NeuroOncology

Non-NF2 mutations have a key effect on inhibitory immune checkpoints and tumor pathogenesis in skull base meningiomas Abstract Aims Skull base meningiomas represent approximately 25% of all meningiomas, nearly 20% of which are atypical or anaplastic. To date, effective medical treatments for meningiomas are still lacking. Genetic aberrations (TRAF7, KLF4, AKT1, and SMO) and the effects of genetic aberrations on the expression of inhibitory immune checkpoint molecules (PD-L1, IDO, and TDO2) in skull base meningiomas are still unclear. Methods Genetic alterations in the four genes were identified in 92 skull base meningiomas by Sanger sequencing. The expression differences in immune checkpoints between mutant and wild-type (WT) tumors were determined by immunohistochemistry (IHC) and Western blot (WB). Results The four mutations were not concurrently detected in the patients with skull base meningiomas. Among the tumors from the KLF4-mutated group, almost half were petroclival meningiomas. KLF4- and TRAF7-mutated tumors were predominantly secretory meningiomas. SMO-mutated tumors exhibited higher calcification, and half of these tumors were observed in the brain midline. Receiver operating characteristic curve analysis indicated that tumor volume can predict KLF4 and TRAF7 mutation status with high sensitivity and specificity, respectively. The IHC and WB analyses indicated that PD-L1, IDO, and TDO2 levels in tumors with TRAF7 mutations were significantly higher than those in WT tumors. Meanwhile, there was a significant difference in TDO2 between tumors with AKT1 mutations and WT tumors. Specifically, TRAF7 mutations could play a key role in skull base meningiomas by regulating the expression of inhibitory immune checkpoints and thus suppressing immune responses. Conclusions Checkpoint inhibitors may be potential strategies for targeted immunotherapies of these mutant meningiomas.

Super-early initiation of temozolomide prolongs the survival of glioblastoma patients without gross-total resection: a retrospective cohort study Abstract Objective The optimal timing of chemoradiotherapy in patients with newly diagnosed glioblastoma (GBM) remains unclear. In this study, we explored the clinical efficacy of super-early initiation of temozolomide (TMZ) in the treatment interval from surgery to radiotherapy. Methods We retrospectively reviewed the clinical data of 375 patients with GBM in our institution from 2012 to 2018. One hundred and sixty-three patients received super-early TMZ within 7 days after craniotomy based on standard Stupp protocol (super-early group, SEG), while two hundred and twelve patients underwent standard Stupp protocol alone (control group, CG). We performed propensity score matching (PSM) to reduce patient selection bias between the two groups. Results Before PSM, both median progression-free survival (PFS) and overall survival (OS) of patients in SEG were longer than those in CG (PFS 11.5 vs. 9.0 months, P = 0.0384 and OS 23.0 vs. 17.0 months, P = 0.0014). After PSM, the clinical efficacy of super-early initiation of TMZ only remained significant in term of OS, which was further validated in Cox hazard proportional model (HR = 0.583, 95% CI 0.384–0.884, P = 0.011). In the subgroup analysis, patients without gross total resection (GTR) or with O6-methylguanine DNA methyltransferase promoter methylation could benefit from super-early initiation of TMZ in both PFS and OS (P < 0.05). No significant difference of treatment emerging adverse events was observed between the two groups (P > 0.05). Conclusions This retrospective study highlights that super-early initiation of TMZ in newly diagnosed GBM may confer to survival benefit, especially for those without GTR.

LncRNA GAS5 regulates the proliferation, migration, invasion and apoptosis of brain glioma cells through targeting GSTM3 expression. The effect of LncRNA GAS5 on glioma cells Abstract Introduction To investigate the effects of lncRNA GAS5 on the proliferation, migration, invasion and apoptosis of brain glioma cells. Methods The expression levels of lncRNA GAS5 and GSTM3 in normal glial cells (HEB) and glioma cells (U251 and U87) were detected by RT-qPCR and western blot, respectively. Glioma cells were transfected with ctrl vector, pcDNA-GAS5, siRNA ctrl (siNC) or GSTM3 siRNA and the effects of lncRNA GAS5 and GSTM3 on the proliferation, migration, invasion and apoptosis of glioma cells were detected by CCK-8 assay, transwell assay and Caspase 3/7 activity assay, respectively. Results The expression of lncRNA GAS5 was significantly decreased in glioma cell lines U251 and U87 compared with normal glial cells HEB (p < 0.01). In addition, overexpression of lncRNA GAS5 inhibited the proliferation, migration and invasion of U251 and U87 cells, and promoted cell apoptosis as demonstrated by the increased activity of Caspase 3/7. Furthermore, GSTM3 was predicted as a target gene of lncRNA GAS5 by bioinformatics analysis and its expression was increased in glioma cells compared with the normal cells as indicated by western blotting and RT-qPCR experimental results. Silencing of GSTM3 with GSTM3 siRNA decreased the proliferation, migration and invasion but increased the apoptosis of glioma cell lines U251 and U87, which was similar to that the effect lncRNA GAS5 over-expression. Conclusion lncRNA GAS5 can effectively inhibit the proliferation, migration and invasion of glioma cells and promote cell apoptosis through targeting GSTM3 expression.

