Pediatric-type high-grade gliomas with PDGFRA amplification in adult patients with Li-Fraumeni syndrome: clinical and molecular characterization of three cases

Li-Fraumeni syndrome (LFS) is an autosomal dominant tumor predisposition syndrome caused by heterozygous germline mutations or deletions in the TP53 tumor suppressor gene. Central nervous system tumors, such as choroid plexus tumors, medulloblastomas, and diffuse gliomas, are frequently found in patients with LFS. Although molecular profiles of diffuse gliomas that develop in pediatric patients with LFS have been elucidated, those in adults are limited. Recently, diffuse gliomas have been divided into pediatric- and adult-type gliomas, based on their distinct molecular profiles. In the present study, we investigated the molecular profiles of high-grade gliomas in three adults with LFS. These tumors revealed characteristic histopathological findings of high-grade glioma or glioblastoma and harbored wild-type IDH1/2 according to whole exome sequencing (WES). However, these tumors did not exhibit the key molecular alterations of glioblastoma, IDH-wildtype such as TERT promoter mutation, EGFR amplification, or chromosome 7 gain and 10 loss. Although WES revealed no other characteristic gene mutations or copy number alterations in high-grade gliomas, such as those in histone H3 genes, PDGFRA amplification was found in all three cases together with uniparental disomy of chromosome 17p, where the TP53 gene is located. DNA methylation analyses revealed that all tumors exhibited DNA methylation profiles similar to those of pediatric-type high-grade glioma H3-wildtype and IDH-wildtype (pHGG H3-/IDH-wt), RTK1 subtype. These data suggest that high-grade gliomas developed in adult patients with LFS may be involved in pHGG H3-/IDH-wt. PDGFRA and homozygous alterations in TP53 may play pivotal roles in the development of this type of glioma in adult patients with LFS.

Obstructive Hydrocephalus Due to Aggressive Posterior Fossa Tumor Exhibiting Histological Characteristics of Pilocytic Astrocytoma in Two Adult Neurofibromatosis Type 1 (NF1) Cases

Neurofibromatosis type 1 (NF1) is an autosomal dominant syndrome caused by germline alteration of the NF1gene. Among various NF1-related manifestations, obstructive hydrocephalus especially in adult NF1 cases is less frequently found. We report two adult NF1 cases exhibiting obstructive hydrocephalus due to an aggressive posterior fossa tumor exhibiting pathological characteristics of pilocytic astrocytoma as NF1-related manifestations. In these two cases, we performed endoscopic third ventriculostomy (ETV) and tumor biopsy as an initial treatment. The initial pathological diagnosis of the tumor is conventional pilocytic astrocytoma. After biopsy both cases revealed rapid tumor growth, therefore, we performed tumor removal, chemotherapy, and radiation therapy during an aggressive clinical course. However, both cases revealed dismal prognosis due to the progression of the tumor in spite of successful management of hydrocephalus by an initial ETV. DNA methylation analysis revealed that the tumor of one case matched high-grade astrocytoma with piloid features (HGAP). Most central nervous system tumors developed in NF1 are less aggressive such as pilocytic astrocytoma; however, recently a few studies revealed that HGAP, which has been a newly introduced malignant tumor in the World Health Organization Classification of Tumors of the Central Nervous System, 5th edition (WHO CNS 5), rarely develops in NF1 cases. These findings suggested that HGAP might be one of the important causes of obstructive hydrocephalus in adult NF1 cases.

Predictive factors of post-operative apathy in patients with diffuse frontal gliomas undergoing awake brain mapping

Patients with diffuse frontal gliomas often present with post-operative apathy after tumour removal. However, the association between apathy and tumour removal of gliomas from the frontal lobe remains unknown. This study aimed to investigate the factors influencing post-operative apathy after tumour removal in patients with diffuse frontal gliomas. We compared the demographics and clinical characteristics of patients with and without post-operative apathy in a cohort of 54 patients who underwent awake brain mapping for frontal gliomas. The frequency of clinical parameters such as left-sided involvement, high-grade tumour types (WHO grades III, IV), main tumour location in the anterior cingulate gyrus (ACC) and/or dorsolateral prefrontal cortex (DLPFC) and orbitofrontal cortex (OFC) was significantly greater in the apathetic group compared to the non-apathetic group. The apathetic group scored significantly lower on neuropsychological assessments such as the Letter Fluency Test among the Word Fluency Tests than the non-pathetic group (p = .000). Moreover, the scores of Parts 3, and 3-1 of the Stroop test were significantly lower in the apathetic group than those in the non-apathetic group (p = .023, .027, respectively). Multivariate model analysis revealed that the appearance of post-operative apathy was significantly related to side of the of lesion [left vs. right, hazard ratio (HR) = 8.00, 95% confidence interval (CI) = 1.36-46.96, p = .021], location of the main tumour in the frontal lobe (ACC/DLPFC/OFC vs. others, HR = 7.99, 95% CI = 2.16-29.59, p = .002), and the Letter Fluency Test (HR = .37, 95% CI = .15-.90, p = .028). Post-operative apathy is significantly associated with ACC and/or DLPFC and OFC in the left hemisphere of diffuse frontal gliomas. Apathy in frontal gliomas is correlated with a decline in the Letter Fluency Test scores. Therefore, this instrument is a potential predictor of post-operative apathy in patients with diffuse frontal gliomas undergoing awake brain mapping.

Endoscopic debulking canalization for optic pathway glioma with obstructive hydrocephalus

Optic pathway gliomas (OPGs) are benign tumors that can stop growing or even shrink. In recent years, surgical resection has not been considered the first-line treatment because of its high risk of complications. Chemotherapy is the mainstay of treatment for growing OPGs. Surgical treatment for OPGs with obstructive hydrocephalus is required. Ventriculoperitoneal shunting is effective for all types of hydrocephalus. However, long-term management is required, especially in pediatric cases, and there is a risk of shunt-related complications over a long lifespan. Debulking surgery for OPGs allows us to avoid shunt placement by creating a waterway and releasing the hydrocephalus. To reduce the surgical risk and invasiveness, we used an endoscopic canalization technique with a small-diameter cylinder. In this article, we present a case of endoscopic canalization of an obstructive hydrocephalus caused by OPGs in a 14-year-old female to illustrate our surgical technique.(Trial registration Registry name and number: Efficacy and safety of the neuro-endoscopic treatment for brain tumors (2019-0254)).

Fifteen-Fraction Radiosurgery Followed by Reduced-Dose Whole-Brain Irradiation With a Total Biologically Effective Dose of >90-100 Gy for a Locally Invasive Brain Metastasis From Lung Adenocarcinoma With a High Dissemination Potential

A deep-seated, locally infiltrative 5.8-cm brain metastasis (BM) involving the ventricular wall and optic radiation is deemed unamenable for a safe total resection, while preventing tumor seeding. Meanwhile, radiotherapeutic management alone for such a BM close to the brainstem is also challenging. We describe such a BM (gross tumor volume [GTV] 40.3 cm3) from lung adenocarcinoma (LAC), located in the left temporo-occipital lobes, with extensive invasion to the tentorium cerebelli and a high potential for dissemination. The BM was treated with 15-fraction(s) (fr) stereotactic radiosurgery (SRS) followed by whole-brain irradiation (WBI) at 27 Gy/15 fr with a 19-day interval. During the SRS, the solid component away from the tentorium showed obvious shrinkage. The cumulative biologically effective doses (BEDs) of the minimum and D99% of the GTV were ≥92.3 Gy and ≥102.6 Gy, respectively, where the BED was based on the linear-quadratic formula at an alpha/beta ratio of 10 (BED10). Despite a maximum response with nearly complete regression at 7.5 months, local tumor regrowth near the tentorial incisura became gradually apparent from 11.2 to 19.3 months. Salvage re-SRS with 53 Gy/10 fr specific to these lesions resulted in obvious regression at 5.8 months. However, radiation injury concomitant with triventriculomegaly progressed from 7.9 to 13.9 months, eventually leading to meningeal dissemination and patient mortality at 34.6 months. This case demonstrates that a BED10 ≥90-100 Gy in 30 fr to the GTV boundary with a more than two-week interval without combined systemic therapy is insufficient for achieving complete local tumor eradication of a 40-cc LAC-BM. Shorter treatment duration with a steeper dose gradient outside and inside the GTV in the SRS or a volumetric modulated arc-based SRS combined with simultaneously integrated WBI may improve efficacy and safety.

Development of machine learning models for predicting unfavorable functional outcomes from preoperative data in patients with chronic subdural hematomas

Chronic subdural hematoma (CSDH) often causes neurological deterioration and is treated with hematoma evacuation. This study aimed to assess the feasibility of various machine learning models to preoperatively predict the functional outcome of patients with CSDH. Data were retrospectively collected from patients who underwent CSDH surgery at two institutions: one for internal validation and the other for external validation. The poor functional outcome was defined as a modified Rankin scale score of 3-6 upon hospital discharge. The unfavorable outcome was predicted using four machine learning algorithms on an internal held-out cohort (n = 188): logistic regression, support vector machine (SVM), random forest, and light gradient boosting machine. The prediction performance of these models was also validated in an external cohort (n = 99). The area under the curve of the receiver operating characteristic curve (ROC-AUC) of each machine learning-based model was found to be high in both validations (internal: 0.906-0.925, external: 0.833-0.860). In external validation, the SVM model demonstrated the highest ROC-AUC of 0.860 and accuracy of 0.919. This study revealed the potential of machine learning algorithms in predicting unfavorable outcomes at discharge among patients with CSDH undergoing burr hole surgery.

