Intraoperative Integrated Diagnostic System for Malignant Central Nervous System Tumors

PURPOSE

The 2021 World Health Organization (WHO) classification of central nervous system (CNS) tumors uses an integrated approach involving histopathology and molecular profiling. Because majority of adult malignant brain tumors are gliomas and primary CNS lymphomas (PCNSL), rapid differentiation of these diseases is required for therapeutic decisions. In addition, diffuse gliomas require molecular information on single-nucleotide variants (SNV), such as IDH1/2. Here, we report an intraoperative integrated diagnostic (i-ID) system to classify CNS malignant tumors, which updates legacy frozen-section (FS) diagnosis through incorporation of a qPCR-based genotyping assay.

EXPERIMENTAL DESIGN

FS evaluation, including GFAP and CD20 rapid IHC, was performed on adult malignant CNS tumors. PCNSL was diagnosed through positive CD20 and negative GFAP immunostaining. For suspected glioma, genotyping for IDH1/2, TERT SNV, and CDKN2A copy-number alteration was routinely performed, whereas H3F3A and BRAF SNV were assessed for selected cases. i-ID was determined on the basis of the 2021 WHO classification and compared with the permanent integrated diagnosis (p-ID) to assess its reliability.

RESULTS

After retrospectively analyzing 153 cases, 101 cases were prospectively examined using the i-ID system. Assessment of IDH1/2, TERT, H3F3AK27M, BRAFV600E, and CDKN2A alterations with i-ID and permanent genomic analysis was concordant in 100%, 100%, 100%, 100%, and 96.4%, respectively. Combination with FS and intraoperative genotyping assay improved diagnostic accuracy in gliomas. Overall, i-ID matched with p-ID in 80/82 (97.6%) patients with glioma and 18/19 (94.7%) with PCNSL.

CONCLUSIONS

The i-ID system provides reliable integrated diagnosis of adult malignant CNS tumors.

Arteries Around the Superior Limiting Sulcus: Motor Complication Avoidance in Insular and Insulo-Opercular Surgery

BACKGROUND AND OBJECTIVES

Insulo-opercular surgery can cause ischemic motor complications. A source of this is the arteries around the superior limiting sulcus (SLS), which reach the corona radiata, but the detailed anatomy remains unclear. To characterize arteries around the SLS including the long insular arteries (LIAs) and long medullary arteries, we classified them and examined their distribution in relation to the SLS, which helps reduce the risk of ischemia.

METHODS

Twenty adult cadaveric hemispheres were studied. Coronal brain slices were created perpendicular to the SLS representing insular gyri (anterior short, middle short, posterior short, anterior long, and posterior long). The arteries within 10-mm proximity of the SLS that reached the corona radiata were excavated and classified by the entry point.

RESULTS

A total of 122 arteries were identified. Sixty-three (52%), 20 (16%), and 39 (32%) arteries penetrated the insula (LIAs), peak of the SLS, and operculum (long medullary arteries), respectively. 100 and six (87%) arteries penetrated within 5 mm of the peak of the SLS. The arteries were distributed in the anterior short gyrus (19%), middle short gyrus (17%), posterior short gyrus (20%), anterior long gyrus (19%), and posterior long gyrus (25%). Seven arteries (5.7%) had anastomoses after they penetrated the parenchyma.

CONCLUSION

Approximately 90% of the arteries that entered the parenchyma and reached the corona radiata were within a 5-mm radius of the SLS in both the insula and operculum side. This suggests that using the SLS as a landmark during insulo-opercular surgery can decrease the chance of ischemia.

Antiplatelet drugs may increase the risk for checkpoint inhibitor-related pneumonitis in advanced cancer patients

BACKGROUND

Immune checkpoint inhibitors (ICIs) are indicated for various cancers and are the mainstay of cancer immunotherapy. They are often associated with ICI-related pneumonitis (CIP), however, hindering a favorable clinical course. Recently, non-oncology concomitant drugs have been reported to affect the efficacy and toxicity of ICIs; however, the association between these drugs and the risk for CIP is uncertain. The aim of this study was to assess the impact of baseline concomitant drugs on CIP incidence in ICI-treated advanced cancer patients.

PATIENTS AND METHODS

This was a single-center retrospective study that included a cohort of 511 patients with advanced cancer (melanoma and non-small-cell lung, head and neck, genitourinary, and other types of cancer) treated with ICIs. Univariable analysis was conducted to identify baseline co-medications associated with CIP incidence. A propensity score matching analysis was used to adjust for potential CIP risk factors, and multivariable analysis was carried out to assess the impact of the identified co-medications on CIP risk.

RESULTS

Forty-seven (9.2%) patients developed CIP. In these patients, the organizing pneumonia pattern was the dominant radiological phenotype, and 42.6% had grade ≥3 CIP, including one patient with grade 5. Of the investigated baseline co-medications, the proportion of antiplatelet drugs (n = 50, 9.8%) was higher in patients with CIP (23.4% versus 8.4%). After propensity score matching, the CIP incidence was higher in patients with baseline antiplatelet drugs (22% versus 6%). Finally, baseline antiplatelet drug use was demonstrated to increase the risk for CIP incidence regardless of cancer type (hazard ratio, 3.46; 95% confidence interval 1.21-9.86).

CONCLUSIONS

An association between concomitant antiplatelet drug use at baseline and an increased risk for CIP was seen in our database. This implies the importance of assessing concomitant medications for CIP risk management.

Genetic alterations that deregulate RB and PDGFRA signaling pathways drive tumor progression in IDH2-mutant astrocytoma

In IDH-mutant astrocytoma, IDH2 mutation is quite rare and biological mechanisms underlying tumor progression in IDH2-mutant astrocytoma remain elusive. Here, we report a unique case of IDH2 mutant astrocytoma, CNS WHO grade 3 that developed tumor progression. We performed a comprehensive genomic and epigenomic analysis for primary and recurrent tumors and found that both tumors harbored recurrent IDH2R172K and TP53R248W mutation with CDKN2A/B hemizygous deletion. We also found amplifications of CDK4 and MDM2 with PDGFRA gain in the recurrent tumor and upregulated protein expressions of these genes. We further developed, for the first time, a xenograft mouse model of IDH2R172K and TP53R248W mutant astrocytoma from the recurrent tumor, but not from the primary tumor. Consistent with parent recurrent tumor cells, amplifications of CDK4 and MDM2 and PDGFRA gain were found, while CDKN2A/B was identified as homozygous deletion in the xenografts, qualifying for integrated diagnosis of astrocytoma, IDH2-mutant, CNS WHO grade 4. Cell viability assay found that CDK4/6 inhibitor and PDGFR inhibitor potently decreased cell viability in recurrent tumor cells, as compared to primary tumor cells. These findings suggest that gene alterations that activate retinoblastoma (RB) signaling pathways and PDGFR may drive tumor progression and xenograft formation in IDH2-mutant astrocytoma, which is equivalent to progressive IDH1-mutant astrocytoma. Also, our findings suggest that these genomic alterations may represent therapeutic targets in IDH2-mutant astrocytoma.

Transvenous embolization for an intraosseous clival arteriovenous fistula via a proper access route guiding a three-dimensional fusion image: illustrative case

BACKGROUND

Intraosseous clival arteriovenous fistulas (AVFs), in which the shunt drains extracranially from the posterior and anterior condylar veins rather than from the cavernous sinus (CS), are rare. Targeting embolization of an intraosseous clival AVF is challenging because of its complex venous and skull base anatomy; therefore, a therapeutic strategy based on detailed preoperative radiological findings is required to achieve a favorable outcome. Here, the authors report the successful targeted embolization of an intraosseous clival AVF using an ingenious access route.

OBSERVATIONS

A 74-year-old woman presented with left-sided visual impairment, oculomotor nerve palsy, and right facial pain. A fusion image of three-dimensional rotational angiography and cone-beam computed tomography revealed a left CS dural AVF and a right intraosseous clival AVF. The shunt flow of the clival AVF drained extracranially from the posterior and anterior condylar veins via the intraosseous venous route. Transvenous embolization was performed by devising suboccipital, posterior condylar, and intraosseous access routes. The symptoms resolved after the bilateral AVFs were treated.

LESSONS

Accurate diagnosis and proper transvenous access based on detailed intraosseous and craniocervical venous information obtained from advanced imaging modalities are key to resolving intraosseous clival AVF.