Correction to: Phase I-II trial of imatinib mesylate (Gleevec; STI571) in treatment of recurrent oligodendroglioma and mixed oligoastrocytoma. North central cancer treatment group study N0272 (ALLIANCE/NCCTG) The last author's first name was truncated in the initial online publication. The original article has been corrected.

Radiotherapy for recurrent intracranial epidermoid cysts without malignant transformation: a single-institution case series Abstract Introduction Recurrent intracranial epidermoid cysts may be difficult to address surgically given their proximity to critical neurovascular structures of the skull base. There are emerging reports of using radiotherapy (RT) for the treatment of recurrent epidermoid cysts. Here, we report a case series of adjuvant fractionated external beam RT for recurrent intracranial epidermoid cysts. Methods A single-institution review of all recurrent epidermoid cysts treated with adjuvant therapy between 2000 and 2017 was performed. Results Eight patients with recurrent epidermoid cysts who underwent adjuvant external beam RT were identified. Average age at initial diagnosis was 42.2 years, and median clinical follow-up after initial diagnosis and RT was 16.4 and 2.9 years, respectively. The median number of surgical resections prior to RT was 3 (range 2–5). Rationale for RT included multiple recurrent disease, rapid recurrence following prior resection, increased risk of further surgical morbidity, and patient preference. Median dose was 50.4 delivered in 1.8 Gy fractions (median 28 fractions). By the date of last follow-up, no patient has demonstrated progression, and there have been no cases of malignant degeneration. Conclusion Adjuvant RT should be considered in the context of recurrent epidermoid cysts to decrease the likelihood of further recurrences.

Identification of PEPT2 as an important candidate molecule in 5-ALA-mediated fluorescence-guided surgery in WHO grade II/III gliomas Abstract Purpose 5-aminolevulinic acid (5-ALA) fluorescence-guided surgery (FGS) appears to be a promising treatment for glioma. However, 5-ALA-mediated fluorescence cannot always be detected in grade II/III gliomas. We hypothesized that gene expression patterns in the Protoporphyrin IX (PpIX) synthesis pathway may be associated with intraoperative fluorescence status of grade II/III gliomas, and then attempted to identify the key molecule of 5-ALA-mediated fluorescence. Methods Using 50 surgically obtained specimens, which were diagnosed as grade II and III gliomas, we analyzed gene expression within the PpIX synthesis pathway to identify candidate molecules according to intraoperative 5-ALA-mediated fluorescence status. The most likely candidate gene was selected and confirmed by protein expression analysis. To evaluate the biological function of the molecule in PpIX synthesis, functional analysis was performed using specific, small interference (si)RNA in the SW-1783 human grade III glioma cell line. Results Among the genes involved in the porphyrin synthesis pathway, the mRNA expression of Peptide transporter 2 (PEPT2) in FGS fluorescence-positive gliomas was significantly higher than that in fluorescence-negative gliomas. Protein expression of PEPT2 was also significantly higher in the fluorescence-positive gliomas, which was confirmed by western blot analysis and immunofluorescence analysis. The siRNA-mediated downregulation of the mRNA and protein expression of PEPT2 led to decreased PpIX fluorescence intensity, as confirmed by fluorescence spectrum analysis. Conclusions The results suggest PEPT2 is an important candidate molecule in 5-ALA-mediated FGS in grade II/III gliomas. As the overexpression of PEPT2 was associated with higher PpIX fluorescence intensity, PEPT2 may improve fluorescence-guided resection in grade II/III gliomas.

Clinical diagnosis of attention-deficit/hyperactivity disorder in survivors of pediatric brain tumors Abstract Purpose Survivors of pediatric brain tumors often have neurodevelopmental late effects, such as inattention. Symptoms may mirror those of attention-deficit/hyperactivity disorder (ADHD), which affects ~ 5–8% of the general population. This retrospective study of survivors followed at a large tertiary care center examined the prevalence of a clinical diagnosis of ADHD, and risk factors associated with ADHD diagnosis and ADHD-related medication use. Methods A retrospective chart review of brain tumor survivors (n = 528), diagnosed between 2000 and 2015, who were at least 6 years old and 2 years from the end of tumor-directed therapy or from diagnosis, if no interventions were received. Clinical and demographic data were extracted from the medical record. Results Survivors were 55.7% male with mean age 8.15 ± 4.4 (0.0–16.0) years at brain tumor diagnosis. The most common diagnoses were low-grade glioma, medulloblastoma, and craniopharyngioma, with 52.5% of tumors supratentorial. Of the survivors, 81.3% received surgery, 40.0% radiation therapy, and 36.6% chemotherapy. Sixty-nine survivors (13.1%) had ADHD diagnoses, 105 (19.9%) had symptoms of ADHD without diagnoses, and 64 (12.1%) had ADHD medication use. ADHD diagnosis was associated with younger age at tumor diagnosis (p = 0.05) and supratentorial tumor location (p = 0.001). ADHD diagnosis was not associated with gender, tumor type, or treatment type. Conclusions Survivors of brain tumors are at increased risk of ADHD and related symptoms. The greatest increase in risk occurs for survivors with diagnoses at younger ages and supratentorial tumors. Additional research is warranted, as select survivors may benefit from behavioral or pharmacologic ADHD treatments to optimize functioning.

