Expression of RINT1 predicts seizure occurrence and outcomes in patients with low-grade gliomas

Multi-omics technologies and molecular biomarkers in brain tumor-related epilepsy

BACKGROUND

Brain tumors are one of the leading causes of epilepsy, and brain tumor-related epilepsy (BTRE) is recognized as the major cause of intractable epilepsy, resulting in huge treatment cost and burden to patients, their families, and society. Although optimal treatment regimens are available, the majority of patients with BTRE show poor resolution of symptoms. BTRE has a very complex and multifactorial etiology, which includes several influencing factors such as genetic and molecular biomarkers. Advances in multi-omics technologies have enabled to elucidate the pathophysiological mechanisms and related biomarkers of BTRE. Here, we reviewed multi-omics technology-based research studies on BTRE published in the last few decades and discussed the present status, development, opportunities, challenges, and prospects in treating BTRE.

METHODS

First, we provided a general review of epilepsy, BTRE, and multi-omics techniques. Next, we described the specific multi-omics (including genomics, transcriptomics, epigenomics, proteomics, and metabolomics) techniques and related molecular biomarkers for BTRE. We then presented the associated pathogenetic mechanisms of BTRE. Finally, we discussed the development and application of novel omics techniques for diagnosing and treating BTRE.

RESULTS

Genomics studies have shown that the BRAF gene plays a role in BTRE development. Furthermore, the BRAF V600E variant was found to induce epileptogenesis in the neuronal cell lineage and tumorigenesis in the glial cell lineage. Several genomics studies have linked IDH variants with glioma-related epilepsy, and the overproduction of D2HG is considered to play a role in neuronal excitation that leads to seizure occurrence. The high expression level of Forkhead Box O4 (FOXO4) was associated with a reduced risk of epilepsy occurrence. In transcriptomics studies, VLGR1 was noted as a biomarker of epileptic onset in patients. Several miRNAs such as miR-128 and miRNA-196b participate in BTRE development. miR-128 might be negatively associated with the possibility of tumor-related epilepsy development. The lncRNA UBE2R2-AS1 inhibits the growth and invasion of glioma cells and promotes apoptosis. Quantitative proteomics has been used to determine dynamic changes of protein acetylation in epileptic and non-epileptic gliomas. In another proteomics study, a high expression of AQP-4 was detected in the brain of GBM patients with seizures. By using quantitative RT-PCR and immunohistochemistry assay, a study revealed that patients with astrocytomas and oligoastrocytomas showed high BCL2A1 expression and poor seizure control. By performing immunohistochemistry, several studies have reported the relationship between D2HG overproduction and seizure occurrence. Ki-67 overexpression in WHO grade II gliomas was found to be associated with poor postoperative seizure control. According to metabolomics research, the PI3K/AKT/mTOR pathway is associated with the development of glioma-related epileptogenesis. Another metabolomics study found that SV2A, P-gb, and CAD65/67 have the potential to function as biomarkers for BTRE.

CONCLUSIONS

Based on the synthesized information, this review provided new research perspectives and insights into the early diagnosis, etiological factors, and personalized treatment of BTRE.

IDH1 mutation predicts seizure occurrence and prognosis in lower-grade glioma adults

Epileptic seizures are frequently the first symptom in glioma patients. However, the causal relationship between glioma and epilepsy is not yet fully understood, as it cannot be explained solely by tumor mass effect or peritumoral factors. In this study, we retrospectively enrolled 320 patients with grade 2-4 glioma who received treatment between January 2019 and July 2022, and explored the biomarkers of seizure occurrence and seizure outcome prediction using univariate and multivariate logistic regression analyses. Our results showed that IDH1 R132H mutation was an independent risk factor for seizure occurrence in lower-grade glioma (LGG) patients (OR = 4.915, 95%CI = 1.713 - 14.103, P = 0.003). Additionally, IDH1 R132H mutation predicted higher seizure-free ratios in LGG patients with intact ATRX expression (OR = 6.793, 95%CI = 1.217 - 37.923, P = 0.029) one year after diagnosis. Therefore, our findings suggest that IDH1 mutation can predict seizure occurrence and control in LGG patients, providing further insights into the relationship between glioma and epilepsy.

