Scalp Nerve Block Alleviates Headaches Associated With Sonication During Transcranial Magnetic Resonance-Guided Focused Ultrasound

BACKGROUND AND OBJECTIVES

In magnetic resonance-guided focused ultrasound (MRgFUS) procedures, headache is a frequent symptom and cause of treatment discontinuation. Herein, we assessed the efficacy of scalp nerve block (SNB) for alleviating headache during MRgFUS procedures.

METHODS

The effect of SNB on intraprocedural headache was examined by retrospectively comparing 2 patient cohorts at a single institution. During the study period from April 2020 to February 2022, an SNB protocol for all patients with a skull density ratio ≤0.55 was instituted on October 6, 2021. The number of patients with a skull density ratio ≤0.55 was 34 before the protocol and 36 afterward. Headache intensity was evaluated using a numerical rating scale (NRS) after each sonication. To evaluate the effect of SNB on headache intensity, multiple regression analysis was performed per patient and per sonication. In the per-patient analysis, the effect of SNB was evaluated using the maximum NRS, mean NRS, and NRS at the first ultrasound exposure that reached 52.5°C. In the per-sonication analysis, the effect of SNB was evaluated not only for the entire sonication but also for sonications classified into ≤9999 J, 10 000 to 29 999 J, and ≥30 000 J energy doses.

RESULTS

With SNB, headache alleviation was observed in the NRS after the first sonication that reached 52.5°C in each patient (β = -2.40, 95% CI -4.05 to -0.758, P = .00499), in the NRS when all sonications were evaluated (β = -0.647, 95% CI -1.19 to -0.106, P = .0201), and in the NRS when all sonications were classified into 10 000 to 29 999 J (β = -1.83, 95% CI -3.17 to -0.485, P = .00889).

CONCLUSION

SNB significantly reduced headache intensity during MRgFUS, especially that caused by sonication with a moderate-energy dose. These findings suggest that scalp nerves play a role in headache mechanisms during MRgFUS.

Mesenchymal stem cells as therapeutic vehicles for glioma

Glioma is a disease with a poor prognosis despite the availability of multimodality treatments, and the development of novel therapies is urgently needed. Challenges in glioma treatment include the difficulty for drugs to cross the blood-brain barrier when administered systemically and poor drug diffusion when administered locally. Mesenchymal stem cells exhibit advantages for glioma therapy because of their ability to pass through the blood-brain barrier and migrate to tumor cells and their tolerance to the immune system. Therefore, mesenchymal stem cells have been explored as vehicles for various therapeutic agents for glioma treatment. Mesenchymal stem cells loaded with chemotherapeutic drugs show improved penetration and tumor accumulation. For gene therapy, mesenchymal stem cells can be used as vehicles for suicide genes, the so-called gene-directed enzyme prodrug therapy. Mesenchymal stem cell-based oncolytic viral therapies have been attempted in recent years to enhance the efficacy of infection against the tumor, viral replication, and distribution of viral particles. Many uncertainties remain regarding the function and behavior of mesenchymal stem cells in gliomas. However, strategies to increase mesenchymal stem cell migration to gliomas may improve the delivery of therapeutic agents and enhance their anti-tumor effects, representing promising potential for patient treatment.

Midline invasion predicts poor prognosis in diffuse hemispheric glioma, H3 G34-mutant: an individual participant data review

INTRODUCTION

Diffuse hemispheric glioma, H3 G34-mutant (DHGs), is a newly categorized tumor in pediatric-type diffuse high-grade gliomas, World Health Organization grade 4, with a poor prognosis. Although prognostic factors associated with genetic abnormalities have been reported, few reports have examined the clinical presentation of DHGs, especially from the viewpoint of imaging findings. In this study, we investigated the relationship between clinical factors, including imaging findings, and prognosis in patients with DHGs.

METHODS

We searched Medline through the PubMed database using two search terms: "G34" and "glioma", between 1 April 2012 and 1 July 2023. We retrieved articles that described imaging findings and overall survival (OS), and added one DHG case from our institution. We defined midline invasion (MI) as invasion to the contralateral cerebrum, brainstem, corpus callosum, thalamus, and basal ganglia on magnetic resonance imaging. The primary outcome was 12-month survival, estimated using Kaplan-Meier curves and logistic regression.

RESULTS

A total of 96 patients were included in this study. The median age was 22 years, and the proportion of male patients was 48.4%. Lesions were most frequently located in the frontal lobe (52.6%). MI was positive in 39.6% of all patients. The median OS was 14.4 months. Univariate logistic regression analysis revealed that OS was significantly worse in the MI-positive group compared with the MI-negative group. Multivariate logistic regression analysis revealed that MI was an independent prognostic factor in DHGs.

CONCLUSIONS

In this study, MI-positive cases had a worse prognosis compared with MI-negative cases.

PREVIOUS PRESENTATIONS

No portion of this study has been presented or published previously.

Dolichoectasia of the ophthalmic artery: a case report on the treatment strategy in endovascular therapy and literature review

BACKGROUND

Dolichoectasia is a rare arterial condition characterized by the dilatation, tortuosity, and elongation of cerebral blood vessels. The vertebrobasilar artery and internal carotid artery are the common sites of dolichoectasia. However, dolichoectasia of the branch arteries, such as the ophthalmic artery (OA), is extremely rare. To the best of our knowledge, this is the first case of ophthalmic dolichoectasia that was successfully treated with endovascular internal coil trapping.

CASE PRESENTATION

A 54-year-old female patient presented with transient left ophthalmalgia and visual disturbance. Magnetic resonance imaging revealed a dilated and elongated left OA compressing the optic nerve at the entrance of the optic canal. However, a previous image that was taken 17 years back revealed that the OA was normal, which suggested the change in dolichoectasia was acquired. Cerebral angiography showed that the dilated and tortuous OA was running from the ophthalmic segment of the left internal carotid artery into the orbit. The symptoms could have been attributed to the direct compression of the dolichoectatic OA in the optic canal. A sufficient anastomosis between the central retinal artery and the middle meningeal artery was identified on external carotid angiography with balloon occlusion of the internal carotid artery. Endovascular treatment with internal trapping of the OA was performed due to ophthalmic symptom progression. Internal coil trapping of the OA was performed at the short segment between the OA bifurcation and the entrance of the optic canal. As expected, the central retinal artery was supplied via the middle meningeal artery after the treatment. The transient visual disturbance was immediately resolved. Ophthalmalgia worsened temporarily after the treatment. However, it completely resolved after several days of oral corticosteroid therapy. Postoperative angiography showed that the origin of the OA was occluded and that the OA in the optic canal was shrunk. The flow of the central retinal arteries via the middle meningeal artery was preserved.

CONCLUSIONS

OA dolichoectasia is rare, and its pathogenesis and long-term visual prognosis are still unknown. However, endovascular therapy can improve symptom by releasing the pressure site in the optic canal.

Improving the Reachability of Contact Aspiration for Acute Ischemic Stroke Using a New Delivery Assist Catheter

OBJECTIVE

This study aimed to improve the reachability of large lumen catheter for contact aspiration during acute ischemic stroke by a new delivery assist catheter.

METHODS

This study included 58 patients with large-vessel stroke treated using endovascular procedures at our institution and affiliated hospitals between July 2021 and January 2023. Contact aspiration, especially contact aspiration using nonpenetrating of thrombus (CANP) technique, was adopted as first-line thrombectomy for localized internal carotid artery, middle cerebral artery proximal (M1 segment), and basilar artery without tandem occlusion in acute stroke. The new delivery assist catheter (AXS Offset catheter, Stryker, Fremont, CA, USA) was standardized after its release. Results of this improved contact aspiration technique using the new delivery assist catheter, including reachability, procedure time, and first-pass effect, were compared with conventional catheters.

RESULTS

Of the 58 patients, 43 underwent only thrombectomy for acute embolic stroke. CANP technique was attempted on 25 patients (25/43, 58.1%). Of these, a normal inner catheter (inner diameter: 0.021 or 0.027 inches) and the new delivery assist catheter were used on 10 (10/25, 40%) and 15 (15/25, 60%) patients, respectively. An aspiration catheter reached the thrombus for 5 patients (5/10, 50%) and 14 patients (14/15 93.3%) in the normal and new delivery assist catheter groups, respectively (P = 0.023). There was no significant difference in the results of contact aspiration due to the delivery catheter.

CONCLUSIONS

The new delivery assist catheter improved the reachability of the aspiration catheter to the thrombus and is an effective device for performing CANP technique.

