An independently validated nomogram for isocitrate dehydrogenase-wild-type glioblastoma patient survival

Background

In 2016, the World Health Organization reclassified the definition of glioblastoma (GBM), dividing these tumors into isocitrate dehydrogenase (IDH)-wild-type and IDH-mutant GBM, where the vast majority of GBMs are IDH-wild-type. Nomograms are useful tools for individualized estimation of survival. This study aimed to develop and independently validate a nomogram for IDH-wild-type patients with newly diagnosed GBM.

Methods

Data were obtained from newly diagnosed GBM patients from the Ohio Brain Tumor Study (OBTS) and the University of California San Francisco (UCSF) for diagnosis years 2007-2017 with the following variables: age at diagnosis, sex, extent of resection, concurrent radiation/temozolomide (TMZ) status, Karnofsky Performance Status (KPS), O⁶-methylguanine-DNA methyltransferase (MGMT) methylation status, and IDH mutation status. Survival was assessed using Cox proportional hazards regression, random survival forests, and recursive partitioning analysis, with adjustment for known prognostic factors. The models were developed using the OBTS data and independently validated using the UCSF data. Models were internally validated using 10-fold cross-validation and externally validated by plotting calibration curves.

Results

A final nomogram was validated for IDH-wild-type newly diagnosed GBM. Factors that increased the probability of survival included younger age at diagnosis, female sex, having gross total resection, having concurrent radiation/TMZ, having a high KPS, and having MGMT methylation.

Conclusions

A nomogram that calculates individualized survival probabilities for IDH-wild-type patients with newly diagnosed GBM could be useful to physicians for counseling patients regarding treatment decisions and optimizing therapeutic approaches. Free software for implementing this nomogram is provided: https://gcioffi.shinyapps.io/Nomogram_For_IDH_Wildtype_GBM_H_Gittleman/.

A phase I study of MGMT-P140K transfected hematopoetic progenitor cells (HPC) combined with TMZ/O6BG dose escalation for newly diagnosed, MGMT unmethylated glioblastoma: Tolerance and evidence of survival benefit

2062

Background: GBM is the most common malignant brain tumor with a median survival of 15 months despite surgery and radio-chemotherapy. The most important mechanism of TMZ resistance is the O6-methylguanine-DNA methyltransferase (MGMT) gene which repairs temozolamide-induced DNA methylation. The MGMT inhibitor O6-benzylguanine (BG) demonstrated efficacy in depleting MGMT and maximizing tumor response in early phase clinical trials. However, MGMT expression is also low in hematopoietic cells, so this approach led to unacceptable bone marrow toxicity and thus has been abandoned. We hypothesized that chemoprotection of hematopoietic HPC with an MGMT mutant (MGMT-P140K) characterized by normal methyltransferase activity, coupled with low affinity for BG would maximize anti-tumor response while enabling patients to tolerate TMZ & BG dose escalation with minimal toxicity. A phase I trial was performed to test this hypothesis. Methods: 10 adults with newly diagnosed MGMT unmethylated, IDH-1 WT, GBM underwent standard surgery and radiation, followed by transplantation with autologous CD34+ HPC engineered to express MGMT-P140K using a lentiviral vector. We tested tolerance and efficacy of three different paradigms for conditioning bone marrow and re-infusion of HPC. To assess chemo-protection, patients’ blood counts and transgene marking were monitored during and after treatment, as was toxicity, response, and progression-free and overall survival. Results: Treatment was moderately toxic with 3/10 patients suffering grade 3-4 hematologic toxicity; no high grade non-hematologic toxicity was observed . Viral transduction rates ranged from 3-75% and were clearly improved in Arm III utilizing BCNU conditioning and intra-patient dose escalation of TMZ/O6GB. In patients tolerating 3 cycles or more, P140K-MGMT gene markings in peripheral blood and bone marrow cells increased 3-26-fold with only mild (Grade 2-3) mylosuppression consistent with chemo-protection as hypothesized. Median PFS and OS was 22 and 31 months respectfully, and three patients in Arm III are healthy and progression free at 36-39 months. OS exceeded RPA predicted survival by 3.3-fold suggesting clinical benefit. Viral insertion site analysis demonstrate lack of clonal dominance. Conclusions: P140K-MGMT transfected HPC enables TMZ/ BG dose escalation with acceptable toxicity and increased survival in a small cohort of selected patients. A phase II study is ongoing. Clinical trial information: NCT01269424.

