The impact of MGMT methylation and IDH-1 mutation on long-term outcome for glioblastoma treated with chemoradiotherapy

Extent of Resection Thresholds in Molecular Subgroups of Newly Diagnosed Isocitrate Dehydrogenase-Wildtype Glioblastoma

BACKGROUND AND OBJECTIVES

Maximizing the extent of resection (EOR) improves outcomes in glioblastoma (GBM). However, previous GBM studies have not addressed the EOR impact in molecular subgroups beyond IDH1/IDH2 status. In the current article, we evaluate whether EOR confers a benefit in all GBM subtypes or only in particular molecular subgroups.

METHODS

A retrospective cohort of newly diagnosed GBM isocitrate dehydrogenase (IDH)-wildtype undergoing resection were prospectively included in a database (n = 138). EOR and residual tumor volume (RTV) were quantified with semiautomated software. Formalin-fixed paraffin-embedded tumor tissues were analyzed by targeted next-generation sequencing. The association between recurrent genomic alterations and EOR/RTV was evaluated using a recursive partitioning analysis to identify thresholds of EOR or RTV that may predict survival. The Kaplan-Meier methods and multivariable Cox proportional hazards regression methods were applied for survival analysis.

RESULTS

Patients with EOR ≥88% experienced 44% prolonged overall survival (OS) in multivariable analysis (hazard ratio: 0.56, P = .030). Patients with alterations in the TP53 pathway and EOR <89% showed reduced OS compared to TP53 pathway altered patients with EOR>89% (10.5 vs 18.8 months; HR: 2.78, P = .013); however, EOR/RTV was not associated with OS in patients without alterations in the TP53 pathway. Meanwhile, in all patients with EOR <88%, PTEN -altered had significantly worse OS than PTEN -wildtype (9.5 vs 15.4 months; HR: 4.53, P < .001).

CONCLUSION

Our results suggest that a subset of molecularly defined GBM IDH-wildtype may benefit more from aggressive resections. Re-resections to optimize EOR might be beneficial in a subset of molecularly defined GBMs. Molecular alterations should be taken into consideration for surgical treatment decisions in GBM IDH-wildtype.

Potential Diagnostic and Clinical Significance of Selected Genetic Alterations in Glioblastoma

Glioblastoma is currently considered the most common and, unfortunately, also the most aggressive primary brain tumor, with the highest morbidity and mortality rates. The average survival of patients diagnosed with glioblastoma is 14 months, and only 2% of patients survive 3 years after surgery. Based on our clinical experience and knowledge from extensive clinical studies, survival is mainly related to the molecular biological properties of glioblastoma, which are of interest to the general medical community. Our study examined a total of 71 retrospective studies published from 2016 through 2022 and available on PubMed that deal with mutations of selected genes in the pathophysiology of GBM. In conclusion, we can find other mutations within a given gene group that have different effects on the prognosis and quality of survival of a patient with glioblastoma. These mutations, together with the associated mutations of other genes, as well as intratumoral heterogeneity itself, offer enormous potential for further clinical research and possible application in therapeutic practice.

Integrating imaging and genomic data for the discovery of distinct glioblastoma subtypes: a joint learning approach

Glioblastoma is a highly heterogeneous disease, with variations observed at both phenotypical and molecular levels. Personalized therapies would be facilitated by non-invasive in vivo approaches for characterizing this heterogeneity. In this study, we developed unsupervised joint machine learning between radiomic and genomic data, thereby identifying distinct glioblastoma subtypes. A retrospective cohort of 571 IDH-wildtype glioblastoma patients were included in the study, and pre-operative multi-parametric MRI scans and targeted next-generation sequencing (NGS) data were collected. L21-norm minimization was used to select a subset of 12 radiomic features from the MRI scans, and 13 key driver genes from the five main signal pathways most affected in glioblastoma were selected from the genomic data. Subtypes were identified using a joint learning approach called Anchor-based Partial Multi-modal Clustering on both radiomic and genomic modalities. Kaplan-Meier analysis identified three distinct glioblastoma subtypes: high-risk, medium-risk, and low-risk, based on overall survival outcome (p < 0.05, log-rank test; Hazard Ratio = 1.64, 95% CI 1.17-2.31, Cox proportional hazard model on high-risk and low-risk subtypes). The three subtypes displayed different phenotypical and molecular characteristics in terms of imaging histogram, co-occurrence of genes, and correlation between the two modalities. Our findings demonstrate the synergistic value of integrated radiomic signatures and molecular characteristics for glioblastoma subtyping. Joint learning on both modalities can aid in better understanding the molecular basis of phenotypical signatures of glioblastoma, and provide insights into the biological underpinnings of tumor formation and progression.

Cognitive functioning in a cohort of high-grade glioma patients

BACKGROUND

High grade gliomas are associated with cognitive problems. The aim of the study was to investigate cognitive functioning in a cohort of patients with high grade glioma, according to isocitrate dehydrogenase (IDH) and methyl guanine methyl transferase (MGMT) status and other clinical characteristics.

PATIENTS AND METHODS

The patients with the high-grade glioma treated in Slovenia in given period of time were included in study. Postoperatively they completed neuropsychological assessment consisting of Slovenian Verbal Learning Test, Slovenian Controlled Oral Word Association Test, Trail Making Test Part A and B and self-evaluation questionnaire. We analysed results (z-scores and dichotomized results) also according to IDH mutation and MGMT methylation. We examined differences between groups using T-test, Mann-Whitney U, χ² and Kendall's Tau tests.