Clinical practice guidelines for the diagnosis and treatment of adult diffuse glioma-related epilepsy

BACKGROUND

Glioma-related epilepsy (GRE) is defined as symptomatic epileptic seizures secondary to gliomas, it brings both heavy financial and psychosocial burdens to patients with diffuse glioma and significantly decreases their quality of life. To date, there have been no clinical guidelines that provide recommendations for the optimal diagnostic and therapeutic procedures for GRE patients.

METHODS

In March 2017, the Joint Task Force for GRE of China Association Against Epilepsy and Society for Neuro-Oncology of China launched the guideline committee for the diagnosis and treatment of GRE. The guideline committee conducted a comprehensive review of relevant domestic and international literatures that were evaluated and graded based on the Oxford Centre for Evidence-Based Medicine Levels of Evidence, and then held three consensus meetings to discuss relevant recommendations. The recommendations were eventually given according to those relevant literatures, together with the experiences in the diagnosis and treatment of over 3000 GRE cases from 24 tertiary level hospitals that specialize in clinical research of epilepsy, glioma, and GRE in China.

RESULTS

The manuscript presented the current standard recommendations for the diagnostic and therapeutic procedures of GRE.

CONCLUSIONS

The current work will provide a framework and assurance for the diagnosis and treatment strategy of GRE to reduce complications and costs caused by unnecessary treatment. Additionally, it can serve as a reference for all professionals involved in the management of patients with GRE.

IDH1 mutation is associated with a higher preoperative seizure incidence in low-grade glioma: A systematic review and meta-analysis

PURPOSE

Gliomas, particularly low-grade gliomas (LGGs), are highly epileptogenic. Seizure is the most common presenting sign of LGG patients and significantly decreases their quality of life. Accordingly, there is a need for a better understanding of the mechanisms and risk factors of glioma-related epilepsy. The current study aimed to perform a comprehensive meta-analysis to investigate the correlation of isocitrate-dehydrogenase 1 (IDH1), an important molecular biomarker for glioma classification and prognosis, to preoperative seizure incidence in LGG.

METHODS

PUBMED, EMBASE, and Web of Science databases were searched for relevant studies. The odds ratio (OR) and corresponding 95% confidence interval (CI) were used as the primary measures to assess the correlation between IDH1 mutation and preoperative seizure incidence.

RESULTS

A total of 722 LGG patients, including 555 patients with IDH1 mutation and 167 patients with wild-type IDH1 were enrolled in the current meta-analysis. The pooled OR was 2.47 (95% CI 1.70-3.57, Z = 4.78, p < 0.01). No significant heterogeneity was observed among all included studies and no publication bias was identified.

CONCLUSION

The current meta-analysis identified that IDH1 mutation was correlated to a higher preoperative seizure incidence in LGG. This result would generate impetus for research on the mechanisms behind this correlation, and provide a new idea for the individualized treatment of glioma-related epilepsy.

Younger age at surgery and lesser seizure frequency as prognostic factors for favorable seizure-related outcome after glioma resection in adults

The identification of variables predictive of good seizure control following surgical tumor resection in adult glioma patients with tumor-related epilepsy would greatly benefit treatment decisions. Therefore, we analyzed the clinical data of adult patients with tumor-related epilepsy who underwent tumor resection at our institute between November 2011 and August 2013. Patients were divided into seizure-free (Engel Ia) and unfavorable outcome groups (Engel Ib-IV), and potential prognostic factors were analyzed. Of 90 patients, 61 (68%) had a favorable outcome at an average of 3 years after surgery. Our analyses indicated that younger age at surgery (P=0.048) and rare seizure frequency (P=0.006) were associated with significantly more favorable postoperative seizure-related outcomes. In conclusion, younger age at surgery and lesser seizure frequency were independent predictors of favorable epileptic seizure control after glioma resection in adults. Thus, early surgical resection is necessary for achieving favorable seizure outcome.

FOXO4 expression is associated with the occurrence and outcome of seizures: An RNA-sequencing analysis of low-grade gliomas

PURPOSE

Epileptic seizures account for most of the initial symptoms in patients with low-grade gliomas (LGGs). Nevertheless, the molecular mechanisms of tumor-associated seizures remain unclear. This study investigated the genetic changes associated with the occurrence and outcome of seizures in patients with LGGs.