[Innovations in Combined Surgery of Endoscopic Transsphenoidal Surgery and Craniotomy]

Combined endoscopic transsphenoidal surgery and craniotomy may be useful for tumors extending into the suprasellar region or ventricles and for tumors extending simultaneously into the nasal sinuses and intracranial space. This method allows two surgeons to share the surgical field while compensating for each other's blind spots and allows for safe tumor removal by separating the normal structure from the tumor and protecting the normal structure. Simultaneous combined endoscopic transsphenoidal surgery and craniotomy require a lot of equipment; however, by devising the layout of the equipment in the operating room, the staff involved in the surgery can perform their roles more effectively. However, this method results in extensive dural and cranial defects, and prevention of cerebrospinal fluid leakage and perioperative surgical site infection is essential. Skull base reconstruction using autologous tissues and medical materials at appropriate locations can reduce the risk of postoperative cerebrospinal fluid leakage and surgical site infection. Furthermore, multilayered reconstruction using restorative medical materials eliminates the need for autologous tissue, is minimally invasive, shortens the operative time, reduces postoperative stress, and shortens the length of hospital stay. A combination of endoscopic transsphenoidal surgery and craniotomy will contribute to the improvement of the safety of highly difficult tumorectomies under a reliable skull base reconstruction method.

Dietary Iron Restriction Protects against Aneurysm Rupture in a Mouse Model of Intracranial Aneurysm

INTRODUCTION

Iron accumulation in vessel walls induces oxidative stress and inflammation, which can cause cerebrovascular damage, vascular wall degeneration, and intracranial aneurysmal formation, growth, and rupture. Subarachnoid hemorrhage from intracranial aneurysm rupture results in significant morbidity and mortality. This study used a mouse model of intracranial aneurysm to evaluate the effect of dietary iron restriction on aneurysm formation and rupture.

METHODS

Intracranial aneurysms were induced using deoxycorticosterone acetate-salt-induced hypertension and a single injection of elastase into the cerebrospinal fluid of the basal cistern. Mice were fed an iron-restricted diet (n = 23) or a normal diet (n = 25). Aneurysm rupture was detected by neurological symptoms, while the presence of intracranial aneurysm with subarachnoid hemorrhage was confirmed by post-mortem examination.

RESULTS

The aneurysmal rupture rate was significantly lower in iron-restricted diet mice (37%) compared with normal diet mice (76%; p < 0.05). Serum oxidative stress, iron accumulation, macrophage infiltration, and 8-hydroxy-2'-deoxyguanosine in the vascular wall were lower in iron-restricted diet mice (p < 0.01). The areas of iron positivity were similar to the areas of CD68 positivity and 8-hydroxy-2'-deoxyguanosine in both normal diet and iron-restricted diet mouse aneurysms.

CONCLUSIONS

These findings suggest that iron is involved in intracranial aneurysm rupture via vascular inflammation and oxidative stress. Dietary iron restriction may have a promising role in preventing intracranial aneurysm rupture.

A Case of High-Grade Glioma in an Eloquent Area Treated with Awake Craniotomy in an 85-year-old Patient

An 85-year-old woman presented with aphasia due to an occupying lesion in the left frontal lobe near the language area. Complete resection of the contrast-enhancing lesion was performed under awake conditions. The pathological diagnosis was anaplastic astrocytoma, and postoperative radiochemotherapy was administered. Awake surgery is a useful technique to reduce postoperative neurological sequelae and to maximize surgical resection. Although the patient was elderly, which is generally considered high risk, she did not have any severe neurological deficits and had a good outcome. Even in the extreme elderly, awake surgery can be useful for gliomas in language cortices.

Multidrug chemotherapy, whole-brain radiation and cytarabine therapy for primary central nervous system lymphoma in elderly patients with dose modification based on geriatric assessment: study protocol for a phase II, multicentre, non-randomised study

INTRODUCTION

Multidrug chemoimmunotherapy with rituximab, high-dose methotrexate, procarbazine and vincristine (R-MPV) is a standard therapy for younger patients with primary central nervous system lymphoma (PCNSL); however, prospective data regarding its use in elderly patients are lacking. This multi-institutional, non-randomised, phase II trial will assess the efficacy and safety of R-MPV and high-dose cytarabine (HD-AraC) for geriatric patients with newly diagnosed PCNSL.

METHODS AND ANALYSIS

Forty-five elderly patients will be included. If R-MPV does not achieve complete response, the patients will undergo reduced-dose, whole-brain radiotherapy comprising 23.4 Gy/13 fractions, followed by local boost radiotherapy comprising 21.6 Gy/12 fractions. After achieving complete response using R-MPV with or without radiotherapy, the patients will undergo two courses of HD-AraC. All patients will undergo baseline geriatric 8 (G8) assessment before HD-AraC and after three, five and seven R-MPV courses. Patients with screening scores of ≥14 points that decrease to <14 points during subsequent treatment, or those with screening scores <14 points that decrease from the baseline during subsequent treatment are considered unfit for R-MPV/HD-AraC. The primary endpoint is overall survival, and the secondary endpoints are progression-free survival, treatment failure-free survival and frequency of adverse events. The results will guide a later phase III trial and provide information about the utility of a geriatric assessment for defining chemotherapy ineligibility.

ETHICS AND DISSEMINATION

This study complies with the latest Declaration of Helsinki. Written informed consent will be obtained. All participants can quit the study without penalty or impact on treatment. The protocol for the study, statistical analysis plan and informed consent form have been approved by the Certified Review Board at Hiroshima University (CRB6180006) (approval number: CRB2018-0011). The study is ongoing within nine tertiary and two secondary hospitals in Japan. The findings of this trial will be disseminated through national and international presentations and peer-reviewed publications.

TRIAL REGISTRATION

jRCTs061180093.

CDKAL1 Drives the Maintenance of Cancer Stem-Like Cells by Assembling the eIF4F Translation Initiation Complex

Cancer stem-like cells (CSCs) have a unique translation mode, but little is understood about the process of elongation, especially the contribution of tRNA modifications to the maintenance of CSCs properties. Here, it is reported that, contrary to the initial aim, a tRNA-modifying methylthiotransferase CDKAL1 promotes CSC-factor SALL2 synthesis by assembling the eIF4F translation initiation complex. CDKAL1 expression is upregulated in patients with worse prognoses and is essential for maintaining CSCs in rhabdomyosarcoma (RMS) and common cancers. Translatome analysis reveals that a group of mRNAs whose translation is CDKAL1-dependent contains cytosine-rich sequences in the 5' untranslated region (5'UTR). Mechanistically, CDKAL1 promotes the translation of such mRNAs by organizing the eIF4F translation initiation complex. This complex formation does not require the enzyme activity of CDKAL1 but requires only the NH2 -terminus domain of CDKAL1. Furthermore, sites in CDKAL1 essential for forming the eIF4F complex are identified and discovered candidate inhibitors of CDKAL1-dependent translation.

CBMS-5 STEAROYL-COA DESATURASE INHIBITOR INDUCES APOPTOSIS VIA ENHANCING LIPOLYSIS IN IDH MUTANT GLIOMA

Background

Little is known about the antineoplastic effect and the mechanism of Stearoyl-CoA desaturase (SCD) inhibitor which catalyzes the biosynthesis of monounsaturated fatty acids (MUFA). Mutant isocitrate dehydrogenase (IDH) catalyzes the NADPH-mediated reduction of α-ketoglutarate (αKG) to 2-hydroxyglutarate (2HG) and causes metabolic reprograming of lipid. In this study, to develop a feasible drug for IDH mutant glioma, we have investigated the changes of the lipid distribution and the mechanism of antineoplastic effect of SCD inhibition in IDH mutant glioma.

Materials and Methods

We prepared genetically engineered glioma cell lines (U251 wild type: U251WT and U251 IDH mutant: U251mut) and patient derived cell lines (TS603 and GSC923). Lipid metabolic analysis was conducted by using Raman imaging spectroscopy and LC-MS, and functional analysis for the role of SCD expression in IDH mutant glioma was investigated by RNA sequence and Western-blotting. Results: In LC-MS analysis of the extracted Endoplasmic Reticulum, MUFAs were distributed significantly higher in IDH mutant than wild type. SCD expression was increased in IDH mutant compared to wild type due to 2HG-mediated upregulation of SCD. Therefore, IDH mutant in which SCD expression level was high indicated high sensitivity to SCD inhibitor, and apoptosis was highly induced in IDH mutant compared to wild type. RNA sequencing was performed in U251mut treated with SCD inhibitor compared to U251mut treated with DMSO, and lipid droplet metabolism-associated RNA expression was significantly changed in U251mut treated with SCD inhibitor. We checked lipid droplet in U251mut with presence or absence of SCD inhibitor, and lipolysis was induced by SCD inhibitor treatment, suggesting that SCD inhibition is associated with the apoptosis in IDH mutant via enhanced lipolysis mechanism.

Conclusions

2HG produced in IDH mutant glioma directly induces SCD expression and enhances sensitivity to SCD inhibitor, which suggests that SCD inhibitor is an IDH mutant glioma-specific treatment strategy.

ET-5 POTENT BYSTANDER EFFECT IN SUICIDE GENE THERAPY USING TK-EXPRESSING STEM CELLS FROM HUMAN EXFOLIATED DECIDUOUS TEETH

Introduction

We investigated HSVTK/GCV suicide gene therapy for malignant glioma, and demonstrated the migration ability and antitumor effect of various tissue-derived pluripotent stem cells. In recent years, stem cells from human exfoliated deciduous teeth (SHED), which have excellent ethical and self-renewal ability, have attracted attention, especially in regenerative medicine. In this study, using SHEDTK transfected with TK, we examined the migration ability and antitumor effect against malignant glioma and metastasis models.