TUG1-mediated R-loop resolution at microsatellite loci as a prerequisite for cancer cell proliferation

Oncogene-induced DNA replication stress (RS) and consequent pathogenic R-loop formation are known to impede S phase progression. Nonetheless, cancer cells continuously proliferate under such high-stressed conditions through incompletely understood mechanisms. Here, we report taurine upregulated gene 1 (TUG1) long noncoding RNA (lncRNA), which is highly expressed in many types of cancers, as an important regulator of intrinsic R-loop in cancer cells. Under RS conditions, TUG1 is rapidly upregulated via activation of the ATR-CHK1 signaling pathway, interacts with RPA and DHX9, and engages in resolving R-loops at certain loci, particularly at the CA repeat microsatellite loci. Depletion of TUG1 leads to overabundant R-loops and enhanced RS, leading to substantial inhibition of tumor growth. Our data reveal a role of TUG1 as molecule important for resolving R-loop accumulation in cancer cells and suggest targeting TUG1 as a potent therapeutic approach for cancer treatment.

Latest classification of ependymoma in the molecular era and advances in its treatment: a review

Ependymoma is a rare central nervous system (CNS) tumour occurring in all age groups and is one of the most common paediatric malignant brain tumours. Unlike other malignant brain tumours, ependymomas have few identified point mutations and genetic and epigenetic features. With advances in molecular understanding, the latest 2021 World Health Organization (WHO) classification of CNS tumours divided ependymomas into 10 diagnostic categories based on the histology, molecular information and location; this accurately reflected the prognosis and biology of this tumour. Although maximal surgical resection followed by radiotherapy is considered the standard treatment method, and chemotherapy is considered ineffective, the validation of the role of these treatment modalities continues. Although the rarity and long-term clinical course of ependymoma make designing and conducting prospective clinical trials challenging, knowledge is steadily accumulating and progress is being made. Much of the clinical knowledge obtained from clinical trials to date was based on the previous histology-based WHO classifications, and the addition of new molecular information may lead to more complex treatment strategies. Therefore, this review presents the latest findings on the molecular classification of ependymomas and advances in its treatment.

Brain metastasis and intracranial leptomeningeal metastasis from malignant peripheral nerve sheath tumors: illustrative cases

BACKGROUND

Malignant peripheral nerve sheath tumors (MPNSTs) are rare soft-tissue tumors. Intracranial metastasis from MPNSTs is quite rare.

OBSERVATIONS

The authors report on a 73-year-old male whose MPNST metastasized to the brain and a 32-year-old male with leptomeningeal metastasis from MPNST and review 41 cases of MPNST that developed intracranial metastasis, as reported in the literature.

LESSONS

Brain metastasis and leptomeningeal metastasis of MPNSTs show different clinical courses and require pathology-specific treatment.

Mutation detection of urinary cell-free DNA via catch-and-release isolation on nanowires for liquid biopsy

Cell-free DNA (cfDNA) and extracellular vesicles (EVs) are molecular biomarkers in liquid biopsies that can be applied for cancer detection, which are known to carry information on the necessary conditions for oncogenesis and cancer cell-specific activities after oncogenesis, respectively. Analyses for both cfDNA and EVs from the same body fluid can provide insights into screening and identifying the molecular subtypes of cancer; however, a major bottleneck is the lack of efficient and standardized techniques for the isolation of cfDNA and EVs from clinical specimens. Here, we achieved catch-and-release isolation by hydrogen bond-mediated binding of cfDNA in urine to zinc oxide (ZnO) nanowires, which also capture EVs by surface charge, and subsequently we identified genetic mutations in urinary cfDNA. The binding strength of hydrogen bonds between single-crystal ZnO nanowires and DNA was found to be equal to or larger than that of conventional hydrophobic interactions, suggesting the possibility of isolating trace amounts of cfDNA. Our results demonstrated that nanowire-based cancer screening assay can screen cancer and can identify the molecular subtypes of cancer in urine from brain tumor patients through EV analysis and cfDNA mutation analysis. We anticipate our method to be a starting point for more sophisticated diagnostic models of cancer screening and identification.

Clinical characteristics and radiological features of glioblastoma, IDH-wildtype, grade 4 with histologically lower-grade gliomas

The 2021 World Health Organization (WHO) classification of central nervous system tumors applied molecular criteria and further integrated histological and molecular diagnosis of gliomas. This classification allows for the diagnosis of isocitrate dehydrogenase wild-type (IDHwt) glioblastoma (GBM), and WHO grade 4 with histologically lower-grade gliomas (LrGGs), even in the absence of high-grade histopathologic features, such as necrosis and/or microvascular proliferation. They contain at least one of the following molecular features: epidermal growth factor receptor amplification, chromosome 7 gain/10 loss, or telomerase reverse transcriptase promoter mutation. In the imaging features at the time of histological diagnosis, a gliomatosis cerebri growth pattern was frequently observed in these tumors. Furthermore, this growth pattern was significantly higher in IDHwt GBM, WHO grade 4, with histological grade II gliomas. Although the exact prognosis of IDHwt GBM, WHO grade 4, with histologically LGGs remains unknown, its OS was approximately 1-2 years similar to that of histologically IDHwt GBM, WHO grade 4, despite histopathological features similar to IDHmut LrGGs. These findings reinforce the need for the analysis of molecular features, regardless of presenting similar clinical characteristics and imaging features to IDHmut LrGGs.

Easy-to-use machine learning system for the prediction of IDH mutation and 1p/19q codeletion using MRI images of adult-type diffuse gliomas

Adult-type diffuse gliomas are divided into Astrocytoma, IDH-mutant, Oligodendroglioma, IDH-mutant and 1p/19q-codeleted and Glioblastoma, IDH-wildtype based on the IDH mutation, and 1p/19q codeletion status. To determine the treatment strategy for these tumors, pre-operative prediction of IDH mutation and 1p/19q codeletion status might be effective. Computer-aided diagnosis (CADx) systems using machine learning have been noted as innovative diagnostic methods. However, it is difficult to promote the clinical application of machine learning systems at each institute because the support of various specialists is essential. In this study, we established an easy-to-use computer-aided diagnosis system using Microsoft Azure Machine Learning Studio (MAMLS) to predict these statuses. We constructed an analysis model using 258 adult-type diffuse glioma cases from The Cancer Genome Atlas (TCGA) cohort. Using MRI T2-weighted images, the overall accuracy, sensitivity, and specificity for the prediction of IDH mutation and 1p/19q codeletion were 86.9%, 80.9%, and 92.0%, and 94.7%, 94.1%, and 95.1%, respectively. We also constructed an reliable analysis model for the prediction of IDH mutation and 1p/19q codeletion using an independent Nagoya cohort including 202 cases. These analysis models were established within 30 min. This easy-to-use CADx system might be useful for the clinical application of CADx in various institutes.

Efficacy and safety of bevacizumab, irinotecan, and temozolomide combination for relapsed or refractory pediatric central nervous system embryonal tumor: a single-institution study

OBJECTIVE

This study aimed to evaluate the efficacy and safety of combination therapy with bevacizumab (Bev), irinotecan (CPT-11), and temozolomide (TMZ) in children with central nervous system (CNS) embryonal tumor relapse.

METHODS

The authors retrospectively examined 13 consecutive pediatric patients with relapsed or refractory CNS embryonal tumors who received combination therapy comprising Bev, CPT-11, and TMZ. Specifically, 9 patients had medulloblastoma, 3 had atypical teratoid/rhabdoid tumor (AT/RT), and 1 had CNS embryonal tumor with rhabdoid features. Of the 9 medulloblastoma cases, 2 were categorized in the Sonic hedgehog subgroup and 6 in molecular subgroup 3 for medulloblastoma.

RESULTS

The complete and partial objective response rates were 66.6% in patients with medulloblastoma and 75.0% in patients with AT/RT or CNS embryonal tumors with rhabdoid features. Furthermore, the 12- and 24-month progression-free survival rates were 69.2% and 51.9% for all patients with recurrent or refractory CNS embryonal tumors, respectively. In contrast, the 12- and 24-month overall survival rates were 67.1% and 58.7%, respectively, for all patients with relapsed or refractory CNS embryonal tumors. The authors observed grade 3 neutropenia, thrombocytopenia, proteinuria, hypertension, diarrhea, and constipation in 23.1%, 7.7%, 23.1%, 7.7%, 7.7%, and 7.7% of patients, respectively. Furthermore, grade 4 neutropenia was observed in 7.1% of patients. Nonhematological adverse effects, such as nausea and constipation, were mild and controlled with standard antiemetics.

CONCLUSIONS

This study demonstrated favorable survival outcomes in patients with relapsed or refractory pediatric CNS embryonal tumors and thus helped to investigate the efficacy of combination therapy comprising Bev, CPT-11, and TMZ. Moreover, combination chemotherapy had high objective response rates, and all adverse events were tolerable. To date, data supporting the efficacy and safety of this regimen in the relapsed or refractory AT/RT population are limited. These findings suggest the potential efficacy and safety of combination chemotherapy in patients with relapsed or refractory pediatric CNS embryonal tumors.

