ROR1 is a novel putative druggable target for diffuse glioma

The cell surface receptor ROR1 is a therapeutic target of growing interest in oncology; however, its role in glioma has not been established thus far. This study analyzed associations between ROR1 mRNA expression and clinical outcomes, and histological and molecular subtypes in four independent glioma (grades II-IV) transcriptomic datasets (The Cancer Genome Atlas-GBMLGG, Chinese Glioma Genome Atlas, Repository for Molecular Brain Neoplasia, and GSE16011), encompassing a total of 2,388 cases. The data strongly suggests that ROR1 may be associated with poorer outcomes and more aggressive disease. Taken together, ROR1 should be further examined as a novel putative druggable target for glioma, a cancer that currently has very limited therapeutic options.

Frameless Robot-Assisted Stereotactic Biopsies for Lesions of the Brainstem – A Series of 103 Consecutive Biopsies

PurposeTargeted treatment for brainstem lesions requires above all a precise histopathological and molecular diagnosis. In the current technological era, robot-assisted stereotactic biopsies represent an accurate and safe procedure for tissue diagnosis. We present our center’s experience in frameless robot-assisted biopsies for brainstem lesions. MethodsWe performed a retrospective analysis of all patients benefitting from a frameless robot-guided stereotactic biopsy at our University Hospital, from 2001 to 2017. Patients consented to the use of data and/or images. The NeuroMate® robot (Renishaw™, UK) was used. We report on lesion location, trajectory strategy, histopathological diagnosis and procedure safety. ResultsOur series encompasses 96 patients (103 biopsies) treated during a 17 years period. Mean age at biopsy: 34.0 years (range 1-78). Most common location: pons (62.1%). Transcerebellar approach: 61 procedures (59.2%). Most common diagnoses: diffuse glioma (67.0%), metastases (7.8%) and lymphoma (6.8%). Non conclusive diagnosis: 10 cases (9.7%). After second biopsy this decreased to 4 cases (4.1%). Overall biopsy diagnostic yield: 95.8%. Permanent disability was recorded in 3 patients (2.9%, all adults), while transient complications in 17 patients (17.7%). Four cases of intra-tumoral hematoma were recorded (one case with rapid decline and fatal issue). Adjuvant targeted treatment was performed in 72.9% of patients. Mean follow-up (in the Neurosurgery Department): 2.2 years. ConclusionFrameless robot-assisted stereotactic biopsies can provide the initial platform towards a safe and accurate management for brainstem lesions, offering a high diagnostic yield with low permanent morbidity.

NI-10 Reclassification of diffuse gliomas based on molecular diagnosis -evaluation of methionine uptake and treatment outcome-

Object: The revised 2016 WHO Classification of Tumours of the Central Nervous System incorporates genetic alterations into the classification system, with the goal of creating more homogenous disease categories with greater prognostic value. In this study, we reclassified diffuse gliomas with molecular diagnosis and examined for 11C-methionine uptake and prognosis. Methods. 182 diffuse glioma patients (Grade II in 42 patients, Grade III in 61 patients, Grade IV in 77 patients) treated at Tokyo Medical and Dental University Hospital from 2000 to 2018 were included in this study. The IDH1/2, ATRX and 1p19q status were analyzed using tumor samples. The tumor-to-normal ratio (T/N) of 11 C-methionine uptake was calculated by dividing the mean standardized uptake value (SUV) for the tumor by the mean SUV of the normal brain. Result. By molecular diagnosis, 11 diffuse astrocytomas and 17 anaplastic astrocytomas were diagnosed as “IDH-mutant”, while 14 diffuse astrocytomas and 29 anaplastic astrocytomas were diagnosed as “IDH-wild”. 5 out of 77 grade IV tumors had IDH mutation. 4 tumors were diagnosed as “Diffuse midline glioma, H3 K27M-mutant”. In the 32 oligodendroglial tumors, 12 oligodendrogliomas and 9 anaplastic oligodendrogliomas were diagnosed as “IDH-mutant and 1p/19q-codeleted”. The median T/N ratios in oligodendroglial tumors with “IDH-mutant and 1p/19q-codeleted” were significantly higher than those in astrocytic tumors with “IDH-mutant”. On the other hand, in tumors with the same genetic background, higher grade tumor has significant higher T/N ratio. Kaplan-Meier survival analysis revealed that oligodendroglial tumors with “IDH-mutant and 1p/19q-codeleted” had significantly better outcomes regardless of WHO grade. Overall survival was 90.9% at 5 years and 77.9% at 10 years in oligodendroglial tumors with “IDH-mutant and 1p/19q-codeleted”. IDH wild tumors had significantly worse outcomes.Conclusions. The results indicated that diffuse glioma categories reclassified with molecular classification correlate with the T/N ratio of methionine and the prognosis.