Methods

In vitro assay: Using Matrigel chamber, the migration ability of SHEDTK to conditioned medium (CM) of glioma cells, lung carcinoma cells, and various tumor growth factors (TGF) was examined. The antitumor effect was examined for cell viability by co-culturing SHEDTK and each tumor cell under the addition of GCV. in vivo assay: Using glioma model mice, SHEDTK migrating around the tumor was confirmed in brain sections. In addition, we co-implanted SHEDTK and administered GCV to glioma and metastasis model as therapeutic models, evaluated tumor reduction effect by bioluminescence, and confirmed survival curves.

Results

In vitro assay: SHEDTK significantly migrated to CM and TGF compared to control. The antitumor effect was observed even when the ratio of each tumor cell to SHEDTK was 128-256 times. in vivo assay: In glioma model mice, SHEDTK migrated around contralateral tumor. In the treatment experiment, the control group died of tumors, whereas the tumor in the treatment group disappeared within the period of GCV administration, and they survived without neurological deficits until 100 days later, and the overall survival time was improved with a statistically significant difference.

Conclusions

We confirmed the migration ability and antitumor effect of SHEDTK on malignant glioma and metastasis models. Suicide gene therapy using SHEDTK was suggested as novel gene therapy. In the future, we plan to conduct translational research such as preclinical studies and physician -initiated clinical trials.

Migration Capacity of Stem Cells from Human Exfoliated Deciduous Teeth Towards Glioma

BACKGROUND

Stem cells from human exfoliated deciduous teeth (SHED) are a mesenchymal stem cell type and have recently attracted attention for their high proliferative rate, multipotency, and immunosuppressive properties. However, SHED have not yet been investigated for anticancer properties. We therefore investigated whether SHED can be used as a treatment modality, particularly for anti-glioma therapy.

METHODS

In vitro, we examined the mobility of SHED and their ability to migrate towards glioma-conditioned medium and specific growth factors secreted by malignant gliomas. In vivo, we transplanted SHED into the left hemisphere of nude mice that had been previously implanted with human malignant glioma U87 cells into the right hemisphere. We assessed whether SHED had tumorigenic potential.

RESULTS

SHED exhibited strong migration ability towards malignant glioma in both in vitro and in vivo assays. In vitro, SHED migrated towards glioma-conditioned medium and specific growth factors such as stem cell factor, platelet-derived growth factor BB, C-X-C motif chemokine ligand 12, and vascular endothelial growth factor. SHED were accumulated around tumor cells in the contralateral hemisphere 1 week after transplantation. Moreover, SHED remained in the brains of nude mice 150 days after transplantation. Finally, we verified that SHED had no malignant transformation or engraftment of SHED in the mouse brain.

CONCLUSIONS

Our findings indicate that SHED can potentially be applied to track malignant glioma.

TMET-03. STEAROYL-COA DESATURASE INHIBITOR SUPPRESSES IDH MUTANT GLIOMA GROWTH VIA ENHANCING LIPOLYSIS

BACKGROUND

Mutant isocitrate dehydrogenase (IDH) produces 2-hydroxyglutarate (D2HG) and causes metabolic reprograming, but so far, little is known about the role of mutant IDH and D2HG in de novo lipogenesis and fatty acids synthesis. In this study, to develop a feasible drug for IDH mutant glioma, we targeted Stearoyl-CoA desaturase 1 (SCD1) catalyzing the biosynthesis of monosaturated fatty acids (MUFA) to suppress IDH mutant glioma progression. Materials and

METHODS

We prepared genetically engineered glioma cell lines (U251 wild type: U251WT and U251 IDHR132H mutant: U251RH), normal human astrocytes (empty vector induced-NHA: NHAEV and IDHR132H mutant: NHARH) and patient derived cell lines. Lipid metabolic analysis was conducted by using LC-MS, and functional analysis for the role of SCD1 expression was investigated by RNA sequence and Western-blotting.

RESULTS

LC-MS analysis of extracted Endoplasmic Reticulum revealed that there was significantly higher amount of MUFA in IDH mutant than wild type. SCD1 expression was increased in IDH mutant compared to wild type due to D2HG-mediated upregulation of SCD1 in IDH mutant. Therefore, IDH mutant in which SCD1 expression level was higher than wild type indicated high sensitivity to SCD inhibitor, and apoptosis was highly induced in IDH mutant compared to wild type. RNA sequencing was performed in U251RH treated with SCD inhibitor compared to U251RH treated with DMSO, and lipid droplet metabolism-associated RNA expression was significantly changed in SCD inhibitor-treated U251RH. Based on the RNA sequence data, we checked lipid droplet in U251RH with presence or absence of SCD inhibitor, and lipolysis was induced by SCD inhibitor treatment, suggesting that SCD inhibition is associated with the apoptosis in IDH mutant via enhanced lipolysis mechanism.

CONCLUSIONS

D2HG produced in IDH mutant glioma directly induces SCD1 expression and enhances sensitivity to SCD inhibitor, which suggests that SCD inhibitor would be IDH mutant glioma-specific treatment strategy.

PATH-04. CURRENT STATUS AND PROSPECTS OF MALIGNANT BRAIN TUMOR TREATMENT IN CANCER GENOMIC MEDICINE

INTRODUCTION

The cancer gene panel test was covered by insurance in June 2019 in Japan. Our institution started the test in May 2020 and has experienced 16 cases. We will report on the current status and future prospects.

METHODS

The subjects were 16 patients (Average age 48.4) who underwent the cancer gene panel test with FoundationOne CDx. [Results] The cases included 9 glioblastomas, 3 anaplastic astrocytomas, 2 anaplastic oligodendrogliomas, an ependymoma, and a pituitary carcinoma. On average, 11.0 genetic changes were detected totally, oncogene mutations were 4.4, and gene mutations of unknown relevance to cancer were 5.6. Major oncogene mutations were IDH1 mutation in 5 cases, ATRX mutation in 2 cases, TP53 mutation in 9 cases, CDKN2A/2B mutation in 5 cases, and BRAF V600E mutation in 1 case. Based on our results, a 25-year-old man with BRAF V600E mutation and a 47-year-old male with IDH1 mutation could be given molecular-targeted drugs. Furthermore, a 59-year-old male with pituitary carcinoma had more than 10 mut/Mb in tumor mutational burden (TMB), indicating that anti-PD-1 antibody drugs can be administered. The chance of finding an appropriate drug by cancer gene panel test is approximately 10-20%. In cases that are resistant to standard treatment, the benefits can be expected if the drugs associated with the cancer gene panel test can be used.

CONCLUSIONS

Comprehensive cancer gene panel test has the potential to provide personalized medicine. And we suggest that the active use of cancer gene panel test may contribute to the development of new drugs with high response rates and the improvement of prognosis.

Current Insights into Mesenchymal Signatures in Glioblastoma

Glioblastoma (GBM) is a fatal primary malignant brain tumor in adults. Despite decades of research, the prognosis for GBM patients is still disappointing. One major reason for the intense therapeutic resistance of GBM is inter- and intra-tumor heterogeneity. GBM-intrinsic transcriptional profiling has suggested the presence of at least three subtypes of GBM: the proneural, classic, and mesenchymal subtypes. The mesenchymal subtype is the most aggressive, and patients with the mesenchymal subtype of primary and recurrent tumors tend to have a worse prognosis compared with patients with the other subtypes. Furthermore, GBM can shift from other subtypes to the mesenchymal subtype over the course of disease progression or recurrence. This phenotypic transition is driven by diverse tumor-intrinsic molecular mechanisms or microenvironmental factors. Thus, better understanding of the plastic nature of mesenchymal transition in GBM is pivotal to developing new therapeutic strategies. In this review, we provide a comprehensive overview of the current understanding of the elements involved in the mesenchymal transition of GBM and discuss future perspectives.

De novo dural arteriovenous fistula after mechanical thrombectomy for cerebral venous thrombosis: A case report

Background:

Although the relationship between dural arteriovenous fistula (dAVF) and cerebral venous thrombosis (CVT) has been reported, the etiology has not been clarified. Here, we report a case of de novo dAVF after mechanical thrombectomy for CVT and discuss the underlying mechanism.

Case Description:

A 61-year-old woman presented with a gradually worsening headache and was diagnosed with severe CVT. Mechanical thrombectomy was performed for the CVT because of progressive neurological deterioration despite anticoagulation therapy. Two years after the initial treatment, angiography revealed a de novo dAVF with a direct shunt of the left convexity cortical vein. Transarterial embolization with Onyx was performed and the shunt was completely obliterated.

Conclusion:

In this report, we describe a case of de novo dAVF with CVT that was treated with mechanical thrombectomy. Even if CVT improves with mechanical thrombectomy, we must be aware of the occurrence of de novo dAVF.

