioma patients

BACKGROUND

Brainstem high-grade gliomas (HGG) are rare lesions with aggressive behavior that pose significant treatment challenges. The operative use of brainstem safe entry zones has made such lesions surgically accessible, though the benefits of aggressive resection have been unclear. This study aimed to clarify the survival in adult patients.

METHODS

We utilized the SEER database (1973-2015) to analyze the association between survival and demographic data, tumor characteristics, and treatment factors in adult patients with brainstem HGGs. Patients without surgical intervention were excluded. Overall survival (OS) was analyzed using univariable and multivariable Cox regression.

RESULTS

Our dataset included a total of 502 brainstem HGG patients of which only those who had undergone surgical intervention were included in the analysis, totaling 103. Mean age was 42.4 ± 14.1 years with 57.2% (n = 59) male. Median OS of the entire cohort was 11.0 months. Median OS for patients receiving biopsy, subtotal resection, and gross total resection were 8, 11, and 16 months, respectively. Age, extent of resection, and radiation therapy were selected into the multivariable model. A significant decrease in survival was seen in older patients, 50-60 years (HR = 2.77, p = 0.002) and ≥ 60 years (HR = 5.30, p < 0.001), compared to younger patients (18-30 years). Partial resection (HR = 0.32, p = 0.006) and GTR (HR = 0.24, p < 0.001) sustained survival benefits compared to patients with biopsy only. Patients receiving postoperative radiation demonstrated no survival benefit (HR = 1.57, p = 0.161) in multivariable regression.

CONCLUSIONS

While survival of brainstem HGG patients remains poor, for surgically accessible HGGs, STR and GTR were associated with a three and fourfold increase in overall survival when compared to biopsy only.

circ_0001730 promotes proliferation and invasion via the miR-326/Wnt7B axis in glioma cells

Aim: To study the role of circRNA (circ_0001730) in glioblastoma. Materials & methods: The interaction between circ_0001730 and miR-326 was confirmed by FISH, RNA pull down, RNA-binding protein immunoprecipitation and luciferase reporter assays. Cell proliferation and growth were determined by MTT, EdU and colony formation assays. Cell migration was assessed by the Boyden assay. Results: The levels of circ_0001730 were elevated in glioblastoma cell lines and tissues. circ_0001730 downregulation suppressed migration and proliferation in glioblastoma cells. SP1 bounds to the promoter of circ_0001730 host gene EPHB4 thereby increasing the expression of circ_0001730. circ_0001730 activated the Wnt/β-catenin pathway via the miR-326/Wnt7B axis. Conclusion: circ_000173 promoted growth and invasion in glioblastoma cells via the miR-326/Wnt7B axis.

High frequency of H3K27M immunopositivity in adult thalamic glioblastoma

Adult thalamic glioblastomas (GBM) are uncommon tumors with limited available molecular data. One of the reported molecular alterations in these tumors is the H3K27M mutation. It has been documented that H3K27M mutation is found in a high proportion of pediatric thalamic gliomas. In this study, we have analyzed the molecular alterations exclusive to adult thalamic GBM. This is a 6 years retrospective study of adult thalamic GBM patients who underwent surgical decompression of the tumor. Clinical data were obtained from the case records. Immunohistochemistry (IHC) was performed on the tumors using antibodies directed against the gene products of R132H mutant isocitrate dehydrogenase 1 (IDH1), alpha-thalassemia/mental retardation X-linked (ATRX), p53, H3K27M, H3K27me3, and V600E mutant BRAF. Molecular analyses were carried out to detect other IDH1 and IDH2 mutations, O⁶ -methylguanine-DNA-methyltransferase gene (MGMT) promoter methylation, and epidermal growth factor gene (EGFR) and telomerase reverse transcriptase gene (TERT) promoter mutations. A total of 42 cases of adult thalamic GBM were studied. The mean age of presentation was 42 years with age range of 19-58 years. Male predominance was noted. All the tumors were IDH wild-type, BRAF (V600E)-immunonegative and unmethylated for MGMT promoter. H3K27M immunopositivity was noted in 60% of tumors. Of these 33.3% were from older adults above the age of 50 years. Of the H3K27M-immunopositive cases, ATRX loss of expression was seen in 32%, p53 immunopositivity in 24% and EGFR amplification in 12%. Higher frequency of TERT promoter mutations was noted in H3K27M-immunonegative cases (58.8%) compared to immunopositive cases (20%). Ours is one of the few studies elucidating the molecular alterations exclusive to adult thalamic GBM. We show a high frequency of H3K27M immunopositivity, suggestive of its mutational status in these tumors, including in older adults.