Combination anti-CXCR4 and anti-PD-1 immunotherapy provides survival benefit in glioblastoma through immune cell modulation of tumor microenvironment Abstract Background Emerging evidence suggests that myeloid cells play a critical role in glioblastoma (GBM) immunosuppression. Disappointing results of recent checkpoint inhibitor trials suggest that combination immunotherapy with alternative agents could be fruitful in overcoming immunosuppression. Overexpression of chemokine receptor CXCR4 is associated with poor prognosis in GBM. We investigate the treatment effects of combination immunotherapy with anti-PD-1 and anti-CXCR4 in a murine glioma model. Methods C57BL/6 mice were implanted with GL261-Luc+ glioma cells and randomized into 4 arms: (1) control (2) anti-PD-1 (3) anti-CXCR4, and (4) anti-PD-1 and anti-CXCR4 therapy. Overall survival and median survival were assessed. Cell populations were assessed by flow cytometry. Results Combination therapy conferred a significant survival benefit compared to control and monotherapy arms. Mice that received combination therapy demonstrated immune memory and decreased populations of immunosuppressive tumor-infiltrating leukocytes, such as monocytic myeloid-derived suppressor cells and microglia within the brain. Furthermore, combination therapy improved CD4+/CD8+ ratios in the brain as well as contributed to increased levels of pro-inflammatory cytokines. Conclusions Anti-CXCR4 and anti-PD-1 combination immunotherapy modulates tumor-infiltrating populations of the glioma microenvironment. Targeting myeloid cells with anti-CXCR4 facilitates anti-PD-1 to promote an antitumor immune response and improved survival rates.

Diagnostic delay and morbidity of central nervous system tumors in children and young adults: a pediatric hospital experience Abstract Introduction For children with central nervous system (CNS) tumors, survival rates remain significantly lower than other childhood malignancies with a substantial increase in disability of survivors. Given this, it is imperative that these children are identified at the earliest sign of symptom onset. Our institution aimed to identify diagnostic delays, morbidity and mortality, and specific barriers that may exist within our specific healthcare system that result in diagnostic delay. Methods A retrospective chart review was performed of newly diagnosed CNS tumors between January 1, 2008 and December 31, 2017. Results 235 patient cases were reviewed, 34 (14.5%) of which had an associated tumor predisposition syndrome. Median age at the time of diagnosis was 9 years (range 1 day to 25 years), with median number of days from symptom onset to definitive diagnosis of 42 days (interquartile range 14–120 days). Delays longer than 60 days occurred in 95 (47.5%) patients. The 10 year relative survival rate for all tumors was 86.8%. Conclusions Our institution had a shorter interval from symptom onset to diagnosis than currently reported in the literature, as well as a decrease in associated morbidity. In addition, for those with longer delays, we were able to characterize the etiology and barriers leading to these delays. With these identified, we are able to utilize this knowledge to further improve education and awareness in community members and healthcare professionals to continue to improve the time to diagnosis in the future.

A critical assessment of the quality of radiation therapy in Israel: time to initiation of treatment of spinal cord compression as an index of efficiency Abstract Introduction Radiotherapy departments function under workload pressure. We examined the process from referral to treatment initiation for spinal cord compression (SCC), one of the most daunting clinical scenarios in oncology. Methods We identified 235 patients with SCC, treated between 2013–2015. Two physicians classified cases as "emergent" or "urgent" (treatment within 24 or 72 h, respectively). Results The distribution of referrals over the week was uniform for inpatients. In contrast, there was a referral peak (62.27%) during the first two workdays for emergency ambulatory patients (p = 0.011). There were few weekend referrals in all groups (3.0%). There was a statistically shorter interval between referral and treatment for emergent versus urgent cases (0.94 days vs. 4.17 days; p < 0.0001, Bonferroni correction p < 0.0005). Conclusion Time elapsed between referral and treatment of SCC may constitute a quality index in neuro-oncology. Modern departments of radiotherapy should determine the degree to which they can successfully implement such treatment. Patients with cancer and their physicians should be taught to recognize signs of SCC to expedite intervention.

Alexandros Sfakianakis
Anapafseos 5 . Agios Nikolaos
Crete.Greece.72100
2841026182

6948891480

alsfakia@gmail.com