Radiomics-based identification of peritumoral infiltration in de novo glioblastoma imaging presents targets amenable for potential targeted extended resection: A neurosurgical survey

e13573

Background: Radiomics-based machine learning tools have been developed to analyze preoperative multiparametric MR images of patients with glioblastoma (GBM) to predict various outcomes of clinical interest, such as survival, molecular mutation status, and subclinical peritumoral infiltration, all before initial surgical resection. Preoperative identification of regions containing the highest probability of subclinical tumor infiltration presents an opportunity for targeted extended resection in the setting of a clinical trial, but the willingness of neurosurgeons to perform such a procedure is not known. Methods: We selected five neurosurgeons from high volume centers ( > 20 GBM surgeries per year) and performed an in silico study of anonymized preoperative images of patients with GBM, with radiomics-based infiltration maps depicting high probabilities of peritumoral infiltration. With regards to these regions beyond the enhancing tumor, we surveyed them on their willingness to attempt biopsy, and asked them to rate whether they felt such a region could be resected. Results: Preoperative maps of 20 patients with GBM, containing 26 regions of interest depicting high-risk peritumoral infiltration regions (distributed among frontal, temporal, occipital, parietal, cerebellar, and deep loci) were presented to five expert neurosurgeons from different institutions. Of the 20 patients, a median of 90% were deemed to be safe to biopsy; a median of 55% were felt to be definitely resectable, and median 35% to be possibly resectable. 85% of the 20 subjects were felt to be good candidates for participation in a clinical trial assessing the feasibility, safety, and efficacy of targeted extended resection. Conclusions: In selected patients, experienced neurosurgeons are willing to attempt targeted extended resection using radiomics-based maps of peritumoral infiltration in the context of a clinical trial. Proceeding with development of such a trial is warranted.

Outcomes of melanoma patients with brain metastases receiving immune checkpoint inhibitor (ICI) therapy

e21028

Background: The effect of ICI therapy on brain metastasis (mets) in melanoma patients has been described, however the impact of genomic alterations and local treatment (trt) including radiation therapy (RT) on CNS outcomes and overall survival (OS) has not yet been explored. Methods: Under institutional IRB approval, we reviewed our electronic medical record to identify patients (pts) with metastatic melanoma and brain mets who received trt with ICI. Trt history, CNS responses as indicated by the treating physician and available genomic data were recorded. OS was estimated using a multivariable Cox regression model adjusting for genomic alteration, age, ICI regimen and brain mets. Results: A total of 49 pts were identified (65% male). Thirty seven pts had testing for tumor genomic alterations (alt, hotspot and comprehensive genomic testing); BRAFV600E( 30%), cKIT(5%), NRAS(16%), no alt (38%). Prior to initiation of ICI, 78% had known CNS mets, of these, 61% received RT. There was no difference in median OS for pts who started RT prior to ICI compared to those without RT (mOS = 75.71 vs 49.4 weeks, p = 0.75). Median OS was improved for those pts who received RT > 90 days prior to initiation of ICI trt however this was not statistically significant (45.7 vs 136 weeks, p = 0.12) and HR = 0.45 (95% CI 0.08, 2.36). OS was not significantly different in pts with genomic alterations compared with those without alterations (p = 0.264). Of the pts with known brain mets at the time of ICI start, 34% had progressive disease at 3 months and 11% were felt to have pseudoprogression. 18% survived to undergo 6-month disease assessment, of these 12% had further progression. All pts with cKIT mutations survived to 6-month disease assessment. 75% of pts with known brain mets developed new lesions, 15% had increased mass size. Pts who developed new brain mets while on trt with ICI had worse survival than those with preexisting brain mets and developed new brain lesions (28 vs 58 weeks, p = 0.05). 6% of all pts developed CNS immune related adverse effects. Conclusions: Most patients with melanoma and known brain metastasis prior to ICI developed new brain lesions as a site of metastatic spread. The development of new brain mets was associated with worse outcomes. Neither genomic alterations nor RT prior to ICI start were associated with improved survival.