Understanding the molecular pathogenesis of primary central nervous system lymphoma by experimental animal models

Primary central nervous system lymphoma (PCNSL) is a rare and invasive diffuse large B cell lymphoma confined in central nervous system (CNS). The effort to press forward the translational progress has been frustrated by the insufficient understanding of immunophenotype of CNS and tumor genetic alterations of PCNSL, and the lack of validated diagnostic biomarkers. Researchers now have a variety of PCNSL animal models at their disposal that resemble the morphology and immunophenotype of PCNSL, however, a careful and detailed re-examination of these animal models is needed to clarify the differences in genetic alterations, migration capability, and immune status. In this review, we present the knowledge about the phenotypic and genotypic features of PCNSL tumor cells, and compile the preclinical animal models of PCNSL with regard to various injection sites, cell origins, recipient animals, and immune status, and elaborate on the tropism and migration of tumor cells and novel therapeutic strategies for PCNSL. We envisage that the selection of suitable animal models will serve as a well-defined preclinical system to understand the molecular pathogenesis of PCNSL, thereby galvanizing the development of novel and potent therapeutic approaches.

Extranodal lymphoma: pathogenesis, diagnosis and treatment

Approximately 30% of lymphomas occur outside the lymph nodes, spleen, or bone marrow, and the incidence of extranodal lymphoma has been rising in the past decade. While traditional chemotherapy and radiation therapy can improve survival outcomes for certain patients, the prognosis for extranodal lymphoma patients remains unsatisfactory. Extranodal lymphomas in different anatomical sites often have distinct cellular origins, pathogenic mechanisms, and clinical manifestations, significantly influencing their diagnosis and treatment. Therefore, it is necessary to provide a comprehensive summary of the pathogenesis, diagnosis, and treatment progress of extranodal lymphoma overall and specifically for different anatomical sites. This review summarizes the current progress in the common key signaling pathways in the development of extranodal lymphomas and intervention therapy. Furthermore, it provides insights into the pathogenesis, diagnosis, and treatment strategies of common extranodal lymphomas, including gastric mucosa-associated lymphoid tissue (MALT) lymphoma, mycosis fungoides (MF), natural killer/T-cell lymphoma (nasal type, NKTCL-NT), and primary central nervous system lymphoma (PCNSL). Additionally, as PCNSL is one of the extranodal lymphomas with the worst prognosis, this review specifically summarizes prognostic indicators and discusses the challenges and opportunities related to its clinical applications. The aim of this review is to assist clinical physicians and researchers in understanding the current status of extranodal lymphomas, enabling them to make informed clinical decisions that contribute to improving patient prognosis.

[Circumscribed Astrocytic Gliomas]

In the fifth edition central nervous system tumours volume of the WHO Classification of Tumours series, gliomas, glioneuronal tumors, and neuronal tumors are divided into six groups. The term "circumscribed" is used to refer to a relatively contained growth pattern, as compared to other inherently "diffuse" tumors. Circumscribed astrocytic gliomas include six types: pilocytic astrocytoma, high-grade astrocytoma with piloid features, pleomorphic xanthoastrocytoma, subependymal giant cell astrocytoma, chordoid glioma, and astroblastoma, MN1-altered. The vast majority of circumscribed astrocytic gliomas harbor genetic alterations in the mitogen-activated protein kinase pathway. Here, we review the circumscribed astrocytic gliomas, including etiology, clinical and imaging features, pathology and molecular genetics, treatment, and prognosis. This study will lead to better understanding of these newly classified tumors.

Epigenetic upregulation of Schlafen11 renders WNT- and SHH-activated medulloblastomas sensitive to cisplatin

BACKGROUND

Intensive chemotherapeutic regimens with craniospinal irradiation have greatly improved survival in medulloblastoma patients. However, survival markedly differs among molecular subgroups and their biomarkers are unknown. Through unbiased screening, we found Schlafen family member 11 (SLFN11), which is known to improve response to DNA damaging agents in various cancers, to be one of the top prognostic markers in medulloblastomas. Hence, we explored the expression and functions of SLFN11 in medulloblastoma.

METHODS

SLFN11 expression for each subgroup was assessed by immunohistochemistry in 98 medulloblastoma patient samples and by analyzing transcriptomic databases. We genetically or epigenetically modulated SLFN11 expression in medulloblastoma cell lines and determined cytotoxic response to the DNA damaging agents cisplatin and topoisomerase I inhibitor SN-38 in vitro and in vivo.

RESULTS

High SLFN11 expressing cases exhibited significantly longer survival than low expressing cases. SLFN11 was highly expressed in the WNT-activated subgroup and in a proportion of the SHH-activated subgroup. While WNT activation was not a direct cause of the high expression of SLFN11, a specific hypomethylation locus on the SLFN11 promoter was significantly correlated with high SLFN11 expression. Overexpression or deletion of SLFN11 made medulloblastoma cells sensitive and resistant to cisplatin and SN-38, respectively. Pharmacological upregulation of SLFN11 by the brain-penetrant histone deacetylase-inhibitor RG2833 markedly increased sensitivity to cisplatin and SN-38 in SLFN11-negative medulloblastoma cells. Intracranial xenograft studies also showed marked sensitivity to cisplatin by SLFN11-overexpression in medulloblastoma cells.

CONCLUSIONS

High SLFN11 expression is one factor which renders favorable outcomes in WNT-activated and a subset of SHH-activated medulloblastoma possibly through enhancing response to cisplatin.

Thigh leiomyosarcoma-derived brain metastasis with intracerebral hematoma: A case report and literature review

Background:

Brain metastases with hematoma are clinically important as they indicate the potential for rapid neurological deterioration. Non-uterine leiomyosarcoma-derived brain metastases are particularly rare, and their clinical features, including the bleeding rate, are unclear. Herein, we present a rare case of thigh leiomyosarcoma-derived brain metastasis with intratumoral hematoma and review previous case reports.

Case Description:

A 68-year-old man with a right thigh leiomyosarcoma presented with multiple brain metastases. The patient received stereotactic radiotherapy; however, he reported sudden right-sided hemiparesis. We found a right frontal irradiated lesion with intratumoral hemorrhage and performed gross total tumor resection. Histopathological examination showed highly atypical cells with prominent necrosis and hemorrhage. Abnormal thin-walled vessels were prominent within the brain tumor, and vascular endothelial growth factor was diffusely expressed immunohistopathologically. To date, 11 cases of brain metastasis from non-uterine leiomyosarcoma, including the present case, have been reported. Of note, six patients had hemorrhage. Three out of six patients presented with hemorrhage before therapeutic intervention, three cases were from residual sites after surgery or radiation.

Conclusion:

More than half the patients with non-uterine leiomyosarcoma-derived brain metastases presented with intracerebral hemorrhage. Furthermore, these patients are at risk of developing rapid neurological deterioration due to intracerebral hemorrhage.

CBMS-1 TARGETING GLUTAMINE METABOLISM IN IDH-MUTANT GLIOMAS

IDH-wildtype and IDH-mutant glioma have different genetical and metabolic background although their histological appearances are similar. To reveal the difference in metabolites between IDH-wildtype and IDH-mutant glioma, two artificial cell lines made from normal human astrocyte, NHAE6E7hTERTRas (IDH-wildtype) and NHAE6E7hTERTIDHmut (IDH-mutant), were investigated. Capillary electrophoresis- and ion chromatography-coupled mass spectrometry revealed the lower amount of glutamine, glutamate and 2-oxoglutarate in NHAE6E7hTERTIDHmut cells than NHAE6E7hTERTRas cells. Pharmacological or genetical inhibition of GLUD1 which converts glutamate to 2-oxoglutarate, suppressed proliferation of the cells by inducing ROS and apoptosis in NHAE6E7hTERTIDHmut cells. ROS inhibitor, NAC suppressed GLUD1 inhibitor-induced ROS, apoptosis, and cytotoxicity in NHAE6E7hTERTIDHmut cells, revealing that cytotoxicity by GLUD1 inhibitor was at least partially due to the inhibitor-induced ROS. Exogeneous dimethyl 2-oxoglutarate rescued the cytotoxicity by GLUD1 inhibitor, suggesting decreased 2-oxoglutarate was associated with GLUD1 inhibitor-induced cytotoxicity. Mutant IDH1 overexpressed glioma cell line showed similar sensitivity to GLUD1 inhibitor to NHAE6E7hTERTIDHmut, which suggested that the difference of sensitivity to GLUD1 inhibitor was due to the status of mutant IDH. In conclusion, GLUD1 inhibitor will be new therapeutic options for IDH-mutant glioma.