Clinical Efficacy of CyberKnife Radiosurgery for Adult Brainstem Glioma: 10 Years Experience at Tianjin CyberKnife Center and Review of the Literature

Background: Brainstem glioma is a rare brain tumor with poor prognosis and difficulty for surgical resection. We sought to retrospectively analyze and evaluate the clinical efficacy of CyberKnife for brainstem gliomas.

Methods: From 2006 to 2015, a total of 21 brainstem gliomas patients who received CyberKnife radiosurgery treatment enrolled in this study and 18 patients with follow up. CyberKnife image-guided radiosurgical system were applied consecutively with the median prescribed total dose of 26 Gy (14–33 Gy) at two to six fractions on days utilizing CyberKnife system, and the median biological equivalent doses of 59.8 Gy (33.6–76.56 Gy). The clinic pathlogical features, survival were analyzed to explore the efficacy of CyberKnife radiosurgery in treatment of brainstem glioma.

Results: With median follow-up of 54.5 months, patients with brainstem gliomas had median overall survival of 19 months, five patients still alive. The primary endpoints of the 1- and 2-year overall survival rates were 87.5 and 52.4%, respectively. During the treatment course, six patients were observed to have pseudoprogression with mass effect on MRI. Four patients developed radiation complications. Grade 2 radiation-related toxicity were observed in three patients and one patient with grade 3.

Conclusion: The efficacy of brainstem gliomas—treated with CyberKnife is efficacious with mild toxicity.

Treatment of adult brainstem glioma with combined antiangiogenic therapy: a case report and literature review

Adult brainstem gliomas belong to a rare and heterogeneous group of brain tumors. The overall prognosis is poor; therapeutic options are limited, given the resistance to radiotherapy and the unclear role of chemotherapy/antiangiogenic therapy. Apatinib, a tyrosine kinase inhibitor that selectively inhibits the vascular endothelial growth factor receptor and mildly inhibits c-Kit, PDGFR-β, RET, and c-SRC, has been reported to show efficacy among some patients with malignant supratentorial gliomas. However, its effect on brainstem glioma has not been reported so far. Herein, a 66-year-old man with brainstem anaplastic astrocytoma isocitrate dehydrogenase (IDH) wild type was treated initially with combined radiotherapy, temozolomide, and apatinib. The patient achieved a complete response by MRI and continues to have an ongoing progression-free survival of over 8 months. To our knowledge, this is the first case report using apatinib to treat brainstem IDH wild-type anaplastic astrocytoma, displaying an excellent outcome. We also summarize cases of adult brainstem glioma treated with antiangiogenic therapy. Experiences using various regimens may improve understanding of this rare disease, and thus help physicians to seek more effective treatments for these patients.

Surgical treatment and prognosis of adult patients with brainstem gliomas

The paper presents 47 adult patients who were surgically treated due to brainstem gliomas. Thirteen patients presented with contrast-enhancing Grades III and IV gliomas, according to the WHO classification, 13 patients with contrast-enhancing tumours originating from the glial cells (Grade I; WHO classification), 9 patients with diffuse gliomas, 5 patients with tectal brainstem gliomas and 7 patients with exophytic brainstem gliomas. During the surgical procedure, neuronavigation and the diffusion tensor tractography (DTI) of the corticospinal tract were used with the examination of motor evoked potentials (MEPs) and somatosensory evoked potentials (SSEPs) with direct stimulation of the fundus of the fourth brain ventricle in order to define the localization of the nuclei of nerves VII, IX, X and XII. Cerebellar dysfunction, damage to cranial nerves and dysphagia were the most frequent postoperative sequelae which were also the most difficult to resolve. The Karnofsky score established preoperatively and the extent of tumour resection were the factors affecting the prognosis. The mean time of progression-free survival (14 months) and the mean survival time after surgery (20 months) were the shortest for malignant brainstem gliomas. In the group with tectal brainstem gliomas, no cases of progression were found and none of the patients died during the follow-up. Some patients were professionally active. Partial resection of diffuse brainstem gliomas did not prolong the mean survival above 5 years. However, some patients survived over 5 years in good condition.