Rapid detection of the MYD88 L265P mutation for pre- and intra-operative diagnosis of primary central nervous system lymphoma

The myeloid differentiation primary response gene 88 (MYD88) L265P mutation is a disease-specific mutation of primary central nervous system lymphoma (PCNSL) among the central nervous system tumors. Accordingly, this mutation is considered a reliable diagnostic molecular marker of PCNSL. As the intra-operative diagnosis of PCNSL is sometimes difficult to achieve using histological examinations alone, intra-operative detection of the MYD88 L265P mutation could be effective for the accurate diagnosis of PCNSL. Herein, we aimed to develop a novel rapid genotyping system (GeneSoC) using real-time polymerase chain reaction (PCR) based on microfluidic thermal cycling technology. This real-time PCR system shortened the analysis time, which enabled the detection of the MYD88 L265P mutation within 15 min. Rapid detection of the MYD88 L265P mutation was performed intra-operatively using GeneSoC in 24 consecutive cases with suspected malignant brain tumors, including 10 cases with suspected PCNSL before surgery. The MYD88 L265P mutation was detected in eight cases in which tumors were pathologically diagnosed as PCNSL after the operation, while wild-type MYD88 was detected in 16 cases. Although two of the 16 cases with wild-type MYD88 were pathologically diagnosed as PCNSL after the operation, MYD88 L265P could be detected in all eight PCNSL cases harboring MYD88 L265P. The MYD88 L265P mutation could also be detected using cell-free DNA derived from the cerebrospinal fluid of two PCNSL cases. Detection of the MYD88 L265P mutation using GeneSoC might not only improve the accuracy of intra-operative diagnosis of PCNSL but also help the future pre-operative diagnosis through liquid biopsy of cerebrospinal fluid.

All-in-One Nanowire Assay System for Capture and Analysis of Extracellular Vesicles from an ex Vivo Brain Tumor Model

Extracellular vesicles (EVs) have promising potential as biomarkers for early cancer diagnosis. The EVs have been widely studied as biological cargo containing essential biological information not only from inside vesicles such as nucleic acids and proteins but also from outside vesicles such as membrane proteins and glycolipids. Although various methods have been developed to isolate EVs with high yields such as captures based on density, size, and immunoaffinity, different measurement systems are needed to analyze EVs after isolation, and a platform that enables all-in-one analysis of EVs from capture to detection in multiple samples is desired. Since a nanowire-based approach has shown an effective capability for capturing EVs via surface charge interaction compared to other conventional methods, here, we upgraded the conventional well plate assay to an all-in-one nanowire-integrated well plate assay system (i.e., a nanowire assay system) that enables charge-based EV capture and EV analysis of membrane proteins. We applied the nanowire assay system to analyze EVs from brain tumor organoids in which tumor environments, including vascular formations, were reconstructed, and we found that the membrane protein expression ratio of CD31/CD63 was 1.42-fold higher in the tumor organoid-derived EVs with a p-value less than 0.05. Furthermore, this ratio for urine samples from glioblastoma patients was 2.25-fold higher than that from noncancer subjects with a p-value less than 0.05 as well. Our results demonstrated that the conventional well plate method integrated with the nanowire-based EV capture approach allows users not only to capture EVs effectively but also to analyze them in one assay system. We anticipate that the all-in-one nanowire assay system will be a powerful tool for elucidating EV-mediated tumor-microenvironment crosstalk.

Imaging features of localized IDH wild-type histologically diffuse astrocytomas: a single-institution case series

Isocitrate dehydrogenase wild-type (IDHwt) diffuse astrocytomas feature highly infiltrative patterns, such as a gliomatosis cerebri growth pattern with widespread involvement. Among these tumors, localized IDHwt histologically diffuse astrocytomas are rarer than the infiltrative type. The aim of this study was to assess and describe the clinical, radiographic, histopathological, and molecular characteristics of this rare type of IDHwt histologically diffuse astrocytomas and thereby provide more information on how its features affect clinical prognoses and outcomes. We retrospectively analyzed the records of five patients with localized IDHwt histologically diffuse astrocytomas between July 2017 and January 2020. All patients were female, and their mean age at the time of the initial treatment was 55.0 years. All patients had focal disease that did not include gliomatosis cerebri or multifocal disease. All patients received a histopathological diagnosis of diffuse astrocytomas at the time of the initial treatment. For recurrent tumors, second surgeries were performed at a mean of 12.4 months after the initial surgery. A histopathological diagnosis of glioblastoma was made in four patients and one of gliosarcoma in one patient. The initial status of IDH1, IDH2, H3F3A, HIST1H3B, and BRAF was "wild-type" in all patients. TERT promoter mutations (C250T or C228T) were detected in four patients. No tumors harbored a 1p/19q codeletion, EGFR amplification, or chromosome 7 gain/10 loss (+ 7/ - 10). We assessed clinical cases of localized IDHwt histologically diffuse astrocytomas that resulted in malignant recurrence and a poor clinical prognosis similar to that of glioblastomas. Our case series suggests that even in patients with histologically diffuse astrocytomas and those who present with radiographic imaging findings suggestive of a localized tumor mass, physicians should consider the possibility of IDHwt histologically diffuse astrocytomas.

CD79B Y196 mutation is a potent predictive marker for favorable response to R-MPV in primary central nervous system lymphoma

BACKGROUND

Rituximab, high-dose methotrexate (HD-MTX), procarbazine and vincristine (R-MPV), has significantly prolonged the survival of patients with primary central nervous system lymphoma (PCNSL), but predictive factors for response to R-MPV have not yet been investigated. Herein, we investigated the correlation of MYD88 L265P and CD79B Y196 mutations, which are the most frequently found molecular alterations in PCNSL, with prognosis of patients with PCNSL treated with R-MPV.

METHODS

We investigated the long-term clinical course and status of MYD88 and CD79B genes in 85 patients with PCNSL treated with R-MPV or HD-MTX treatment, and the correlation of these genetic mutations with prognosis.

RESULTS

R-MPV achieved an excellent tumor control rate (61.6% and 69.9% of 5-year progression-free and overall survival rates, respectively). While MYD88 L265P mutation had no significant effect on survival, patients with CD79B Y196 mutations exhibited prolonged survival (p < 0.05). However, the association of CD79B Y196 mutation with a better prognosis was not observed in the HD-MTX cohort, which indicated that CD79B Y196 mutation was a predictive marker for a favorable response to R-MPV. Furthermore, we established an all-in-one rapid genotyping system for these genetic mutations.

CONCLUSIONS

In conclusion, CD79B Y196 mutation is a potent predictive marker for favorable response to R-MPV in PCNSL. The rapid identification of MYD88 L265P and CD79B Y196 mutations can be helpful not only for the accurate molecular diagnosis of PCNSL but also for the prediction of response to R-MPV.

MPC-20 CLINICAL AND MOLECULAR FEATURES OF GLIOBLASTOMAS ARISING IN THE SETTING OF LI FRAUMENI SYNDROME

Introduction

Li Fraumeni Syndrome (LFS) is a rare autosomal dominant tumor predisposition syndrome caused by germline alterations of the TP53. Brain tumors are included in LFS core cancers. Choroid plexus carcinomas and medulloblastomas tend to present in pediatric LFS patients, while gliomas tend to present in adult LFS patients. There are few previous reports about gliomas arising in the setting of LFS. Here, we report clinical and molecular features of three cases of glioblastoma arising in the setting of LFS.

Results

Mean age at diagnosis was 40 years (range: 32-45). Two patients were male. Two patients had medical history of multiple tumors and family history of brain tumors. Magnetic resonance imaging of each patients revealed a left cerebellar peduncle lesion, a right parietal lobe lesion and two lesions in the pons and right parietal lobe, respectively. Pathological diagnoses of all cases were glioblastomas, IDH-wildtype. All patients underwent chemoradiotherapy after surgery. Mean progression free survival was 10.4 months (range: 5.1-17.0). All patients were admitted to palliative care mean 17.3 months (range: 14.4-21.4) after diagnosis. All patients had heterozygous germline mutations of TP53. Genetic analysis of tumor tissues revealed TP53 mutation and PDGFRA amplification in all patients. In all cases, mutation spots of TP53 in tumor-derived DNA were consistent with those of germ line mutations. In all cases, copy number alteration of TP53 gene in tumor-derived DNA were not detected. EGFR amplification, the combination of gain of chromosome 7 and loss of chromosome 10 (7+/10-) and mutations of IDH, H3F3A, BRAF genes and TERT gene promoter were not detected in all tumor-derived DNA.

Conclusion

We experienced three cases of glioblastoma, IDH-wildtype arising in the setting of LFS. Clinical courses of all cases were poor. Notably, all tumor tissues harbored TP53 mutation and PDGFRA amplification, while no tumor tissues harbored TERTp mutation, EGFR amplification and 7+/10-.

DDDR-39. IDENTIFICATION OF A NOVEL THERAPEUTIC TARGET THAT IS SYNTHETICALLY LETHAL WITH MUTANT IDH INHIBITOR IN GLIOMA USING THE CRISPR/CAS9 GENOME EDITING TECHNOLOGY

Diffuse glioma is the most frequent and malignant neuroepithelial tumor in the central nervous system. IDH mutations are the most frequent genetic mutations in adult gliomas. The WHO Classification of Tumors, 5th edition, volume 6: Central Nervous System Tumours revised in 2021, defines the presence of IDH mutations in gliomas as astrocytoma IDH-mutant and oligodendroglioma IDH-mutant and 1p/19q-codeleted. In addition, more than 90% of IDH mutations found in gliomas are IDH1 R132H mutation. Several clinical trials of mutant IDH1 inhibitors targeting the IDH1 R132H mutation have shown their efficacy, but it has also been reported that IDH1 inhibitors alone may not provide sufficient tumor suppression. In this study, we performed genome-wide knockout screening using CRISPR/Cas9 genome editing technology to search for new drug targets that are synergistic with the mutant IDH1 inhibitor DS-1001b. The results of CRISPR screening and RNA sequence analysis revealed that several metabolism-related genes are factors that define resistance to mutant IDH inhibitor. In a tumor suppression study, treatment of two IDH1 R132H mutant glioma cell lines (MGG152 and BT142) with mutant IDH1 inhibitor suppressed production of the oncometabolite D2-HG, but did not significantly alter cell growth. However, when mutant IDH1 inhibitor were combined with inhibitor for metabolism-related genes, cell survival was significantly reduced, and the effects were synergistic. In this study, we found that administration of mutant IDH inhibitors to IDH mutant gliomas significantly altered intratumor metabolism using various molecular approaches. We then identified targets that, when combined with mutant IDH inhibitor, provide synergistic tumor suppression. These results are expected to provide a new therapeutic approach for a subset of patients who have difficulty responding to mutant IDH1 inhibitors.