RESULTS

Out of 275 patients in the cohort, we included 90. Forty-six percent of patients were unable to participate due to poor performance status and other conditions related to tumour. Patients with the IDH mutation were younger, with better performance status, larger proportions of grade III tumours and MGMT methylation. In this group cognitive functioning is significantly better in the domains of immediate recall, short delayed recall and delayed recall, and in the fields of executive functioning and recognition. There were no differences in cognitive functioning in regard to MGMT status. Grade III tumours were associated with more frequent MGMT methylation. Self-assessment proved week tool, associated only with immediate recall.

CONCLUSIONS

We found no differences in cognitive functioning according to MGMT status, but cognition was better when IDH mutation was present. In a cohort study of patients with high-grade glioma, almost half were unable to participate in a study, which points to an overrepresentation of patients with better cognitive functioning in the research.

Molecular marker testing and reporting completeness for adult-type diffuse gliomas in the United States

Background

A newly developed brain molecular marker (BMM) data item was implemented by US cancer registries for individuals diagnosed with brain tumors in 2018-including IDH and 1p/19q-co-deletion statuses for adult-type diffuse gliomas. We thus investigated the testing/reporting completeness of BMM in the United States.

Methods

Cases of histopathologically confirmed glioblastoma, astrocytoma, and oligodendroglioma diagnosed in 2018 were identified in the National Cancer Database. Adjusted odds ratios (ORadj) and 95% confidence intervals (CI) of BMM testing/reporting were evaluated for association with the selected patient, treatment, and facility-level characteristics using multivariable logistic regression. As a secondary analysis, predictors of MGMT promoter methylation testing/reporting among IDH-wildtype glioblastoma individuals were assessed. Key limitations of the BMM data item were that it did not include any details regarding testing technique or assay type and could not distinguish between a lack of testing and a lack of cancer registry reporting of testing results.

Results

Among 8306 histopathologically diagnosed adult-type diffuse gliomas nationally, overall BMM testing/reporting completeness was 81.1%. Compared to biopsy-only cases, odds of testing/reporting increased for subtotal (ORadj= 1.38 [95% CI: 1.20-1.59], P < .001) and gross total resection (ORadj=1.50 [95% CI: 1.31-1.72], P < .001). Furthermore, the odds were lowest at community centers (hospitals (67.3%; ORadj=0.35 [95% CI: 0.26-0.46], P < .001) and highest at academic/NCI-designated comprehensive cancer centers (85.4%; referent). By geographical location, BMM testing/reporting completeness ranged from a high of 86.8% at New England (referent) to a low of 76.0 % in the West South Central region (ORadj=0.57 [95% CI: 0.42-0.78]; P < .001). Extent of resection, Commission-on-Cancer facility type, and facility location were additionally significant predictors of MGMT testing/reporting among IDH-wildtype glioblastoma cases.

Conclusions

Initial BMM testing/reporting completeness for individuals with adult-type diffuse gliomas in the United States was promising, although patterns varied by hospital attributes and extent of resection.

Congress of neurological surgeons systematic review and evidence-based guidelines update on the role of neuropathology in the management of progressive glioblastoma in adults

TARGET POPULATION

These recommendations apply to adult patients with progressive or recurrent glioblastoma (GBM).

QUESTION

For adult patients with progressive glioblastoma does testing for Isocitrate Dehydrogenase (IDH) 1 or 2 mutations provide new additional management or prognostic information beyond that derived from the tumor at initial presentation?

RECOMMENDATION

Level III: Repeat IDH mutation testing is not necessary if the tumor is histologically similar to the primary tumor and the patient's clinical course is as expected.

QUESTION

For adult patients with progressive glioblastoma does repeat testing for MGMT promoter methylation provide new or additional management or prognostic information beyond that derived from the tumor at initial presentation and what methods of detection are optimal?

RECOMMENDATION

Level III: Repeat MGMT promoter methylation is not recommended.

QUESTION

For adult patients with progressive glioblastoma does EGFR amplification or mutation testing provide management or prognostic information beyond that provided by histologic analysis and if performed on previous tissue samples, does it need to be repeated?

RECOMMENDATION

Level III: In cases that are difficult to classify as glioblastoma on histologic features EGFR amplification testing may help in classification. If a previous EGFR amplification was detected, repeat testing is not necessary. Repeat EGFR amplification or mutational testing may be recommended in patients in which target therapy is being considered.

QUESTION

For adult patients with progressive glioblastoma does large panel or whole genome sequencing provide management or prognostic information beyond that derived from histologic analysis?

RECOMMENDATION

Level III: Primary or repeat large panel or whole genome sequencing may be considered in patients who are eligible or interested in molecularly guided therapy or clinical trials.

QUESTION

For adult patients with progressive glioblastoma should immune checkpoint biomarker testing be performed to provide management and prognostic information beyond that obtained from histologic analysis?

RECOMMENDATION

Level III: The current evidence does not support making PD-L1 or mismatch repair (MMR) enzyme activity a component of standard testing.

QUESTION

For adult patients with progressive glioblastoma are there meaningful biomarkers for bevacizumab responsiveness and does their assessment provide additional information for tumor management and prognosis beyond that learned by standard histologic analysis?

