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Background Terminology to describe extent of resection in glioblastoma is inconsistent across clinical trials. A surgical classification system was previously proposed based upon residual contrast-enhancing (CE) tumor. We aimed to (1) explore the prognostic utility of the classification system and (2) define how much removed non-CE tumor translates into a survival benefit. Methods The international RANO resect group retrospectively searched previously compiled databases from 7 neuro-oncological centers in the USA and Europe for patients with newly diagnosed glioblastoma per WHO 2021 classification. Clinical and volumetric information from pre- and postoperative MRI were collected. Results We collected 1,008 patients with newly diagnosed IDHwt glioblastoma. 744 IDHwt glioblastomas were treated with radiochemotherapy per EORTC-26981/22981 (TMZ/RT→TMZ) following surgery. Among these homogenously treated patients, lower absolute residual tumor volumes (in cm3) were favorably associated with outcome: patients with “maximal CE resection” (class 2) had superior outcome compared to patients with “submaximal CE resection” (class 3) or “biopsy” (class 4). Extensive resection of non-CE tumor (≤5 cm3 residual non-CE tumor) was associated with better survival among patients with complete CE resection, thus defining class 1 (“supramaximal CE resection”). The prognostic value of the resection classes was retained on multivariate analysis when adjusting for molecular and clinical markers. Conclusions The proposed “RANO categories for extent of resection in glioblastoma” are highly prognostic and may serve for stratification within clinical trials. Removal of non-CE tumor beyond the CE tumor borders may translate into additional survival benefit, providing a rationale to explicitly denominate such “supramaximal CE resection.”

PURPOSE In patients with diffuse low-grade glioma (LGG), the extent of surgical tumor resection (EOR) has a controversial role, in part because a randomized clinical trial with different levels of EOR is not feasible. METHODS In a 20-year retrospective cohort of 392 patients with IDH-mutant grade 2 glioma, we analyzed the combined effects of volumetric EOR and molecular and clinical factors on overall survival (OS) and progression-free survival by recursive partitioning analysis. The OS results were validated in two external cohorts (n = 365). Propensity score analysis of the combined cohorts (n = 757) was used to mimic a randomized clinical trial with varying levels of EOR. RESULTS Recursive partitioning analysis identified three survival risk groups. Median OS was shortest in two subsets of patients with astrocytoma: those with postoperative tumor volume (TV) > 4.6 mL and those with preoperative TV > 43.1 mL and postoperative TV ≤ 4.6 mL. Intermediate OS was seen in patients with astrocytoma who had chemotherapy with preoperative TV ≤ 43.1 mL and postoperative TV ≤ 4.6 mL in addition to oligodendroglioma patients with either preoperative TV > 43.1 mL and residual TV ≤ 4.6 mL or postoperative residual volume > 4.6 mL. Longest OS was seen in astrocytoma patients with preoperative TV ≤ 43.1 mL and postoperative TV ≤ 4.6 mL who received no chemotherapy and oligodendroglioma patients with preoperative TV ≤ 43.1 mL and postoperative TV ≤ 4.6 mL. EOR ≥ 75% improved survival outcomes, as shown by propensity score analysis. CONCLUSION Across both subtypes of LGG, EOR beginning at 75% improves OS while beginning at 80% improves progression-free survival. Nonetheless, maximal resection with preservation of neurological function remains the treatment goal. Our findings have implications for surgical strategies for LGGs, particularly oligodendroglioma.

Background The role of surgery for incidentally discovered diffuse incidental low-grade gliomas (iLGGs) is debatable and poorly documented in current literature. Objective The aim was to identify factors that influence survival for patients that underwent surgical resection of iLGGs in a large multicenter population. Methods Clinical, radiological, and surgical data were retrospectively analyzed in 267 patients operated for iLGG from 4 neurosurgical Centers. Univariate and multivariate analyses were performed to identify predictors of overall survival (OS) and tumor recurrence (TR). Results The OS rate was 92.41%. The 5- and 10-year estimated OS rates were 98.09% and 93.2%, respectively. OS was significantly longer for patients with a lower preoperative tumor volume (P = .001) and higher extent of resection (EOR) (P = .037), regardless the WHO-defined molecular class (P = .2). In the final model, OS was influenced only by the preoperative tumor volume (P = .006), while TR by early surgery (P = .028). A negative association was found between preoperative tumor volumes and EOR (rs = −0.44, P < .001). The median preoperative tumor volume was 15 cm3. The median EOR was 95%. Total or supratotal resection of T2-FLAIR abnormality was achieved in 61.62% of cases. Second surgery was performed in 26.22%. The median time between surgeries was 5.5 years. Histological evolution to high-grade glioma was detected in 22.85% of cases (16/70). Permanent mild deficits were observed in 3.08% of cases. Conclusions This multicenter study confirms the results of previous studies investigating surgical management of iLGGs and thereby strengthens the evidence in favor of early surgery for these lesions.