Long noncoding RNA DANCR mediates cisplatin resistance in glioma cells via activating AXL/PI3K/Akt/NF-κB signaling pathway

Malignant glioma is an aggressive type of brain tumor with poor prognosis and mostly incurable. Although cisplatin is used for adjuvant chemotherapy against glioma, intrinsic and acquired resistance restricts the application of cisplatin. Long noncoding RNA (lncRNA) DANCR is reported to regulate the differentiation and progression of several cancers. However, whether DANCR participates in cisplatin resistance of glioma is still unknown. In this study, we found that DANCR expression was negatively correlated with cisplatin sensitivity in glioma cells. Gain-of and loss-of function assays revealed that DNACR attenuated cisplatin-induced cell proliferation inhibition in vitro and xenograft growth suppression in vivo. Furthermore, DNACR also attenuated cisplatin-induced cell apoptosis in vitro and in vivo. Mechanistically, we found that DANCR upregulated AXL via competitively binding miR-33a-5p, miR-33b-5p, miR-1-3p, miR-206, and miR-613. Through upregulating AXL, DANCR activated PI3K/Akt/NF-κB signaling pathway in glioma cells. Inhibiting AXL/PI3K/Akt/NF-κB signaling pathway reversed the effects of DANCR on cisplatin resistance. In conclusion, we identified a cisplatin-resistance associated lncRNA DANCR. DANCR promotes cisplatin resistance via activating AXL/PI3K/Akt/NF-κB signaling pathway in glioma. Our data suggested that DANCR would be a potential biomarker for predicting cisplatin sensitivity and a therapeutic target for enhancing cisplatin efficacy in glioma.

A Primary Cerebellar Glioblastoma Multiforme Mimicking Vestibular Schwannoma

Cerebellar glioblastoma multiforme (cGBM) is rare in adults, accounting for <1% of all patients with glioblastoma multiforme (GBM). The accurate diagnosis of cGBM is important for establishing a suitable therapeutic schedule. However, the diagnosis of cerebellar GBM is not usually suspected preoperatively because of its rarity. Generally, patients with cGBMs typically presented with symptoms of raised intracranial pressure, and infrequently cerebellar symptoms such as gait ataxia and disequilibrium. Nevertheless, the authors reported a cGMB patient, with his clinical presentations and imaging characteristics mimicking a vestibular schwannoma. To the best of our knowledge, this is the first reported patient with cGBM mimicking a vestibular schwannoma. Furthermore, the diagnosis, treatment, and prognosis for cGBM were broadly investigated.

Genetic and immune features of resectable malignant brainstem gliomas

We surveyed common genetic mutations (IDH1, H3F3A, PPM1D, and TP53) and immune features (PD-L1 expression and CD8⁺ T cell tumor infiltration) in a series of 62 malignant brainstem gliomas that were resected via microsurgery. IDH1 mutations were mutually exclusive with H3F3A mutations. IDH1 mutations appeared only in adults and occurred more frequently in tumors larger than 10cm³ (8/29 vs 1/32, Fisher’s exact test, p=0.010). H3F3A mutations occurred more frequently in children and adolescent patients (19/24 vs 18/38, chi-square test, p=0.013), low preoperative Karnofsky Performance Scale (KPS) patients (10/11 vs 20/43, chi-square test, p=0.021), and higher grade brainstem gliomas (8/21 in grade II vs 16/24 in grade III vs 13/17 in grade IV; chi-square test, p=0.038). PPM1D mutations clustered in H3F3A-mutated tumors (12/37), whereas were rare in H3F3A wildtype tumors (1/25). MGMT promoter methylations clustered in IDH1-mutated tumors (4/9), but were rare in H3F3A-mutated tumors (1/37). PD-L1 staining was detected in 59.7% of brainstem glioma specimens (37/62). High intra-tumoral CD8⁺ T cell density was less frequent in the H3F3A-mutated than H3F3A-wild-type tumors (4/37 vs. 11/25, p=0.005). Patients with H3F3A-mutated tumors (13.8 months overall survival) had much worse prognoses than those with IDH1-mutated (54.9 months, p=0.001) or H3F3A-IDH1 co-wildtype tumors (38.4 months, p=0.001). H3F3A mutations independently increased the relative risk of death as much as 4.19-fold according to a multivariate Cox regression model. Taken together, resectable malignant brainstem gliomas can be classified into three subtypes: H3F3A-mutated, IDH1 mutated and H3F3A-IDH1 co-wildtype tumors, which have distinct clinical characteristics, prognoses, genetic and immune features.