GEN-13 PAIRED MUTATIONAL ANALYSIS IN SECONDARY NERVOUS SYSTEM LYMPHOMA AND PCNSL SYSTEMIC RELAPSE REVEALS DRIVER MUTATION CANDIDATES IN THE CENTRAL NERVOUS SYSTEM

Primary central nervous system lymphoma (PCNSL) is an aggressive extranodal non-Hodgkin lymphoma confined to the brain, eyes, and the spinal cord. The mechanism of central nervous system (CNS) tropism in PCNSL has not been fully elucidated. Diffuse large B cell lymphomas (DLBCLs) occasionally present with distant recurrence, which can involve inside and outside the CNS. Secondary central nervous system lymphomas (SCNSLs) are CNS relapse of systemic lymphoma. PCNSLs also rarely present with systemic relapse. We have previously reported in our study of whole exome sequencing that PCNSLs harbor frequent mutations in genes of B cell receptor pathway members and aberrant somatic hypermutation (aSHM) target genes. Although several genetic alterations were identified as more frequent in PCNSLs compared with systemic lymphomas, specific genetic alterations which serve as the driver for CNS tropism in PCNSLs has not been identified. In order to search for mutations which might serve as driver mutations in the CNS, we have performed targeted sequencing in paired samples from patients with recurrent lymphomas, either SCNSLs or PCNSL systemic relapses, using Ion Torrent multiplex PCR. Mutational profiles were compared between the primary and recurrent tumor. Six cases (four SCNSL cases and two PCNSL systemic relapse cases) were analyzed. Of note, in the SCNSL cases, several de novo mutations were enriched only among the recurrent CNS tumors. Among these mutations, BTG2 mutations were observed in 3/4 (75%), and B2M and KLHL14 mutations were observed in 2/4 (50%) cases. In the two PCNSL systemic relapse cases, KMT2D mutations were enriched only in the recurrent systemic tumors. It is suggested that these de novo mutations in the recurrent CNS tumors might serve as driver mutations in the CNS. Further analysis in larger cohorts, and functional studies are required in order to validate these findings.

ET-7 EVALUATION OF HYPOXIA-TARGETING RADIOPHARMACEUTICAL64CU-ATSM FOR PET MONITORING WITH LOCAL THERAPY IN HIGH-GRADE GLIOMA MODEL

World Health Organization (WHO)-defined central nervous system (CNS) grade 4 high-grade gliomas (HGGs) are highly aggressive brain cancers characterized by the presence of hypoxia within a rapidly-growing tumor mass. Due to invasion to the surrounding brain parenchyma, these tumors commonly recur locally, despite aggressive surgical resection, and new therapeutic approaches are required for local tumor control. Here, we show a positron emission tomography (PET) integrated local therapy (PETx), to target HGGs. This technique consists of a one-step local theranostic application, followed by PET monitoring, with a hypoxia-targeting radiopharmaceutical 64Cu-diacetyl-bis (N4-methylthiosemicarbazone) (64Cu-ATSM). We examined the safety and therapeutic potential of 64Cu-ATSM PETx for HGG patient-derived xenograft (PDX) tumors, which recapitulated the parent tumor phenotype of high expression of hypoxia-inducible factor-1α and BNIP3, biomarkers of tissue hypoxia. Biodistribution, dosimetry, and toxicity studies of 64Cu-ATSM local administration determined the maximum tolerated dose (MTD) to be 3.7 MBq in mouse. PETx using the MTD dose of 64Cu-ATSM indicated high tumor penetration, distribution, and retention of 64Cu-ATSM in PDX tumors, as compared to sham-treated mice. The 64Cu-ATSM PETx promoted DNA double-strand breaks, followed by apoptosis in tumors, and extensively prolonged overall survival with tolerable systemic toxicity. These findings indicate the potential of 64Cu-ATSM PETx to induce high uptake in the hypoxic tumor microenvironment, and strong therapeutic effects in PDX models. These findings establish 64Cu-ATSM PETx as a potential novel theranostic approach to facilitate local control of WHO CNS grade 4 HGGs.

EXTH-03. HSP90 INHIBITION OVERCOMES RESISTANCE TO MOLECULAR TARGETED THERAPY IN BRAFV600E MUTANT HIGH-GRADE GLIOMA

INTRODUCTION

Molecular targeted therapy using BRAF and/or MEK inhibitors has been applied to BRAFV600E mutant high-grade gliomas (HGGs); however, the therapeutic effect is limited by the emergence of drug resistance.

METHODS

We established multiple paired BRAFV600E mutant HGG patient-derived xenograft (PDX) models based on tissues collected prior to and at relapse after molecular targeted therapy. Using these models, we dissected treatment resistant mechanisms for molecular targeted therapy and explored therapeutic targets to overcome resistance in BRAFV600E HGG models in vitro and in vivo.

RESULTS

We found that, despite causing no major genetic and epigenetic changes, BRAF and/or MEK inhibitor treatment deregulated multiple negative feedback mechanisms, which led to the re-activation of the MAPK pathway through c-Raf and AKT signaling. This altered oncogenic signaling primarily mediated resistance to molecular targeted therapy in BRAFV600E mutant HGG. To overcome this resistance mechanism, we performed a high-throughput drug screening to identify therapeutic agents that potently induce additive cytotoxicity with BRAF and MEK inhibitors. We discovered that HSP90 inhibition combined with BRAF/MEK inhibition coordinately deactivated the MAPK and AKT/mTOR pathways, and subsequently induced apoptosis via dephosphorylation of GSK3β (Ser9) and inhibition of Bcl-2 family proteins. This mediated potent cytotoxicity in vitro and in vivo in refractory models with acquired resistance to molecular-targeted therapy.

CONCLUSIONS

The combination of an HSP90 inhibitor with BRAF or MEK inhibitors can overcome the limitations of the current therapeutic strategies for BRAFV600E mutant HGG.

Availability of tracheal shift in the chest X-ray image as pre-treatment evaluation of mechanical thrombectomy

BACKGROUND

The use of mechanical thrombectomy (MT) for treatment of acute large vessel occlusion has recently increased. Prompt and timely guiding catheter (GC) induction is necessary to improve prognosis of MT and reduce the time for recanalization. However, difficulties in GC induction are encountered in some patients. This GC induction depends mainly on the aortic arch structure. Therefore, this study focused on assessing presence of tracheal shift on chest X-ray images as pre-treatment evaluation method for GC induction due to its wide availability as an indicator for status of the mediastinum.

METHODS

We retrospectively examined 33 patients who underwent MT at our facilities between April 2017 and March 2021. The patients were divided into two groups according to presence or absence of tracheal shift on chest X-ray images. Background characteristics and treatment courses in these two groups were compared.

RESULTS

Among 33 patients, tracheal shift was observed on the chest X-ray images of 14 patients. Furthermore, tracheal shift was positively correlated with the time of GC induction (32.9 min vs. 11.6 min, [p < 0.05]) and the female sex (p = 0.03). Additionally, tracheal shift exhibited correlations with multiple risk factors of atherosclerosis (p = 0.04).

CONCLUSIONS

In patients with tracheal shift, GC induction could be expectedly difficult. Therefore, advanced disinfection of the right upper arm and affected side of the neck during MT in preparation for changing an approach route is required.

HSP90 inhibition overcomes resistance to molecular targeted therapy in BRAFV600E mutant high-grade glioma

PURPOSE

Molecular targeted therapy using BRAF and/or MEK inhibitors has been applied to BRAFV600E mutant high-grade gliomas (HGGs); however, the therapeutic effect is limited by the emergence of drug resistance.

EXPERIMENTAL DESIGN

We established multiple paired BRAFV600E mutant HGG patient-derived xenograft (PDX) models based on tissues collected prior to and at relapse after molecular targeted therapy. Using these models, we dissected treatment resistant mechanisms for molecular targeted therapy and explored therapeutic targets to overcome resistance in BRAFV600E HGG models in vitro and in vivo.

RESULTS

We found that, despite causing no major genetic and epigenetic changes, BRAF and/or MEK inhibitor treatment deregulated multiple negative feedback mechanisms, which led to the re-activation of the MAPK pathway through c-Raf and AKT signaling. This altered oncogenic signaling primarily mediated resistance to molecular targeted therapy in BRAFV600E mutant HGG. To overcome this resistance mechanism, we performed a high-throughput drug screening to identify therapeutic agents that potently induce additive cytotoxicity with BRAF and MEK inhibitors. We discovered that HSP90 inhibition combined with BRAF/MEK inhibition coordinately deactivated the MAPK and AKT/mTOR pathways, and subsequently induced apoptosis via dephosphorylation of GSK3β (Ser9) and inhibition of Bcl-2 family proteins. This mediated potent cytotoxicity in vitro and in vivo in refractory models with acquired resistance to molecular-targeted therapy.

CONCLUSIONS

The combination of an HSP90 inhibitor with BRAF or MEK inhibitors can overcome the limitations of the current therapeutic strategies for BRAFV600E mutant HGG.

Evaluation of Tumor Cell Infiltration to the Skull in Dermatofibrosarcoma Protuberans of the Scalp: Case Report and Literature Review

Dermatofibrosarcoma protuberans (DFSP) originates from the dermal layer of the skin; the optimum treatment is an extended marginal resection. We describe a case of DFSP of the scalp with a skull invasive defect that was thoroughly examined pathologically to determine the optimum length of surgical margins. The tumor cells infiltrated up to 26 mm into the dermal tissues, whereas no infiltrating tumor cells were present in the skull, indicating the combination of marginal resection of the dermal tissues and lower of the skull can be a clinically relevant strategy for treatment of DFSP cases with skull invasion.