Introduction Anaplastic oligodendrogliomas are high-grade gliomas defined molecularly by 1p19q co-deletion. There is no curative therapy, and standard of care includes surgical resection followed by radiation and chemotherapy. However, the benefit of up-front radiation with chemotherapy compared to chemotherapy alone has not been demonstrated in a randomized control trial. Given the potential long-term consequences of radiation therapy, such as cognitive impairment, arteriopathy, endocrinopathy, and hearing/visual impairment, there is an effort to balance longevity with radiation toxicity. Methods We performed a retrospective single institution analysis of survival of patients with anaplastic oligodendroglioma over 20 years. Results 159 patients were identified as diagnosed with an anaplastic oligodendroglioma between 1996 and 2016. Of those, 40 patients were found to have AO at original diagnosis and had documented 1p19q co-deletion with a median of 7.1 years of follow-up (range: 0.6–16.7 years). After surgery, 45 % of patients were treated with radiation and chemotherapy at diagnosis, and 50 % were treated with adjuvant chemotherapy alone. The group treated with chemotherapy alone had a trend of receiving more cycles of chemotherapy than patients treated with radiation and chemotherapy upfront (p = 0.051). Median overall survival has not yet been reached. The related risk of progression in the upfront, adjuvant chemotherapy only group was almost 5-fold higher than the patients who received radiation and chemotherapy (hazard ratio = 4.85 (1.74–13.49), p = 0.002). However, there was no significant difference in overall survival in patients treated with upfront chemotherapy compared to patients treated upfront with chemotherapy and radiation (p = 0.8). Univariate analysis of age, KPS, extent of resection, or upfront versus delayed radiation was not associated with improved survival. Conclusions Initial treatment with adjuvant chemotherapy alone, rather than radiation and chemotherapy, may be an option for some patients with anaplastic oligodendroglioma, as it is associated with similar overall survival despite shorter progression free survival.

Gliomas are infiltrative primary brain tumors that often invade functional cortical and subcortical regions, and they mandate individualized brain mapping strategies to avoid postoperative neurological deficits. It is well known that maximal safe resection significantly improves survival, while postoperative deficits minimize the benefits associated with aggressive resections and diminish patients’ quality of life. Although non-invasive imaging tools serve as useful adjuncts, intraoperative stimulation mapping (ISM) is the gold standard for identifying functional cortical and subcortical regions and minimizing morbidity during these challenging resections. Current mapping methods rely on the use of low-frequency and high-frequency stimulation, delivered with monopolar or bipolar probes either directly to the cortical surface or to the subcortical white matter structures. Stimulation effects can be monitored through patient responses during awake mapping procedures and/or with motor-evoked and somatosensory-evoked potentials in patients who are asleep. Depending on the patient’s preoperative status and tumor location and size, neurosurgeons may choose to employ these mapping methods during awake or asleep craniotomies, both of which have their own benefits and challenges. Regardless of which method is used, the goal of intraoperative stimulation is to identify areas of non-functional tissue that can be safely removed to facilitate an approach trajectory to the equator, or center, of the tumor. Recent technological advances have improved ISM’s utility in identifying subcortical structures and minimized the seizure risk associated with cortical stimulation. In this review, we summarize the salient technical aspects of which neurosurgeons should be aware in order to implement intraoperative stimulation mapping effectively and safely during glioma surgery.