RECOMMENDATION

Level III: No established Bevacizumab biomarkers are currently available based upon the inclusion criteria of this guideline.

Prognostic value of O 6-methylguanine-DNA methyltransferase methylation in isocitrate dehydrogenase mutant gliomas

Background

Patients with isocitrate dehydrogenase (IDH) mutant gliomas have been associated with longer survival time than those that are IDH wild-type. Previous studies have shown the prognostic value of O ⁶ -methylguanine-DNA methyltransferase (MGMT) promoter methylation for glioblastoma multiforme (GBM), which are predominantly IDH wild-type. Little is known of the prognostic value of MGMT methylation status for IDH mutant gliomas.

Methods

We retrospectively identified IDH mutant gliomas patients between 2011 and 2020 that were tested for MGMT promoter methylation. We generated Kaplan-Meier estimator curves and performed Cox proportional hazard models for overall survival (OS) and progression-free survival (PFS) to compare the outcomes of MGMT promoter methylated versus MGMT unmethylated patients.

Results

Of 419 IDH mutant gliomas with MGMT promoter methylation testing, we identified 54 GBMs, 223 astrocytomas, and 142 oligodendrogliomas. 62.3% patients had MGMT methylated tumors while 37.7% were MGMT unmethylated. On Kaplan-Meier analysis, median OS for all MGMT methylated patients was 17.7 years and 14.6 years for unmethylated patients. Median PFS for all MGMT methylated patients was 7.0 years and for unmethylated patients 5.2 years. After univariate subgroup analysis, MGMT methylation is only prognostic for OS and PFS in GBM, and for OS in anaplastic oligodendroglioma and anaplastic oligodendroglioma for OS. In multivariate analysis, MGMT unmethylated GBM patients carry a higher risk of death (HR 7.72, 95% CI 2.10-28.33) and recurrence (HR 3.85, 95% CI 1.35-10.96).

Conclusions

MGMT promoter methylation is associated with better OS and PFS for IDH mutant GBM. MGMT promoter methylation testing for other IDH mutant glioma subtypes may not provide additional information on prognostication.

The Impact of IDH1 Mutation and MGMT Promoter Methylation on Recurrence-Free Interval in Glioblastoma Patients Treated With Radiotherapy and Chemotherapeutic Agents

The aim of this study is to investigate the relationship between isocitrate dehydrogenase-1 (IDH1) mutation and O⁶-methylguanine-DNA methyltransferase (MGMT) promoter methylation with recurrence-free interval in glioblastoma patients treated with chemoradiotherapies. Clinical data were collected from 82 patients with totally resected glioblastoma and treated with adjuvant therapies from 2014 to 2019. IDH1 mutation was assessed by immunohistochemistry and MGMT promoter methylation was assessed by different sequencing methods. IDH1 mutation was present in 32 cases and 50 cases were IDH1 wildtype; 54 and 28 patients had unmethylated and methylated MGMT promoter, respectively, Of the 82 patients, 62 patients received chemoradiotherapy while 20 patients only received radiation. Approximately, 61% of patients had a tumor recurrence after 1 year, and 39% showed a recurrence before 1 year of treatment. There was no significant relationship between IDH1 mutation and MGMT promoter methylation (p-value = 0.972). Patients with IDH1 mutation and their age <50 years showed a significant difference in recurrence-free interval (p-value = 0.014). Difference in recurrence-free interval was also statistically observed in patients with unmethylated MGMT promoter and treated with chemoradiotherapies (p-value = 0.031), by which they showed a late tumor recurrence (p-value = 0.016). This revealed that IDH1 mutation and MGMT methylation are independent prognostic factors in glioblastoma. Although IDH1-mutant glioblastomas showed late tumor recurrence in patients less than 50 years old, the type of treatment modalities may not show additional beneficial outcome. Patients with unmethylated MGMT and IDH1 mutation, treated with different chemoradiotherapies, showed a late tumor recurrence.

Relative oxygen extraction fraction (rOEF) MR imaging reveals higher hypoxia in human epidermal growth factor receptor (EGFR) amplified compared with non-amplified gliomas

PURPOSE

Epidermal growth factor receptor (EGFR) amplification promotes gliomagenesis and is linked to lack of oxygen within the tumor microenvironment. Using hypoxia-sensitive spin-and-gradient echo echo-planar imaging and perfusion MRI, we investigated the influence of EGFR amplification on tissue oxygen availability and utilization in human gliomas.

METHODS

This study included 72 histologically confirmed EGFR-amplified and non-amplified glioma patients. Reversible transverse relaxation rate (R₂'), relative cerebral blood volume (rCBV), and relative oxygen extraction fraction (rOEF) were calculated for the contrast-enhancing and non-enhancing tumor regions. Using Student t test or Wilcoxon rank-sum test, median R₂', rCBV, and rOEF were compared between EGFR-amplified and non-amplified gliomas. ROC analysis was performed to assess the ability of imaging characteristics to discriminate EGFR amplification status. Overall survival (OS) was determined using univariate and multivariate cox models. Kaplan-Meier survival curves were plotted and compared using the log-rank test.

RESULTS

EGFR amplified gliomas exhibited significantly higher median R₂' and rOEF than non-amplified gliomas. ROC analysis suggested that R₂' (AUC = 0.7190; P = 0.0048) and rOEF (AUC = 0.6959; P = 0.0156) could separate EGFR status. Patients with EGFR-amplified gliomas had a significantly shorter OS than non-amplified patients. Univariate cox regression analysis determined both R₂' and rOEF significantly influence OS. No significant difference was observed in rCBV between patient cohorts nor was rCBV found to be an effective differentiator of EGFR status.