Sex is an important prognostic factor for glioblastoma but not for nonglioblastoma

Background

Glioblastoma (GBM) is the most common and most malignant glioma. Nonglioblastoma (non-GBM) gliomas (WHO Grades II and III) are invasive and also often fatal. The goal of this study is to determine whether sex differences exist in glioma survival.

Methods

Data were obtained from the National Cancer Database (NCDB) for years 2010 to 2014. GBM (WHO Grade IV; N = 2073) and non-GBM (WHO Grades II and III; N = 2963) were defined using the histology grouping of the Central Brain Tumor Registry of the United States. Non-GBM was divided into oligodendrogliomas/mixed gliomas and astrocytomas. Sex differences in survival were analyzed using Kaplan-Meier and multivariable Cox proportional hazards models adjusted for known prognostic variables.

Results

There was a female survival advantage in patients with GBM both in the unadjusted (P = .048) and adjusted (P = .003) models. Unadjusted, median survival was 20.1 months (95% CI: 18.7-21.3 months) for women and 17.8 months (95% CI: 16.9-18.7 months) for men. Adjusted, median survival was 20.4 months (95% CI: 18.9-21.6 months) for women and 17.5 months (95% CI: 16.7-18.3 months) for men. When stratifying by age group (18-55 vs 56+ years at diagnosis), this female survival advantage appeared only in the older group, adjusting for covariates (P = .017). Women (44.1%) had a higher proportion of methylated MGMT (O⁶-methylguanine-DNA methyltransferase) than men (38.4%). No sex differences were found for non-GBM.

Conclusions

Using the NCDB data, there was a statistically significant female survival advantage in GBM, but not in non-GBM.

A PTPmu Biomarker is Associated with Increased Survival in Gliomas

An integrated approach has been adopted by the World Health Organization (WHO) for diagnosing brain tumors. This approach relies on the molecular characterization of biopsied tissue in conjunction with standard histology. Diffuse gliomas (grade II to grade IV malignant brain tumors) have a wide range in overall survival, from months for the worst cases of glioblastoma (GBM) to years for lower grade astrocytic and oligodendroglial tumors. We previously identified a change in the cell adhesion molecule PTPmu in brain tumors that results in the generation of proteolytic fragments. We developed agents to detect this cell surface-associated biomarker of the tumor microenvironment. In the current study, we evaluated the PTPmu biomarker in tissue microarrays and individual tumor samples of adolescent and young adult (n = 25) and adult (n = 69) glioma populations using a fluorescent histochemical reagent, SBK4-TR, that recognizes the PTPmu biomarker. We correlated staining with clinical data and found that high levels of the PTPmu biomarker correlate with increased survival of glioma patients, including those with GBM. Patients with high PTPmu live for 48 months on average, whereas PTPmu low patients live only 22 months. PTPmu high staining indicates a doubling of patient survival. Use of the agent to detect the PTPmu biomarker would allow differentiation of glioma patients with distinct survival outcomes and would complement current molecular approaches used in glioma prognosis.

Lifetime Occurrence of Brain Metastases Arising from Lung, Breast, and Skin Cancers in the Elderly: A SEER-Medicare Study

BACKGROUND

The Surveillance, Epidemiology, and End Results (SEER) Program recently released data on brain metastases (BM) diagnosed during primary cancer staging workup ("synchronous" BM, or SBM); this study examines the incidence of SBM compared with that of lifetime BM (LBM) identified using Medicare claims for patients diagnosed with lung cancer, breast cancer, or melanoma.