Recent studies have elucidated that gliomas remodel neuronal circuits, and distinct intratumoral regions maintain functional connectivity through a subpopulation of synaptogenic malignant cells expressing Thrombospondin-1 (TSP-1, encoded by the THBS1 gene). Single-cell RNA sequencing analyses of our primary glioblastoma patient samples identified a significant downregulation of immune response signatures in myeloid cells and lymphoid cells in functionally connected intratumoral regions characterized by upregulated THBS1. Understanding the biological significance of immunosuppression within functionally connected intratumoral regions may uncover therapeutic vulnerabilities. Here, we investigate glioma-neuronal-immune crosstalk across clinical tumor specimens and preclinical syngeneic models through bulk and single-cell RNA sequencing (13,670 cells), flow cytometry, and spatial transcriptomics. Using an SB28 murine glioma cell line that endogenously expresses Thbs1 at high levels, we generated a CRISPR Thbs1-knock-out (KO) cell line. In bulk RNA-sequencing data performed on orthotopic tumor models, Thbs1-KO tumors were characterized by the downregulated expression of synapse-associated genes and synaptogenic factors and the recovered expression of genes related to immune response. It highlighted the important role of Thrombospondin-1 in synaptogenesis and immunosuppression consistent with the observation from our primary patient tumor samples. Flow cytometry revealed that tumor-associated macrophages isolated from Thbs1-KO tumors were more polarized toward the pro-inflammatory “M1-like” phenotype (median M1/M2 ratio = 0.6 [WT] vs. 1.34 [KO], p < 0.006). Unbiased gene expression program analysis using spatial transcriptomics for in vivo tumor-harboring mouse brains demonstrated a significant negative correlation between signatures of synaptogenesis (represented by Ntng1 and Nlgn3 genes) and those of immune response (represented by Nfkb1 and Cd83 genes). SB28-Thbs1-KO syngeneic models demonstrated slower tumor growth and significantly longer survival compared to Thbs1-WT counterparts (19 days [WT] vs. 25 days [KO], p < 4.5E-5). The survival difference was abrogated in B6-SCID immunodeficient mice, indicating the critical role of adaptive immunity in the survival advantage associated with Thrombospondin-1 downregulation. Our results identify previously unknown immunosuppression mechanisms in the context of glioma-induced intratumoral connectivity via Thrombospondin-1. Future therapeutic strategies targeting this glioma-neuronal-immune crosstalk may open up new avenues for glioblastoma immunotherapy. Citation Format: Takahide Nejo, Saritha Krishna, Christian Jimenez, Akane Yamamichi, Jacob S. Young, Tiffany Chen, Senthilnath Lakshmanachetty, Payal Watchmaker, Abrar Choudhury, Hirokazu Ogino, David R. Raleigh, Shawn L. Hervey-Jumper, Hideho Okada. Glioma-induced neuronal remodeling promotes regional immunosuppression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2497.

INTRODUCTION Fractionated radiotherapy is a first-line treatment for glioblastoma, but daily ionizing radiation prevents durable immune infiltration of the tumor microenvironment. Hypofractionated radiotherapy is used to treat glioblastomas at recurrence, but the impact of hypofractionated radiotherapy on the glioblastoma immune microenvironment is incompletely understood. Here we define immune microenvironment changes across multiple immunocompetent intracranial mouse models of glioblastoma after treatment with ionizing radiation mimicking stereotactic radiosurgery (SRS) in humans. METHODS Syngeneic GL261 (3x105 cells/mouse) or SB28 glioblastoma cells (3x104 cells/mouse) were implanted into the frontal lobe of immunocompetent C57BL/6J mice (18 mice/arm x 4 arms). Intracranial bioluminescence was used to assess glioblastoma growth. After tumor engraftment, glioblastomas were treated with conformal SRS (18Gy/1Fx) or sham. Glioblastomas were collected for histologic, single-cell, or molecular analyses 5 days after treatment (6 mice/arm) or at the time of euthanasia after monitoring for survival (12 mice/arm). Glioblastoma immune microenvironment responses were assessed using (1) H&E, (2) single cell mass cytometry (CyTOF) or IHC to define or validate immune cell changes, respectively, or (3) multiplexed cytokine assays to elucidate molecular mechanisms reprograming the glioblastoma immune microenvironment in response to SRS. RESULTS SRS attenuated glioblastoma growth and prolonged survival compared to sham treatment in both immunocompetent intracranial mouse models (GL261: 14 days versus 27 days, p< 0.001, SB28: 19 days versus 22 days, p=0.001). CyTOF showed SRS decreased immunosuppressive macrophage infiltration and increased microglia or CD8+ T cell infiltration of the glioblastoma immune microenvironment. Histologic analyses validated T cell and microglia infiltration after SRS. Glioblastoma cytokine analysis revealed inhibition of pro-tumor/anti-inflammatory cytokines (IL6, LIF) after SRS. CONCLUSIONS Single-fraction SRS durably reprograms glioblastoma macrophage, microglia, and CD8+ T cell populations in preclinical models, suggesting SRS or inhibition of pro-tumor/anti-inflammatory mechanisms underlying the immunosuppressive glioblastoma microenvironment represent immunogenic therapies that may offer a benefit to patients with glioblastoma.