CONCLUSION

Imaging of tumor oxygen characteristics revealed EGFR-amplified gliomas to be more hypoxic and contribute to shorter patient survival than EGFR non-amplified gliomas.

Valganciclovir as Add-On to Standard Therapy in Secondary Glioblastoma

Patients with glioblastoma have a very poor prognosis despite aggressive therapeutic strategies. Cytomegalovirus has been detected in >90% of glioblastoma tumors. This virus can affect tumor progression and may represent a novel glioblastoma therapy target. We report, here, a retrospective survival analysis of patients with secondary glioblastoma who were treated with the anti-viral drug valganciclovir at Karolinska University Hospital in Stockholm. We performed survival analyses of eight patients with secondary glioblastoma who were treated with a standard dose of valganciclovir as an add-on to second-line therapy after their disease progression to glioblastoma. Thirty-six patients with secondary glioblastoma admitted during the same time period who received similar treatment and care served as contemporary controls. The patients treated with valganciclovir showed an increased median overall survival after progression to glioblastoma compared with controls (19.1 versus 12.7 months, p = 0.0072). This result indicates a potential positive effect of valganciclovir in secondary glioblastoma, which is in agreement with our previous observation that valganciclovir treatment improves the outcomes of patients with newly diagnosed glioblastoma. Larger randomized studies are warranted to prove this hypothesis.

Main genetic differences in high-grade gliomas may present different MR imaging and MR spectroscopy correlates

OBJECTIVE

To assess whether the main genetic differences observed in high-grade gliomas (HGG) will present different MR imaging and MR spectroscopy correlates that could be used to better characterize lesions in the clinical setting.

METHODS

Seventy-nine patients with histologically confirmed HGG were recruited. Immunohistochemistry analyses for isocitrate dehydrogenase gene 1 (IDH1), alpha thalassemia mental retardation X-linked gene (ATRX), Ki-67, and p53 protein expression were performed. Tumour radiological features were examined on MR images. Metabolic profile and infiltrative pattern were assessed with MR spectroscopy. MR features were analysed to identify imaging-molecular associations. The Kaplan-Meier method and the Cox regression model were used to identify survival prognostic factors.

RESULTS

In total, 17.7% of the lesions were IDH1-mutated, 8.9% presented ATRX-mutated, 70.9% presented p53 unexpressed, and 22.8% had Ki-67 > 5%. IDH1 wild-type tumours had higher levels of mobile lipids (p = 0.001). The tumour-infiltrative pattern was higher in HGG with unexpressed p53 (p = 0.009). Mutated ATRX tumours presented higher levels of glutamate and glutamine (Glx) (p = 0.001). An association was observed between Glx tumour levels (p = 0.038) and Ki-67 expression (p = 0.008) with the infiltrative pattern. Survival analyses identified IDH1 status, age, and tumour choline levels as independent predictors of prognostic significance.

CONCLUSIONS

Our results suggest that IDH1-wt tumours are more necrotic than IDH1-mut. And that the presence of an infiltrative pattern in HGG is associated with loss of p53 expression, Ki-67 index, and Glx levels. Finally, tumour choline levels could be used as a predictive factor in survival in addition to the IDH1 status to provide a more accurate prediction of survival in HGG patients.

KEY POINTS

• IDH1-wt tumours present higher levels of mobile lipids than IDH1-mut. • Mutated ATRX tumours exhibit higher levels of glutamate and glutamine. • Loss of p53 expression, Ki-67 expression, and glutamate and glutamine levels may contribute to the presence of an infiltrative pattern in HGG.

Survival benefit of lobectomy for glioblastoma: moving towards radical supramaximal resection

PURPOSE

Extent of resection remains a paramount prognostic factor for long-term outcomes for glioblastoma. As such, supramaximal resection or anatomic lobectomy have been offered for non-eloquent glioblastoma in an attempt to improve overall survival. Here, we conduct a propensity-matched analysis of patients with non-eloquent glioblastoma who underwent either lobectomy or gross total resection of lesion to investigate the efficacy of supramaximal resection of glioblastoma.

METHODS

Patients who underwent initial surgery for gross total resection or lobectomy for non-eloquent glioblastoma at our tertiary care referral center from 2010 to 2019 were included for this propensity-matched survival analysis. Propensity scores were generated with the following covariates: age, location, preoperative KPS, product of perpendicular maximal tumor diameters, and product of perpendicular FLAIR signal diameters. Inverse probability of treatment weighting (IPTW) with generated propensity scores was used to compare progression-free survival and overall survival.

RESULTS

Sixty-nine patients were identified who underwent initial resection of glioblastoma for non-eloquent glioblastoma from 2010 to 2019 (GTR = 37, lobectomy = 32). Using IPTW, overall survival (30.7 vs. 14.1 months) and progression-free survival (17.2 vs. 8.1 months were significantly higher in the lobectomy cohort compared to the GTR group (p < 0.001). There was no significant difference in pre-op or post-op KPS or complication rates between the two groups.

CONCLUSION

Our propensity-matched study suggests that lobectomy for non-eloquent glioblastoma confers an added survival benefit compared to GTR alone. For patients with non-eloquent glioblastoma, a supramaximal resection by means of an anatomic lobectomy should be considered as a primary surgical treatment in select patients if feasible.