METHODS

The clinical characteristics and gene profile data of 86 patients with LGGs were collected from the Chinese Glioma Genome Atlas database. Gene expression was analyzed based on whole-genome RNA sequencing. The genes with significantly different expressions between patients with and without seizures were identified. Additionally, the Engel Epilepsy Surgery Outcome Scale was applied to evaluate the seizure outcomes at 6 months after tumor resection.

RESULTS

In patients with LGGs, the expression of Forkhead Box O4 (FOXO4) was significantly different between the seizure and non-seizure groups, and high FOXO4 expression was found to be associated with a low risk of seizure occurrences (p=0.026). This result was validated by using the clinical information and RNA sequence data from The Cancer Genome Atlas database (p=0.005). FOXO4 was additionally identified as a predictor of seizure outcomes in patients with LGGs at 6 months after tumor resection (p=0.018).

CONCLUSIONS

The results of our genomic analysis suggest that low FOXO4 expression is a significant risk factor for epileptic seizures in patients with LGGs and is associated with the seizure outcome. FOXO4 may be a potential therapeutic target for tumor-associated epilepsy.

Rates of Seizure Freedom After Surgical Resection of Diffuse Low-Grade Gliomas

OBJECTIVE

Patients with diffuse low-grade gliomas (DLGGs) typically present with seizures. We sought to review the neurosurgical literature for seizure outcome after resection of these tumors.

METHODS

Using PubMed, we identified surgical series reporting seizure freedom rates for grade II astrocytoma, oligoastrocytoma, and oligodendroglioma. Inclusion criteria included seizure outcomes reported specifically for DLGGs and at least 10 patients with follow-up data.

RESULTS

Twelve articles met the inclusion criteria. The median seizure-free rate after surgery in these patients was 71%, with an interquartile range of 64%-82%. In 10 studies, more than 60% of patients were seizure free. Studies used varying reporting times for seizure outcome determination. In the 6 studies that reported postoperative antiepileptic medication use, 5%-69% of seizure-free patients were weaned off these agents (median, 32%). The durability of seizure freedom has not been clearly studied to date. The most commonly reported prognostic factor for seizure freedom after resection was increasing extent of resection.

CONCLUSIONS

Among articles reporting seizure outcomes after resection of DLGG, the median seizure-free rate was 71% (interquartile range, 64%-82%). Seizure freedom is likely associated with extent of resection.

Predictors and mechanisms of epilepsy occurrence in cerebral gliomas: What to look for in clinicopathology

Gliomas, especially low-grade gliomas, are highly epileptogenic brain tumors. Histopathological information is valuable in evaluating the diagnosis and/or biologic behavior of various gliomas. Here we explored the clinical data and histopathological predictors of the occurrence of epilepsy in patients with gliomas. A retrospective study examined 310 consecutive patients who had undergone surgical treatment for gliomas in our institution from January 2013 to January 2015. Clinical data and pathological examination results were analyzed. Literatures regarding the predictors and etiology of glioma associated epileptic seizures in the period of 1995-2015 were also reviewed. A total of 234 (75.5%) astrocytic tumors and 76 (24.5%) oligodendrial tumors were included. At diagnosis, 33.6% of patients had epileptic seizures. Multivariate analysis revealed cortex involvement (OR=7.991, 95%CI=1.599-39.926), lower World Health Organization grade (OR=3.584, 95%CI=1.032-12.346) and topoisomerase II (TopoII) positivity (OR=0.943, 95%CI=0.903-0.982) were strong predictors for preoperative epileptic seizures. Gender, disease course, tumor classification, location or volume did not significantly affect epileptic seizure occurrence. Forty-three publications involved glioma-associated epilepsy were found in PubMed online database and key data were extracted and summarized. The present studies on glioma-related epilepsy are relatively limited and inconsistent. Low-grade gliomas, cortex involvement and TopoII positivity were independent predictors of a history of epileptic seizures at diagnosis. Further studies to examine the underlying mechanism of topoisomerase II as well as other molecules in epilepsy occurrence in brain gliomas are needed in the future.