Understanding the molecular landscape and microenvironment of melanoma brain metastases is critical to devise improved treatments. Here, we perform bulk and single cell genomic analysis of melanoma brain metastases to identify molecular correlates of clinical outcome. 84 consecutive patients who underwent surgical resection at a single institution with a histo-pathologically confirmed diagnosis of melanoma brain metastasis were retrospectively identified. In 60 patients (71%) with sufficient brain metastasis tissue for targeted next generation sequencing, DNA mutations were assessed with a CLIA certified sequencing assay. Single nuclear RNA sequencing using the 10x platform was performed on n=6 samples from treatment naïve patients. Overall survival (OS) and CNS progression free survival (CNS PFS) from time of brain metastasis diagnosis were estimated using the Kaplan-Meier method. The median patient age was 62 years old (range: 25-78 years), and the median clinical follow up was 17 months. A total of 33 patients (39%) had BRAFV600E melanoma brain metastases. Multivariate analysis incorporating age, performance status, and extracranial disease revealed BRAF status was an independent prognostic factor for OS (p< 0.05). In patients undergoing targeted next generation sequencing, the most common pathogenic variant was TERT promoter mutation (n=44; 73%). With regard to TCGA molecular melanoma subgroups, NRAS mutant (n=22; 37%) brain metastases were most common followed by BRAF mutant (n=20; 33%), NF1 mutant (n=11; 18%), and triple wildtype (n=7; 12%). Evaluation of clinical outcomes in the context of next generation sequencing results revealed no differences by TERT status but demonstrated worse overall survival in the BRAF mutant molecular group (p< 0.01, log-rank test). Single nuclear sequencing of 36,115 nuclei across 6 samples revealed BRAF wildtype tumors exhibit greater infiltrating immune cell populations including microglia and T cell subtypes. Future work will require integration of these findings with different systemic therapy regimens and across larger, prospective, multi-institutional cohorts.

INTRODUCTION Predictors of postoperative leptomeningeal disease (LMD) after resection of brain metastases (BMs) are not well defined. OBJECTIVE This study examined rates and predictors of LMD, including subtypes, in patients who underwent resection of a BM followed by postoperative radiation.Method: A retrospective, single-center study was conducted examining overall LMD, classical LMD (cLMD), and nodular LMD (nLMD) risk. Logistic regression and a Cox proportional hazards analyses were performed to identify risk factors associated with LMD. Random forest models were constructed to predict LMD and differentiate cLMD versus nLMD. Accuracy and the area under the receiver operating characteristic curve (AUROC) were calculated to evaluate the models.Result: Of the 217 patients in the cohort, 47 (21.7%) developed postoperative LMD with 19(8.8%) cLMD cases and 28(12.9%) nLMD cases . Six-, 12-, and 24-month LMD-free survival rates were 92.3%, 85.6%, and 71.4%, respectively. Patients with cLMD had worse survival outcomes from LMD diagnosis compared to nLMD (2.4 vs 6.9 mo, Log-rank p=0.02), and treatment of LMD was associated with improved survival for both cLMD and nLMD subtypes. Multivariate Cox hazard analysis identified cerebellar/insular/occipital location (HR 3.25, 95% CI 1.73-6.11, p=0.0003), absence of extracranial disease (HR 2.49, 95% CI 1.27-4.88, p=0.008), and ventricle contact (HR 2.82, 95% CI 1.5-5.3, p=0.001) to be associated with postoperative LMD. A predictive model using random forest analysis with an AUROC of 0.87 in a test cohort identified tumor location, systemic disease status, and tumor volume as the most important factors associated with LMD. Both regression analysis and random forest analysis identified postoperative systemic therapy exposure as the main factor differentiating cLMD from nLMD development. CONCLUSION Tumor location, absence of extracranial disease at the time of surgery, contact with a ventricle, and increased tumor volume are associated with LMD. Classical LMD is associated with worse prognosis compared to nLMD.

Meningiomas are the most common non-metastatic brain tumors, and although the majority are relatively slow-growing and histologically benign, a subset of meningiomas are aggressive and remain challenging to treat. Despite a standard of care that includes surgical resection and radiotherapy, and recent advances in meningioma molecular grouping, there are no systemic medical options for patients with meningiomas that are resistant to standard interventions. Misactivation of the cell cycle at the level of CDK4/6 is common in high-grade or molecularly aggressive meningiomas, and CDK4/6 has emerged as a potential target for systemic meningioma treatments. In this review, we describe the preclinical evidence for CDK4/6 inhibitors as a treatment for high-grade meningiomas and summarize evolving clinical experience with these agents. Further, we highlight upcoming clinical trials for patients meningiomas, and discuss future directions aimed at optimizing the efficacy of these therapies and selecting patients most likely to benefit from their use.