METHODS

Incidence proportions (IP) and age-adjusted rates for each of SEER SBM and Medicare LBM are presented along with measures of concordance between the two sources of data, where Medicare LBM were defined by several combinations of diagnosis and putative diagnostic imaging procedure codes.

RESULTS

The SBM IP in lung, breast, and melanoma cancers were 9.6%, 0.3%, and 1.1%, respectively; the corresponding LBM IP were 13.5%, 1.8%, and 3.6%. The greatest SBM IP among patients with lung cancer was 13.4% for non-small cell lung cancer, and among patients with breast cancer was 0.7% for triple-negative breast cancer. The greatest LBM IP among lung cancers was 23.1% in small-cell lung cancer, and among breast cancers was 4.2% for cases of the triple negative subtype.

CONCLUSIONS

Using a large dataset that is representative of the elderly population in the United States, these analyses estimate synchronous and lifetime incidence of BM in lung cancers, breast cancers, and melanomas.

IMPACT

These and other population-based estimates may be used to guide development of BM screening policy and evaluation of real-world data sources.

Plant Virus-Like Particle In Situ Vaccine for Intracranial Glioma Immunotherapy

Despite aggressive multi-modality treatment with surgery, radiation and chemotherapies, malignant glioma inevitably recurs and has dismal survival rates. Recent progress in immunotherapy has led to a resurgence of interest, and immunotherapies are being investigated for treatment of glioma. However, the unique brain anatomy and a highly immunosuppressive glioma microenvironment pose significant challenges to achieving efficacy. Thus, there is a critical need for assessment of next-generation immunotherapies for glioma. In this study, we have investigated the efficacy of the nanoparticle platform technology based on plant-derived Cowpea mosaic virus like particles (empty CPMV or eCPMV) to instigate a potent immune response against intracranial glioma. CPMV immunotherapy has been shown to efficiently reverse the immunosuppressive tumor microenvironments in pre-clinical murine models of dermal melanoma and metastatic melanoma, metastatic breast cancer, intraperitoneal ovarian cancer and in canine patients with oral melanoma. In the present study, we demonstrate that in situ administration of CPMV immunotherapy in the setting of glioma can effectively recruit unique subset of effector innate and adaptive immune cells to the brain parenchyma while reducing immune suppressive cellular population, leading to regression of intracranial glioma. The in situ CPMV nanoparticle vaccine offers a potent yet safe and localized immunotherapy for intracranial glioma.

Chromatin landscapes reveal developmentally encoded transcriptional states that define human glioblastoma

Mack et al. defined active chromatin landscapes of glioblastoma stem cells (GSCs) and primary tumor specimens, revealing novel transcriptional regulatory circuits and therapeutic targets. Super-enhancers identified essential transcription factors that underlie GSC identity and intertumoral diversity, potentially informing precision medicine.

Glioblastoma is an incurable brain cancer characterized by high genetic and pathological heterogeneity. Here, we mapped active chromatin landscapes with gene expression, whole exomes, copy number profiles, and DNA methylomes across 44 patient-derived glioblastoma stem cells (GSCs), 50 primary tumors, and 10 neural stem cells (NSCs) to identify essential super-enhancer (SE)–associated genes and the core transcription factors that establish SEs and maintain GSC identity. GSCs segregate into two groups dominated by distinct enhancer profiles and unique developmental core transcription factor regulatory programs. Group-specific transcription factors enforce GSC identity; they exhibit higher activity in glioblastomas versus NSCs, are associated with poor clinical outcomes, and are required for glioblastoma growth in vivo. Although transcription factors are commonly considered undruggable, group-specific enhancer regulation of the MAPK/ERK pathway predicts sensitivity to MEK inhibition. These data demonstrate that transcriptional identity can be leveraged to identify novel dependencies and therapeutic approaches.

Magnetic Resonance Fingerprinting to Characterize Childhood and Young Adult Brain Tumors

OBJECT

Magnetic resonance fingerprinting (MRF) allows rapid, simultaneous mapping of T1 and T2 relaxation times and may be an important diagnostic tool to measure tissue characteristics in pediatric brain tumors. We examined children and young adults with primary brain tumors to determine whether MRF can discriminate tumor from normal-appearing white matter and distinguish tumor grade.