PATH-19. CLINICAL AND MOLECULAR FEATURES OF GLIOBLASTOMA, IDH-WILDTYPE ARISING IN THE SETTING OF LI FRAUMENI SYNDROME

INTRODUCTION

Li Fraumeni Syndrome (LFS) is a rare autosomal dominant tumor predisposition syndrome caused by germline alterations of the TP53. Brain tumors are included in LFS core cancers. Choroid plexus carcinomas and medulloblastomas tend to occur in pediatric LFS patients, while gliomas tend to occur in adult LFS patients. There are few previous reports about gliomas arising in the setting of LFS. Here, we report clinical and molecular features of three cases of glioblastoma, IDH-wildtype arising in the setting of LFS.

RESULTS

Mean age at diagnosis was 40 years (range: 32-45). Two patients were male. Two patients had medical history of multiple tumors and family history of brain tumors. Magnetic resonance imaging of each patients revealed a left cerebellar peduncle lesion with faint contrast-enhancement, a right parietal lobe lesion with nodular contrast-enhancement and two lesions in the pons (no enhancement) and right parietal lobe (ring enhancement), respectively. All patients underwent chemotherapy including temozolomide and/or bevacizumab combined with radiation therapy (60Gy) after surgery. Mean progression free survival was 10.4 months (range: 5.1-17.0). All patients were admitted to palliative care mean 17.3 months (range: 14.4-21.4) after diagnosis. All patients harbored heterozygous germline mutations of TP53. Whole exome sequencing and copy number analysis of tumor tissues revealed TP53 mutation and PDGFRA amplification in all patients. However, EGFR amplification, the combination of gain of chromosome 7 and loss of chromosome 10 (7+/10-) and mutations of IDH, H3F3A, BRAF and TERT promoter were not detected in all tissues.

CONCLUSION

We experienced three cases of glioblastoma, IDH-wildtype arising in the setting of LFS. Although tumor locations and radiographic features were varied, all clinical courses were poor. Notably, all tumor tissues harbored TP53 mutation and PDGFRA amplification, while no tumor tissues harbored TERT promoter mutation, EGFR amplification and 7+/10-.

BIOM-58. ROLE OF CD79B Y196 MUTATION IN PCNSL AS A POTENT PREDICTIVE MARKER FOR FAVORABLE RESPONSE TO R-MPV TREATMENT AND DEVELOPMENT OF RAPID ALL-IN-ONE GENOTYPING SYSTEM FOR MOLECULAR MARKERS OF PCNSL

Although high-dose methotrexate (HD-MTX)-based chemotherapy, such as rituximab, HD-MTX, procarbazine and vincristine (R-MPV) regimen, has significantly prolonged the survival of patients with primary central nervous system lymphoma (PCNSL), predictive factors for response to R-MPV have not yet been investigated. Then, we investigated the correlation of MYD88 L265P and CD79B Y196 mutations, which are the most frequently found molecular alterations in PCNSL, with prognosis of patients with PCNSL treated with R-MPV. 47 and 21 patients with PCNSL treated with R-MPV and HD-MTX respectively were included, and correlation of their MYD88 and CD79B status with prognosis was analyzed. R-MPV achieved an excellent tumor control rate (61.6% and 69.9% of 5-year progression-free and overall survival rates, respectively). Among the 47 patients, 36 harbored MYD88 L265P or CD79B Y196 mutations. While the MYD88 L265P mutation had no significant effect on survival, patients with CD79B Y196 mutations exhibited prolonged survival (P &lt; 0.05). However, the association of the CD79B Y196 mutation with a better prognosis was not observed in the HD-MTX cohort, which indicated that the CD79B Y196 mutation was a predictive marker for a favorable response to R-MPV. Furthermore, we established an all-in-one rapid genotyping system for these genetic mutations. This system enabled the detection of these genetic mutations in a small amount of biopsy samples within 90 min. In conclusion, we revealed that the CD79B Y196 mutation is associated with a good response to R-MPV, and the rapid and accurate genotyping system for MYD88 L265P and CD79B Y196 mutations that we developed in this study will enable reliable rapid molecular diagnosis and early prediction of response to R-MPV, which might help to determine the best treatment strategy for PCNSL.

Endoscopic Trans-Mini-Cylinder Biopsy for Intraparenchymal Brain Lesions

OBJECTIVE

The biopsy procedure is intended to obtain an adequate specimen volume from the targeted area while ensuring minimal damage to the normal brain. We performed navigation-guided endoscopic biopsy using a small-diameter cylinder to reduce the invasiveness of the biopsy procedure and ensure a sufficient amount of tissue is collected. We examined whether it is possible to reduce brain tissue injury by using a small-diameter cylinder and improve safety and effectiveness by using an endoscope to directly observe the lesion and achieve hemostasis.

METHODS

Patients who underwent endoscopic biopsy surgery using a 6-mm-diameter cylinder for intraparenchymal lesions were enrolled in this study. Postoperative hematoma formation and the extent of trajectory scarring were assessed.

RESULTS

Fifty-two procedures performed on 51 patients were analyzed in this study. Postoperative neurological deterioration was not observed in any patient. A pathological diagnosis was made for all patients. Postoperative computed tomography revealed no hematoma after 49 procedures and a small hematoma after 3 procedures, and no patients required additional treatment. A postoperative trajectory scar less than 5 mm in diameter was observed after 30 procedures, a scar of 5-10 mm was observed after 19 procedures, a scar larger than 10 mm was observed after 3 procedures at 1 week after surgery, and 40, 6 and 0 scars were observed at 3 months after surgery.

CONCLUSIONS

Endoscopic biopsy using a small-diameter cylinder is a possible alternative biopsy technique for intraparenchymal lesions. This surgical technique is useful, especially in patients at risk of hemorrhagic complications.

11C-methionine- and 18F-FDG-PET double-negative metastatic brain tumor from lung adenocarcinoma with paradoxical high 18F-FDG uptake: A case report

Background:

Imaging with 18F-fluorodeoxyglucose (FDG)-positron emission tomography (PET) and 11C-methionine (MET)-PET can delineate primary and metastatic brain tumors. Lesion size affects the sensitivity of both scans and histopathological features can also influence FDG-PET, but the effects on MET-PET have not been elucidated.

Case Description:

We report an unusual case of metastatic brain tumors without accumulation of FDG or MET, contrasting with high FDG uptake in the primary lung lesion. The brain lesions were identified as adenocarcinoma with a more mucus-rich background, contributing to the indistinct accumulation of both FDG and MET.

Conclusion:

Histopathological characteristics can affect both MET and FDG accumulation, leading to findings contradicting those of the primary lesion.

Primary central nervous system malignant lymphoma in a patient with rheumatoid arthritis receiving tocilizumab: illustrative case

BACKGROUND

Although the risk of developing malignant lymphoma is higher in patients with rheumatoid arthritis (RA) than in the general population, primary central nervous system lymphoma (PCNSL) in patients with RA is extremely rare. In recent years, there has been concern that biological disease-modifying antirheumatic drugs (bDMARDs), widely administered to patients with RA, might increase the risk of cancer development. The authors report the first case of PCNSL in a patient with RA receiving the bDMARD tocilizumab.

OBSERVATIONS

A 70-year-old man who was diagnosed with RA in 2010 was treated with low-dose methotrexate (MTX) from 2010 to 2015. Tocilizumab was commenced in 2012. In 2018, he developed gait disturbances, and gadolinium-enhanced magnetic resonance imaging showed multiple contrast-enhanced lesions in the basal ganglia and brain stem. Stereotactic brain biopsy led to the diagnosis of diffuse large B-cell lymphoma, and finally PCNSL was diagnosed. He was treated with five courses of MTX 3.5 g/m2, and his disease has been in remission for 34 months.

LESSONS

Low-dose MTX and bDMARDs are associated with the concern of increased cancer risk in patients with RA. Because tocilizumab has been in use for a relatively short time, further accumulation of cases and careful follow-up are necessary.

Direct intracranial invasion of eccrine spiradenocarcinoma of the scalp: a case report and literature review

Background

Eccrine spiradenocarcinoma (SC), also known as malignant eccrine spiradenoma, is a rare malignant cutaneous adnexal neoplasm arising from long-standing benign eccrine spiradenoma. Malignant skin tumors rarely show direct intracranial invasion. However, once the intracranial structure is infiltrated, curative excision with sufficient margins can become extremely difficult, particularly when the venous sinuses are involved. No effective adjuvant therapies have yet been established. Here, we report an extremely rare case of scalp eccrine SC with direct intracranial invasion, which does not appear to have been reported previously.