Background Genomic profiling studies of diffuse gliomas have led to new improved classification schemes that better predict patient outcomes compared to conventional histomorphology alone. One example is the recognition that patients with IDH-wildtype diffuse astrocytic gliomas demonstrating lower-grade histologic features but genomic and/or epigenomic profile characteristic of glioblastoma typically have poor outcomes similar to patients with histologically diagnosed glioblastoma. Here we sought to determine the clinical impact of prospective genomic profiling for these IDH-wildtype diffuse astrocytic gliomas lacking high-grade histologic features but with molecular profile of glioblastoma. Methods Clinical management and outcomes were analyzed for 38 consecutive adult patients with IDH-wildtype diffuse astrocytic gliomas lacking necrosis or microvascular proliferation on histologic examination that were genomically profiled on a prospective clinical basis revealing criteria for an integrated diagnosis of “diffuse astrocytic glioma, IDH-wildtype, with molecular features of glioblastoma, WHO grade IV” per cIMPACT-NOW criteria. Results We identified that this diagnosis consists of two divergent clinical scenarios based on integration of radiologic, histologic, and genomic features that we term “early/evolving” and “undersampled” glioblastoma, IDH-wildtype. We found that prospective genomically guided identification of early/evolving and undersampled IDH-wildtype glioblastoma resulted in more aggressive patient management and improved clinical outcomes compared to a biologically matched historical control patient cohort receiving standard-of-care therapy based on histomorphologic diagnosis alone. Conclusions These results support routine use of genomic and/or epigenomic profiling to accurately classify glial neoplasms, as these assays not only improve diagnostic classification but critically lead to more appropriate patient management that can improve clinical outcomes.

Immunotherapies seek to unleash the immune system against cancer cells. While a variety of immunotherapies exist, one of the most commonly used is immune checkpoint blockade, which refers to the use of antibodies to interfere with immunosuppressive signaling through immune checkpoint molecules. Therapies against various checkpoints have had success in the clinic across cancer types. However, the efficacy of checkpoint inhibitors has varied across different cancer types and non-responsive patient populations have emerged. Non-responders to these therapies have highlighted the importance of understanding underlying mechanisms of resistance in order to predict which patients will respond and to tailor individual treatment paradigms. In this review we discuss the literature surrounding tumor mediated mechanisms of immune checkpoint resistance. We also describe efforts to overcome resistance and combine checkpoint inhibitors with additional immunotherapies. Finally, we provide insight into the future of immune checkpoint blockade, including the need for improved preclinical modeling and predictive biomarkers to facilitate personalized cancer treatments for patients.

Under-enrollment in clinical trials significantly limits valid analyses of clinical interventions and generalizability of findings. Often it results in premature study termination, with estimates of 22% to 50% of clinical trials terminated due to poor accrual. Currently, there are limited reports addressing the influence of race/ethnicity and socioeconomic status on clinical trial enrollment in adult glioma patients. The goal of this study was to test the hypothesis that race and socioeconomic status negatively impact therapeutic clinical trial enrollment. 988 adult patients were identified from the UCSF Tumor Board Registry and analyzed to determine the rate of therapeutic clinical trial screening and study enrollment. At initial diagnosis, 43.6% and 17.5% of glioma patients were screened and enrolled in a therapeutic clinical trial, respectively. At recurrence, 49.8% and 26.3% of patients were screened and enrolled in a clinical trial, respectively. Thirty-three percent of the study population belonged to a NIH-designated underrepresented minority group; Asian/Pacific-Islander comprised 19.6% of the overall cohort. On univariate analysis, only in-state location, distance to the hospital, and WHO grade were associated with enrollment at initial diagnosis and recurrence. Minority status, insurance type, median household income, and percent below poverty were not associated with clinical trial enrollment. Minority and socioeconomic status did not impact adult glioma clinical trial enrollment. Proximity to the tertiary care cancer center may be an important consideration for minority patients. Patient screening should be carefully considered in order to avoid bias based on minority and socioeconomic status.