Verbal and memory deficits caused by aphasic status epilepticus after resection of a left temporal lobe glioma

Background:

Nonconvulsive status epilepticus (NCSE) is induced by common neurosurgical conditions, for example, trauma, stroke, tumors, and surgical interventions in the brain. The aggressiveness of the treatment for NCSE depends on its neurological prognosis. Aphasic status epilepticus (ASE) is a subtype of focal NCSE without consciousness impairment. The impact of ASE on neurological prognosis is poorly documented. We describe a case of postoperative ASE resulting in verbal and memory deficits.

Case Description:

A 54-year-old, right-handed man with focal impaired awareness seizures underwent partial resection for a left temporal lobe tumor. No neurological deficits were observed immediately after surgery. Three days later, however, a focal to bilateral tonic-clonic seizure (FBTCS) occurred, followed by aphasia. Electroencephalography revealed 1.5 Hz left-sided periodic discharges. He was diagnosed with ASE. Multiple anti-seizure drugs were ineffective for the resolution of the patient’s verbal disturbance. Nine days after the FBTCS, deep sedation with intravenous anesthetics was performed and the ASE stopped. Thereafter, his symptoms gradually improved. However, the prolonged ASE resulted in verbal and memory deficits. Automated hippocampal volumetry revealed an approximate decrease of 20% on the diseased side on magnetic resonance imaging 3 months after surgery.

Conclusion:

Prolonged ASE can induce verbal and memory deficits. Early intervention with intravenous anesthetics is required to obtain a favorable neurological prognosis.

Superficial siderosis and nonobstructive hydrocephalus due to subependymoma in the ventricle: An illustrative case report

Background:

Intraventricular tumors can generally result in obstructive hydrocephalus as they grow. Rarely, however, some intraventricular tumors develop superficial siderosis (SS) and trigger hydrocephalus, even though the tumor has hardly grown. Here, we present an illustrative case of SS and nonocclusive hydrocephalus caused by subependymoma of the lateral ventricles.

Case Description:

A 78-year-old man with an intraventricular tumor diagnosed 7 years ago had been suffering from gait disturbance for 2 years. He also developed cognitive impairment. Intraventricular tumors showed little growth on annual magnetic resonance imaging (MRI). MRI T2-star weighted images (T2*WI) captured small intratumoral hemorrhages from the beginning of the follow-up. Three years before, at the same time as the onset of ventricular enlargement, T2*WI revealed low intensity in the whole tumor and cerebral surface. Subsequent follow-up revealed that this hemosiderin deposition had spread to the brain stem and cerebellar surface, and the ventricles had expanded further. Cerebrospinal fluid (CSF) examination revealed xanthochromia. The tumor was completely removed en bloc. Histopathological findings were consistent with those of subependymoma. Although CSF findings improved, SS and hydrocephalus did not improve. Therefore, the patient underwent a lumboperitoneal shunt for CSF diversion after tumor resection.

Conclusion:

Some intraventricular tumors cause SS and nonobstructive hydrocephalus due to microbleeding, even in the absence of tumor growth. T2*WI and, if necessary, timely CSF examination can allow identification of presymptomatic SS. This follow-up strategy may provide a favorable course by facilitating early intervention in patients with intraventricular lesions, not just subependymomas.

ET-1 Translational research platform for malignant brain tumors

Introduction: The standard therapy for malignant brain tumors includes surgery and combination therapy with radiation and chemotherapy, but to provide individualized treatment based on the biological and molecular genetic background of the tumor, integrate genetic information with various functional data are required. In this study, we present an overview of our integrated approaches for translational research and clinical management. Methods: In glioma, pre-and intra-operative clinical information, including intraoperative genetic diagnosis, and intraoperative rapid immunohistochemistry is obtained, then a multidisciplinary treatment approach is started based on these integrated data. Specimens collected intraoperatively are cryopreserved for future analysis, and primary cultured cells are routinely collected. The cultured cells are transplanted into the brain of immunodeficient mice to establish patient-derived xenograft model (PDX). Genetic screening, such as IDH, TERT, BRAF, H3F3A mutation and MGMT methylation analysis are routinely assessed within a few days after surgery and used as information for integrated diagnosis. In case of PDX establishment or recurrence, we perform whole exon sequencing or comprehensive genomic assessment to identify genetic abnormalities. If genomic alterations for possible molecular targeted therapy are identified, we assess drug sensitivity test in vitro and in vivo, which are utilized for research to develop optimal molecular targeted therapy. The results, such as the therapeutic effects of molecular targeted drugs, are used for clinical applications. Results: Since the platform was established, we have treated a total of 286 patients, including 189 gliomas and 37 central nervous system lymphomas based on the integrated information. We are currently collecting clinical data to examine if this integrated approach could provide clinical benefit.Conclusion: The translational research system for malignant brain tumors plays an important role in the promotion of clinical and basic research.

SPDR-1 HSP90 inhibition overcomes resistant to molecular targeted therapy in BRAFV600E mutant glioblastoma

The BRAFV600E mutation results in the constitutive activation of downstream mitogen activated protein kinase (MAPK) pathway that promotes tumor growth. Recently, molecular targeted therapy using BRAF/MEK inhibitor has been reported for BRAFV600E mutant high-grade glioma, but the therapeutic effect is limited by the emergence of drug resistance. Herein, we established paired BRAFV600E mutant glioblastoma (GBM) patient-derived xenograft (PDX) models, which were derived from tumors at prior to and recurrence after molecular targeted therapy. These PDX models were found to extensively recapitulate the histology, genetic abnormalities, and even the clinical course of the patients. Furthermore, BRAF/MEK inhibitor gradually caused resistance in cell lines derived from specimens that initially responded to molecular targeted therapy. In this study, genomic and epigenomic changes had little effect on the resistance mechanism. On the other hand, we found that hyperactivation of the MAPK pathway through c-Raf and the AKT/mTOR pathway primarily caused resistance to molecular targeted therapy in BRAFV600E mutant GBM. Through a high throughput drug screening, we find that HSP90 inhibitor with BRAF/MEK inhibitor coordinately deactivates MAPK pathway and AKT/mTOR pathway, and mediates potent toxicity in vitro and in vivo in refractory and acquired resistant models. These findings support that this therapeutic approach can overcome the limitation of current molecular targeted therapy in BRAFV600E mutant GBM.

ET-8 Integrated diagnostic approach to predict prognosis for malignant gliomas

Previous studies indicated that MGMT promoter methylation status with IDH and TERT promotor mutation are major prognostic factors in glioma. In addition to these molecular features, we have been assessing drug sensitivity against several chemotherapeutic agents, including temozolomide (TMZ). Here, we examined if this combined information could strongly predict drug sensitivity and the prognosis in glioma patients. One hundred and twenty-five IDH wild-type gliomas (WHO grade III and grade IV) were included in this study and retrospectively analyzed. Among them, we focused on 37 patients with partial surgical resection and biopsy to assess radiological difference on MRI. The primary cultured tumor cells were exposed with several compounds for 72 hours, then ATP based cell viability assay was performed. The favorable radiological therapeutic effect was found in 6 out of 8 (75%) with MGMT promoter methylated cases, while unfavorable in 23 of 29 (79.3%) with MGMT promoter unmethylated cases (p=0.008). The drug screening assay demonstrated that 7 of 10 cases with favorable TMZ sensitivity in vitro showed response on MRI, whereas 22 of 27 (81.5%) cases with TMZ resistance in vitro indicated tumor progression (p=0.006). Of note, all 5 cases with sensitive to TMZ and methylated MGMT promoter demonstrated favorable radiological response (p=0.002). These 5 cases tended to survive longer (median survival time, 697 days) as compared to others (median survival time, 391 days, p=0.13). These data indicate that integrated approach with genomic assessment and drug screening test may predict therapeutic response to chemotherapy and contribute selecting optimal therapy in glioma patients.

Relationship of early intensive- or coronary care unit admission and post-discharge performance of activities of daily living in patients with acute decompensated heart failure

Background

The management of acute decompensated heart failure (ADHF) often requires intensive care. However, the effects of early intensive care unit (ICU)/coronary care unit (CCU) admission on activities of daily living (ADL) in ADHF patients have not been precisely evaluated. Thus, we assessed whether early ICU entry can improve post-discharge ADL performance in these patients.

Methods and results

ADHF patients (New York Heart Association I–III) admitted on emergency between April 1, 2014, and December 31, 2018, were selected from the Diagnosis Procedure Combination database and divided into ICU/CCU (ICU) and general ward (GW) groups according to the hospitalization type on admission day 1. The propensity score was calculated to create matched cohorts where treatment assignment (ICU/CCU admission) is independent of measured baseline confounding factors including ADL at admission. The primary outcome was post-ADL defined according to the Barthel index (BI) at discharge. Secondary outcomes included length of stay (LOS) and total hospitalization cost (expense). Overall, 12,231 patients were eligible, and propensity score matching created 2,985 pairs. After matching, post-ADL was significantly higher in the ICU group (GW 71.5±35.3 vs. ICU 78.2±31.2, P&lt;0.001, difference in mean 6.7 (95% CI 5.1–8.4) points). After matching, LOS was significantly shorter and expenses were significantly higher in the ICU group. Subanalyses showed that patients with low ADL at admission (BI&lt;60) mainly benefited from early ICU/CCU entry.