Deep Learning of Imaging Phenotype and Genotype for Predicting Overall Survival Time of Glioblastoma Patients

Glioblastoma (GBM) is the most common and deadly malignant brain tumor. For personalized treatment, an accurate pre-operative prognosis for GBM patients is highly desired. Recently, many machine learning-based methods have been adopted to predict overall survival (OS) time based on the pre-operative mono- or multi-modal imaging phenotype. The genotypic information of GBM has been proven to be strongly indicative of the prognosis; however, this has not been considered in the existing imaging-based OS prediction methods. The main reason is that the tumor genotype is unavailable pre-operatively unless deriving from craniotomy. In this paper, we propose a new deep learning-based OS prediction method for GBM patients, which can derive tumor genotype-related features from pre-operative multimodal magnetic resonance imaging (MRI) brain data and feed them to OS prediction. Specifically, we propose a multi-task convolutional neural network (CNN) to accomplish both tumor genotype and OS prediction tasks jointly. As the network can benefit from learning tumor genotype-related features for genotype prediction, the accuracy of predicting OS time can be prominently improved. In the experiments, multimodal MRI brain dataset of 120 GBM patients, with as many as four different genotypic/molecular biomarkers, are used to evaluate our method. Our method achieves the highest OS prediction accuracy compared to other state-of-the-art methods.

Sex-specific impact of patterns of imageable tumor growth on survival of primary glioblastoma patients

Background

Sex is recognized as a significant determinant of outcome among glioblastoma patients, but the relative prognostic importance of glioblastoma features has not been thoroughly explored for sex differences.

Methods

Combining multi-modal MR images, biomathematical models, and patient clinical information, this investigation assesses which pretreatment variables have a sex-specific impact on the survival of glioblastoma patients (299 males and 195 females).

Results

Among males, tumor (T1Gd) radius was a predictor of overall survival (HR = 1.027, p = 0.044). Among females, higher tumor cell net invasion rate was a significant detriment to overall survival (HR = 1.011, p < 0.001). Female extreme survivors had significantly smaller tumors (T1Gd) (p = 0.010 t-test), but tumor size was not correlated with female overall survival (p = 0.955 CPH). Both male and female extreme survivors had significantly lower tumor cell net proliferation rates than other patients (M p = 0.004, F p = 0.001, t-test).

Conclusion

Despite similar distributions of the MR imaging parameters between males and females, there was a sex-specific difference in how these parameters related to outcomes.

Pretreatment Geriatric Assessments of Elderly Patients with Glioma: Development and Implications

Glioma is the most frequent primary brain tumor affecting adults, and the most lethal type is glioblastoma (GBM); currently, the available therapies only provide palliation. The treatments for low-grade glioma (LGG) include neurosurgical resection, watchful waiting, radiotherapy and chemotherapy, while the therapeutic strategies for high-grade glioma (HGG), particularly in elderly patients, have evolved to include radiotherapy, chemotherapy, and targeted monotherapy based on the characteristics of the investigated patients. Proper assessments aiming to predict and achieve the most satisfying prognosis among patients prior to surgery, radiotherapy, chemotherapy, targeted therapy or immunotherapy help summarize the pretreatment characteristics of patients, providing doctors comprehensive information to consider while determining whether the patients could benefit from ongoing treatments and deciding the proper treatment strategy for subsequent phases. This article aims to rigorously review the most recent evidence and discuss current mainstream assessments before the initiation of proper treatments for glioma, thus highlighting the potential necessity of pretreatment assessments.

Glioblastoma: from volumetric analysis to molecular predictors

BACKGROUND

Despite decades of therapeutic and molecular refinements, the prognosis of patients with glioblastoma (GBM) still remains unfavorable. Integrative clinical studies allow a better understanding of the natural evolution of GBM. To assess independent predictors of overall survival (OS) and progression free survival (PFS) clinical, surgical, molecular and radiological variables were evaluated. A novel preoperative volumetric magnetic resonance imaging (MRI) index for tumor prognosis in GBM patients was investigated.

METHODS

A cohort of 195 cases of patients operated for newly GBM were analyzed. Extent of tumoral resection (EOR), tumor growth pattern, expressed by preoperative volumetric ΔT1-T2 MRI index, molecular markers such as O6-methylguanine-DNA methyltransferase (MGMT) methylation and isocitrate dehydrogenase 1/2 (IDH1/2) mutation, were analyzed. Analysis of survival was done using Cox-proportional hazard models.

RESULTS

The 1-, 2- years estimated OS and PFS rate for the whole population were 61% and 27%, 38% and 17%, respectively. A better survival rate, both in terms of survival and tumor progression, was observed in patient with higher EOR (p=0.000), younger age (p=0.000), MGMT methylation status (p=0.001) and lower preoperative ΔT1-T2 MRI index (p=0.004). Regarding the tumor growth pattern a cut-off value of 0.75 was found to discriminate patient with different prognosis. Patients with a preoperative ΔT1-T2 MRI index <0.75 had a 1-year estimated OS of 67%, otherwise patients with a preoperative ΔT1-T2 MRI index >0.75 hada 1-year estimated OS of 34%.