Efficacy of HSV-TK/GCV system suicide gene therapy using SHED expressing modified HSV-TK against lung cancer brain metastases

Lung cancer is one of the most common cancers, and the number of patients with intracranial metastases is increasing. Previously, we developed an enzyme prodrug suicide gene therapy based on the herpes simplex virus thymidine kinase (HSV-TK)/ganciclovir (GCV) system using various mesenchymal stem cells to induce apoptosis in malignant gliomas through bystander killing effects. Here, we describe stem cells from human exfoliated deciduous teeth (SHED) as gene vehicles of the TK/GCV system against a brain metastasis model of non-small cell lung cancer (NSCLC). We introduced the A168H mutant TK (TK^A168H) into SHED to establish the therapeutic cells because of the latent toxicity of wild type. SHED expressing TK^A168H (SHED-TK) exhibited chemotaxis to the conditioned medium of NSCLC and migrated toward implanted NSCLC in vivo. SHED-TK demonstrated a strong bystander effect in vitro and in vivo and completely eradicated H1299 NSCLC in the brain. SHED-TK cells implanted intratumorally followed by GCV administration significantly suppressed the growth of H1299 and improved survival time. These results indicate that the TK^A168H variant is suitable for establishing therapeutic cells and that intratumoral injection of SHED-TK followed by GCV administration may be a useful strategy for therapeutic approaches.

[Prevention of and Countermeasures for Surgical Site Infection in the Field of Skull Base Surgery]

In neurosurgery, perioperative surgical site infection(SSI)is associated with complicated postoperative management, prolonged hospital stay, and patient stress. In this article, we review SSI in the field of skull base surgery, including endoscopic endonasal surgery, and discuss ways to prevent SSI. In a craniotomy, in which the frontal sinus is revealed, prevention of cerebrospinal fluid(CSF)leakage by reliable repair of the dura and frontal sinus reduces SSI. In addition, prevention of postoperative CSF leakage by reliable skull base reconstruction in endoscopic endonasal surgery contributes to the prevention of SSI. Prophylactic antibiotics are often reported to be useful, and cephalosporin or sulbactam/ampicillin intravenous injections are generally used. There are insufficient data to recommend lumbar drainage for the management of SSI and postoperative CSF leak. Skull base surgery is often a clean-contaminated surgery, and serious complications can be prevented by proper understanding and performance of the appropriate method as required. However, no studies with a high level of evidence on SSI in the field of skull base surgery exist. New large randomized controlled trials are expected to evaluate the efficacy of prophylactic antibiotics in skull base surgery.

Combination of Ad-SGE-REIC and bevacizumab modulates glioma progression by suppressing tumor invasion and angiogenesis

Reduced expression in immortalized cells/Dickkopf-3 (REIC/Dkk-3) is a tumor suppressor and its overexpression has been shown to exert anti-tumor effects as a therapeutic target gene in many human cancers. Recently, we demonstrated the anti-glioma effects of an adenoviral vector carrying REIC/Dkk-3 with the super gene expression system (Ad-SGE-REIC). Anti-vascular endothelial growth factor treatments such as bevacizumab have demonstrated convincing therapeutic advantage in patients with glioblastoma. However, bevacizumab did not improve overall survival in patients with newly diagnosed glioblastoma. In this study, we examined the effects of Ad-SGE-REIC on glioma treated with bevacizumab. Ad-SGE-REIC treatment resulted in a significant reduction in the number of invasion cells treated with bevacizumab. Western blot analyses revealed the increased expression of several endoplasmic reticulum stress markers in cells treated with both bevacizumab and Ad-SGE-REIC, as well as decreased β-catenin protein levels. In malignant glioma mouse models, overall survival was extended in the combination therapy group. These results suggest that the combination therapy of Ad-SGE-REIC and bevacizumab exerts anti-glioma effects by suppressing the angiogenesis and invasion of tumors. Combined Ad-SGE-REIC and bevacizumab might be a promising strategy for the treatment of malignant glioma.

Genomic Profiling of a Case of Glioneuronal Tumor with Neuropil-like Islands

Glioneuronal tumor with neuropil-like islands (GNTNI) is a very rare subtype of glioneuronal tumor. We present a case of a 62-year-old man with GNTNI. Two adjacent lesions in the left parietal lobe were removed by left parietal craniotomy. The histological findings were glial cell proliferation and scattered rosettes consisting of synaptophysin-positive and NeuN-positive cells, leading to the diagnosis of GNTNI. Target sequencing revealed a genetic alteration similar to glioblastoma, IDH-wild type, which suggested adjuvant therapies. There are few previous reports on the treatment of this disease, and the patient should be followed carefully.

Occurrence of De Novo Dural Arteriovenous Fistula After Transvenous Embolization of Dural Arteriovenous Fistula: Case Reports of Two Patients

Development of de novo dural arteriovenous fistula (DAVF) at a different site after resolution of an initial DAVF, is rare. Here we report two cases, which we encountered in our hospital. A 68-year-old woman presented with pulsatile tinnitus on the left side. Cerebral angiography demonstrated a left anterior condylar confluence (ACC) DVAF and she underwent transvenous embolization. Four years after this treatment, she presented with tinnitus on the left side, and cerebral angiography revealed a right DAVF around the sinus of the lesser sphenoid wing. Another 69-year-old woman presented with left-sided orbital bruits, chemosis, and conjunctival hyperemia. Cerebral angiography showed left cavernous sinus (CS) DAVF, for which she underwent transvenous embolization for CS DAVF. One year later, she developed a left ACC and transverse-sigmoid sinus (TSS) DAVF.

Implications of immune cells in oncolytic herpes simplex virotherapy for glioma

Despite current progress in treatment, glioblastoma (GBM) remains a lethal primary malignant tumor of the central nervous system. Although immunotherapy has recently achieved remarkable survival effectiveness in multiple malignancies, none of the immune checkpoint inhibitors (ICIs) for GBM have shown anti-tumor efficacy in clinical trials. GBM has a characteristic immunosuppressive tumor microenvironment (TME) that results in the failure of ICIs. Oncolytic herpes simplex virotherapy (oHSV) is the most advanced United States Food and Drug Administration-approved virotherapy for advanced metastatic melanoma patients. Recently, another oHSV, Delytact^®, was granted conditional approval in Japan against GBM, highlighting it as a promising treatment. Since oncolytic virotherapy can recruit abundant immune cells and modify the immune TME, oncolytic virotherapy for immunologically cold GBM will be an attractive therapeutic option for GBM. However, as these immune cells have roles in both anti-tumor and anti-viral immunity, fine-tuning of the TME using oncolytic virotherapy will be important to maximize the therapeutic efficacy. In this review, we discuss the current knowledge of oHSV, with a focus on the role of immune cells as friend or foe in oncolytic virotherapy.

Molecular Mechanisms and Clinical Challenges of Glioma Invasion

Glioma is the most common primary brain tumor, and its prognosis is poor. Glioma cells are highly invasive to the brain parenchyma. It is difficult to achieve complete resection due to the nature of the brain tissue, and tumors that invade the parenchyma often recur. The invasiveness of tumor cells has been studied from various aspects, and the related molecular mechanisms are gradually becoming clear. Cell adhesion factors and extracellular matrix factors have a strong influence on glioma invasion. The molecular mechanisms that enhance the invasiveness of glioma stem cells, which have been investigated in recent years, have also been clarified. In addition, it has been discussed from both basic and clinical perspectives that current therapies can alter the invasiveness of tumors, and there is a need to develop therapeutic approaches to glioma invasion in the future. In this review, we will summarize the factors that influence the invasiveness of glioma based on the environment of tumor cells and tissues, and describe the impact of the treatment of glioma on invasion in terms of molecular biology, and the novel therapies for invasion that are currently being developed.

Abstract TP256: The Role Of Dietary Iron Restriction In The Pathophysiology Of Intracranial Aneurysm Rupture

Background: Iron is an essential element for maintaining vascular wall, however iron depositions in vascular wall cause tissue damage by oxidative stress via Fenton/Haber-Weiss reaction. We hypothesized that iron promotes intracranial aneurysmal formation and rupture through oxidative stress and vascular inflammation. Using a mouse model of intracranial aneurysm, we examined whether iron restriction reduces aneurysm formation and rupture.

Methods: To induce aneurysm, we combined induced systemic hypertension (deoxycorticosterone acetate-salt hypertension) and a single injection of elastase (35mU) into the cerebrospinal fluid at the right basal cistern. The mice were divided into two groups and fed with iron restricted diet (IRD) (0.32mg/100g) or normal diet (ND) (600mg/100g) for 5 weeks.

Results: IRD significantly reduced the aneurysmal rupture compared to ND (ND versus IRD: 76% versus 37%; P < 0.05). Whereas, there was no significant difference in the overall incidence of aneurysms between the ND and IRD groups (ND versus IRD: 68% versus 69%; P =1.00).

Conclusion: Our data demonstrate that iron restriction reduces intracranial aneurysm rupture.

A novel technique for fence-post tube placement in glioma using the robot-guided frameless neuronavigation technique under exoscope surgery: patient series

BACKGROUND

Robotic technology is increasingly used in neurosurgery. The authors reported a new technique for fence-post tube placement using robot-guided frameless stereotaxic technology with neuronavigation in patients with glioma.