Conclusions

Early ICU/CCU entry was beneficially associated with post-ADL in patients with emergency ADHF admission. ADL at admission might serve as a useful criterion for ICU admission.

Funding Acknowledgement

Type of funding sources: None.

Implantable cardioverter-defibrillator therapy after resuscitation from cardiac arrest in vasospastic angina

Background

Patients with vasospastic angina (VSA) who are resuscitated from sudden cardiac arrest (SCA) are at high risk of recurrent cardiovascular events. However, there are no recommendations for implantable cardioverter-defibrillator (ICD) therapy in the VSA and SCA patient guidelines.

Purpose

This study investigated the prognostic impact of ICD therapy on patients with VSA and SCA.

Methods

The present multi-center registry included 280 patients who were resuscitated from SCA and received ICD implantation as secondary prophylaxis. The patients were divided into two groups according to the presence of VSA. The primary endpoint was a composite of all-cause death and appropriate ICD therapy, including appropriate anti-tachycardia pacing and shock for recurrent ventricular arrhythmias.

Results

Of 280 patients, 51 (18%) had VSA. Among those without VSA, ischemic cardiomyopathy was the leading cause of SCA (38%), followed by non-ischemic cardiomyopathies and Brugada syndrome (Table 1). During the median follow-up period of 3.8 years, 23 (8%) patients died, and 72 (26%) underwent appropriate ICD therapy. The incidence of the primary endpoint was not significantly different between patients with and without VSA (24% vs 33%, p=0.19). Further, the incidence of the primary endpoint was not significantly different among the etiologies (Figure 1)

Conclusions

In a cohort of patients who underwent ICD implantation as secondary prophylaxis, long-term clinical outcomes were comparable between those with VSA and those with other cardiac diseases after SCA. The results suggest that ICD therapy may be considered in patients with VSA and those with other etiologies after resuscitation from SCA.

Funding Acknowledgement

Type of funding sources: None. Table 1. Patient characteristics and outcomesFigure 1. Incidence of the primary endpoint

GLI3 Is Associated With Neuronal Differentiation in SHH-Activated and WNT-Activated Medulloblastoma

Glioma-associated oncogene homolog 3 (GLI3), whose main function is to inhibit GLI1, has been associated with neuronal differentiation in medulloblastoma. However, it is not clear what molecular subtype(s) show increased GLI3 expression. GLI3 levels were assessed by immunohistochemistry in 2 independent cohorts, including a total of 88 cases, and found to be high in both WNT- and SHH-activated medulloblastoma. Analysis of bulk mRNA expression data and single cell RNA sequencing studies confirmed that GLI1 and GLI3 are highly expressed in SHH-activated medulloblastoma, whereas GLI3 but not GLI1 is highly expressed in WNT-activated medulloblastoma. Immunohistochemical analysis has shown that GLI3 is expressed inside the neuronal differentiated nodules of SHH-activated medulloblastoma, whereas GLI1/2 are expressed in desmoplastic areas. In contrast, GLI3 is diffusely expressed in WNT-activated medulloblastoma, whereas GLI1 is suppressed. Our data suggest that GLI3 may be a master regulator of neuronal differentiation and morphology in these subgroups.

[Glioma Cell Biology]

In this review, I summarized the biology of gliomas. Through past clinical and basic studies, I reviewed the evidence of the cell of origin of gliomas and the presence of brain tumor-initiating cells in gliomas, which are driven by multiple genomic alterations. In addition, the complicated tumor heterogeneity and neuronal-glioma network were studied. These mechanisms may underlie the treatment resistance and poor prognosis and support the identification of novel therapeutic targets for gliomas.

Sirtuin activation targets IDH-mutant tumors

BACKGROUND

Isocitrate dehydrogenase (IDH)-mutant tumors exhibit an altered metabolic state and are critically dependent upon nicotinamide adenine dinucleotide (NAD+) for cellular survival. NAD+ steady-state levels can be influenced by both biosynthetic and consumptive processes. Here, we investigated activation of sirtuin (SIRT) enzymes, which consume NAD+ as a coenzyme, as a potential mechanism to reduce cellular NAD+ levels in these tumors.

METHODS

The effect of inhibition or activation of sirtuin activity, using (i) small molecules, (ii) clustered regularly interspaced short palindromic repeat/CRISPR associated protein 9 gene editing, and (iii) inducible overexpression, was investigated in IDH-mutant tumor lines, including patient-derived IDH-mutant glioma lines.

RESULTS

We found that Sirt1 activation led to marked augmentation of NAD+ depletion and accentuation of cytotoxicity when combined with inhibition of nicotinamide phosphoribosyltransferase (NAMPT), consistent with the enzymatic activity of SIRT1 as a primary cellular NAD+ consumer in IDH-mutant cells. Activation of Sirt1 through either genetic overexpression or pharmacologic Sirt1-activating compounds (STACs), an existing class of well-tolerated drugs, led to inhibition of IDH1-mutant tumor cell growth.

CONCLUSIONS

Activation of Sirt1 can selectively target IDH-mutant tumors. These findings indicate that relatively nontoxic STACs, administered either alone or in combination with NAMPT inhibition, could alter the growth trajectory of IDH-mutant gliomas while minimizing toxicity associated with cytotoxic chemotherapeutic regimens.

Practical Arachnoid Anatomy for the Technical Consideration of Galen Complex Dissection: Cadaveric and Clinical Evaluation

BACKGROUND

The occipital transtentorial approach (OTA) is a very useful but challenging approach to expose the pineal region because the deep-seated arachnoid membranes usually fold and extend over the great vein of Galen (GVG), leading to dense and poor visibility. In addition, the practical aspects of arachnoid anatomy are not well understood. We aimed to develop a safe surgical procedure for the OTA according to the practical aspects of arachnoid anatomy.

METHODS

The procedure is shown through an illustrative video of surgery and cadaver. Five cadavers were analyzed for their arachnoid structures and the surgical procedures via the OTA, in strict compliance with legal and ethical requirements.

RESULTS

All cadavers showed a 2-layered arachnoid structure-one belonging to the occipital lobe, and the other to the cerebellum. According to our cadaveric analysis, the arachnoid attachment of the tentorial apex can be peeled bluntly, with an average distance of 10.2 mm. For our clinical presentation, a pineal tumor with hydrocephalus was detected in a 14-year-old boy. While using the OTA and expanding the deep surgical field, we detached the membrane from the tentorial apex and bluntly peeled it to reveal the deep veins. Finally, gross total removal of the tumor was achieved.

CONCLUSIONS

A 2-layered arachnoid structure interposes the GVG from above and below the tentorium. The arachnoid membrane below the tentorium can be peeled off bluntly from the GVG to the attachment bundle limited by the penetrating veins. This detachment technique is useful for safe enlargement of the surgical field for the OTA.

IDH-Mutant Astrocytoma With Chromosome 19q13 Deletion Manifesting as an Oligodendroglioma-Like Morphology

Partial deletions in chromosomes 1p and 19q are found in a subset of astrocytic tumors; however, it remains unclear how these alterations affect their histological features and prognosis. Herein, we present 3 cases of isocitrate dehydrogenase (IDH)-mutant astrocytoma with chromosome 19q13 deletion. In the first case, the primary tumor harbored an IDH1 mutation with chromosome 1p/19q partial deletions, which covered 19q13 and exhibited a durable initial response to radiotherapy and temozolomide (TMZ) treatment. However, the tumor lost the chromosome 1p/19q partial deletions at recurrence and became resistant to TMZ. Histologically, an oligodendroglioma-like feature was found in the primary tumor but not in the recurrent tumor. Capicua transcriptional repressor (CIC), located on 19q13, was less expressed in the primary tumor but was highly expressed in the recurrent tumor. Similar histological findings were observed in 2 other astrocytic tumors with IDH1 or IDH2 mutations. These tumors also had chromosome 19q13 deletion, including the CIC gene, weakly expressed CIC, and oligodendroglioma-like morphology. These tumors recurred at 6 and 32 months, respectively. These findings suggest that IDH-mutant astrocytoma with chromosome 19q13 partial deletion, including the CIC gene, may induce an oligodendroglioma-like phenotype, but the clinical prognosis may not be similar to that of genetically defined oligodendroglioma.