INTRODUCTION Recent developments in the biology of malignant gliomas have demonstrated that glioma cells interact with neurons through both paracrine signaling and electrochemical synapses. Glioma-neuron interactions consequently modulate the excitability of local neuronal circuits, and it is unclear the extent to which glioma-infiltrated cortex can meaningfully participate in neural computations. For example, gliomas may result in a local disorganization of activity that impedes the transient synchronization of neural oscillations. Alternatively, glioma-infiltrated cortex may retain the ability to engage in synchronized activity, in a manner similar to normal-appearing cortex, but exhibit other altered spatiotemporal patterns of activity with subsequent impact on cognitive processing. METHODS Here, we acquired invasive electrophysiologic recordings to sample both normal-appearing and glioma-infiltrated cortex during speech initiation in order to measure language task-related circuit dynamics of IDH-wild-type glioblastoma patients. We then applied an information theoretical framework to directly compare the encoding capacity and decodability of signals arising from these regions. RESULTS We find that glioma-infiltrated cortex engages in synchronous activity during task performance in a manner similar to normal-appearing cortex, but recruits a diffuse spatial network. On a temporal scale, we show that glioma-infiltrated cortex has lower capacity for information encoding when performing nuanced tasks such as speech production of monosyllabic versus polysyllabic words. As a result, temporal decoding strategies for distinguishing monosyllabic from polysyllabic words were feasible for signals arising from normal-appearing cortex, but not from glioma-infiltrated cortex. CONCLUSION These findings inform our understanding of cognitive processing in patients with malignant gliomas and have implications for patient survival, neuromodulation, and prosthetics in patients with malignant gliomas.

Glioblastoma (GBM) is an incurable brain tumor with a median survival of approximately 15 months despite an aggressive standard of care that includes surgery, chemotherapy, and ionizing radiation. Mouse models have advanced our understanding of GBM biology and the development of novel therapeutic strategies for GBM patients. However, model selection is crucial when testing developmental therapeutics, and each mouse model of GBM has unique advantages and disadvantages that can influence the validity and translatability of experimental results. To shed light on this process, we discuss the strengths and limitations of 3 types of mouse GBM models in this review: syngeneic models, genetically engineered mouse models, and xenograft models, including traditional xenograft cell lines and patient-derived xenograft models.

Recent evidence indicates that diffuse gliomas engage with neurons at the single-unit and circuit level through differing mechanisms. Certain malignant gliomas form glioma-neuron excitatory glutamatergic synapses and modulate neuron-neuron synapses through activity-dependent paracrine signaling, while others establish glioma-glioma connections via tumor microtubes. It is therefore possible that diffuse gliomas remodel neuronal circuits in a defined and predictable manner and demonstrate distinct electrophysiological profiles with prognostic and therapeutic significance. Here we apply machine learning principles in 140 patients across glioma subtypes to uncover unique electrophysiological features non-invasively via magnetoencephalography (discovery dataset) followed by feature validation using subdural electrocorticography (validation dataset). Following spatial-temporal registration, we fit an elastic net logistic regression classifier to distinguish between power spectra arising from glioma-remodeled cortex and within-subject control conditions. Model significance was determined non-parametrically by re-training each model 1,000 times with randomly permuted class labels and testing the true phi coefficient against the null distribution. In the discovery dataset, we were able to classify glioma infiltration based on tumor intrinsic neuronal activity (p < 0.05) in 127 patients (90.7%). We identified 30 electrophysiological features which revealed increased power in the delta range (1-4 Hz) and decreased power in the beta range (12-20 Hz) as a unique signature of glioma remodeling (p < 0.05) which was preserved in the validation dataset as well as across WHO 2021 diffuse glioma subtypes. In order to identify gene expression programs and signaling mechanisms that may contribute to glioma-induced remodeling but are potentially not identified in the current clinical classification scheme, we assessed targeted, next generation sequencing and DNA mutations as covariates, which again demonstrated the significance of the delta-beta spectral features. These data support converging mechanisms of glioma-induced neuronal network remodeling across tumor subtypes, setting the stage for novel therapies such as neuromodulation.

BACKGROUND Terminology to describe extent of resection in glioblastoma is inconsistent across clinical trials. A surgical classification system was previously proposed based upon residual contrast-enhancing (CE) tumor. We aimed to (I) explore the prognostic utility of the classification system and (II) define how much removed non-CE tumor translates into a survival benefit. METHODS The international RANO resect group retrospectively searched the databases from seven neuro-oncological centers in the USA and Europe for patients with newly diagnosed glioblastoma per WHO 2021 classification. Clinical and volumetric information from pre- and post-operative MRI were collected. RESULTS We collected 1021 patients with newly diagnosed glioblastoma, including 1008 IDHwt patients. 744 IDHwt glioblastomas were treated with radiochemotherapy per EORTC 26981/22981 (TMZ/RT→TMZ) following surgery. Among such homogenously treated patients, lower absolute residual tumor volumes (in cm3) were favorably associated with outcome: patients with ‘maximal CE resection’ (class 2) had superior outcome compared to patients with ‘submaximal CE resection’ (class 3) or ‘biopsy’ (class 4) (median OS: 19 versus 15 versus 10 months; p=0.001). Extensive resection of non-CE tumor (≤ 5 cm3 residual non-CE tumor) provided an additional survival benefit in patients with complete CE resection, thus defining class 1 (‘supramaximal CE resection’) (median OS: 24 versus 19 months; p=0.008). The prognostic value of the resection classes was retained on multivariate analysis when adjusting for molecular and clinical markers including MGMT promotor status. Relative tumor reduction (in percentage) was not prognostic for outcome on multivariate analysis, and inter-rater agreement for CE and non-CE tumor on post-operative MRI was sufficient. CONCLUSION The proposed “RANO categories for extent of resection in glioblastoma” are highly prognostic and may serve for stratification of clinical trials. Removal of non-CE tumor beyond the CE tumor borders translates into additional survival benefit, providing a rationale to explicitly denominate such a ‘supramaximal CE resection’.