Overexpression of Protease Serine 8 Inhibits Glioma Cell Proliferation, Migration, and Invasion via Suppressing the Akt/mTOR Signaling Pathway

Protease serine 8 (PRSS8), a serine peptidase, has a widespread expression in normal epidermal cells. Recently, many researchers demonstrated downregulation of PRSS8 in cancer tissues as well as its tumor suppressor role in cancer development. However, the biological functions of PRSS8 in glioma remain unclear. In the current study, we demonstrated a decreased expression of PRSS8 in glioma tissues and cell lines. PRSS8 upregulation inhibited glioma cell proliferation, migration, and invasion. In addition, xenograft experiments showed that PRSS8 overexpression suppressed glioma cell growth in vivo. We also found that upregulated PRSS8 reduced the protein expression levels of p-Akt and p-mTOR in glioma cells. Taken together, our study demonstrated that overexpression of PRSS8 inhibited glioma cell proliferation, migration, and invasion via suppressing the Akt/mTOR signaling pathway. Therefore, PRSS8 may act as a novel therapeutic target for glioma.

MicroRNA-141 inhibits glioma cells growth and metastasis by targeting TGF-β2

MicroRNA-141 (miR-141) has been reported to function as tumor suppressor in many types of cancer. However, the molecular function and underlying mechanisms of miR-141 in glioma is still unknown. The aims of this study were to investigate miR-141 expression and determine its biological function and underlying mechanism in glioma. In this study, we found that miR-141 expression levels, both in glioma cell lines and in tissues, were significantly lower than that in a normal human astrocyte cell line or adjacent non-cancerous tissues. Overexpression of miR-141 significantly inhibited glioma cell proliferation, colony formation, migration and invasion in vitro, as well as suppressed glioma tumor growth in vivo. In addition, transforming growth factor beta 2 (TGF-β2) was identified as a target of miR-141 in glioma cells. TGF-β2 expression was also found to be upregulated, and negatively associated with miR-141 in glioma tissues. TGF-β2 over-expression partly reversed the effect caused by transfection of miR-141 mimic. These findings together suggested that miR-141 functioned as tumor suppressor by targeting TGF-β2, and that miR-141 might be a promising therapeutic strategy for future treatment of glioma.

Brainstem Glioma in Adults

Brainstem gliomas are not nearly as common in adults as they are in children. They are likely the final common consequence not of a single disease process but of several. They can be difficult to diagnose, and are challenging to treat. Clinical studies of this diagnosis are few and generally small. Because of these factors, our understanding of the biology of adult brainstem glioma is incomplete. However, the knowledge base is growing and progress is being made. In this article, we review the current state of knowledge for brainstem glioma in adults and identify key areas for which additional information is required.

Adult brainstem gliomas

Brainstem gliomas in adults are a rare and heterogeneous group of brain tumors that vary with regard to underlying pathology, radiographic appearance, clinical course and prognosis. Diffuse intrinsic pontine gliomas represent the most common subtype. Although still considered aggressive and most often lethal, these brain tumors are associated with a more insidious clinical course and more favorable prognosis compared to the highly aggressive form in children. Treatment options for patients with brainstem gliomas still are limited and insufficiently studied. A better understanding of the pathobiology of these tumors will be crucial for the development of more specific and effective therapies. Cancer 2016. © 2016 American Cancer Society. Cancer 2016;122:2799-2809. © 2016 American Cancer Society.

Adult Brainstem Glioblastoma Multiforme: Long-term Survivor

Adult, malignant brainstem gliomas are rare entities that often cause treatment conundrums due to the difficulty of surgical resection and, therefore, the absence of pathological diagnosis. This leads to a reliance on radiological imaging for diagnosis, which can often be unreliable. These shortcomings have made the treatment of brainstem gliomas challenging with unpredictable outcomes. The mainstay of treatment consists of chemotherapy and radiation; however, recurrence is inevitable. Predicting outcomes has been the major difficulty in treating these patients as adult malignant brainstem gliomas Grade II have a median survival between five to seven years while Grades III and IV are between 10-17 months (with some studies showing significantly longer survival in Grade III). Here, we present the case of a patient with the pathologic diagnosis of a right brachium pontis glioblastoma who had a remarkable survival of 73 months, whereas the expected median survival for these patients is 10-17 months.