METHODS

MRF was performed in 23 patients (14 children and 9 young adults) with brain tumors (19 low-grade glioma, 4 high-grade tumors). T1 and T2 values were recorded in regions of solid tumor (ST), peritumoral white matter (PWM), and contralateral white matter (CWM). Nonparametric tests were used for comparison between groups and regions.

RESULTS

Median scan time for MRF and a sequence for tumor localization was 11 min. MRF-derived T1 and T2 values distinguished ST from CWM (T1: 1,444 ± 254 ms vs. 938 ± 96 ms, p = 0.0002; T2: 61 ± 22 ms vs. 38 ± 9 ms, p = 0.0003) and separated high-grade tumors from low-grade tumors (T1: 1,863 ± 70 ms vs. 1,355 ± 187 ms, p = 0.007; T2: 90 ± 13 ms vs. 56 ± 19 ms, p = 0.013). PWM was distinct from CWM (T1: 1,261 ± 359 ms vs. 933 ± 104 ms, p = 0.0008; T2: 65 ± 51 ms vs. 38 ± 8 ms, p = 0.008), as well as from tumor (T1: 1,261 ± 371 ms vs. 1,462 ± 248 ms, p = 0.047).

CONCLUSIONS

MRF is a fast sequence that can rapidly distinguish important tissue components in pediatric brain tumor patients. MRF-derived T1 and T2 distinguished tumor from normal-appearing white matter, differentiated tumor grade, and found abnormalities in peritumoral regions. MRF may be useful for rapid quantitative measurement of tissue characteristics and distinguish tumor grade in children and young adults with brain tumors.

N6-methyladenine DNA Modification in Glioblastoma

Genetic drivers of cancer can be dysregulated through epigenetic modifications of DNA. Although the critical role of DNA 5-methylcytosine (5mC) in the regulation of transcription is recognized, the functions of other non-canonical DNA modifications remain obscure. Here, we report the identification of novel N⁶-methyladenine (N⁶-mA) DNA modifications in human tissues and implicate this epigenetic mark in human disease, specifically the highly malignant brain cancer glioblastoma. Glioblastoma markedly upregulated N⁶-mA levels, which co-localized with heterochromatic histone modifications, predominantly H3K9me3. N⁶-mA levels were dynamically regulated by the DNA demethylase ALKBH1, depletion of which led to transcriptional silencing of oncogenic pathways through decreasing chromatin accessibility. Targeting the N⁶-mA regulator ALKBH1 in patient-derived human glioblastoma models inhibited tumor cell proliferation and extended the survival of tumor-bearing mice, supporting this novel DNA modification as a potential therapeutic target for glioblastoma. Collectively, our results uncover a novel epigenetic node in cancer through the DNA modification N⁶-mA.

Laser-Induced Interstitial Thermotherapy of Gliomas

Laser-induced interstitial thermotherapy (LITT) is a modern minimally invasive treatment modality applied for management of a variety of diseases. Recent developments of techniques for precise targeting of the lesion, accurate delivery of the prescribed therapeutically effective thermal doses, and real-time visualization of the induced tissue damage during the procedure by means of intraoperative MR thermometry have stimulated a number of clinical studies testing LITT in cases of different brain pathologies, including gliomas. This modality is particularly attractive in patients with recurrent, deep-seated, and/or critically located neoplasms refractory to other treatments, where it can effectively demonstrate improvement of prognosis providing high quality of life and eliminating the risks of open tumor resection. Low morbidity rates associated with LITT and short hospital stay result in decreased cost of hospitalization. The effectiveness of thermal therapies, particularly after long-term follow-up, still needs evaluation in carefully planned randomized clinical trials, whereas elucidating the effects of laser treatment at the molecular, cellular, and organic levels will continue to expand the boundaries of its clinical applicability in neuro-oncology.