COT-1 Clinical Questions and Answers about Glioma-Related Epilepsy (GRE): Real-world data in Wakayama Medical University Hospital

Introduction: In glioma patients, epilepsy not infrequently occurred and anti-epileptic drugs (AEDs) are commonly used. In this study, we revealed the real-world data on clinical practice of glioma-related epilepsy in Wakayama Medical University Hospital (WMUH). Methods. We collected clinical and molecular data of glioma patients operated at WMUH from January 1996 to December 2020 and analyzed the data to answer clinical questions as follows: 1) location/histology related GRE, 2) molecular features related GRE, 3) prophylactic AEDs and postoperative seizure, 4) tumor progression and convulsion, 5) GRE and survival. Results. Fifty-five of 113 glioma patients (49%) presented with seizure. CQ1. In tumors located at frontal, temporal and parietal lobe, the occurrence rate of GRE was 27/39 (69%), 13/19 (69%) and 9/14 (64%), respectively. Patients with glioblastoma, astrocytic tumors and oligodendroglial tumors presented with GRE at the rate of 26/54 (48%), 14/30 (47%) and 12/13 (92%), respectively. CQ2. GRE occurred in tumors with IDH mutated (16 cases, 29%), TERT mutated (32 cases, 58%) and MGMT methylated (32 cases, 58%). CQ3. Seizure in peri- or postoperative period occurred in 14 cases (12%); 4 cases in AED(+) group (4/29, 14%) and 10 cases in AED(-) group (10/84, 12%). CQ4. Tumor progression became apparent at the time of seizure in 12 cases (12/55, 22%). CQ5. According to the prognostic IDH/TERT classification of diffuse glioma cases (n = 94), overall survival (OS) times of GRE(+) cases tended to be longer than that of GRE(-) ones, especially in IDH wildtype/TERT mutated group (22.7 months vs. 8.3 months, p = 0.0397). Conclusion. GRE is likely associated with specific clinical and molecular features. Seizure in glioma patients can occur in specific situation regardless of the use of AEDs. Possible better prognosis of GRE(+) cases requires further investigation.

MPC-1 DNA methylome analysis suggested the presence of “true” IDH-wildtype lower-grade gliomas

Background: There will be significant changes in the diagnosis of IDH-wildtype adult-type gliomas in the upcoming 5th edition of the WHO Classification of Central Nervous System Tumours. IDH-wildtype lower grade gliomas (IDHwt LGGs) that harbor molecular features of glioblastoma (EGFR amplification, the combination of whole chromosome 7 gain and whole chromosome 10 loss (7+/10-), or TERT promoter mutations) will be diagnosed as glioblastomas (GBMs), while IDH-wildtype astrocytomas will not be included as a separate tumor type. However, IDHwt LGGs are a very heterogeneous group of tumors, and further investigation is warranted particularly in those without molecular features of glioblastoma. To elucidate the biology of IDHwt LGGs, we analyzed DNA methylation profile and survival time. Materials and Methods: Of the 724 adult-type diffuse glioma samples from a multi-institutional study, 64 IDHwt LGG, including 54 without any of molecular features of GBM and 10 with PDGFRA amplification or TERT promoter mutation, were examined using Infinium MethylationEPIC BeadChip. The raw data files (IDAT files) were analyzed by the web-based DNA methylation classifier provided by DKFZ (MolecularNeuropathology.org) or by R (Version 4.0.4) using the minfi (1.34.0) and Rtsne (0.15) packages. [Result] Twenty-three out of 54 IDHwt LGGs matched known methylation classes using the DKFZ methylation classifier. In t-Distributed Stochastic Neighbor Embedding clustering analysis, 20 cases formed a cluster within the methylation class family glioblastoma, IDH-wildtype, mainly subclass RTK I (“GBM” cluster). Another 29 IDHwt LGGs formed an independent cluster (“LGG” cluster) separate from any of the existing reference groups near but not overlapping with several subtypes of pediatric-type lower grade gliomas. The “LGG” cluster cases had significantly longer overall survival than the “GBM” cluster cases. Discussion: Methylation profiling showed that IDHwt LGGs without molecular features of GBM were heterogeneous group of tumors. Our data suggested the presence of “true” IDHwt LGGs with intermediate prognosis.