Case presentation

An 81-year-old woman presented with a large swelling on the parietal scalp 12 years after resection of spiradenoma from the same site. The tumor showed intracranial invasion with involvement of the superior sagittal sinus and repeated recurrences after four surgeries with preservation of the sinus. The histopathological diagnosis was eccrine SC. Adjuvant high-precision external beam radiotherapy (EBRT) proved effective after the third surgery, achieving remission of the residual tumor. The patient died 7 years after the first surgery for SC.

Conclusions

Scalp SC with direct intracranial invasion is extremely rare. Radical resection with tumor-free margins is the mainstay of treatment, but the involvement of venous sinuses makes this unfeasible. High-precision EBRT in combination with maximal resection preserving the venous sinuses could be a treatment option for local tumor control.

Recent Molecular and Genetic Findings in Intramedullary Spinal Cord Tumors

The study of genetic alterations and molecular biology in central nervous system (CNS) tumors has improved the accuracy of estimations of patient prognosis and tumor categorization. Therefore, the updated 2021 World Health Organization (WHO) classification includes various diagnostic genes, molecules, and pathways for diagnosis, as well as histological findings. These findings are expected both to have diagnostic applications and to facilitate new targeted therapies that target tumor-specific genetic changes and molecular biology. Intramedullary spinal cord tumors (IMSCTs) are rare CNS tumors that are difficult to treat because they occur in eloquent areas. Although the genetic underpinnings of IMSCTs remain unclear compared to their intracranial counterparts, the genetic characteristics of these tumors are gradually being revealed. Here, we describe the major changes in the new 2021 WHO classification and review the major types of IMSCTs, with an emphasis on their clinical features and genetic alterations.

Supratotal Resection of Gliomas With Awake Brain Mapping: Maximal Tumor Resection Preserving Motor, Language, and Neurocognitive Functions

Gliomas are a category of infiltrating glial neoplasms that are often located within or near the eloquent areas involved in motor, language, and neurocognitive functions. Surgical resection being the first-line treatment for gliomas, plays a crucial role in patient outcome. The role of the extent of resection (EOR) was evaluated, and we reported significant correlations between a higher EOR and better clinical prognosis of gliomas. However, recurrence is inevitable, even after aggressive tumor removal. Thus, efforts have been made to achieve extended tumor resection beyond contrast-enhanced mass lesions in magnetic resonance imaging (MRI)-defined areas, a process known as supratotal resection. Since it has been reported that tumor cells invade beyond regions visible as abnormal areas on MRI, imaging underestimates the true spatial extent of tumors. Furthermore, tumor cells have the potential to spread 10–20 mm away from the MRI-verified tumor boundary. The primary goal of supratotal resection is to maximize EOR and prolong the progression-free and overall survival of patients with gliomas. The available data, as well as our own work, clearly show that supratotal resection of gliomas is a feasible technique that has improved with the aid of awake functional mapping using intraoperative direct electrical stimulation. Awake brain mapping has enabled neurosurgeons achieve supratotal resection with favorable motor, language, and neurocognitive outcomes, ensuring a better quality of life in patients with gliomas.

Increased Risk of Thyroid Dysfunction by PD-1 and CTLA-4 Blockade in Patients Without Thyroid Autoantibodies at Baseline

BACKGROUND

Previous studies showed that although the risk of thyroid dysfunction [thyroid immune-related adverse events (irAEs)] induced by anti-programmed cell death-1 antibodies (PD-1-Ab) was as low as 2% to 7% in patients negative for anti-thyroid antibodies (ATAs) at baseline, it was much higher (30%-50%) in patients positive for ATAs. However, whether a similar increase occurs with combination therapy using PD-1-Ab plus anti-cytotoxic T-lymphocyte antigen-4 antibody (CTLA-4-Ab) is unknown.

METHODS

A total of 451 patients with malignancies treated with PD-1-Ab, CTLA-4-Ab, or a combination of PD-1-Ab and CTLA-4-Ab (PD-1/CTLA-4-Abs) were evaluated for ATAs at baseline and for thyroid function every 6 weeks for 24 weeks after treatment initiation and then observed until the last clinical visit.

RESULTS

Of the 451 patients, 51 developed thyroid irAEs after immunotherapy [41 of 416 (9.9%) treated with PD-1-Ab, 0 of 8 (0%) treated with CTLA-4-Ab, and 10 of 27 (37.0%) treated with PD-1/CTLA-4-Abs]. The cumulative incidence of thyroid irAEs was significantly higher in patients who were positive vs negative for ATAs at baseline after both PD-1-Ab [28/87 (32.2%) vs 13/329 (4.0%), P < 0.001] and PD-1/CTLA-4-Abs [6/10 (60.0%) vs 4/17 (23.5%), P < 0.05] treatments. The risk of thyroid irAEs induced by PD-1/CTLA-4Abs, which was significantly higher than that induced by PD-1-Ab, in patients negative for ATAs at baseline was not statistically different from that induced by PD-1-Ab in patients positive for ATAs at baseline.

CONCLUSIONS

This study showed that the incidence of thyroid irAEs was high and not negligible after PD-1/CTLA-4-Abs treatment even in patients negative for ATAs at baseline.

Survival Benefit of Supratotal Resection in a Long-term Survivor of IDH-wildtype Glioblastoma: A Case Report and Literature Review

Glioblastoma multiforme (GBM) is an aggressive cancer type, with fewer than 3–5% of patients surviving for more than 3 years. We describe a 48-year-old right-handed man who presented with generalized seizure attacks. Magnetic resonance imaging (MRI) revealed a heterogeneous gadolinium-enhancing lesion in the left inferior parietal lobule. The patient underwent awake surgery, and tumor resection included abnormalities on T2-weighted MRI, with subcortical mapping used to identify the deep functional boundaries. After supratotal resection, the tumor was diagnosed as GBM without isocitrate dehydrogenase (IDH) 1 and 2 mutations. At a follow-up evaluation, 9 years and 2 months after the surgery, the patient appeared healthy, and no relapse or recurrence was observed. We present the case of a long-term survivor of IDH-wildtype GBM. This case suggests that supratotal resection with intraoperative awake brain mapping can improve survival without impairing the patient’s neurological functions.

MPC-5 Characteristics of H3 G34-mutant gliomas

Introduction: Diffuse hemispheric gliomas, H3 G34-mutant (DHG H3G34-mutant) are newly recognized infiltrating gliomas of the cerebral hemispheres of pediatric and young adult patients. We experienced 6 DHG H3G34-mutant cases. In this study, we describe the clinical, radiological and pathological characteristics of these cases.

Result: Mean age at diagnosis was 16.8 years (range:10–26). Three patients were male. Among six cases, tumors located in cerebral cortex in five cases and multiple sites including basal ganglia and cortex in a case. All tumors showed no or only a faint contrast-enhancement and harbored restriction of diffusion. One patient underwent total resection, four underwent partial resection and one underwent biopsy. Pathological diagnosis were CNS embryonal tumors (n=3/6), glioblastoma, IDH-wildtype (n=2/6) and anaplastic astrocytoma, IDH-wildtype (n=1/5). All cases were negative for Olig2 and positive for GFAP in immunohistochemistry. Mean Ki-67 index was 38% (range: 10–60%). All cases revealed at least one of mitosis, necrosis or microvascular proliferation. Especially, mitosis was the most frequently found (n=5/6). The H3F3A mutations were G34R mutations in all cases. One case revealed a characteristic mutation pattern, therefore now we are performing further examination. Adjuvant chemoradiotherapies were performed for all cases. Mean progression free survival was 10.1 months (range: 1.6–33.1).

Discussion: As published literatures reported, all cases exhibited restriction of diffusion and negative for Olig2. For a cerebral hemispheric tumor of pediatric or young adult patient which shows restriction of diffusion and no contrast-enhancement, and of which pathological findings is malignant and olig2 is negative, genetic analysis of H3F3A gene might be essential.

TB-2 Patient-derived meningioma organoid model demonstrates FOXM1 dependent tumor proliferation

Recent comprehensive studies have revealed several molecular alterations that are frequently found in meningiomas. However, effective treatment reagents targeting specific molecular alterations have not yet been identified because of the limited number of representative research models of meningiomas.

We established 18 organoid models comprising of two malignant meningioma cells (HKBMM and IOMM-Lee), 10 benign meningiomas, four malignant meningiomas, and two solitary fibrous tumors (SFTs). Using immunohistochemistry and molecular analyses consisting of whole exome sequencing, RNA-seq, and DNA methylation analyses, we compared the histological findings and molecular profiling of organoid models with those of parental tumors. The organoids exhibited consistent histological features and molecular profiles with those of the parental tumors. Using a public database of meningioma, we identified that upregulated forkhead box M1 (FOXM1) was correlated with increased tumor proliferation. Overexpression of FOXM1 in benign meningioma organoids increased organoid proliferation; depletion of FOXM1 in malignant organoids decreased proliferation. Additionally, thiostrepton, a FOXM1 inhibitor combined with radiation therapy, significantly inhibited proliferation of malignant meningioma organoid models (P<0.01).

An organoid model for meningioma enabled us to elucidate the tumor biology of meningioma along with potent treatment targets for meningioma.

ML-11 Tirabrutinib treatment for recurrent or refractory PCNSL

Since 2020, tirabrutinib which is a Bruton’s tyrosine kinase (BTK) inhibitor has been available for recurrent or refractory PCNSL cases. The number of studies reporting efficiency and adverse effect of tirabrutinib treatment for recurrent or refractory PCNSL has been limited yet. In this study, we investigated clinical course of eight refractory or recurrent PCNSL cases treated with tirabrutinib in our institute.