CONCLUSIONS

In this investigation longer survival is associated with younger age, EOR, promoter methylation of MGMT and preoperative tumor volumetric features expressed by ΔT1-T2 MRI index. The preoperative ΔT1-T2 MRI index could be a promising prognostic factor potentially useful in GBM management. Future investigations based on multiparametric MRI data and next generation sequences analysis, may better clarify this result.

Complete radiological response following subtotal resection in three glioblastoma patients under treatment with Tumor Treating Fields

Glioblastoma multiforme (GBM) treatment consists of surgery, radiotherapy and chemotherapy with Temozolomide (TMZ). After subtotal resection (STR), residual tumors rarely undergo spontaneous regression. Overall survival (OS) and progression-free survival (PFS) are reduced when compared with gross total resection. There is evidence that adding Tumor Treating Fields (TTFields) to standard management may lead to a significant increase in PFS and OS. In 2015 and 2016, STR was performed in 27 patients with GBM. Of these, four subsequently received TTFields therapy in addition to chemotherapy. The present study presents a series of three patients with GBM (44-54 years; isocitrate dehydrogenase wild-type, methylated O6-methylguanine-DNA methyltransferase promoter) that were treated with radiochemotherapy and TTFields after STR. Therapy with TTFields started concomitantly to TMZ following radiotherapy and was maintained for 14, 24 and 37 months. TTFields were used as monotherapy in one case, as TMZ treatment had to be stopped due to toxicity for 1 month. In all patients, TTFields therapy was well tolerated at high compliance levels, resulting in complete response (CR) after 4, 5 and 7 months, respectively. Two patients remain tumor-free at 16 and 40 months after STR. One patient exhibited multifocal recurrence 11 months after the beginning of TTFields treatment but remains alive, presenting a mild neurological decline 24 months after starting TTFields. All three presented patients gave written informed consent for their data to be published. In conclusion, the current report detailed three patients with GBM who underwent STR and were subsequently treated with TMZ and TTFields. TTFields treatment was tolerated well and was applied accurately and with high compliance by these patients, which may have contributed to the complete response. Four of the 27 patients treated with STR received additional TTFields treatment. Three of these 4 showed a CR, while a CR was observed only 2 of the remaining 23 patients without TTFields. The current series supports the effects in clinical practice, as demonstrated in recent clinical trials. The results also demonstrated that adjuvant TTFields therapy can structurally affect residual tumors after STR.

Glioma surgery: From preservation of motor skills to conservation of cognitive functions

The first step of glioma treatment is surgery. Extent of resection (EOR) improves patient survival if surgery does not negatively impair a patient's neurological status. However, how surgery affects the patient's quality of life (QOL) has been less studied, especially as regards cognitive aspects. In our study, we retrospectively analyzed our cases with awake surgery. In all patients, surgical excision was stopped when active functions were intraoperatively identified. A neuropsychological assessment was performed both before and after surgery (5 days and 1 month after). Writing, motor speech, comprehension, expression, reading, pragmatics, attention, memory, problem solving and visuoperceptive functions were evaluated and scored with the NOMS scale. We found no differences in the median values of writing and motor speech, while there was a difference in the following variables: comprehension, expression, reading, pragmatics, attention, memory, problem solving and visuoperceptive functions. Moreover, the Dunn test did not show any difference between preoperative evaluation and evaluation performed 30 days after surgery regarding comprehension, expression, reading, pragmatics, attention, problem solving and visuoperceptive functions. However, there was a difference between preoperative and postoperative evaluation for memory. This retrospective study shows that awake surgery could be a reasonable possibility to preserve a patient's QOL achieving an EOR >82% of the Total Tumor Volume (Fluid-attenuated inversion recovery (FLAIR) hyperintense region in low-grade gliomas and enhancing nodules plus FLAIR hyperintense region in high-grade gliomas). In this series memory was the only aspect that had an impairment after surgery without a complete recovery at one month after surgery.

Molecular profile of long-term survivors of glioblastoma: A scoping review of the literature

Molecular aberrations of malignancy are becoming widely recognized as important predictive and prognostic markers for treatment response and survival in oncology and have been linked to the discovery of novel treatment targets. This area of research in glioblastoma continues to evolve. The aim of this scoping review was to document the hallmark molecular characteristics of long-term survivors of glioblastoma. MEDLINE, Scopus and EMBASE were searched with core concepts: (1) glioblastoma, (2) long-term survivor and (3) molecular OR mutation. A thematic analysis was undertaken of the 18 included studies. Four main classes of characteristics were obtained: IDH mutation, MGMT methylation, other known characteristics and novel discoveries. While MGMT methylation or the combination with IDH mutation are suggested to be hallmark characteristics, there remains enough uncertainty to suggest further factors may be involved, such as CD34 expression. Further research is required to accurately describe hallmark molecular characteristics of long-term survivors to assist in defining these patients at diagnosis, preventing treatment complications and discovering novel treatments.