OBSERVATIONS

Surgery was performed using the StealthStation S8 linked to the Stealth Autoguide cranial robotic guidance platform and a high-resolution three-dimensional (3D) surgical microscope. A surgical plan was created to determine the removal area using fence-post tube placement at the tumor and normal brain tissue boundary. Using this surgical plan, the robotic system allowed quick and accurate fence-post tube positioning, automatic alignment of the needle insertion and measurement positions in the brain, and quick and accurate puncture needle insertion into the brain tumor. Use of a ventricular drainage tube for the outer needle cylinder allowed placement of the puncture needle in a single operation. Furthermore, use of a high-resolution 3D exoscope allowed the surgeon to simultaneously view the surgical field image and the navigation screen with minimal line-of-sight movement, which improved operative safety. The position memory function of the 3D exoscope allowed easy switching between the exoscope and the microscope and optimal field of view adjustment.

LESSONS

Fence-post tube placement using robot-guided frameless stereotaxic technology, neuronavigation, and an exoscope allows precise glioma resection.

BOT-3 Prognostic Factors of CNS Germ Cell Tumors; Molecular and Histopathological Analyses on 154 Cases from the iGCT Consortium

Background: Germ cell tumors (GCTs) preferentially occurs in pediatric and young adult age groups. Chemo- and radiation therapies cause long-term sequelae in their later lives. We searched for clinical and histopathological features to predict the prognosis and affect treatment response, with a future goal of treatment stratification.Methods: A total of 154 GCT cases were included in the analysis. Total of 114 germinoma cases underwent measurement of tumor cell content on H-E specimen, and 82 GCT cases underwent 450K methylation analysis. 12p gain was determined on methylation-based copy number computation and FISH. Association with progression-free and overall survival (PFS/OS) was investigated. Results: The tumor cell content was widely distributed from <5% to 90% in the specimens, with a median value of 50%. Patients with a higher tumor cell content (>=50%) showed shorter PFS than those with a lower tumor cell content (<50 %) (p=0.03). In the multivariate analysis with tumor location, tumor cell content was the sole statistically significant prognostic factor (p=0.04). 12p gain was found in 25-out-of-82 cases (30%) and was more frequent in NGGCTs, particularly in cases with malignant components. The presence of 12p gain correlated with shorter PFS and OS, even with histology and tumor markers incorporated in the multivariate analysis. Among NGGCTs, 12p gain still had prognostic significance for PFS and OS. The 12p copy number status was shared among histological components in mixed GCTs. Whole-genome amplification was suggested by FISH.Conclusions: We found that tumor cell content significantly affected the prognosis of germinomas. 12p gain predicts the presence of malignant components of NGGCTs, and poor prognosis of the patients. Furthermore, 12p is likely to be an early event in the tumorigenesis of CNS GCT. These potentially open the possibility of leveraging these pathological and molecular factors in the future clinical trials when stratifying the treatment intensity.

CBMS-3 Potent bystander effect in suicide gene therapy using genetically engineered stem cells from human exfoliated deciduous teeth

HSV thymidine kinase (TK)/ganciclovir (GCV) has a long history of application in malignant glioma and we have previously demonstrated its bystander effect on gliomas using several stem cell types as a vehicle. The main reason for applying stem cells is that they have a unique tumor-trophic activity that allows them to deliver TK genes efficiently to nearby the tumor. Stem cells from human exfoliated deciduous teeth (SHED) are mesenchymal stem cells easily harvested from dental pulp and no studies have reported suicide gene therapy using SHED as a carrier for malignant gliomas. For transduction of SHED with the HSVTK gene (SHEDTK), we used HSVTK retrovirus-producing cells.In vitro experiments showed a significant migration ability of SHEDTK toward tumor-conditioned medium and representative tumor growth factors. We also detected a significant bystander effect of SHEDTK on gliomas in the presence of GCV. In vitro time-lapse imaging showed that both SHEDTK and glioma cells underwent gradual morphological apoptosis and activation of caspase 3/7 was observed in both cell types. In intracranial tumor models using nude mice, SHEDTK migrated around the U87 cell mass implanted in the contralateral hemisphere. Additionally, coculture suspensions of SHEDTK and U87-luciferase cells were xeno-transplanted followed by intraperitoneal administration of GCV for 10 days. All mice of treatment group survived for more than 100 days, whereas those treated without GCV died of tumor growth with median survival of 42 days after tumor implantation. Furthermore, pre-existing intracranial U87 model mice were injected intratumorally with SHEDTK followed by GCV administration as described above. The tumor volume was significantly reduced during the treatment period, and over-all surivial in treatment group is prolonged significantly to that of control groups. These results indicate that SHEDTK-based suicide gene therapy might offer a new promising therapeutic modality for human malignant gliomas.

ACT-8 Current status and prospects for the treatment of malignant glioma using cancer gene panel tests

Introduction: The cancer gene panel test was covered by insurance in June 2019. Our institution started the test in May 2020 and has experienced 10 cases, so we will report on the current status and future prospects. Methods: The subjects were 10 patients who underwent the cancer gene panel test using FoundationOne CDx. Results:The cases included 8 glioblastomas, an anaplastic astrocytoma, and an anaplastic oligodendroglioma. The total number of tumor mutational burden (TMB) was judged to be low in all cases, and the microsatellite instability test (MSI) showed no instability in all cases (MSI-Stable). The total number of genetic changes detected was 11 ± 5.0, oncogene mutations were 5.3 ± 2.4, and gene mutations of unknown relevance to cancer were 5.7 ± 2.8. Major oncogene mutations were IDH1 mutation in 4 cases, ATRX mutation in 2 cases, TP53 mutation in 6 cases, and BRAF V600E mutation in 1 case. Based on the test results, a 25-year-old man with BRAF V600E mutation was initiated into the NCCH1901 study (Patient-Proposed Healthcare Services). A case with IDH1 mutation (47-year-old male) entered a phase I clinical trial of a mutant IDH1 inhibitor. It is estimated that the chance of finding an appropriate drug by cancer gene panel test is about 10–20%. However, in cases that are resistant to standard treatment, the benefits can be expected if the drugs associated with the cancer gene panel test can be used. Conclusions: Although Malignant gliomas are often TMB-low and MSI-stable and the response rate to molecular-targeted drugs and other therapies is not high, there are some cases that can be salvaged by performing the cancer gene panel test. It is suggested that the active use of cancer gene panel test may contribute to the development of new drugs with high response rates and the improvement of prognosis.

Low tumor cell content predicts favorable prognosis in germinoma patients

Background

Germinoma preferentially occurs in pediatric and young adult age groups. Although they are responsive to treatment with chemotherapy and radiation, the treatment may cause long-term sequelae in their later lives. Here, we searched for clinical and histopathological features to predict the prognosis of germinoma and affect treatment response.

Methods

A total of 114 germinoma cases were included in the analysis. We investigated the association between clinical factors, tumor cell content, and progression-free survival (PFS).

Results

The tumor cell content was widely distributed from <5% to 90% in the specimens, with a median value of 50%. Female patients showed higher tumor cell content in the specimens (P = .002). Cases with lesions at atypical sites showed shorter PFS than those with lesions at other sites (P = .03). Patients with a higher tumor cell content (≥50%) showed shorter PFS than those with a lower tumor cell content (<50%) (P = .03). In multivariate analysis, tumor cell content was the only statistically significant prognostic factor (P = .04). Among the 7 cases treated with local radiation and chemotherapy, all 3 cases that recurred (2 outside of the radiation field, 1 unknown) had tumor cell content of ≥50% in the original specimen, whereas all 4 cases without recurrence had tumor cell contents of <50%.

Conclusions

We found that tumor cell content significantly affected the prognosis of germinomas. Although validation of these results using an independent and larger cohort is necessary, this potentially opens the possibility of leveraging this pathological factor in future clinical trials when stratifying the treatment intensity.

[Gene Therapy and Viral Therapy for Malignant Glioma]

Malignant gliomas have a poor prognosis despite advances in surgical procedures, radiotherapy, and the emergence of new treatments have improved outcomes. One of these new treatments is gene therapy, which has been developed as a new therapeutic strategy. Recently, new methods and approaches have been developed. Gene therapy involves the introduction of genes or cells into a glioma, or the human body, to treat gliomas; various genes such as cancer-suppressing genes, immunomodulation cytokine-related genes, and suicide genes are used in this treatment. Viral therapy is a treatment that oncolytic viral replicates in tumor cells to destroy tumors. Various viral genes can also be used as therapeutic genes. Currently, the most well-studied and accumulated viruses are adenoviruses and HSV-1. Various clinical trials have been conducted using gene therapy and viral therapy, some of which are scheduled to be approved in the near future. Gene therapy and viral therapy have dramatically improved and have developed progressively since their first clinical use.