Eight PCNSL cases treated with tirabrutinib included four recurrent cases and four refractory cases. Five cases obtained CR or PR after 26.8 days administration of tirabrutinib and other two cases also exhibited obvious improvement of clinical symptoms after 23.5 days administration of tirabrutinib. Among three cases exhibiting intraocular lesions, two cases revealed improvement of visual dysfunction and the other case obtained SD status of intraocular lesion. The most frequently found adverse effect was the skin rash. CTCAE grade 2 (n=2) or 3 (n=2) rash was found after mean 16 days or 94 days of tirabrutinib administration, respectively. Two cases with grade 3 rash could start taking the low-dose tirabrutinib after improvement of rash. Althouth one case experienced shingles, no other case experienced serious adverse effects.

Although adverse effect of rash was frequently found, we could obtain high response rate of tirabrutinib treatment for recurrent or refractory PCNSL cases. We need to establish quantitative assessment method for analysis of treatment response of tirabrutinib for intraocular lesions.

STMO-6 Impact of the extent of resection on the survival of patients with lower grade gliomas using awake brain mapping

Purpose: The aim of this study was to assess the effect of the extent of resection (EOR) of tumors on survival in a series of patients with lower-grade gliomas (LGGs) who underwent awake brain mapping.

Methods: We retrospectively analyzed 126 patients with LGGs in the dominant and non-dominant hemisphere who underwent awake brain surgery at the same institution between December 2012 and May 2020.

Results: The median progression-free survival (PFS) rate of patients with LGGs in the group with an EOR &gt;100 %, including supratotal resection (n = 47; median survival [MS], not reached), was significantly higher than that in the group with an EOR &lt;100% (n = 79; MS, 43.1 months; 95% CI: 37.8–48.4 months; p = 0.04). In patients with diffuse astrocytomas and anaplastic astrocytomas, the group with EOR &gt;100 %, including supratotal resection (n = 25; MS, not reached), demonstrated a significantly better PFS rate than did the group with an EOR &lt;100% (n = 45; MS, 35.8 months; 95% CI: 19.9–51.6 months; p = 0.03). Supratotal or gross total resection was correlated with better PFS in IDH-mutant type of diffuse astrocytomas and anaplastic astrocytomas (n = 19; MS, not reached vs. n = 35; MS, 40.6 months; 95% CI: 22.3–59.0 months; p = 0.02). By contrast, supratotal or gross total resection was not associated with longer PFS rates in patients with IDH-wild type of diffuse astrocytomas and anaplastic astrocytomas.

Conclusions: It is noteworthy that supratotal or gross total resection significantly correlated with better PFS in IDH-mutant type of WHO grade II and III astrocytic tumors. In light of our finding that EOR did not correlate with PFS in patients with aggressive IDH-wild type of diffuse astrocytomas and anaplastic astrocytomas, we suggest treatments that are more intensive will be needed for the control of these tumors.

Reliability of IDH1-R132H and ATRX and/or p53 immunohistochemistry for molecular subclassification of Grade 2/3 gliomas

Since the World Health Organization 2016 classification (2016 WHO), genetic status has been incorporated into the diagnosis of Grade 2/3 gliomas (lower-grade gliomas). Therefore, immunohistochemistry (IHC) of IDH1-R132H, ATRX, and p53 have been used in place of genetic status. We report the associations between histological findings, IHC, and genetic status. We performed IHC of IDH1-R132H, ATRX, and p53 in 76 lower-grade gliomas and discussed its validity based on the 2016 WHO and the upcoming 2021 WHO classification. The sensitivity and specificity of anti-ATRX, p53, and IDH1-R132H IHC were 40.9%/98.1%, 78.6%/85.4%, and 90.5%/84.6%, respectively. Among 21 IDH1-mutant gliomas without 1p/19q codeletion, two gliomas (9.5%) mimicked the so-called classic for oligodendroglioma (CFO) in their morphology. Of the 42 gliomas with 1p/19q codeletion, four cases were difficult to diagnose as oligodendroglioma through morphological examination. Moreover, there were three confusing cases with ATRX mutations but with retained ATRX-IHC positivity. The lessons learned from this study are as follows: (1) ATRX-IHC and p53-IHC should be supplementary to morphological diagnosis, (2) rare IDH mutations other than IDH1 R132H should be considered, and (3) there is no complete alternative test to detect molecular features of glioblastoma under the 2021 WHO classification.

Mathematical Modeling and Mutational Analysis Reveal Optimal Therapy to Prevent Malignant Transformation in Grade II IDH-Mutant Gliomas

Isocitrate dehydrogenase-mutant low-grade gliomas (IDHmut-LGG) grow slowly but frequently undergo malignant transformation, which eventually leads to premature death. Chemotherapy and radiotherapy treatments prolong survival, but can also induce genetic (or epigenetic) alterations involved in transformation. Here, we developed a mathematical model of tumor progression based on serial tumor volume data and treatment history of 276 IDHmut-LGGs classified by chromosome 1p/19q codeletion (IDH^mut/1p19q^codel and IDH^mut/1p19q^noncodel) and performed genome-wide mutational analyses, including targeted sequencing and longitudinal whole-exome sequencing data. These analyses showed that tumor mutational burden correlated positively with malignant transformation rate, and chemotherapy and radiotherapy significantly suppressed tumor growth but increased malignant transformation rate per cell by 1.8 to 2.8 times compared with before treatment. This model revealed that prompt adjuvant chemoradiotherapy prolonged malignant transformation-free survival in small IDHmut-LGGs (≤ 50 cm³). Furthermore, optimal treatment differed according to genetic alterations for large IDHmut-LGGs (> 50 cm³); adjuvant therapies delayed malignant transformation in IDH^mut/1p19q^noncodel but often accelerated it in IDH^mut/1p19q^codel. Notably, PI3K mutation was not associated with malignant transformation but increased net postoperative proliferation rate and decreased malignant transformation-free survival, prompting the need for adjuvant therapy in IDH^mut/1p19q^codel. Overall, this model uncovered therapeutic strategies that could prevent malignant transformation and, consequently, improve overall survival in patients with IDHmut-LGGs. SIGNIFICANCE: A mathematical model successfully estimates malignant transformation-free survival and reveals a link between genetic alterations and progression, identifying precision medicine approaches for optimal treatment of IDH-mutant low-grade gliomas.

Newly Established Patient-derived Organoid Model of Intracranial Meningioma

BACKGROUND

Recent comprehensive studies have revealed several molecular alterations that are frequently found in meningiomas. However, effective treatment reagents targeting specific molecular alterations have not yet been identified because of the limited number of representative research models of meningiomas.

METHODS

We performed organoid cultures using meningioma cells and meningioma tumor tissues. Using immunohistochemistry and molecular analyses consisting of whole exome sequencing, RNA-seq, and DNA methylation analyses, we compared the histological findings and molecular profiling of organoid models with those of parental tumors. Further, using these organoid models together with a public database of meningiomas, we explored molecular alterations, which are a potent treatment target for meningioma.

RESULTS

We established 18 organoid models comprising of two malignant meningioma cells (HKBMM and IOMM-Lee), 10 benign meningiomas, four malignant meningiomas, and two solitary fibrous tumors (SFTs). The organoids exhibited consistent histological features and molecular profiles with those of the parental tumors. Using a public database, we identified that upregulated forkhead box M1 (FOXM1) was correlated with increased tumor proliferation. Overexpression of FOXM1 in benign meningioma organoids increased organoid proliferation; depletion of FOXM1 in malignant organoids decreased proliferation. Additionally, thiostrepton, a FOXM1 inhibitor combined with radiation therapy, significantly inhibited proliferation of malignant meningioma organoid models.

CONCLUSIONS

An organoid model for meningioma enabled us to elucidate the tumor biology of meningioma along with potent treatment targets for meningioma.

Impact of the extent of resection on the survival of patients with grade II and III gliomas using awake brain mapping

PURPOSE

The aim of this study was to assess the effect of the extent of resection (EOR) of tumors on survival in a series of patients with grade II and III gliomas (GII/III-gliomas) who underwent awake brain mapping.

METHODS

We retrospectively analyzed 126 patients with GII/III-gliomas in the dominant and non-dominant hemisphere who underwent awake brain surgery at the same institution between December 2012 and May 2020.

RESULTS

EOR cut-off values for improved progression-free survival (PFS) were determined by a receiver operator characteristic (ROC) analysis of 5-year PFS. The ROC for EOR showed a cut-off value of ≥ 85.3%. The median PFS rate of patients with GII/III-gliomas in the group with an EOR ≥ 100%, including supratotal resection (n = 47; median survival [MS], not reached), was significantly higher than that in the group with an EOR < 90% (n = 52; MS, 43.1 months; 95% CI 37.7-48.5 months; p = 0.03). In patients with diffuse astrocytomas and anaplastic astrocytomas, the group with EOR ≥ 100%, including supratotal resection (n = 25; MS, not reached), demonstrated a significantly better PFS rate than did the group with an EOR < 100% (n = 45; MS, 35.8 months; 95% CI 19.9-51.6 months; p = 0.03). Supratotal or gross total resection was correlated with better PFS in IDH-mutant type of diffuse astrocytomas and anaplastic astrocytomas (n = 19; MS, not reached vs. n = 35; MS, 40.6 months; 95% CI 22.3-59.0 months; p = 0.02). By contrast, supratotal or gross total resection was not associated with longer PFS rates in patients with IDH-wild type of diffuse astrocytomas and anaplastic astrocytomas.