Circulating MACC1 Transcripts in Glioblastoma Patients Predict Prognosis and Treatment Response

Glioblastoma multiforme is the most aggressive primary brain tumor of adults, but lacks reliable and liquid biomarkers. We evaluated circulating plasma transcripts of metastasis-associated in colon cancer-1 (MACC1), a prognostic biomarker for solid cancer entities, for prediction of clinical outcome and therapy response in glioblastomas. MACC1 transcripts were significantly higher in patients compared to controls. Low MACC1 levels clustered together with other prognostically favorable markers. It was associated with patients’ prognosis in conjunction with the isocitrate dehydrogenase (IDH) mutation status: IDH1 R132H mutation and low MACC1 was most favorable (median overall survival (OS) not yet reached), IDH1 wildtype and high MACC1 was worst (median OS 8.1 months), while IDH1 wildtype and low MACC1 was intermediate (median OS 9.1 months). No patients displayed IDH1 R132H mutation and high MACC1. Patients with low MACC1 levels receiving standard therapy survived longer (median OS 22.6 months) than patients with high MACC1 levels (median OS 8.1 months). Patients not receiving the standard regimen showed the worst prognosis, independent of MACC1 levels (low: 6.8 months, high: 4.4 months). Addition of circulating MACC1 transcript levels to the existing prognostic workup may improve the accuracy of outcome prediction and help define more precise risk categories of glioblastoma patients.

Integrative analysis of DNA methylation suggests down-regulation of oncogenic pathways and reduced somatic mutation rates in survival outliers of glioblastoma

The study of survival outliers of glioblastoma can provide important clues on gliomagenesis as well as on the ways to alter clinical course of this almost uniformly lethal cancer type. However, there has been little consensus on genetic and epigenetic signatures of the long-term survival outliers of glioblastoma. Although the two classical molecular markers of glioblastoma including isocitrate dehydrogenase 1 or 2 (IDH1/2) mutation and O6-methylguanine DNA methyltransferase (MGMT) promoter methylation are associated with overall survival rate of glioblastoma patients, they are not specific to the survival outliers. In this study, we compared the two groups of survival outliers of glioblastoma with IDH wild-type, consisting of the glioblastoma patients who lived longer than 3 years (n = 17) and the patients who lived less than 1 year (n = 12) in terms of genome-wide DNA methylation profile. Statistical analyses were performed to identify differentially methylated sites between the two groups. Functional implication of DNA methylation patterns specific to long-term survivors of glioblastoma were investigated by comprehensive enrichment analyses with genomic and epigenomic features. We found that the genome of long-term survivors of glioblastoma is differentially methylated relative to short-term survivor patients depending on CpG density: hypermethylation near CpG islands (CGIs) and hypomethylation far from CGIs. Interestingly, these two patterns are associated with distinct oncogenic aspects in gliomagenesis. In the long-term survival glioblastoma-specific sites distant from CGI, somatic mutations of glioblastoma are enriched with higher DNA methylation, suggesting that the hypomethylation in long-term survival glioblastoma can contribute to reduce the rate of somatic mutation. On the other hand, the hypermethylation near CGIs associates with transcriptional downregulation of genes involved in cancer progression pathways. Using independent cohorts of IDH1/2- wild type glioblastoma, we also showed that these two patterns of DNA methylation can be used as molecular markers of long-term survival glioblastoma. Our results provide extended understanding of DNA methylation, especially of DNA hypomethylation, in cancer genome and reveal clinical importance of DNA methylation pattern as prognostic markers of glioblastoma.

Defining a prognostic score based on O6-methylguanine-DNA methyltransferase cut-off methylation level determined by pyrosequencing in patients with glioblastoma multiforme

PURPOSE

Epigenetic variations in the O6-methylguanine-methyltransferase gene had been widely associated with a favorable impact on survival in patients affected by glioblastoma multiforme (GBM). Aim of this study is to explore a scoring system based on the gene promoter methylation in order to predict patients' prognosis.

METHODS

A series of 128 patients with GBM was retrospectively analyzed. A training set and a validations set were then generated. The methylation level of CpGi from 74 to 83 was determined by pyrosequencing. In accordance to previous literature, each island was assigned with 1 point if the corresponding methylation level was higher than 9%. The sum consisted in a score that went from 0 (all CpGi < 9%) to 10 (all CpGi ≥ 9%). A threshold capable to detect a favorable outcome (overall survival, OS > 24 months) was identified by ROC analysis.

RESULTS

Median OS and follow-up were 14 and 32.6 months respectively. Among the total population, 35% of the pts had a score of 0, while 29% had a score of 10. A score ≥ 6 was associated with a favorable prognosis also when corrected for age (> 70 vs. ≤ 70 years) and ECOG performance status (0-1 vs. 2-3). Similar results were observed also in terms of PFS. Results were consistent in the training and in the validation set.

CONCLUSIONS

The present manuscript explored a novel scoring system capable to take into consideration the methylation status of each single CpGi, capable to better predict prognosis in GBM patients.

Long noncoding RNA HOXB13-AS1 regulates HOXB13 gene methylation by interacting with EZH2 in glioma

Dysregulation of long noncoding RNAs (lncRNAs) has been implicated in human diseases, in particular, cancers. In this study, we determined the expression of an lncRNA, HOXB13‐AS1, involving in glioma. We showed that HOXB13‐AS1 was significantly upregulated in glioma tissues and cells and was negatively correlated with its surrounding gene HOXB13 levels. Functional experiments in vitro and in vivo revealed that high level of HOXB13‐AS1 increased cell proliferation and tumor growth by promoting cell cycle progression. Conversely, knockdown of HOXB13‐AS1 resulted in decreased cell proliferation and tumor growth. Mechanistically, we showed that HOXB13‐AS1 overexpression increased DNMT3B‐mediated methylation of adjacent gene HOXB13 promoter by binding with the enhancer of zeste homolog 2 (EZH2) using bisulfite sequencing PCR (BSP), epigenetically suppressing HOXB13 expression. Additionally, the interaction between HOXB13‐AS1 and HOXB13 was validated by RNA immunoprecipitation (RIP) and chromatin immunoprecipitation (ChIP) assays using antibody against to EZH2. Taken together, our study indicated that HOXB13‐AS1 could regulate HOXB13 gene expression by methylation HOXB13 promoter and acts as an epigenetic oncogenic in glioma.