Feasibility of Mechanical Thrombectomy for Acute Ischemic Stroke Patients Aged 90 Years or Older Compared to Younger Patients

Mechanical thrombectomy (MT) is a proven treatment for acute ischemic stroke (AIS). However, the efficacy of this treatment is uncertain for very elderly patients. This study aimed to investigate the safety and effectiveness of MT in 90 years or older patients compared with younger patients. We retrospectively reviewed AIS patients treated with MT between October 2018 and June 2020 in our institution. Patients were divided into two groups: aged ≥90 and <90 years. We compared the following factors: functional outcome at discharge, in-hospital death, successful recanalization, and complications. Multivariate logistic regression analysis for the good functional outcome was performed. In consideration of pre-stroke basic activities of very elderly patients, we defined the good functional outcome as modified Rankin Scale (mRS) 0–3. In all, 66 patients were included, and 19 patients (28%) were ≥90 years old. Pre-stoke mRS was higher in ≥90-year-old patients (p = 0.01). In ≥90-year-old patients, we achieved successful recanalization in 17 patients (90%), and only one patient experienced hemorrhagic complication related with the procedure. The good functional outcome (mRS: 0–3) at discharge were six patients (32%) in ≥90 years old versus 19 patients (40%) in <90 years old (p = 0.6). Three patients died in hospital in each group (16% versus 6%) (p = 0.3). Only the stroke severity was negatively related with the good functional outcome in a multivariate analysis. In conclusion, for ≥90-year-old patients compared with younger patients, MT is an equally feasible therapy. Patients should not be excluded from MT based on age alone.

Histopathological Composition of Thrombus in Acute Ischemic Stroke May Vary Even Within the Same Patient: A Preliminary Study Examining Clots According to Their Area of Retrieval

Objective

Mechanical thrombectomy enables histopathological examination of clots in patients who have suffered acute ischemic strokes. Many studies have described about the relationship between the histopathological compositions of retrieved thrombi and imaging findings, clinical outcomes, and stroke etiology without consensus. In this study, we examined the histological composition of thrombi according to their retrieval site and methods.

Methods

We divided retrieved clots into three parts (those retrieved from the proximal and distal parts of the stent retriever, and those aspirated through the guiding catheter) and then histopathologically analyzed their compositions by measuring the area occupied by red blood cells (RBCs), fibrin/platelets (F/Ps), and white blood cells (WBCs).

Results

Each specimen showed various composition even within the same patient. For example, the area occupied by RBCs was 20.9% ± 12.1%, 30.5% ± 13.5%, and 41.3% ± 16.1% in the clot retrieved from the proximal and distal parts of the stent retriever, and those aspirated through the guiding catheter, respectively.

Conclusion

Histopathological clot composition may vary even within the patient. Further research is needed to investigate more objective methods of histopathological analysis and their clinical significance.

Differentiated glioblastoma cells accelerate tumor progression by shaping the tumor microenvironment via CCN1-mediated macrophage infiltration

Glioblastoma (GBM) is the most lethal primary brain tumor characterized by significant cellular heterogeneity, namely tumor cells, including GBM stem-like cells (GSCs) and differentiated GBM cells (DGCs), and non-tumor cells such as endothelial cells, vascular pericytes, macrophages, and other types of immune cells. GSCs are essential to drive tumor progression, whereas the biological roles of DGCs are largely unknown. In this study, we focused on the roles of DGCs in the tumor microenvironment. To this end, we extracted DGC-specific signature genes from transcriptomic profiles of matched pairs of in vitro GSC and DGC models. By evaluating the DGC signature using single cell data, we confirmed the presence of cell subpopulations emulated by in vitro culture models within a primary tumor. The DGC signature was correlated with the mesenchymal subtype and a poor prognosis in large GBM cohorts such as The Cancer Genome Atlas and Ivy Glioblastoma Atlas Project. In silico signaling pathway analysis suggested a role of DGCs in macrophage infiltration. Consistent with in silico findings, in vitro DGC models promoted macrophage migration. In vivo, coimplantation of DGCs and GSCs reduced the survival of tumor xenograft-bearing mice and increased macrophage infiltration into tumor tissue compared with transplantation of GSCs alone. DGCs exhibited a significant increase in YAP/TAZ/TEAD activity compared with GSCs. CCN1, a transcriptional target of YAP/TAZ, was selected from the DGC signature as a candidate secreted protein involved in macrophage recruitment. In fact, CCN1 was secreted abundantly from DGCs, but not GSCs. DGCs promoted macrophage migration in vitro and macrophage infiltration into tumor tissue in vivo through secretion of CCN1. Collectively, these results demonstrate that DGCs contribute to GSC-dependent tumor progression by shaping a mesenchymal microenvironment via CCN1-mediated macrophage infiltration. This study provides new insight into the complex GBM microenvironment consisting of heterogeneous cells.

The NRG3/ERBB4 signaling cascade as a novel therapeutic target for canine glioma

Canine glioma is a common brain tumor with poor prognosis despite surgery and/or radiation therapy. Therefore, newer and more effective treatment modalities are needed. Neuregulin 3 (NRG3) has known to be a ligand of ERBB4. This study aimed to investigate the usefulness of the NRG3/ERBB4 signaling cascade as a novel therapeutic target in canine glioma. We found out that microRNA (miR)-190a was downregulated in canine brain tumor tissues, including glioma and meningioma. miR-190a directly targeted NRG3 and inhibited the growth of canine glioma cells. The level of p-Akt, which is a downstream target of ERBB4 signaling, was decreased by transfection with miR-190a. NRG3 silencing also suppressed cell growth and decreased the levels of p-Akt and p-ERK1/2, and NRG3 overexpression exhibited opposed effects in canine glioma J3T-1 cells. The mRNA level of erbb4 was significantly upregulated in glioma tissues compared with that in normal brain tissues and meningioma tissues. Furthermore, compared with gefitinib and lapatinib, afatinib exerted a greater inhibitory effect on the growth of canine glioma cells. In conclusion, NRG3/ERBB4 signaling is negatively regulated by miR-190a and contributes to the growth of canine glioma cells, indicating that it may be a promising therapeutic target in canine glioma.

RARE-32. PEDIATRIC METASTATIC SKULL BASE CHORDOMA WITH TP53 MUTATION – A CASE REPORT AND REVIEW OF THE LITERATURE

Chordoma is an uncommon bone tumor arising from notochordal remnant, which accounts for 1–4% of all bone malignancies. It commonly occurs along the cranial-spinal axis, and skull base is one of most frequent sites, representing 35–49% of all chordoma cases. Surgical resection is widely accepted as the first choice of treatment. There are only limited number of reports about pediatric chordoma cases, and its biological behavior including genetic backgrounds were largely unknown. Here, we present a 5 year-old girl with a large aggressive skull base chordoma of 6 cm in maximum diameter, which eventually had multiple systemic metastasis. We initially tried chemotherapy based on the protocol for the osteosarcoma, but in vain. Because the tumor was highly vascularized on angiography, after embolization of the feeding arteries and bilateral internal maxillary arteries, endoscopic endonasal surgery was performed. The tumor was sufficiently removed, achieving effective mass reduction, and the residual tumors involving the lower cranial nerves and craniocervial junction were additionally treated with Gamma Knife radiosurgery. However, one month later, it showed systemic metastasis to bilateral cervical lymph nodes and lung. We tried chemotherapy with nivolmab and imatinib for this patient, whereas they showed the partial effect. The genetic analysis revealed somatic TP53 c.569C>T, (p.P190L) mutation in chordoma specimen. In the past literature, we found only one study of the adult chordoma cases, in which majority of the patients had somatic TP53 mutation (p.P72R). Further investigation with large number of the cases is essential to clarify the molecular biology of pediatric chordomas.

SURG-21. ENDO- AND EXOSCOPIC SURGERY FOR PEDIATRIC NEUROSURGICAL OPERATION

INTRODUCTION

Recently endo- and exoscopic surgeries have been gradually performed in neurosurgery. To improve the accuracy and safety of our endoscopic procedures, we are currently trialing 4K or 8K systems. Here we report our experience of endo- and exoscopic procedures for pediatric neurosurgery.

METHODS

We retrospectively identified 22 patients (15 males, 7 females; mean age, 9.2 years) who underwent surgery for sellar lesions and intraventricular or intraparenchymal lesions with an endo- or exoscopic procedure at our institute between 2010 and 2020. We used a full HD endoscope system (Storz) and an organic electroluminescence (EL) monitor (Sony), and a 4K system (Sony and Olympus). VITOM 3D (Storz) was used as the exoscope. Videoscope (Olympus) was used as a flexible scope for intraventricular tumors.

RESULTS

We performed surgical procedures as 11 biopsies, 6 third ventriculostomies, 5 resections, and 3 fenestrations. The full HD system with organic EL monitor presented high color contrast. We could easily distinguish between tumor microstructure and the normal structure with the 4K system comparing to full HD. Moreover, electronic zoom function enabled us to discriminate tumor boundaries without having to move the endoscope closer. As a result, we could delineate the surgical working space. VITOM 3D was simple to sharpen the focus on the wider surgical field, similar to the application of an operating microscope.