HGG-51. PAIRED EPITHELIOID GLIOBLASTOMA PATIENT DERIVED XENOGRAFT MODELS WITH/WITHOUT MOLECULAR TARGET THERAPY

Epithelioid glioblastoma (E-GBM) predominantly arises at younger age and promotes dismal prognosis. Because of its rare etiology, pathological and genetical characterization of E-GBM remains elusive. Herein, we report 2 patient-derived E-GBM xenograft (PDX) models from young adult patients (YMG62 and YMG89) with BRAFV600E and TERT promoter mutation. The YMG62 patient received dabrafenib with trametinib, while YMG89 patient received dabrafenib monotherapy after recurrence with Stupp regimen. These molecular target therapies were initially responded, but gradually became resistant (YMG62R and YMG89R) and resulted in lethal. Treatment resistant cells were collected from CSF. These primary cells were propagated at multiple passage in vitro. Paired PDX models were established from initial and recurrent cells. All PDX tumors were preferentially disseminated and negative expression of GFAP, which were recapitulated to the patient characteristics. BRAF and MEK inhibitor moderately suppressed cell viability of YMG62 and YMG89 in vitro. However, BRAF and MEK inhibitor became resistant at recurrence in vitro. Western blotting indicated retained phospho-MEK expression after BRAF/MEK inhibitor treatment in recurrent cells, which implies crucial role of MEK activation for tumor maintenance in BRAFV600E mutant E-GBM. Together, paired E-GBM PDX models with/without molecular target therapy recapitulate patient characteristics, which may contribute to elucidate tumor biology and establish novel therapeutic target in E-GBM.

CBMS-04 Novel xenograft model to clarify tumor progressive mechanism and therapeutic target in primary central nervous system lymphoma

Primary central nervous system lymphoma (PCNSL) is a rare lymphoma of the central nervous system and has a dismal prognosis despite intensive chemotherapy. Recent genomic analyses have identified recurrent genetic alterations in Primary central nervous system lymphoma (PCNSL). However, lack of clinically representative PCNSL models has diminished our understanding of the pathogenic mechanisms of those genetic events. Here, we established 14 patient-derived orthotopic xenografts (PDOXs). Comprehensive analysis showed that PDOXs faithfully retained the phenotypic, metabolic, and genetic features with 100 % concordance of MYD88 and CD79B mutations present in immuno-competent PCNSL patients. Notably, orthotopic xenograft formation was consistently dependent on deregulated signaling through the RelA/p65-hexokinase 2 (HK-2) axis. MYD88/CD79B mutations and Pin1 activation, or LMP1 and Pin1 activation, converge on the RelA/p65-HK-2 signaling in immunocompetent and EBV-positive PCNSL, respectively. Genetic and pharmacological inhibition of this key signaling axis potently suppressed PCNSL tumor growth in vitro and in vivo. Additionally, our models further offer a platform for predicting clinical chemotherapeutics efficacy. Therefore, our models provide critical insights into pathogenic mechanisms and therapeutic discovery in PCNSL.

CS-03 BRAF V600E mutation mediates FDG-methionine uptake mismatch in polymorphous low-grade neuroepithelial tumor of the young

We present a case of a 14-year old boy with tumor-associated refractory epilepsy. Positron emission tomography imaging demonstrated a region with heterogeneous high 11 C-methionine uptake and a region with homogenous low 18 F- fluorodeoxyglucose uptake within the tumor. Histopathological and genomic analyses confirmed the tumor as BRAF V600E-mutated PLNTY (polymorphous low-grade neuroepithelial tumor of the young). Within the high-methionine-uptake region, we observed increased protein levels of L-type amino acid transporter 1 (LAT1) and constituents of the mitogen-activated protein kinase (MAPK) pathway. We also found that LAT1 expression was linked to BRAF V600E mutation and subsequent activation of MAPK signaling. Pharmacological inhibition of the MAPK pathway suppressed LAT1 expression and cell viability in PLNTY cells. Collectively, our results indicate that BRAF V600E mutation-activated MAPK signaling induces specific metabolic alterations in PLNTY, and may represent an attractive target in the treatment of the disease.

SPDR-01 Paired epithelioid glioblastoma patient-derived xenograft models to evaluate resistant mechanism for molecular target therapy

Epithelioid glioblastoma (E-GBM) arises at younger age, commonly disseminates to cerebrospinal fluid, and results in dismal prognosis. About half of E-GBM harbors BRAF V600E mutation, thus BRAF/MEK inhibitors are expected to be specifically sensitive to E-GBM like other BRAF V600E mutant carcinomas. However, therapeutic effect is limited by the emergence of drug resistance. To overcome this issue, it is crucial to elucidate the treatment resistance mechanisms by clinically representative models. Herein, we establish 2 paired E-GBM patient-derived xenograft (PDX) models from young adult patients (YMG62 and YMG89) with BRAF V600E, TERT promoter mutations and CDKN2A homozygous deletions. The YMG62 patient received dabrafenib with trametinib, while YMG89 patient received dabrafenib monotherapy after recurrence with standard treatment. The YMG62 patient was refractory to combination therapy. The YMG89 patient was initially responded to dabrafenib, but gradually became resistant and the 2 patients died due to CNS dissemination. Paired PDX models were established from tumors prior and after molecular target therapy. All PDXs were formed as CNS dissemination model, which were recapitulated to the patient characteristics. BRAF/MEK inhibitors strongly suppressed cell viability in primary tumor (YMG89P). However, BRAF/MEK inhibitors became resistant in recurrent tumor (YMG89R). YMG62 paired PDXs were resistant to molecular target therapy. Western blotting indicated retained MAPK signaling pathway and/or increased AKT phosphorylation after BRAF/MEK inhibitors treatment in refractory and recurrent cells, which indicates crucial role of re-activation in the MAPK signaling pathway and/or PI3 kinase pathway for tumor maintenance in BRAF V600E mutant E-GBM. We have done high throughput drug screening to identify compounds to overcome resistant to molecular target therapy. Our established E-GBM paired PDX models recapitulate patient characteristics, which may uncover treatment resistant mechanism and novel therapeutic target in E-GBM.

BIOM-54. A RAPID GENOTYPING PANEL FOR SENSITIVE AND SPECIFIC SEGREGATION OF CNS PATHOLOGIES

Primary central nervous system lymphoma (PCNSL) remains challenging to diagnose due to nonspecific clinical and radiologic features and low diagnostic yields of cerebrospinal fluid (CSF) studies. We sought to characterize the diagnostic approach of suspected PCNSL, in order to improve clinical workflow. We first reviewed 1,007 new brain lesions of unknown etiology that included PCNSL in the radiologic differential diagnosis. The most common final diagnoses included high-grade glioma (28.2%) and PCNSL (14.6%). Diagnostic biopsies were frequently performed for high-grade glioma (100%) and PCNSL (94.4%), while CSF was frequently sampled for PCNSL (78.7%). We next identified 159 patients with an established new diagnosis of PCNSL. CSF studies were non-diagnostic in 86.7% of cases, whereas biopsy was positive in 93%. However, intraoperative histopathology was inconclusive for PNCSL in 54.5%, likely contributing to 22% of patients undergoing surgical resection. These challenges resulted in 12 days median time to treatment initiation, and readmission for further workup or treatment initiation in 27% of patients. These results indicated the need for a rapid, sensitive and specific platform to segregate PCNSL and glioma using CSF and tissue samples. We developed a qPCR-based assay to genotype the MYD88 L265P hotspot mutation from CSF and plasma within 80 minutes of sample acquisition. Results were concordant with orthogonal DNA sequencing in extracts from 87 archived specimens, with detection limits of 490pg of input genomic DNA and 0.15% mutant allele frequency. When performed simultaneously with assays for TERT promoter, IDH1/2, H3F3A and BRAF point mutations, the resulting panel accurately segregated PCNSL and adult diffuse glioma molecular diagnoses in 87 archived specimens and 19 prospective liquid biopsies, including cases of lymphoma and glioma. We propose that inclusion of targeted analysis of these mutually exclusive recurrent molecular alterations characterizing gliomas and PCNSL will facilitate rapid, sensitive diagnosis from solid and liquid biopsies.