Abstract 4220: Heterogeneous distribution of prognostic protein markers in glioblastoma

Background: Glioblastoma (GBM) is the most common and lethal primary malignant brain tumor in adults. The heterogeneity of the disease leads to significant variability in response to standard therapy (surgery plus concurrent radiation and temozolomide). An accurate and reliable predictor of patient prognosis represents an unmet need to improve the care of GBM patients. While protein markers are an effective readout of cellular function, proteomics has rarely been utilized in GBM prognostic marker discovery. Experimental Procedures: GBM patients were prospectively recruited (Ohio Brain Tumor Study) and proteomics discovery using liquid chromatography mass spectrometry analysis (LC MS/MS) was performed in a discovery set of 27 patients including 13 short-term survivors (< 9 months, STS) and 14 long-term survivors (>= 18 months, LTS). Statistically significant proteins were evaluated in two independent datasets, including in18 samples micro-dissected from multiple tumor areas of 6 GBM patients. Results: Proteomics discovery identified 11,941 peptides in 2,495 unique proteins, with 172 proteins exhibiting significant dysregulation when comparing STS and LTS. Proteins involved in glycolysis/TCA cycle were up-regulated in STS compared to LTS by examination of individual targets as well as upon application of a novel protein and peptide pathway enrichment analysis. Validation of these dysregulated proteins and other protein markers from the literature in our first validation set (18 samples micro-dissected from n=6 patients) demonstrated that they were very unevenly distributed throughout individual patients' tumors. Several proteins overcame the heterogeneous nature of the tumors and were both prognostic markers differentially expressed between LTS and STS, as well as potential drug targets owing to their even distribution throughout the tumor. Protein abundance of significant marker proteins were verified in a second independent validation set using Western immunoblots. Conclusion: The current study verified the importance of metabolism in GBM pathology and demonstrated the heterogeneous nature of GBMs at the protein level.

Citation Format: Lindsay C. Stetson, Quinn T. Ostrom, Peter Liao, Andrew E. Sloan, Mark R. Chance, Jill S. Barnholtz-Sloan. Heterogeneous distribution of prognostic protein markers in glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4220.

First results on survival from a large Phase 3 clinical trial of an autologous dendritic cell vaccine in newly diagnosed glioblastoma

Background

Standard therapy for glioblastoma includes surgery, radiotherapy, and temozolomide. This Phase 3 trial evaluates the addition of an autologous tumor lysate-pulsed dendritic cell vaccine (DCVax^®-L) to standard therapy for newly diagnosed glioblastoma.

Methods

After surgery and chemoradiotherapy, patients were randomized (2:1) to receive temozolomide plus DCVax-L (n = 232) or temozolomide and placebo (n = 99). Following recurrence, all patients were allowed to receive DCVax-L, without unblinding. The primary endpoint was progression free survival (PFS); the secondary endpoint was overall survival (OS).

Results

For the intent-to-treat (ITT) population (n = 331), median OS (mOS) was 23.1 months from surgery. Because of the cross-over trial design, nearly 90% of the ITT population received DCVax-L. For patients with methylated MGMT (n = 131), mOS was 34.7 months from surgery, with a 3-year survival of 46.4%. As of this analysis, 223 patients are ≥ 30 months past their surgery date; 67 of these (30.0%) have lived ≥ 30 months and have a Kaplan-Meier (KM)-derived mOS of 46.5 months. 182 patients are ≥ 36 months past surgery; 44 of these (24.2%) have lived ≥ 36 months and have a KM-derived mOS of 88.2 months. A population of extended survivors (n = 100) with mOS of 40.5 months, not explained by known prognostic factors, will be analyzed further. Only 2.1% of ITT patients (n = 7) had a grade 3 or 4 adverse event that was deemed at least possibly related to the vaccine. Overall adverse events with DCVax were comparable to standard therapy alone.

Conclusions

Addition of DCVax-L to standard therapy is feasible and safe in glioblastoma patients, and may extend survival.