MiR-506 functions as a tumor suppressor in glioma by targeting STAT3

MicroRNA-506 (miR-506) has been reported to act as a tumor suppressive or an oncogenic miRNA in different types of tumors. However, the roles and underlying molecular mechanism of miR-506 in glioma remain unclear. In the present study, we performed quantitative PCR to investigate the level of miR-506 in 36 pairs of glioma tumor and matched adjacent tissues, and found that miR-506 was downregulated in the glioma tumors compared to the expression in the adjacent normal tissues. Furthermore, a functional assay found that ectopic expression of miR-506 in glioma cells markedly suppressed cell proliferation, colony formation, migration and invasion, and suppressed tumor growth in vivo. Moreover, signal transducer and activator of transcription 3 (STAT3) was identified as a direct target of miR-506. Western blot assay showed that overexpression of miR-506 not only induced changes in STAT3 expression but also altered expression of its downstream genes, including, Bcl2, cyclin D1 and matrix metalloproteinase 2 (MMP-2), in the human glioma cells. In addition, STAT3 mRNA expression was increased in the glioma tissues, and was inversely correlated with miR-506. Importantly, overexpression of STAT3 in glioma cells attenuated the suppressive effects of miR-506 on cell proliferation, colony formation, migration and invasion. These results showed that miR-506 functions as a tumor suppressor in glioma by targeting STAT3, suggesting that miR-506 may serve as a potential target in the treatment of human glioma.

MicroRNA-126 acts as a tumor suppressor in glioma cells by targeting insulin receptor substrate 1 (IRS-1)

MicroRNA (miR-126) was reported to be downregulated and to act as a tumor suppressor in cancers of the lung, cervix, bladder, breast, liver and prostate. However, the precise roles and underling mechanisms of miR-126 in glioma remain largely unknown. This study is aimed to study the role of miR-126 in the progression of glioma and to elucidate underlying miR-126-mediated mechanisms in glioma. Our results revealed that miR-126 was downregulated in the collected glioma specimen, compared with non-cancerous brain tissues. Restored miR-126 expression inhibited cell proliferation, colony formation, migration and invasion, and induced cell cycle arrest at G0/G1 phase and cell apoptosis of U-87 MG glioma cells. Overexpression of miR-126 was also able to suppress the growth of U-87 MG glioma xenografts in mice. Furthermore, insulin receptor substrate 1 (IRS-1) were identified as a target of miR-126, and showed that it was negatively regulated by miR-126 in glioma cells. We also demonstrated that overexpression of miR-126 suppressed PI3K and AKT activation, which contribute to suppress tumor growth of glioma. Taken together, these findings showed that miR-126 functions as a tumor suppressor in glioma cells by targeting IRS-1 expression via the PI3K/AKT signaling pathways, suggesting that miR-126 might be a novel target for therapeutic strategies in glioma.

Adult brainstem gliomas: Correlation of clinical and molecular features

BACKGROUND

Brainstem gliomas are rare in adults and overall have superior survival outcomes compared to pediatric brainstem gliomas.

PATIENTS AND METHODS

We conducted a retrospective data and tissue analysis of all adult patients (≥ 18 years old) with World Health Organization (WHO) Grade II, III, and IV brainstem gliomas in the University of Texas MD Anderson Cancer Center institutional database from 1990 to 2012.

RESULTS

We identified 143 cases in adults ages 18 and over. There were 28 glioblastomas, 43 anaplastic astrocytomas, 15 diffuse astrocytomas, and 11 gliomas not otherwise specified, and in 46 cases the diagnosis was made radiographically. 128 (89.5%) cases were classified radiographically as diffuse and of the focal tumors, 9 of the 15 were WHO Grade III or IV tumors. Increasing tumor grade and contrast enhancement were associated with significantly reduced overall survival. The median overall survival for the entire cohort was 32.1 months similar to previously published studies. Two of 25 grade II and III tumors, and 1 of 17 glioblastomas had IDH1 mutations on immunohistochemical testing. Nine cases had sufficient tissue for mutation profiling, 1 case had a BRAF V600E mutation and 2 had 2 PIK3CA mutations.

CONCLUSIONS

Survival outcomes for adult WHO Grade II to IV brainstem gliomas were similar to supratentorial IDH1 wild-type tumors of similar grade and histology. Potentially actionable mutations can be identified from small biopsy samples in a subset of adult brainstem gliomas.