Machine learning modeling of genome-wide copy number alteration signatures reliably predicts IDH mutational status in adult diffuse glioma

Knowledge of 1p/19q-codeletion and IDH1/2 mutational status is necessary to interpret any investigational study of diffuse gliomas in the modern era. While DNA sequencing is the gold standard for determining IDH mutational status, genome-wide methylation arrays and gene expression profiling have been used for surrogate mutational determination. Previous studies by our group suggest that 1p/19q-codeletion and IDH mutational status can be predicted by genome-wide somatic copy number alteration (SCNA) data alone, however a rigorous model to accomplish this task has yet to be established. In this study, we used SCNA data from 786 adult diffuse gliomas in The Cancer Genome Atlas (TCGA) to develop a two-stage classification system that identifies 1p/19q-codeleted oligodendrogliomas and predicts the IDH mutational status of astrocytic tumors using a machine-learning model. Cross-validated results on TCGA SCNA data showed near perfect classification results. Furthermore, our astrocytic IDH mutation model validated well on four additional datasets (AUC = 0.97, AUC = 0.99, AUC = 0.95, AUC = 0.96) as did our 1p/19q-codeleted oligodendroglioma screen on the two datasets that contained oligodendrogliomas (MCC = 0.97, MCC = 0.97). We then retrained our system using data from these validation sets and applied our system to a cohort of REMBRANDT study subjects for whom SCNA data, but not IDH mutational status, is available. Overall, using genome-wide SCNAs, we successfully developed a system to robustly predict 1p/19q-codeletion and IDH mutational status in diffuse gliomas. This system can assign molecular subtype labels to tumor samples of retrospective diffuse glioma cohorts that lack 1p/19q-codeletion and IDH mutational status, such as the REMBRANDT study, recasting these datasets as validation cohorts for diffuse glioma research.

MPC-13 The evaluation of the shift of trend in lower grade glioma diagnoses based on each era`s criteria

It is found that molecular characteristics in lower grade gliomas (LrGGs) such as codeletion of 1p/19q and IDH mutation was found to be more accurate to predict the patient`s clinical outcome compared to morphological diagnoses alone. Since the revision WHO2016 classification of LrGGs, molecular characteristics were implemented as diagnostic standard for LrGGs diagnoses. In the other hand, morphological diagnostic standard before WHO2016 classification era was determined by different considerations and therapeutic strategies. The malignancy grades were also majorly determined by morphological diagnoses only. This study re-evaluated 20 years of LrGG cases in single institution based on WHO2007 morphological criteria and compared them to the original institutional diagnoses from each era. The study samples were originally grade II-III diffuse glioma-diagnosed cases resected from 1990 to 2016. Biopsy cases were excluded. IDH mutation was analyzed by Sanger sequence and 1p/19 codeletion status was analyzed by Comparative Genome Hybridization (CGH). As the result 93 cases were collected and based on original diagnoses, more than 50% cases are astrocytomas. Compared to re-assessment by morphological diagnoses (WHO 2007), case numbers of astrocytoma diagnoses are decreased whereas oligodendroglioma and oligoastrocytoma case numbers are increased. But, based on WHO2016 criteria, the case number of astrocytomas is again found to be increased. From comparison between original institutional diagnoses and re-assessment results, it is found that there is a shift of trend from astrocytoma to oligodendroglioma and from grade II to grade III. Comparison between morphological diagnoses (WHO2007) and molecular (WHO2016) found that astrocytoma diagnoses remain unchanged meanwhile 45% of oligodendroglioma diagnoses were shifted into astrocytomas. There is a probability that there are high frequency of morphologically diagnosed oligodendroglioma tumors which are having molecular characteristics of astrocytoma. There is a trend that diagnosed grade II LrGGs are actually grade III based on re-assessment diagnosis.