Glioblastoma responses to immune checkpoint inhibition (ICI) are rare, and the molecular mechanisms underlying ICI responses are incompletely understood. Thus, serial glioblastoma samples are valuable resources for identifying biomarkers or therapeutic targets to increase the efficacy of ICI in patients with glioblastoma. We obtained paired glioblastoma samples from 7 patients who underwent sequential surgery, ICI, and eventual salvage surgery for recurrence. Patients were distinguished as ICI responders (n=3) or non-responders (n=4) based on (1) MRI evidence of tumor stability/reduction over 6+ months after ICI, or (2) pathologic evidence of predominant treatment effect at the time of salvage surgery after ICI. FFPE sections from each tumor (n=14) were stained using H&E or IHC/IF for macrophages/microglia (CD68) or T cells (CD3) and analyzed using light or fluorescence microscopy. Six regions-of-interest (ROIs) comprising viable tumor were selected neuropathologist from each sample (n=84 ROIs). ROIs were analyzed using quantitative spatial profiling of 72 proteins on the Nanostring Digital Profiler platform. Glioblastomas responding to ICI were enriched in T-cell proteins (CD3, CD4, CD8) and T-cell activation markers (CD25) at the time of salvage compared to initial surgery. Markers of MAPK signaling were suppressed in pre-ICI samples compared to post-ICI samples in responders. p-ERK was suppressed in post-ICI samples compared to pre-ICI samples in non-responders. Myeloid proteins (CD68, CD163, CD11c) were enriched in post-ICI samples compared to pre-ICI samples in non-responders. Principle components analysis revealed p-ERK and immune proteins (CD3, CD4, CD8, CD20, CD11c, CTLA4, CD68, CD45, CD56, and CD127) accounted for 62% of the variance among pre-ICI and post-ICI samples in responders. In conclusion, temporospatial protein profiling of human glioblastomas reveals molecular mechanisms and biomarkers underlying responses to immune checkpoint inhibition. These data establish a foundation for functional studies to reprogram the immunosuppressive glioblastoma microenvironment and sensitize tumors to immune checkpoint inhibition.

The glioblastoma microenvironment is an immunosuppressive barrier to therapeutic innovation. We hypothesized intratumor convection enhanced delivery (CED) of gene therapy vectors could reprogram the glioblastoma immune microenvironment and elucidate therapeutic vulnerabilities. To test this, SB28 or GL261 glioblastoma allografts were implanted into immunocompetent mice and treated with CED of attenuated adeno-associated virus 9 vectors (AAV9) encoding experimental cytokines (Il1b, Ccl4, or Apoa1) underlying infiltration or activation of anti-tumor immune cells in other intracranial tumors. Serial intracranial bioluminescence was used to assess glioblastoma growth and animals were monitored for survival. The impact of gene therapy perturbations on the glioblastoma immune microenvironment was assessed using histology, immunohistochemistry, single-cell mass cytometry (CyTOF), and multiplexed cytokine assays. Serial body weight and systemic cytokine measurements showed no evidence of treatment toxicity. AAV9-APOA1 or AAV9-IL1B gene therapy CED treatments attenuated SB28 growth and prolonged survival, decreasing immunosuppressive macrophage infiltration and increasing CD8 T cell and microglia infiltration of the glioblastoma microenvironment compared to control AAV9 vectors. Gene therapy CED treatments did not attenuate GL261 growth or prolong survival, but CyTOF of human glioblastomas (n=6) in comparison to preclinical models revealed untreated GL261 glioblastomas were endogenously enriched in CD8 T cells and other lymphoid lineages compared to untreated SB28 or human glioblastomas. Multiplexed cytokine assays demonstrated suppression of intratumor IL6 is a conserved mechanism of action underlying glioblastoma gene therapy responses. Single-cell RNA sequencing analysis of 32,877 cells from human glioblastomas (n=11) showed IL6 is predominantly produced by radial glial like cancer stem cells or endothelial cells in the tumor microenvironment. In support of these findings, survival from intracranial SB28 glioblastomas was prolonged in Il6 knockout C57BL/6J mice compared to wildtype mice. In summary, we report a novel strategy using gene therapy and CED to reprogram the glioblastoma immune microenvironment, revealing IL6 drives glioblastoma immunosuppression and growth.