CONCLUSIONS

The present study demonstrates a significant association between tumor EOR and survival in patients with GII/III gliomas. The EOR cut-off value for 5-year PFS was ≥ 85.3%. It is noteworthy that supratotal or gross total resection significantly correlated with better PFS in IDH-mutant type of WHO grade II and III astrocytic tumors. In light of our finding that EOR did not correlate with PFS in patients with aggressive IDH-wild type of diffuse astrocytomas and anaplastic astrocytomas, we suggest treatments that are more intensive will be needed for the control of these tumors.

Urinary MicroRNA-Based Diagnostic Model for Central Nervous System Tumors Using Nanowire Scaffolds

There are no accurate mass screening methods for early detection of central nervous system (CNS) tumors. Recently, liquid biopsy has received a lot of attention for less-invasive cancer screening. Unlike other cancers, CNS tumors require efforts to find biomarkers due to the blood-brain barrier, which restricts molecular exchange between the parenchyma and blood. Additionally, because a satisfactory way to collect urinary biomarkers is lacking, urine-based liquid biopsy has not been fully investigated despite the fact that it has some advantages compared to blood or cerebrospinal fluid-based biopsy. Here, we have developed a mass-producible and sterilizable nanowire-based device that can extract urinary microRNAs efficiently. Urinary microRNAs from patients with CNS tumors (n = 119) and noncancer individuals (n = 100) were analyzed using a microarray to yield comprehensive microRNA expression profiles. To clarify the origin of urinary microRNAs of patients with CNS tumors, glioblastoma organoids were generated. Glioblastoma organoid-derived differentially expressed microRNAs (DEMs) included 73.4% of the DEMs in urine of patients with parental tumors but included only 3.9% of those in urine of noncancer individuals, which suggested that many CNS tumor-derived microRNAs could be identified in urine directly. We constructed the diagnostic model based on the expression of the selected microRNAs and found that it was able to differentiate patients and noncancer individuals at a sensitivity and specificity of 100 and 97%, respectively, in an independent dataset. Our findings demonstrate that urinary microRNAs extracted with the nanowire device offer a well-fitted strategy for mass screening of CNS tumors.

Intraoperative seizure outcome of levetiracetam combined with perampanel therapy in patients with glioma undergoing awake brain surgery

OBJECTIVE

This study aimed to evaluate the efficacy of levetiracetam (LEV) combined with perampanel (PER) therapy for intraoperative seizure treatment to determine whether a combination of LEV and PER can aid in the prevention of intraoperative intractable seizures during awake surgery.

METHODS

The authors performed a retrospective cohort study in 78 consecutive patients with glioma who underwent awake surgery using intraoperative direct electrical stimulation mapping. To prevent intraoperative seizures, 50 patients were treated with the antiepileptic drug LEV only (LEV group) from January 2017 to January 2019, while the remaining 28 patients were treated with LEV plus PER (LEV + PER group) between March 2019 and January 2020. LEV (1000-3000 mg) and/or PER (2-4 mg) were administered before the surgery.

RESULTS

Preoperative seizures with International League Against Epilepsy (ILAE) class II-VI occurred in 44% of the patients in the LEV group and in 35.7% of patients in the LEV + PER group, with no significant difference between groups (p = 0.319). Total intraoperative seizures occurred in 18 patients (36.0%) in the LEV therapy group and in 2 patients (7.1%) in the LEV + PER group (p = 0.009). Of these, there were no patients (0%) with intractable seizures in the LEV + PER group. Regarding factors that influence intraoperative seizures in glioma patients during awake brain surgery, multivariate logistic regression models revealed that the occurrence of intraoperative seizures was significantly related to the involvement of motor-related regions (positive vs negative, HR 6.98, 95% CI 1.71-28.56, p = 0.007), preoperative seizure (ILAE class II-VI vs ILAE class I, HR 4.44, 95% CI 1.22-16.11, p = 0.024), and LEV + PER group (positive vs negative, HR 0.07, 95% CI 0.01-0.44, p = 0.005). Treatment-related adverse effects were rare and mild, including sleepiness, tiredness, and dizziness in both treatment groups.

CONCLUSIONS

This study demonstrates that LEV + PER therapy is significantly associated with a lower risk of intraoperative seizures compared with LEV therapy alone in patients with glioma during awake brain mapping. These findings will help neurosurgeons conduct safe and reliable awake surgeries and reduce the rate of intraoperative intractable seizures during such procedures.

LGG-56. INFANTILE HEMISPHERIC BRAIN TUMOR WITH A GOPC-ROS1 FUSION GENE: A CASE REPORT

INTRODUCTION

Infantile hemispheric gliomas with ROS1 fusion genes have been reported to have a relatively poor prognosis. Treatment using a ROS1 inhibitor is expected to generate less toxicity and effective for brain tumors with ROS1 fusion genes. CASE PRESENTATION: A one-month-old female presented with a seizure, and a large hypervascular mass in the right hemisphere was found on MRI. The tumor was not biopsied over concerns of an increased risk for bleeding. The mass was clinically diagnosed as an atypical teratoid rhabdoid tumor. She received neoadjuvant chemotherapy using the modified EU-RHAB protocol. The tumor gradually decreased to 70% of its original size with a reduction of vascularity. A near-total resection (> 95%) was performed at eight months of age. Pathological examination revealed the unusual histology with immunostaining positive for INI-1, GFAP, synaptophysin, neurofilament, and slightly positive for NeuN. MIB-1 labeling index was 6%. The pathological diagnosis was a glioneuronal tumor with desmoplastic infantile ganglioglioma-like features, suggestive of low grade. She received adjuvant chemotherapy with carboplatin and vincristine, which is the standard treatment for low-grade gliomas, and achieved a partial response. The GOPC-ROS1 fusion gene was detected in the tumor by FoundationOne^Ⓡ CDx.

CONCLUSION

Chemotherapy may effectively reduce the size of an infant’s brain tumor which is initially considered to be inoperable. A gene profile should be performed as soon as possible in order to direct appropriate management.

Expression of programmed cell death ligand-1 by immune cells in the microenvironment is a favorable prognostic factor for primary diffuse large B-cell lymphoma of the central nervous system

Primary diffuse large B-cell lymphoma (DLBCL) of the central nervous system (PCNS-DLBCL) is rare. Thirty-nine patients consecutively diagnosed as having PCNS-DLBCL were analyzed to highlight the prognostic value of the expression of programmed cell death ligand-1 (PD-L1) by neoplastic cells and immune cells in the microenvironment. They were positive for CD20 in all (100%), CD5 in two (5%), CD10 in nine (23%), BCL-2 in 27 (69%), BCL-6 in 34 (87%), and MUM-1 in 37 (95%). Only one case was positive for neoplastic PD-L1, with an unexpectedly long clinical course of 92 months. The remaining 38 cases were further divided into three groups based on the percentage of PD-L1⁺ cells among microenvironmental immune cells. Cutoffs of < 5%, 5-40%, and ≥ 40% successfully stratified mean prognoses with three-year overall survival (OS) of 21%, 63%, and 100% (P = 0.009), respectively. Progression-free survival (PFS) and OS were different between the groups with and without methotrexate (MTX)-containing chemotherapy (P = 0.007 and P < 0.001, respectively). Multivariate analysis identified three independent adverse factors of OS: PD-L1 negativity (< 5%) on microenvironmental immune cells (P = 0.027), deep structure involvement (P = 0.034), and performance status (PS) 2-4 (P = 0.009). The study showed that PD-L1 expression on immune cells in the microenvironment was associated with prognosis among patients with PCNS-DLBCL.

TB-03 Newly Established Meningioma Organoid Model Elucidated an Important Role of FOXM1 in Meningioma Progression

Meningioma is the most frequently occurring intracranial neoplasms in adults. Tumor removal surgery and radiotherapy were the widely accepted standard treatment for meningioma. Most meningioma cases were cured by extended total removal. However, some tumors develop in locations less amenable to resection, resulting in tumor recurrence after incomplete tumor removal followed by radiotherapy. Although several comprehensive studies have revealed frequently found molecular alterations of meningiomas, effective treatment reagents targeting specific molecular alterations have not been identified yet because of limited number of representative research models such as tumor cell lines or animal models of meningiomas. Recently developed 3D culture technologies have led to the development of novel cancer models, termed organoid models, due to their quite high efficiency of establishment. In this study, we established primary organoid culture methods using malignant meningioma cell lines (e.g. HKBMM and IOMM-Lee) and patient-derived meningioma tissues. Using this novel method, we have been able to establish six organoid models (four WHO grade I meningiomas, one WHO grade III one and one solitary fibrous tumor (SFT)) using tumor tissues derived from six consecutive patients with 100% success rate. Histological analyses, whole exome sequencing and copy number analyses revealed that these organoids exhibited consistent histological features and molecular profiling with those of parental tumors. Using public database, we identified upregulated FOXM1 was correlated with increased tumor proliferation. Over-expression of FOXM1 in benign meningioma organoids increased organoid proliferation, while depletion of FOXM1 in malignant ones decreased their proliferation. We revealed that novel organoid model for meningioma enable to shed light on the tumor biology of meningioma.

Long-term survival in patients with primary intracranial germ cell tumors treated with surgery, platinum-based chemotherapy, and radiotherapy: a single-institution study

OBJECTIVE

The current study aimed to evaluate the treatment outcomes and toxicities of patients with intracranial germ cell tumors (GCTs).