CONCLUSION

In pediatric neurosurgery, an endo- or exoscope enables clear visual recognition of a boundary between tumor and normal area.

MS-2 Minimally invasive glioma surgery with navigation system and tubular retractor

Navigation systems are reliable and safe for neurological surgery. Navigation is an attractive and innovative therapeutic option. Recently, endo and exoscopic surgeries have been gradually increasing in neurosurgery. We are currently trialing to use 4K and 8K systems to improve the accuracy and safety of our surgical procedures. Surgeries for deep-seated tumors are challenging because of the difficulty in creating a corridor and observing the interface between lesions and the normal area. In total, 315 patients underwent surgery at Okayama University between 2017 and 2019. Among them, we experienced 92 glioma surgeries using navigation systems. Preoperatively, we performed computed tomography imaging and contrast-enhanced magnetic resonance imaging (MRI) for the neuronavigation system. We experienced Curve(TM) Image Guided Surgery (BrainLab, Munich, Germany). The surgical trajectory was planned with functional MRI and diffusion tensor imaging to protect the eloquent area and critical vasculature of the brain. We used a clear plastic tubular retractor system, the ViewSite Brain Access System, for surgery of deep seated gliomas. We gently inserted and placed the ViewSite using the neuronavigation. The tumor was observed and resected through the ViewSite tubular retractor under a microscope and endoscope. If the tumor was large, we switched the ViewSite tubular retractor to brain spatulas to identify the boundary between the normal brain and lesion. We are currently using the combination of the tubular retractor and brain spatulas using navigation system. Here, we present and analyze our preoperative simulation, surgical procedure, and outcomes.

NI-01 Usefulness of preoperative evaluation of glioma elasticity by the magnetic resonance elastography

Introduction: The elasticity of intracranial tumors is difficult to assess non-invasively because the lesion is surrounded by the skull. Therefore, intracranial tumors have not been verified before surgery in terms of elastic modulus. Magnetic resonance elastography (MRE) is an epoch-making method capable of non-invasively imaging the elasticity of internal organs. We have examined the elasticity of meningiomas and pituitary adenomas and reported their usefulness. This time, we measured the glioma elasticity and verified usefulness of MRE.

Method: Twenty-four gliomas (mean age 51.8±15.7 years, male: female = 17: 7) who underwent tumor resection after MRE imaging from July 2017 to May 2020 were targeted. The average elasticity was measured as an evaluation of tumor elastic modulus by MRE. Gliomas were divided into a low-grade glioma group (LGG: Grade 1, 2) and a high-grade glioma group (HGG: Grade 3, 4). Then, a comparative statistical study was conducted.

Results: The average values of the average elasticity of LGG group (9 cases) and HGG group (15 cases) were 1.8±0.8 kPa and 2.5±0.8 kPa, respectively. The average elasticity was significantly higher in the HGG group (p=0.023). In the ROC analysis, the cutoff value was 2.1 kPa (sensitivity 70%, specificity 70%). Therefore, it was suggested that the tumor is likely to be HGG when the average elasticity is 2.1 kPa or more.

Discussion: The glioma elasticity by preoperative MRE was significantly higher in the HGG group. Based on actual surgical experience, the tumor seems to be hard in the HGG group, and it was judged to be consistent with this our MRE research. The preoperative evaluation of glioma elasticity by MRE was considered useful, and it might help in planning a surgical strategy considering malignant grade.

TERT promoter mutation confers favorable prognosis regardless of 1p/19q status in adult diffuse gliomas with IDH1/2 mutations

TERT promoter mutations are commonly associated with 1p/19q codeletion in IDH-mutated gliomas. However, whether these mutations have an impact on patient survival independent of 1p/19q codeletion is unknown. In this study, we investigated the impact of TERT promoter mutations on survival in IDH-mutated glioma cases. Detailed clinical information and molecular status data were collected for a cohort of 560 adult patients with IDH-mutated gliomas. Among these patients, 279 had both TERT promoter mutation and 1p/19q codeletion, while 30 had either TERT promoter mutation (n = 24) or 1p/19q codeletion (n = 6) alone. A univariable Cox proportional hazard analysis for survival using clinical and genetic factors indicated that a Karnofsky performance status score (KPS) of 90 or 100, WHO grade II or III, TERT promoter mutation, 1p/19q codeletion, radiation therapy, and extent of resection (90-100%) were associated with favorable prognosis (p < 0.05). A multivariable Cox regression model revealed that TERT promoter mutation had a significantly favorable prognostic impact (hazard ratio = 0.421, p = 0.049), while 1p/19q codeletion did not have a significant impact (hazard ratio = 0.648, p = 0.349). Analyses incorporating patient clinical and genetic information were further conducted to identify subgroups showing the favorable prognostic impact of TERT promoter mutation. Among the grade II-III glioma patients with a KPS score of 90 or 100, those with IDH-TERT co-mutation and intact 1p/19q (n = 17) showed significantly longer survival than those with IDH mutation, wild-type TERT, and intact 1p/19q (n = 185) (5-year overall survival, 94% and 77%, respectively; p = 0.032). Our results demonstrate that TERT promoter mutation predicts favorable prognosis independent of 1p/19q codeletion in IDH-mutated gliomas. Combined with its adverse effect on survival among IDH-wild glioma cases, the bivalent prognostic impact of TERT promoter mutation may help further refine the molecular diagnosis and prognostication of diffuse gliomas.

Detailed Arterial Anatomy and Its Anastomoses of the Sphenoid Ridge and Olfactory Groove Meningiomas with Special Reference to the Recurrent Branches from the Ophthalmic Artery

BACKGROUND AND PURPOSE

Detailed arterial anatomy of the sphenoid ridge and olfactory groove meningiomas is complicated due to the fine angioarchitecture and anastomoses between each feeder. Herein, we present details of the arterial anatomy and the relationships of feeders in these lesions.

MATERIALS AND METHODS

This study included 20 patients admitted to our department between April 2015 and March 2020. Conditions of subjects consisted of 16 sphenoid ridge meningiomas and 4 olfactory groove meningiomas. We mainly analyzed arterial anatomy using 3D rotational angiography and slab MIP images of these lesions. We also analyzed the anastomoses of each feeder.

RESULTS

We found that 19 (95%), 15 (75%), and 15 (75%) lesions had feeders from the ophthalmic, internal carotid, and external carotid arteries, respectively. As feeders from the ophthalmic artery, recurrent meningeal arteries were involved in 18 lesions (90%). Fifteen lesions (75%) had anastomoses between each feeder.

CONCLUSIONS

Most of the meningiomas in the sphenoid ridge and olfactory groove had feeders from the ophthalmic and internal carotid arteries. There were various anastomoses between each feeder. This is the first report to demonstrate the detailed arterial anatomy and frequency of recurrent branches from the ophthalmic artery and their anastomoses using detailed imaging techniques.

Integrated clinical, histopathological, and molecular data analysis of 190 central nervous system germ cell tumors from the iGCT Consortium

BACKGROUND

We integrated clinical, histopathological, and molecular data of central nervous system germ cell tumors to provide insights into their management.

METHODS

Data from the Intracranial Germ Cell Tumor Genome Analysis (iGCT) Consortium were reviewed. A total of 190 cases were classified as primary germ cell tumors (GCTs) based on central pathological reviews.

RESULTS

All but one of the cases that were bifocal (neurohypophysis and pineal glands) and cases with multiple lesions including neurohypophysis or pineal gland were germinomas (34 of 35). Age was significantly higher in patients with germinoma than other histologies. Comparison between tumor marker and histopathological diagnoses showed that 18.2% of histopathologically diagnosed germinomas were marker positive and 6.1% of non-germinomatous GCTs were marker negative, suggesting a limitation in the utility of markers or histopathology alone using small specimens for diagnosis. Comparison between local and central histopathological diagnoses revealed a discordance of 12.7%. Discordance was significantly less frequent in biopsy cases, implying difficulty in detecting all histopathological components of heterogeneous GCTs. Germinomas at the typical sites (neurohypophysis or pineal gland) showed a better progression-free survival than those at atypical sites (P = 0.03). A molecular clinical association study revealed frequent mitogen-activated protein kinase (MAPK) pathway mutations in males (51.4% vs 14.3%, P = 0.007), and phosphatidylinositol-3 kinase/mammalian target of rapamycin (PI3K/mTOR) pathway mutations in basal ganglia cases (P = 0.004). Basal ganglia cases also had frequent chromosomal losses. Some chromosomal aberrations (2q, 8q gain, 5q, 9p/q, 13q, 15q loss) showed potential prognostic significance.

CONCLUSIONS

The in-depth findings of this study regarding clinical and molecular heterogeneity will increase our understanding of the pathogenesis of this enigmatic tumor.