Epilepsy-related brain tumors

Seizures are among the most common presentations of brain tumors. Several tumor types can cause seizures in varying rates; neuroglial tumors and the gliomas are the most common ones. Brain tumors are the second most common cause of focal intractable epilepsy in epilepsy surgery series, with the highest frequency being dysembryoplastic neuroepithelial tumors and gangliogliomas. Seizure management is an important part of the treatment of patients with brain tumors. This review discusses clinical features and management of seizures in patients with brain tumors, including, neuroglial tumors, gliomas, meningioma and metastases; with the help of recent literature data. Tumor-related seizures are focal seizures with or without secondary generalization. Seizures may occur either as initial symptom or during the course of the disease. Brain tumors related epilepsy tends to be resistant to antiepileptic drugs and treatment of tumor is main step also for the seizure treatment. Early surgery and extent of the tumor removal are important factors for achieving seizure freedom particularly in neuroglial tumors and low grade gliomas. During selection of the appropriate antiepileptic drug, the general approach to partial epilepsies can be followed. There are several factors influencing epileptogenesis in brain tumor-related epilepsy which also explains clinical heterogeneity of epilepsy among tumor types. Identification of molecular markers may guide future therapeutic approaches and further studies are needed to prove antitumor effects of different antiepileptic drugs.

Biomarkers related with seizure risk in glioma patients: A systematic review

Increasing evidence indicates that genetic biomarkers play important roles in the development of glioma-associated seizures. Thus, we performed a systematic review to summarise biomarkers that are associated with seizures in glioma patients. An electronic literature search of public databases (PubMed, Embase and Medline) was performed using the keywords glioma, seizure and epilepsy. A totall of 26 eligible studies with 2224 cases were included in this systematic review of publications to 20 June, 2016. Genetic biomarkers such as isocitrate dehydrogenase 1 (IDH1) mutations, low expression of excitatory amino acid transporter 2 (EAAT2), high xCT expression, overexpression of adenosine kinase (ADK) and low expression of very large G-protein-coupled receptor-1 (VLGR1) are primarily involved in synaptic transmission, whereas BRAF mutations, epidermal growth factor receptor (EGFR) amplification, miR-196b expression and low ki-67 expression are associated with regulation of cell proliferation. However, there is limited evidence regarding the roles of RAD50 interactor 1 (RINT1) and olig2 in epileptogenesis among glioma patients. Glioma-related seizure was related to the dysfunction of tumor microenvironment. Our findings may provide new mechanistic insights into targeted therapy for glioma-related seizures and may result in the development of multi-target therapies.

ADAM9 Expression Is Associate with Glioma Tumor Grade and Histological Type, and Acts as a Prognostic Factor in Lower-Grade Gliomas

The A disintegrin and metalloproteinase 9 (ADAM9) protein has been suggested to promote carcinoma invasion and appears to be overexpressed in various human cancers. However, its role has rarely been investigated in gliomas and, thus, in the current study we have evaluated ADAM9 expression in gliomas and examined the relevance of its expression in the prognosis of glioma patients. Clinical characteristics, RNA sequence data, and the case follow-ups were reviewed for 303 patients who had histological, confirmed gliomas. The ADAM9 expression between lower-grade glioma (LGG) and glioblastoma (GBM) patients was compared and its association with progression-free survival (PFS) and overall survival (OS) was assessed to evaluate its prognostic value. Our data suggested that GBM patients had significantly higher expression of ADAM9 in comparison to LGG patients (p < 0.001, t-test). In addition, among the LGG patients, aggressive astrocytic tumors displayed significantly higher ADAM9 expression than oligodendroglial tumors (p < 0.001, t-test). Moreover, high ADAM9 expression also correlated with poor clinical outcome (p < 0.001 and p < 0.001, log-rank test, for PFS and OS, respectively) in LGG patients. Further, multivariate analysis suggested ADAM9 expression to be an independent marker of poor survival (p = 0.002 and p = 0.003, for PFS and OS, respectively). These results suggest that ADAM9 mRNA expression is associated with tumor grade and histological type in gliomas and can serve as an independent prognostic factor, specifically in LGG patients.