METHODS

This study retrospectively included 110 consecutive patients (70 patients in the germinomatous group and 40 patients in the nongerminomatous GCT [NGGCT] groups) receiving surgery, platinum-based chemotherapy, and radiotherapy for newly diagnosed primary intracranial GCTs. In the authors' protocol, patients with GCTs were further divided into the following four groups: the germinomatous group and the NGGCT groups (mature teratoma, intermediate prognosis, or poor prognosis).

RESULTS

The median overall survival (OS) and progression-free survival (PFS) rates of the patients in the germinomatous group were significantly higher than those in the NGGCT group (p < 0.001). The 5-, 10-, and 20-year OS rates in the germinomatous group were 97.1%, 95.7%, and 93.2%, respectively, with a median follow-up of 11.0 years. On the contrary, the 5-, 10-, and 20-year OS rates in the NGGCT group were 67.3%, 63.4%, and 55.4%, respectively. The 5-, 10-, and 20-year PFS rates were 91.4%, 86.6%, and 86.6%, respectively, in the germinomatous group, whereas those of the NGGCT group were approximately 67.4%, 60.2%, and 53.5%, respectively. Based on the four types of classification in our study, the 5-, 10-, and 20-year OS rates in the NGGCT intermediate prognosis group were 78.9%, 71.8%, and 53.8%, respectively. On the contrary, the 3- and 5-year OS rates in the NGGCT poor prognosis group were 42.9% and 34.3%, respectively. Moreover, toxicities with the treatment of intracranial GCTs were found to be tolerable in the present study population. The multivariate survival models for OS in the NGGCT intermediate prognosis and poor prognosis groups demonstrated that only the alpha-fetoprotein status was significantly associated with worsened OS (HR 3.88, 95% CI 1.29-11.66; p = 0.02).

CONCLUSIONS

The authors found that platinum-based chemotherapy and radiotherapy result in favorable survival outcomes in patients with germinomatous GCTs. Clinical outcomes were still unfavorable in the NGGCT intermediate prognosis and poor prognosis groups; therefore, a new protocol that increases the survival rate of patients belonging in both groups should be considered.

Genetic analysis in patients with newly diagnosed glioblastomas treated with interferon-beta plus temozolomide in comparison with temozolomide alone

PURPOSE

This study aimed to explore the genetic alterations and to identify good responders in the experimental arm in the tumor samples from newly diagnosed glioblastoma (GBM) patients enrolled in JCOG0911; a randomized phase II trial was conducted to compare the efficacy of interferonβ (IFNβ) plus temozolomide (TMZ) with that of TMZ alone.

EXPERIMENTAL

DESIGN: Of 122 tumors, we performed deep targeted sequencing to determine the somatic mutations, copy number variations, and tumor mutation burden; pyrosequencing for O⁶-methylguanine-DNA methyltransferase (MGMT) promoter methylation; Sanger sequencing for the telomerase reverse transcriptase (TERT) promoter; and microsatellite instability (MSI) testing in 95, 91, 91 and 72 tumors, respectively. We performed a multivariable Cox regression analysis using backward stepwise selection of variables including clinical factors (sex, age, performance status, residual tumor after resection, tumor location) and genetic alterations.

RESULTS

Deep sequencing detected an IDH1 mutation in 13 tumors (14%). The MGMT promoter methylation by quantitative pyrosequencing was observed in 41% of the tumors. A mutation in the TERT promoter was observed in 69% of the tumors. While high tumor mutation burden (> 10 mutations per megabase) was seen in four tumors, none of the tumors displayed MSI-high. The clinical and genetic factors considered as independent favorable prognostic factors were gross total resection (hazard ratio [HR]: 0.49, 95% confidence interval, 0.30-0.81, P = 0.0049) and MGMT promoter methylation (HR: 0.43, 0.21-0.88, P = 0.023). However, tumor location at the temporal lobe (HR: 1.90, 1.22-2.95, P = 0.0046) was an independent unfavorable prognostic factor. No predictive factors specific to the TMZ + IFNβ + Radiotherapy (RT) group were found.

CONCLUSION

This additional sub-analytical study of JCOG0911 among patients with newly diagnosed GBM showed that tumor location at the temporal lobe, gross total resection, and MGMT promoter methylation were significant prognostic factors, although no factors specific to IFNβ addition were identified.

Aberrant Active cis-Regulatory Elements Associated with Downregulation of RET Finger Protein Overcome Chemoresistance in Glioblastoma

RET finger protein (RFP) forms a complex with histone deacetylase 1, resulting in aberrant deacetylation of H3K27ac and dysregulation of cis-regulatory elements. We evaluated the modulatory effects of RFP knockdown on cis-regulatory elements, gene expression, and chemosensitivity to temozolomide both in glioblastoma cells and in an intracranial glioblastoma model. The combination of RFP knockdown and temozolomide treatment markedly suppressed the glioblastoma cell growth due to oxidative stress and aberrant cell cycle and increased survival time in mice with glioblastoma. ChIP-seq and RNA-seq revealed that RFP knockdown increased or decreased activity of numerous cis-regulatory elements that lie adjacent to genes that control functions such as apoptosis, mitosis, DNA replication, and cell cycle: FOXO1, TBP2, and PARPBP. This study suggests that RFP contributes to chemoresistance via aberrant deacetylation of histone H3 at K27, whereas dysregulation of RFP-associated cis-regulatory elements in glioma and RFP knockdown combined with temozolomide is an effective treatment strategy for lethal glioma.

Trautmann-focused mastoidectomy for a simple, safe presigmoid approach: technical note

The presigmoid approach (PSA) is selected to obtain more lateral access to cerebellopontine angle tumors, brainstem cavernous malformations, or vertebrobasilar artery aneurysms than the standard retrosigmoid approach. However, mastoidectomy for the PSA can be considered time-consuming and to carry a higher risk of complications due to the anatomical complexity of the region. The authors established a method of minimized mastoidectomy focused on exposing Trautmann's triangle as the corridor for the PSA while maximizing procedural simplicity and safety and maintaining a sufficient operative view. The authors present their method of minimized mastoidectomy in a cadaver dissection and operative cases, showing potential as a useful option for the PSA.

H3F3A mutant allele specific imbalance in an aggressive subtype of diffuse midline glioma, H3 K27M-mutant

Diffuse midline glioma, H3 K27M-mutant is a lethal brain tumor located in the thalamus, brain stem, or spinal cord. H3 K27M encoded by the mutation of a histone H3 gene such as H3F3A plays a pivotal role in the tumorigenesis of this type of glioma. Although several studies have revealed comprehensive genetic and epigenetic profiling, the prognostic factors of these tumors have not been identified to date. In various cancers, oncogenic driver genes have been found to exhibit characteristic copy number alterations termed mutant allele specific imbalance (MASI). Here, we showed that several diffuse midline glioma, H3 K27M-mutant exhibited high variant allele frequency (VAF) of the mutated H3F3A gene using droplet digital polymerase chain reaction (ddPCR) assays. Whole-genome sequencing (WGS) revealed that these cases had various copy number alterations that affected the mutant and/or wild-type alleles of the H3F3A gene. We also found that these MASI cases showed a significantly higher Ki-67 index and poorer survival compared with those in the lower VAF cases (P < 0.05). Our results indicated that the MASI of the H3F3A K27M mutation was associated with the aggressive phenotype of the diffuse midline glioma, H3 K27M-mutant via upregulation of the H3 K27M mutant protein, resulting in downregulation of H3K27me3 modification.

PATH-36. MACHINE LEARNING TO DETECT GLIOMAS IN URINE-BASED LIQUID BIOPSY

BACKGROUND

Diffuse gliomas are the most common primary malignant brain tumors, whose overall prognosis is quite dismal. Tumor-cell-secreted extracellular vesicles (EVs) participate in physiological and pathological processes and have potential applications to diagnostics of malignant tumors including diffuse gliomas. Because urine is less invasive to collect, development of early diagnosis based on urine EVs is eagerly awaited. In this study, we captured urine EVs of patients with gliomas efficiently with the nanowire device and compared expression profile of microRNAs (miRNAs) within urine EVs with that of healthy donors to identify diagnostic accuracy by a machine learning algorithm.

METHODS

62 patients with diffuse gliomas, including 27 glioblastoma and 35 lower grade gliomas, and 100 healthy donors were analyzed, along with orthotopic transplant mouse model. Urinary EVs were obtained with the nanowire device which could collect EVs more efficiently than the conventional ultracentrifugation method (Yasui et.al., Science Adv.2017). Machine learning methods were performed to select the miRNAs which could distinguish patients with gliomas from healthy control.

RESULTS

More than 2400 miRNAs were obtained from all urine samples. We identified miRNA panels that provided high diagnostic accuracy of diffuse gliomas (92.5%). There were 440 miRNAs whose expression increased by more than 1.5 fold (p< 0.05) as compared to healthy donor samples (glioma-upregulated miRNAs), whereas the expression of 87 miRNAs decreased to less than 2/3-fold (p< 0.05) (glioma-downregulated miRNAs). Mouse miRNAs which were homologous to glioma-upregulated and -downregulated miRNAs showed significantly high and low level expressions, respectively, in glioma mouse models as compared to normal control mice, confirming the reliability of urine miRNA-based diagnosis. Furthermore, some of these glioma-upregulated miRNAs has been reported to be involved in tumor progression.

CONCLUSIONS

miRNAs obtained from urine could be biomarkers for detection of gliomas by machine learning and some of these could be associated with tumor progression.