O⁶-methylguanine DNA-methyltransferase (MGMT) promoter methylation status is a prognostic factor in newly diagnosed glioblastoma patients. However, it is not yet clear whether, and if so how, MGMT methylation status may change. Moreover, it is unknown whether the prognostic role of this epigenetic feature is retained during the disease course. A retrospective analysis was made using a database of 614 glioblastoma patients treated prospectively from January 2000 to August 2008. We evaluated only patients who met the following inclusion criteria: age ≥18 years; performance status 0-2; histological diagnosis of glioblastoma at both first and second surgery for recurrence; postoperative treatment consisting of: (i) radiotherapy (RT) followed by adjuvant temozolomide (TMZ) until 2005 and (ii) TMZ concurrent with and adjuvant to RT after 2005; a time interval ≥3 months between first and second surgery. MGMT status was evaluated at first and second surgery in all 44 patients (M:F 32:12, median age: 49 years, range: 27–67 years). In 38 patients (86.4%), MGMT promoter status was assessable at both first and second surgery. MGMT methylation status, changed in 14 patients (37%) of second surgery samples and more frequently in methylated than in unmethylated patients (61.5% vs 24%, P = .03). The median survival was significantly influenced only by MGMT methylation status determined at first surgery (P = .04). Significant changes in MGMT methylation status during the course of GBM occur more frequently in MGMT methylated than unmethylated cases. MGMT methylation status determined at first surgery appears to be of prognostic value; however, it is not predictive of outcome following second surgery.

The identification of biomarkers of the transformation of normal to epileptic tissue would help to stratify patients at risk of epilepsy following brain injury and inform new treatment strategies. MicroRNAs (miRNAs) are an attractive option in this direction. In this study, miRNA microarrays were performed on laser-microdissected hippocampal granule cell layer (GCL) and on plasma, at different time points in the development of pilocarpine-induced epilepsy in the rat: latency, first spontaneous seizure and chronic epileptic phase. Sixty-three miRNAs were differentially expressed in the GCL when considering all time points. Three main clusters were identified that separated the control and chronic phase groups from the latency group and from the first spontaneous seizure group. MiRNAs from rats in the chronic phase were compared to those obtained from the laser-microdissected GCL of epileptic patients, identifying several miRNAs (miR-21-5p, miR-23a-5p, miR-146a-5p and miR-181c-5p) that were up-regulated in both human and rat epileptic tissue. Analysis of plasma samples revealed different levels between control and pilocarpine-treated animals for 27 miRNAs. Two main clusters were identified that segregated controls from all other groups. Those miRNAs that are altered in plasma before the first spontaneous seizure, like miR-9a-3p, may be proposed as putative biomarkers of epileptogenesis.

Object: The authors retrospectively analyzed and compared seizure outcome in a series of 28 patients with temporomesial glioneuronal tumors associated with epilepsy who underwent 1 of 2 different epilepsy surgery procedures: lesionectomy or tailored resection. Methods: The 28 patients were divided into 2 groups, with 14 cases in each group. In Group A, surgery was limited to the tumor (lesionectomy), whereas Group B patients underwent tailored resection involving removal of the tumor and the epileptogenic zone as identified by a neurophysiological noninvasive presurgical study. Results: In Group A (10 male and 4 female patients) the interval between onset of seizures and surgery ranged from 1 to 33 years (mean 10.6 years). Patients' ages ranged from 3 to 61 years (mean 23.1 years). The epileptogenic lesion was on the left side in 6 patients and the right in 8 patients. Mean follow-up was 9.8 years (range 6.5–15 years). The Engel classification system, used to determine postoperative seizure outcome, showed 6 patients (42.8%) were Engel Class I and 8 (57.1%) were Engel Class II. In Group B (6 male and 8 female patients) the interval between onset of seizures and surgery ranged from 0.5 to 25 years (mean 8.6 years). Patients' ages ranged from 3 to 48 years (mean 22.3 years). The tumor and associated epileptogenic area was on the right side in 8 patients and the left in 6 patients. Mean follow-up duration was 3.5 years (range 1–6.5 years). Postoperative seizure outcome was Engel Class I in 13 patients (93%) and Engel Class II in 1 (7.1%). Conclusions: The authors' results demonstrate a better seizure outcome for temporomesial glioneuronal tumors associated with epilepsy in patients who underwent tailored resection rather than simple lesionectomy (p = 0.005). For temporomesial glioneuronal tumors associated with epilepsy, performing a presurgical noninvasive neurophysiological study intended to identify the epileptogenic zone is necessary for planning a tailored surgery. Using this surgical strategy, the presence of temporomesial glioneuronal tumors constitutes a predictive factor of excellent seizure outcome, and therefore surgical treatment can be offered early to avoid both the consequences of uncontrolled seizures as well as the side effects of pharmacological therapy.