Clinical and immunological correlates of long term survival in glioblastoma

Glioblastoma (GBM) is the most common and most aggressive type of primary brain tumour in adults. It represents 54% of all gliomas and 16% of all brain tumours (Ostrom et al. 2016). Despite surgery and treatment with radiotherapy plus an oral alkylating agent, temozolomide (TMZ), tumours invariably recur, and the patient survival is an average of ~14–16 months. In this review we summarise the current understanding of multiple factors that may affect survival of patients with GBMs. In particular, we discuss recent advancements in surgery and detection of genomic-based markers with prognostic values, such as IDH1/2 mutations, MGMT gene promoter methylation, and TERT gene promoter alterations. We address the issue of tumour heterogeneity and evolution that may result in different parts of the same tumour exhibiting different GBM subtypes and in subtype switching, which may restrict the usefulness of the expression-based classification as a prognostic marker before relapse. The determinants of long-term survival in patients with IDH1/2wt GBM, beyond MGMT promoter methylation, remain to be identified, and even the absence of both IDH1/2 mutations and MGMT promoter methylation does not preclude long-term survival. These findings suggest that host-derived factors, such as immune system responsiveness may contribute to long-term survival in such patients. We report the results of high-throughput approaches, suggesting links between long-term survival and enhanced immune-related gene expression. The further search for new gene candidates, promoter methylation status, and specific features of host immunity should provide prognostic biomarkers for the evaluation of survival of IDH1 wild-type/non-G-CIMP GBMs.

Combining Clinical and Molecular Data to Predict the Benefits of Carmustine Wafers in Newly Diagnosed High-Grade Gliomas

PURPOSE OF REVIEW

The purpose of this study was to retrospectively evaluate the use of carmustine wafers (CWs) in the management of high-grade gliomas (HGGs). The data from our monoinstitutional series was compared with studies reported in the literature. Special emphasis was placed on the evaluation of side effects and the analysis of extent of resection and molecular profile as risk factors.

RECENT FINDINGS

The implantation of CWs into the resection cavity during HGG treatment to deliver localized chemotherapy, followed by the Stupp protocol, remains debated in a clinical setting, largely due to the lack of appropriate phase III studies. Given the high expense and poorly characterized side effects associated with CW treatment, identification of patients most likely to benefit from this therapy could be clinically relevant. CWs may represent an effective and safe first-line treatment for patients with HGG that exhibit complete tumor resection and harboring a methylated MGMT promoter. Our investigation showed a much larger group of patients exhibiting long-term survival (> = 36 months), strongly supporting a potential survival benefit conferred via CW treatment. The pre-surgical definition of the MGMT promoter status could be of clinical use in identifying "good responders" to CW implantation.

O6-methylguanine-DNA-methyltransferase immunostaining intensity in glioblastoma

Immunohistochemistry (IHC) for O⁶-methylguanine-DNA-methyltransferase (MGMT) has shown heterogeneous results. Cell staining intensity has not been included as a quantifiable variable in IHC analyses. We performed MGMT IHC in 29 patients diagnosed as glioblastoma classifying cells into three categories based on nuclear staining intensity compared with adjacent endothelium. The median proportions of strong-moderate, weak and no staining cells were 10%, 16% and 71%, respectively. The proportion of positive cases for MGMT expression varies from 38% to 52% depending on the classification of weakly stained cells. This letter challenges previous studies that have not included intensity as a variable for IHC analysis.

Tumor location and patient age predict biological signatures of high-grade gliomas

Prognostic factors for high-grade gliomas include patient age, IDH1 mutation, MGMT methylation, and Ki67 value. We assessed the predictive role of topographic location of gliomas for their biological signatures. Collecting all neuroradiological and histological data of patients with histologically proven HGG, we performed a retrospective monocentric study. A predictive value of frontal location for a lower Ki67 value (especially in the left hemisphere) and mutation of IDH1 (especially in the right hemisphere) was found. Temporal location was predictive for IDH1 wild-type. Involvement of the parietal lobe was found to be predictive of methylated MGMT, while insular lobe involvement predicted an unmethylated MGMT. There was no statistically significant difference of IDH1 mutation and MGMT methylation between left and right sides.

Magnetic Resonance Spectroscopy for Detection of 2-Hydroxyglutarate as a Biomarker for IDH Mutation in Gliomas

Mutations in the isocitrate dehydrogenase (IDH)1/2 genes are highly prevalent in gliomas and have been suggested to play an important role in the development and progression of the disease. Tumours harbouring these mutations exhibit a significant alteration in their metabolism resulting in the aberrant accumulation of the oncometabolite 2-hydroxygluarate (2-HG). As well as being suggested to play an important role in tumour progression, 2-HG may serve as a surrogate indicator of IDH status through non-invasive detection using magnetic resonance spectroscopy (MRS). In this review, we describe the recent efforts in developing MRS methods for detection and quantification of 2-HG in vivo and provide an assessment of the role of the 2-HG in gliomagenesis and patient prognosis.