Neurosurgery for brain metastasis from breast cancer

Breast cancer is the most common malignancy among women worldwide, and the main cause of death in patients with breast cancer is metastasis. Metastasis to the central nervous system occurs in 10% to 16% of patients with metastatic breast cancer, and this rate has increased because of recent advancements in systemic chemotherapy. Because of the various treatments available for brain metastasis, accurate diagnosis and evaluation for treatment are important. Magnetic resonance imaging (MRI) is one of the most reliable preoperative examinations not only for diagnosis of metastatic brain tumors but also for estimation of the molecular characteristics of the tumor based on radiographic information such as the number of lesions, solid or ring enhancement, and cyst formation. Surgical resection continues to play an important role in patients with a limited number of brain metastases and a relatively good performance status. A single brain metastasis is a good indication for surgical treatment followed by radiation therapy to obtain longer survival. Surgical removal is also considered for two or more lesions if neurological symptoms are caused by brain lesions of >3 cm with a mass effect or associated hydrocephalus. Although maximal safe resection with minimal morbidity is ideal in the surgical treatment of brain tumors, supramarginal resection can be achieved in select cases. With respect to the resection technique, en bloc resection is generally recommended to avoid leptomeningeal dissemination induced by piecemeal resection. An operating microscope, neuronavigation, and intraoperative neurophysiological monitoring are essential in modern neurosurgical procedures, including tumor resection. More recently, supporting surgical instruments have been introduced. The use of endoscopic surgery has dramatically increased, especially for intraventricular lesions and in transsphenoidal surgery. An exoscope helps neurosurgeons to comfortably operate regardless of patient positioning or anatomy. A tubular retractor can prevent damage to the surrounding brain tissue during surgery and is a useful instrument in combination with both an endoscope and exoscope. Additionally, 5-aminolevulinic acid (5-ALA) is a promising reagent for photodynamic detection of residual tumor tissue. In the near future, novel treatment options such as high-intensity focused ultrasound (HIFU), laser interstitial thermal therapy (LITT), oncolytic virus therapy, and gene therapy will be introduced.

Primary Central Nervous System Methotrexate-associated Lymphoproliferative Disorder in a Patient with Rheumatoid Arthritis: Case Report and Review of Literature

Methotrexate (MTX) is an immunosuppressor that is widely used to treat autoimmune diseases, including rheumatoid arthritis (RA). However, it can have serious adverse effects including a lymphoma: MTX-associated lymphoproliferative disorder (MTX-LPD). Extranodal lesions are common in MTX-LPD patients. However, MTX-LPD in the central nervous system (CNS) is extremely rare with few reported cases. Here, we describe a case of primary CNS MTX-LPD in a patient with RA, with a review of the literature. A 68-year-old woman who had received MTX for her RA for more than 10 years was referred to our hospital. Head magnetic resonance imaging (MRI) showed multiple lesions with heterogeneous contrast enhancement scattered throughout both hemispheres. As immunosuppression caused by MTX was suspected, MTX was discontinued, based on a working diagnosis of MTX-LPD. We performed an open biopsy of her right temporal lesion. Histopathologic examination showed atypical CD20+ lymphoid cells, leading to a definitive diagnosis of diffuse large B-cell lymphoma (DLBCL). In situ hybridization of an Epstein-Barr virus-encoded small RNA (EBER) was positive. Sanger sequencing confirmed that both MYD88 L265 and CD79B Y196 mutations were absent. The LPD regressed after stopping MTX. Follow-up head MRI at 8 months after surgery showed no evidence of recurrence. Although primary CNS MTX-LPD is extremely rare, it should be included in the differential diagnosis when a patient receiving MTX develops CNS lesions. Diagnosis by biopsy and MTX discontinuation are required as soon as possible.

Development of a novel gripping test for the evaluation of the finger fine motor ability in MPTP-treated monkeys

Assessing the finger fine motor ability is extremely important. However, conventional behavioral tests in monkeys are complicated and costly. We attempted to develop a new task to assess the precise finger grip in Parkinson's disease monkeys based on the principles of objectification, multipurpose, and simplification. This study involved seven adult male cynomolgus monkeys. A gripping test based on the previous food reaching test was developed. Parallel experiments of food reaching test and gripping test affected by the treatments of levodopa and deep brain stimulation of the subthalamic nucleus were performed to verify the utility of the gripping test. We found that gross motor ability (measured by food reaching test) could be significantly improved by both the subthalamic nucleus and levodopa administration, which reproduced the results of our previous study. The finger fine motor ability (measured by the gripping test) could be significantly improved by levodopa administration, but not by the subthalamic nucleus. Our results verified the utility and reliability of the gripping test, which is a simple, convenient, and objective task for evaluating the finger fine motor skill in Parkinson's disease monkeys. Mechanisms of the efficacy of deep brain stimulation on fine motor ability require further investigation.

Annexin A2-STAT3-Oncostatin M receptor axis drives phenotypic and mesenchymal changes in glioblastoma

Glioblastoma (GBM) is characterized by extensive tumor cell invasion, angiogenesis, and proliferation. We previously established subclones of GBM cells with distinct invasive phenotypes and identified annexin A2 (ANXA2) as an activator of angiogenesis and perivascular invasion. Here, we further explored the role of ANXA2 in regulating phenotypic transition in GBM. We identified oncostatin M receptor (OSMR) as a key ANXA2 target gene in GBM utilizing microarray analysis and hierarchical clustering analysis of the Ivy Glioblastoma Atlas Project and The Cancer Genome Atlas datasets. Overexpression of ANXA2 in GBM cells increased the expression of OSMR and phosphorylated signal transducer and activator of transcription 3 (STAT3) and enhanced cell invasion, angiogenesis, proliferation, and mesenchymal transition. Silencing of OSMR reversed the ANXA2-induced phenotype, and STAT3 knockdown reduced OSMR protein expression. Exposure of GBM cells to hypoxic conditions activated the ANXA2–STAT3–OSMR signaling axis. Mice bearing ANXA2-overexpressing GBM exhibited shorter survival times compared with control tumor-bearing mice, whereas OSMR knockdown increased the survival time and diminished ANXA2-mediated tumor invasion, angiogenesis, and growth. Further, we uncovered a significant relationship between ANXA2 and OSMR expression in clinical GBM specimens, and demonstrated their correlation with tumor histopathology and patient prognosis. Our results indicate that the ANXA2–STAT3–OSMR axis regulates malignant phenotypic changes and mesenchymal transition in GBM, suggesting that this axis is a promising therapeutic target to treat GBM aggressiveness.

Intracranial Mesenchymal Chondrosarcoma Lacking the Typical Histopathological Features Diagnosed by HEY1-NCOA2 Gene Fusion

Intracranial mesenchymal chondrosarcoma (MCS) is a rare neoplasm. The diagnosis of MCS is confirmed by the presence of a biphasic pattern on histological examination, comprising undifferentiated small round cells admixed with islands of well-differentiated hyaline cartilage; however, a differential diagnosis may be challenging in some cases. A 28-year-old woman with a 2-month history of headache was referred to our hospital. Radiologic studies showed an extra-axial lobulated mass composed of calcified and uncalcified areas occupying the left middle fossa. Surgical resection was planned, but her headache suddenly worsened before her planned hospital admission and she was admitted as an emergency. Radiologic studies showed an acute hemorrhage in the uncalcified part of the mass. The mass was resected via the left zygomatic approach after embolization of the feeder vessels. The most likely histopathological diagnosis was MCS. However, the typical bimorphic pattern was not identified in our surgical samples; each undifferentiated area and well-differentiated area was observed separately in different tissue specimens, and no islands of well-differentiated hyaline cartilage were identified within the undifferentiated areas in the same specimen. Molecular assays confirmed the presence of HEY1-NCOA2 fusion. IRF2BP2-CDX1 fusion and IDH1/2 mutations were negative. The final diagnosis of MCS was made based on the presence of HEY1-NCOA2 gene fusion. MCS should be included in the differential diagnosis when radiologic studies show an extra-axial lobulated mass with calcification. Furthermore, molecular demonstration of HEY1-NCOA2 gene fusion may help make a precise diagnosis of MCS, especially in surgical samples lacking the typical histopathological features.

Precise MEP monitoring with a reduced interval is safe and useful for detecting permissive duration for temporary clipping

Although temporary clipping of the parent artery is an indispensable technique in clipping surgery for intracranial aneurysms, the permissive duration of temporary clipping is still not well known. The aim of this study is to confirm the safety of precise motor evoked potential (MEP) monitoring and to estimate the permissive duration of temporary clipping for middle cerebral artery (MCA) aneurysm based on precise MEP monitoring results. Under precise MEP monitoring via direct cortical stimulation every 30 seconds to 1 minute, surgeons released a temporary clip and waited for MEP amplitude to recover following severe (>50%) reduction of MEP amplitude during temporary clipping. Precise MEP monitoring was safely performed. Twenty-eight instances of temporary clipping were performed in 42 MCA aneurysm clipping surgeries. Because precise MEP monitoring could be used to determine when to release a temporary clip even with a severe reduction in MEP amplitude due to lengthy temporary clipping, no patients experienced permanent postoperative hemiparesis. Based on logistic regression analysis, if a temporary clip is applied for 312 seconds or more, there is a higher probability of a severe reduction in MEP amplitude. We should therefore release temporary clips after 5 minutes in order to avoid permanent postoperative hemiparesis.