Trial registration Funded by Northwest Biotherapeutics; Clinicaltrials.gov number: NCT00045968; https://clinicaltrials.gov/ct2/show/NCT00045968?term=NCT00045968&rank=1; initially registered 19 September 2002

Introduction to Laser Ablation Video Supplement

Laser ablation (also known as laser interstitial thermal therapy [LITT]) has emerged as an important new technology for treating various disorders of the brain and spine. As with any new or emerging technology, there is a learning curve for its optimal use, and video tutorials can be important learning tools to help bridge gaps in knowledge for those who wish to become more familiar with laser ablation. In this special supplement to Neurosurgical Focus, videos illustrate laser ablation's use in the treatment of epilepsy and failed radiosurgery, as well as technical aspects of performing these procedures in eloquent brain and in the spine. We hope that these videos will enable you to enhance your understanding of the evolving use of laser ablation for disorders of the brain or spine. It is the editors' sincere hope that this will be helpful either in your own practice or in determining whether to refer to a neurosurgical colleague experienced in this field.

Integrated genomic analysis of survival outliers in glioblastoma

Background

To elucidate molecular features associated with disproportionate survival of glioblastoma (GB) patients, we conducted deep genomic comparative analysis of a cohort of patients receiving standard therapy (surgery plus concurrent radiation and temozolomide); "GB outliers" were identified: long-term survivor of 33 months (LTS; n = 8) versus short-term survivor of 7 months (STS; n = 10).

Methods

We implemented exome, RNA, whole genome sequencing, and DNA methylation for collection of deep genomic data from STS and LTS GB patients.

Results

LTS GB showed frequent chromosomal gains in 4q12 (platelet derived growth factor receptor alpha and KIT) and 12q14.1 (cyclin-dependent kinase 4), and deletion in 19q13.33 (BAX, branched chain amino-acid transaminase 2, and cluster of differentiation 33). STS GB showed frequent deletion in 9p11.2 (forkhead box D4-like 2 and aquaporin 7 pseudogene 3) and 22q11.21 (Hypermethylated In Cancer 2). LTS GB showed 2-fold more frequent copy number deletions compared with STS GB. Gene expression differences showed the STS cohort with altered transcriptional regulators: activation of signal transducer and activator of transcription (STAT)5a/b, nuclear factor-kappaB (NF-κB), and interferon-gamma (IFNG), and inhibition of mitogen-activated protein kinase (MAPK1), extracellular signal-regulated kinase (ERK)1/2, and estrogen receptor (ESR)1. Expression-based biological concepts prominent in the STS cohort include metabolic processes, anaphase-promoting complex degradation, and immune processes associated with major histocompatibility complex class I antigen presentation; the LTS cohort features genes related to development, morphogenesis, and the mammalian target of rapamycin signaling pathway. Whole genome methylation analyses showed that a methylation signature of 89 probes distinctly separates LTS from STS GB tumors.

Conclusion

We posit that genomic instability is associated with longer survival of GB (possibly with vulnerability to standard therapy); conversely, genomic and epigenetic signatures may identify patients where up-front entry into alternative, targeted regimens would be a preferred, more efficacious management.

An independently validated nomogram for individualized estimation of survival among patients with newly diagnosed glioblastoma: NRG Oncology RTOG 0525 and 0825

Background

Glioblastoma (GBM) is the most common primary malignant brain tumor. Nomograms are often used for individualized estimation of prognosis. This study aimed to build and independently validate a nomogram to estimate individualized survival probabilities for patients with newly diagnosed GBM, using data from 2 independent NRG Oncology Radiation Therapy Oncology Group (RTOG) clinical trials.

Methods

This analysis included information on 799 (RTOG 0525) and 555 (RTOG 0825) eligible and randomized patients with newly diagnosed GBM and contained the following variables: age at diagnosis, race, gender, Karnofsky performance status (KPS), extent of resection, O6-methylguanine-DNA methyltransferase (MGMT) methylation status, and survival (in months). Survival was assessed using Cox proportional hazards regression, random survival forests, and recursive partitioning analysis, with adjustment for known prognostic factors. The models were developed using the 0525 data and were independently validated using the 0825 data. Models were internally validated using 10-fold cross-validation, and individually predicted 6-, 12-, and 24-month survival probabilities were generated to measure the predictive accuracy and calibration against the actual survival status.