Several biomarkers have been proposed as useful parameters to better specify the prognosis or to delineate new target therapy strategies for glioblastoma patients. MicroRNAs could represent putative target molecules, considering their role in tumorigenesis, cancer progression and their specific tissue expression. Although several studies have tried to identify microRNA signature for glioblastoma, a microRNA profile is still far from being well‐defined.In this work the expression of 19 microRNAs (miR‐7, miR‐9, miR‐9∗, miR‐10a, miR‐10b, miR‐17, miR‐20a, miR‐21, miR‐26a, miR‐27a, miR‐31, miR‐34a, miR‐101, miR‐137, miR‐182, miR‐221, miR‐222, miR‐330, miR‐519d) was evaluated in sixty formalin‐fixed and paraffin‐embedded glioblastoma samples using a locked nucleic acid real‐time PCR. Moreover, a comparison of miRNA expressions was performed between primary brain neoplasias of different grades (grades IV–I).The analysis of 14 validated miRNA expression in the 60 glioblastomas, using three different non‐neoplastic references as controls, revealed a putative miRNA signature: mir‐10b and miR‐21 were up‐regulated, while miR‐7, miR‐31, miR‐101, miR‐137, miR‐222 and miR‐330 were down‐regulated in glioblastomas. Comparing miRNA expression between glioblastoma group and gliomas of grades I–III, 3 miRNAs (miR‐10b, mir‐34a and miR‐101) showed different regulation statuses between high‐grade and low‐grade tumors. miR‐10b was up‐regulated in high grade and significantly down‐regulated in low‐grade gliomas, suggesting that could be a candidate for a GBM target therapy.This study provides further data for the identification of a miRNA profile for glioblastoma and suggests that different‐grade neoplasia could be characterized by different expression of specific miRNAs.

OBJECTIVE: In the past decade, the role of the endoscopic endonasal approach (EEA) has relevantly evolved for skull base tumors. In this study, the authors review their surgical experience with using an EEA in the treatment of clival chordomas, which are deep and infiltrative skull base lesions, and they highlight the advantages and limitations of this ventral approach.METHODS: All consecutive cases of chordoma treated with an EEA between 1998 and 2015 at a single institution are included in this study. Preoperative assessment consisted of neuroimaging (MRI and CT with angiography sequences) and endocrinological, neurological, and ophthalmological evaluations, which were repeated 3 months after surgery and annually thereafter. Postoperative adjuvant therapies were considered.RESULTS: Sixty-five patients (male/female ratio 1:0.9) were included in this study. The median age was 48 years (range 9–80 years). Gross-total resection (GTR) was achieved in 47 cases (58.7%). On univariate analysis, primary procedures (p = 0.001), location in the superior or middle third of the clivus (p = 0.043), extradural location (p = 0.035), and histology of conventional chordomas (p = 0.013) were associated with a higher rate of GTR. The complication rate was 15.1%, and there were no perioperative deaths. Most complications did not result in permanent sequelae and included 2 CSF leaks (2.5%), 5 transient cranial nerve VI palsies (6.2%), and 2 internal carotid artery injuries (2.5%), which were treated with coil occlusion of the internal carotid artery without neurological deficits. Three patients (3.8%) presented with complications resulting in permanent neurological deficits due to a postoperative hematoma (1.2%) causing a hemiparesis, and 2 permanent ophthalmoplegias (2.5%). Seventeen patients (26.2%) have died of tumor progression over the course of follow-up (median 52 months, range 7–159 months). Based on Kaplan-Meier analysis, the survival rate was 77% at 5 years and 57% at 10 years. On multivariate analysis, the extent of tumor removal (p = 0.001) and the absence of previous treatments (p = 0.001) proved to be correlated with a longer survival rate.CONCLUSIONS: The EEA was associated with a high rate of tumor removal and symptom control, with low morbidity and preservation of a good quality of life. These results allow for a satisfactory overall survival rate, particularly after GTR and for primary surgery. Considering these results, the authors believe that an EEA can be a helpful tool in chordoma surgery, achieving a good balance between as much tumor removal as possible and the preservation of an acceptable patient quality of life.