TAMI-20. POLY(ADP-RIBOSE) GLYCOHYDROLASE INHIBITION SEQUESTERS NAD+ TO POTENTIATE THE METABOLIC LETHALITY OF ALKYLATING CHEMOTHERAPY IN IDH MUTANT TUMOR CELLS

Mutations in IDH1 or IDH2 characterize the majority of diffuse infiltrative gliomas of younger adulthood. DNA alkylator chemotherapy has proven to be an effective treatment for IDH mutant glioma, yet recurrences remain frequent and improved treatments are needed. Upon exposure of cancer cells to DNA alkylating agents, poly(ADP-ribose) polymerases (PARPs) catalyze the transient oligomerization of nicotinamide adenine dinucleotide (NAD+) into poly-ADP-ribose (PAR) chain-assemblies, which stimulate the DNA damage response. Here, we find that, in IDH mutant glioma cells, alkylator-induced cytotoxicity is dramatically augmented by pharmacologic inhibition or genetic knockout of the PAR breakdown enzyme poly(ADP-ribose) glycohydrolase (PARG). Mechanistically, we show this augmentation is driven by a metabolic state pairing amplified alkylator-induced DNA damage with catastrophic depletion of NAD+. IDH mutant cancer cells have low basal levels of NAD+, rendering them vulnerable to prolonged NAD+ depletion. Either of two clinically-utilized monofunctional alkylators, procarbazine (PCZ) or temozolomide (TMZ), when exposed to multiple IDH mutant lines, activated PARP conversion of cellular NAD+ monomers into polymerized PAR. Subsequent PAR breakdown and recycling of NAD+ monomers was then halted by concomitant PARG inactivation, amplifying PARylation-mediated DNA damage signaling and critically depleting free NAD+, resulting in profound cytotoxicity. This effect was partially reversed by NAD+ rescue supplementation, confirming the key contribution of metabolic stress. Combined alkylator treatment and PARG inhibition in vivo maximized both NAD+ depletion and cytotoxicity in an endogenous IDH mutant cancer model. Thus, alkyating DNA damaging agents expose a metabolic liability in IDH mutant cancers, and subsequent targeted blockade of PAR breakdown and NAD+ metabolite recovery can exploit this vulnerability to provide genotype-specific therapeutic benefit.

NIMG-29. DEVELOPING AUTOMATIC SEGMENTATION METHOD FOR BRAIN TUMOR MR IMAGES THAT CAN BE USED AT MULTIPLE FACILITIES

BACKGROUND

Manual segmentation of brain tumor images from a large volume of MR images generated in clinical routines is difficult and time-consuming. Hence, it is imperative to develop a machine learning model for automated segmentation of brain tumor images.

PURPOSE

Machine learning models for automated MR image segmentation of gliomas may be useful. However, the image differences among facilities cause performance degradation and impede successful automatic segmentation. In this study, we proposed a method to solve this issue.

METHODS

We used the data from the Multimodal Brain Tumor Image Segmentation Benchmark (BraTS) and the Japanese cohort (JC) datasets collected from 10 facilities. Three models for tumor segmentation were developed. The BraTS model was trained on the BraTS dataset, and the JC model was trained on the JC dataset; whereas, the Fine-tuning model was a fine-tuned BraTS model using the JC dataset.

RESULTS

MR images of 544 patients were obtained for the JC dataset. Half of the JC dataset was used for independent testing. The Dice coefficient score of the JC model for the JC dataset was 0.779± 0.137, whereas that of the BraTS model was remarkably lower (0.717 ± 0.207). The mean of the Fine-tuning models for the JC dataset was 0.769 ± 0.138. There was a significant difference between the BraTS and JC models (P &lt; 0.0001) and the BraTS and Fine-tuning models (P = 0.002); however, no significant difference was observed between the JC and Fine-tuning models (P = 0.673).

CONCLUSIONS

Application of the BraTS model to heterogeneous datasets can significantly reduce its performance; however, fine-tuning can solve this issue. Since our fine-tuning method only requires less than 20 cases, this methodology is particularly useful for a facility where there are a few glioma cases.

Greater coronary lipid core plaque assessed by near-infrared spectroscopy intravascular ultrasound in patients with elevated xanthine oxidoreductase: a mechanistic insight

Background

Elevated serum uric acid level was reportedly associated with greater coronary lipid plaque. Xanthine oxidoreductase (XOR) is a rate-limiting enzyme in purine metabolism and believed to play important roles in coronary atherosclerosis. However, the relation of XOR to coronary lipid plaque and its mechanism are unclear.

Purpose

The aim of this study was to assess the impact of XOR on coronary lipid plaque and the associated factors with XOR in coronary artery disease (CAD).

Methods

Patients with stable CAD undergoing elective percutaneous coronary intervention under near-infrared spectroscopy intravascular ultrasound (NIRS-IVUS) guidance were prospectively enrolled. They were divided into three groups according to serum XOR activities; low, normal, and high. Coronary lipid core plaques in non-target vessels were evaluated by NIRS-IVUS with lipid core burden index (LCBI) and a maximum LCBI in 4 mm (maxLCBI4mm). Systemic endothelial function and inflammation were assessed with reactive hyperemia index (RHI) and high-sensitivity C-reactive protein, neutrophil-to-lymphocyte ratio, and platelet-to-lymphocyte ratio.

Results

Of 68 patients, 26, 31, and 11 were classified as low, normal, and high XOR activity groups. LCBI (474.4±171.6 vs. 347.4±181.6 vs. 294.0±155.9, p=0.04) and maxLCBI4mm (102.1±56.5 vs. 65.6±48.5 vs. 55.6±37.8, p=0.04) were significantly higher in high XOR group than in normal and low XOR groups. Although RHI was significantly correlated with body mass index, diabetes, current smoking, and high-density lipoprotein cholesterol, no relation was found between XOR activity and RHI (Figure). There were also no relations between XOR activity and high-sensitivity C-reactive protein, neutrophil-to-lymphocyte ratio, or platelet-to-lymphocyte ratio (Figure).

Conclusion

Elevated XOR activity was associated with greater coronary lipid plaque in patients with stable CAD, without significant relations to systemic endothelial function and inflammation.

Funding Acknowledgement

Type of funding source: None

Comparison of clinical characteristics between patients with microvascular and epicardial coronary artery spasm

Background

Coronary functional abnormalities including both epicardial and microvascular coronary artery spasm represent an important role responsible for myocardial ischemia in patients with angina and nonobstructive coronary artery disease. However, clinical characteristics associated with microvascular spasm (MVS) have not been fully evaluated.

Purpose

The aim of this study was to assess differences in clinical features between patients with MVS and epicardial coronary spasm.

Methods

A total of 732 consecutive patients with suspected angina who presented nonobstructive coronary arteries and underwent intracoronary acetylcholine provocation test were retrospectively enrolled in this study. Epicardial coronary spasm was defined as total or subtotal occlusion of epicardial coronary arteries accompanied by chest pain and/or ischemic electrocardiographic changes in response to acetylcholine provocation test. MVS was diagnosed when chest pain and/or ischemic electrocardiographic changes developed after administration of acetylcholine in the absence of epicardial coronary spasm. Clinical characteristics were compared between patients with MVS and epicardial coronary spasm.

Results

Of all patients, 83 patients (11%) had MVS, 367 (50%) had epicardial coronary spasm, and the other patients (39%) showed neither MVS nor epicardial coronary spasm. Patients with MVS tended to be older (65.6±12.7 vs. 63.0±12.3 years, P=0.088) and were more frequently female (60.2% vs. 41.1%, P=0.0016) in comparison with patients with epicardial coronary spasm. Patients with MVS were less likely to be smokers (8.6% vs. 22.9%, P=0.0018), while there were no significant differences in the other coronary risk factors such as hypertension, dyslipidemia, and diabetes mellitus. Serum uric acid were significantly lower in patients with MVS (4.9±1.1 vs. 5.4±1.3 mg/dl, P=0.0018).

Conclusion

Our study demonstrated that patients with MVS had distinctive clinical background from those with epicardial coronary spasm, suggesting different mechanisms may involve the development of MVS.

Funding Acknowledgement

Type of funding source: None

Age-related differences and vascular function test findings in patients with vasospastic angina

Background

Vasospastic angina (VSA) accounts for the majority of angina cases with no epicardial stenosis and develops amongawide range of age, which is reportedly induced by coronary functional abnormalities including endothelial dysfunction and smooth muscle hypercontraction. However, the relation of noninvasive vascular function tests to VSA remains to be fully elucidated.

Purpose

The aim of this study was to assess differences in clinical characteristics and findings from noninvasive vascular function tests among groups by age in patients with VSA.

Methods

We enrolled a total of 732 patients with angina who underwent intracoronary acetylcholine provocation test. VSA was defined as total or subtotal occlusion of epicardial coronary arteries accompanied by chest pain and/or ischemic electrocardiographic changes in response to acetylcholine administration. Patients with VSA were divided into 3 groups by age (young [&lt;50 years], intermediate [50–64 years], and elderly group [≥65 years]). Noninvasive vascular function test findings such as ankle-brachial index (ABI), brachial-ankle pulse wave velocity (baPWV), andpercentage of mean arterial pressure (%MAP) were compared among groups by age in patients with VSA.