Results

A final nomogram was built using the Cox proportional hazards model. Factors that increased the probability of shorter survival included greater age at diagnosis, male gender, lower KPS, not having total resection, and unmethylated MGMT status.

Conclusions

A nomogram that assesses individualized survival probabilities (6-, 12-, and 24-mo) for patients with newly diagnosed GBM could be useful to health care providers for counseling patients regarding treatment decisions and optimizing therapeutic approaches. Free software for implementing this nomogram is provided: http://cancer4.case.edu/rCalculator/rCalculator.html.

A novel use of the NeuroBlate SideFire probe for minimally invasive disconnection of a hypothalamic hamartoma in a child with gelastic seizures

The authors describe the case of a 22-month-old boy who presented with gelastic seizures and developmental delay. Magnetic resonance imaging and video-electroencephalography monitoring revealed a primarily intraventricular hypothalamic hamartoma and gelastic seizures occurring 20-30 times daily. The patient was treated with various regimens of antiepileptic medications for 16 months, but the seizures remained medically intractable. At 3 years of age, he underwent stereotactic laser ablation with an aim of disconnection of the lesion. The procedure was performed with the NeuroBlate SideFire probe. To the authors' knowledge, this is the first reported use of this technology for this procedure and serves as proof of concept. There were no perioperative complications, and 2 years postprocedure, the patient remains seizure free with marked behavioral and cognitive improvements.

Brain tumor biobanking in the precision medicine era: building a high-quality resource for translational research in neuro-oncology

The growth of precision medicine has made access to biobanks with high-quality, well-annotated neuro-oncology biospecimens critical. Developing and maintaining neuro-oncology biobanks is best accomplished through multidisciplinary collaboration between clinicians and researchers. Balancing the needs and leveraging the skills of all stakeholders in this multidisciplinary effort is of utmost importance. Collaboration with a multidisciplinary team of clinicians, health care team members, and institutions, as well as patients and their families, is essential for access to participants in order to obtain informed consent, collect samples under strict standard operating procedures, and accurate and relevant clinical annotation. Once a neuro-oncology biobank is established, development and implementation of policies related to governance and distribution of biospecimens (both within and outside the institution) is of critical importance for sustainability. Proper implementation of a governance process helps to ensure that the biospecimens and data can be utilized in research with the largest potential benefit. New NIH and peer-reviewed journal policies related to public sharing of 'omic' data generated from stored biospecimens create new ethical challenges that must be addressed in developing informed consents, protocols, and standard operating procedures. In addition, diversification of sources of funding for the biobanks is needed for long-term sustainability.

Targeting glioma stem cells through combined BMI1 and EZH2 inhibition

Glioblastomas are lethal cancers defined by angiogenesis and pseudopalisading necrosis. Here, we demonstrate that these histological features are associated with distinct transcriptional programs, with vascular regions showing a proneural profile, and hypoxic regions showing a mesenchymal pattern. As these regions harbor glioma stem cells (GSCs), we investigated the epigenetic regulation of these two niches. Proneural, perivascular GSCs activated EZH2, whereas mesenchymal GSCs in hypoxic regions expressed BMI1 protein, which promoted cellular survival under stress due to downregulation of the E3 ligase RNF144A. Using both genetic and pharmacologic inhibition, we found that proneural GSCs are preferentially sensitive to EZH2 disruption, whereas mesenchymal GSCs are more sensitive to BMI1 inhibition. Given that glioblastomas contain both proneural and mesenchymal GSCs, combined EZH2 and BMI1 targeting proved more effective than either agent alone both in culture and in vivo, suggesting that strategies that simultaneously target multiple epigenetic regulators within glioblastomas may be effective in overcoming therapy resistance caused by intratumoral heterogeneity.