Results

Of all patients, 367 (50.1%) were diagnosed as VSA with intracoronary acetylcholine test, including 66 (18.0%), 113 (30.8%), and 188 (51.2%) patients in the young, intermediate, and elderly groups. Among groups by age, there was no significant difference in gender (female, 31.8% vs. 40.7% vs. 44.7%, P=0.19). Patients in the young group were more often smokers and alcohol drinkers than those in the intermediate and elderly groups, while the prevalence of hypertension, dyslipidemia, and diabetes were lower in younger patients. A history of percutaneous coronary intervention was less frequently found in the young group compared tothe intermediate and elderly groups (7.6% vs. 16.8% vs. 20.7%, P=0.033). The baPWV was higher in the elderly group (1424±232 vs. 1537±247 vs. 1774±358 cm/s, P&lt;0.0001), while there was no difference in ABI between the 3 groups. %MAP at arms was significantly and progressively decreased with an increase in age (54.0±4.5% vs. 53.0±2.6% vs. 51.2±2.8%, P&lt;0.0001).

Conclusion

Our study demonstrated that there were distinct age-related differences in clinical characteristics of patients with VSA. The higher %MAP in younger patients suggests that more impaired endothelial dysfunction may play a role in the development of VSA in this age group.

Funding Acknowledgement

Type of funding source: None

A Hyperactive RelA/p65-Hexokinase 2 Signaling Axis Drives Primary Central Nervous System Lymphoma

Primary central nervous system lymphoma (PCNSL) is an isolated type of lymphoma of the central nervous system and has a dismal prognosis despite intensive chemotherapy. Recent genomic analyses have identified highly recurrent mutations of MYD88 and CD79B in immunocompetent PCNSL, whereas LMP1 activation is commonly observed in Epstein-Barr virus (EBV)-positive PCNSL. However, a lack of clinically representative preclinical models has hampered our understanding of the pathogenic mechanisms by which genetic aberrations drive PCNSL disease phenotypes. Here, we establish a panel of 12 orthotopic, patient-derived xenograft (PDX) models from both immunocompetent and EBV-positive PCNSL and secondary CNSL biopsy specimens. PDXs faithfully retained their phenotypic, metabolic, and genetic features, with 100% concordance of MYD88 and CD79B mutations present in PCNSL in immunocompetent patients. These models revealed a convergent functional dependency upon a deregulated RelA/p65-hexokinase 2 signaling axis, codriven by either mutated MYD88/CD79B or LMP1 with Pin1 overactivation in immunocompetent PCNSL and EBV-positive PCNSL, respectively. Notably, distinct molecular alterations used by immunocompetent and EBV-positive PCNSL converged to deregulate RelA/p65 expression and to drive glycolysis, which is critical for intracerebral tumor progression and FDG-PET imaging characteristics. Genetic and pharmacologic inhibition of this key signaling axis potently suppressed PCNSL growth in vitro and in vivo. These patient-derived models offer a platform for predicting clinical chemotherapeutics efficacy and provide critical insights into PCNSL pathogenic mechanisms, accelerating therapeutic discovery for this aggressive disease. SIGNIFICANCE: A set of clinically relevant CNSL xenografts identifies a hyperactive RelA/p65-hexokinase 2 signaling axis as a driver of progression and potential therapeutic target for treatment and provides a foundational preclinical platform. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/23/5330/F1.large.jpg.

BRAF V600E mutation mediates FDG-methionine uptake mismatch in polymorphous low-grade neuroepithelial tumor of the young

We present a case of a 14-year old boy with tumor-associated refractory epilepsy. Positron emission tomography imaging demonstrated a region with heterogeneous high ¹¹C-methionine uptake and a region with homogenous low ¹⁸F-fluorodeoxyglucose uptake within the tumor. Histopathological and genomic analyses confirmed the tumor as BRAF V600E-mutated polymorphous low-grade neuroepithelial tumor of the young (PLNTY). Within the high-methionine-uptake region, we observed increased protein levels of L-type amino acid transporter 1 (LAT1), a major transporter of methionine; c-Myc; and constituents of the mitogen-activated protein kinase (MAPK) pathway. We also found that LAT1 expression was linked to the BRAF V600E mutation and subsequent activation of MAPK signaling and c-Myc. Pharmacological and genetic inhibition of the MAPK pathway suppressed c-Myc and LAT1 expression in BRAF V600E-mutated PLNTY and glioblastoma cells. The BRAF inhibitor dabrafenib moderately suppressed cell viability in PLNTY. Collectively, our results indicate that BRAF V600E mutation-activated MAPK signaling and downstream c-Myc induces specific metabolic alterations in PLNTY, and may represent an attractive target in the treatment of the disease.

BRAF V600E mutation mediates FDG-methionine uptake mismatch in polymorphous low-grade neuroepithelial tumor of the young

We present a case of a 14-year old boy with tumor-associated refractory epilepsy. Positron emission tomography imaging demonstrated a region with heterogeneous high ¹¹C-methionine uptake and a region with homogenous low ¹⁸F-fluorodeoxyglucose uptake within the tumor. Histopathological and genomic analyses confirmed the tumor as BRAF V600E-mutated polymorphous low-grade neuroepithelial tumor of the young (PLNTY). Within the high-methionine-uptake region, we observed increased protein levels of L-type amino acid transporter 1 (LAT1), a major transporter of methionine; c-Myc; and constituents of the mitogen-activated protein kinase (MAPK) pathway. We also found that LAT1 expression was linked to the BRAF V600E mutation and subsequent activation of MAPK signaling and c-Myc. Pharmacological and genetic inhibition of the MAPK pathway suppressed c-Myc and LAT1 expression in BRAF V600E-mutated PLNTY and glioblastoma cells. The BRAF inhibitor dabrafenib moderately suppressed cell viability in PLNTY. Collectively, our results indicate that BRAF V600E mutation-activated MAPK signaling and downstream c-Myc induces specific metabolic alterations in PLNTY, and may represent an attractive target in the treatment of the disease.

Poly(ADP-ribose) Glycohydrolase Inhibition Sequesters NAD+ to Potentiate the Metabolic Lethality of Alkylating Chemotherapy in IDH-Mutant Tumor Cells

NAD⁺ is an essential cofactor metabolite and is the currency of metabolic transactions critical for cell survival. Depending on tissue context and genotype, cancer cells have unique dependencies on NAD⁺ metabolic pathways. PARPs catalyze oligomerization of NAD⁺ monomers into PAR chains during cellular response to alkylating chemotherapeutics, including procarbazine or temozolomide. Here we find that, in endogenous IDH1-mutant tumor models, alkylator-induced cytotoxicity is markedly augmented by pharmacologic inhibition or genetic knockout of the PAR breakdown enzyme PAR glycohydrolase (PARG). Both in vitro and in vivo, we observe that concurrent alkylator and PARG inhibition depletes freely available NAD⁺ by preventing PAR breakdown, resulting in NAD⁺ sequestration and collapse of metabolic homeostasis. This effect reversed with NAD⁺ rescue supplementation, confirming the mechanistic basis of cytotoxicity. Thus, alkylating chemotherapy exposes a genotype-specific metabolic weakness in tumor cells that can be exploited by PARG inactivation. SIGNIFICANCE: Oncogenic mutations in the isocitrate dehydrogenase genes IDH1 or IDH2 initiate diffuse gliomas of younger adulthood. Strategies to maximize the effectiveness of chemotherapy in these tumors are needed. We discover alkylating chemotherapy and concurrent PARG inhibition exploits an intrinsic metabolic weakness within these cancer cells to provide genotype-specific benefit.See related commentary by Pirozzi and Yan, p. 1629.This article is highlighted in the In This Issue feature, p. 1611.

Incision Edge "Lifting Method" in Cerebral Bypass Surgery: A Novel Optional Technique for Narrow or Thin Recipient Arteries

BACKGROUND

Cerebral bypass surgery, such as the superficial temporal artery-middle cerebral artery bypass, is one of the essential procedures for cerebral revascularization. However, very narrow or thin blood vessels will increase the risk of anastomotic problems, such as occurs in Moyamoya disease. For such vessels, we have devised a "lifting method" in the recipient arteriotomy. In the present study, we have introduced this novel optional technique and evaluated its effects.

METHODS

The lifting method is a procedure of lifting the incision edge of a linear incision on the recipient vessel to widen the ostium. We attempted the lifting method in 23 consecutive patients (41 arteries) and, as a historical control, compared the results with those from the conventional method in 25 consecutive patients (37 arteries) for the previous 3 years. We compared patient age, years of surgical experience, recipient vessel diameter, anastomotic events, and final patency. As a subanalysis, the same evaluations were performed separately for patients with Moyamoya disease. Furthermore, the time required for the lifting procedure was measured retrospectively.

RESULTS

The incidence of anastomotic events with the conventional method was 13.5% overall and 19% in those with Moyamoya disease. No adverse events occurred with the lifting method (P < 0.05). No statistically significant differences were found for the other factors, including final patency between the 2 groups. The time required for the lifting procedure averaged 1 minute, 15 seconds.

CONCLUSIONS

Use of the lifting method widens and secures the ostium in a recipient vessel and greatly facilitates operability. We have found it to be a foolproof method enabling safe and reliable anastomosis even with narrow or thin vessels.