Gliomas remodel neuronal circuits and distinct intratumoral regions maintain functional connectivity through a subpopulation of synaptogenic malignant cells expressing Thrombospondin-1 (TSP-1, encoded by the Thbs1 gene). Single-cell RNA sequencing analyses of primary patient samples identified a significant downregulation of immune response in myeloid cells and lymphoid cells in high functionally connected intratumoral regions characterized by upregulated TSP-1. Understanding the functional significance of immunosuppression within functionally connected intratumoral regions may uncover therapeutic vulnerabilities. Here, we investigate glioma-neuronal-immune crosstalk across clinical tumor specimens and preclinical syngeneic models through bulk and single-cell RNA sequencing (13,670 cells), flow cytometry, and spatial transcriptomics. Using an SB28 murine glioma cell line with endogenous Thbs1 stably expressed, we generated a CRISPR Thbs1-knock-out (KO) cell line. Bulk RNA-sequencing demonstrated that Thbs1-WT tumors exhibited gene expression programming consistent with synapse-associated genes and synaptogenic factors, recapitulating enriched connectivity in primary patient samples. Flow cytometry of brain-infiltrating leukocytes revealed that macrophages isolated from Thbs1-KO tumors were more frequently polarized into the pro-inflammatory “M1-like” phenotype (median M1/M2 ratio = 0.6 [WT] vs 1.34 [KO], p < 0.006). Unbiased gene expression program analysis using spatial transcriptomics for in vivo tumor-harboring mouse brains demonstrated a significant spatial overlap of signatures of synaptogenesis (represented by Ntng1 and Nlgn3 genes) and downregulated immune response (represented by Nfkb1 and Cd83 genes). SB28-Thbs1-KO syngeneic models demonstrated slower tumor growth and significantly longer survival compared to Thbs1-WT counterparts (19 days [WT] vs 25 days [KO], p < 4.5E-5). The survival difference was abrogated in the B6-SCID immunodeficient mice, indicating the critical role of adaptive immunity in the survival advantage associated with TSP-1 inhibition. Our results identify previously unknown immunosuppression mechanisms in the context of glioma-induced intratumoral connectivity via Thbs1. Future therapeutic strategies targeting this glioma-neuronal-immune crosstalk may open up new avenues for glioblastoma immunotherapy.

BACKGROUND While resection of brain metastases (BMs) offers favorable local disease control, factors and genetic alterations associated with local recurrence are not well defined. This study examined patient, tumor, treatment, and genetic factors associated with local recurrence. METHODS A retrospective, single-center study was conducted with patients who underwent resection of a BM with available clinical outcome and genetic data available. Local recurrence was the primary outcome of the study. Next-generation sequencing of coding regions in over 500 cancer genes was performed to detect mutations. Cox proportional hazards analysis was performed to identify patient, tumor, treatment, and genetic factors associated with local recurrence. RESULTS We identified 91 patients who underwent surgical resection of a BM with available data, of which 80 (87.1%) underwent preoperative radiotherapy or received some form of adjuvant radiation to the resection cavity. Primary pathologies in the cohort included non-small cell lung cancer (24.2%), melanoma (24.2%), breast cancer (16.5%), gastrointestinal cancers (13.2%), gynecologic cancers (4.4%), renal cell carcinoma (4.4%), and other cancers (13.2%). Eleven patients (12.1%) developed postoperative recurrence at the surgical site with 6- and 12-month PFS of 91.2% and 84.2%. Multivariate Cox proportional hazard analysis identified cancer type (Gyn and RCC vs Others: OR 39.4, p=0.002), CDK2NA/B co-deletion (OR 37.52, p=0.0009), PIK3R1 mutation (OR 56.88, p=0.003), and SMAD4 mutation (OR 134.8, p=0.0007) to be associated with time to local recurrence. Overall survival and length of follow-up were not different based on mutational status of these genes, demonstrating that results were not due to survival bias. CONCLUSIONS Genetic alterations within BMs impact clinical outcomes after surgical resection. Further work is needed to determine if targeted therapies for BMs with these alterations can decrease rates of local recurrence.

The discovery of immune checkpoint molecules heralded a revolution in cancer therapy that targets the immune system to achieve a long-lasting anti-tumor effect [1]. There has been an explosion of s...

2007 Background: Improvements in risk stratification of meningioma are needed to guide post-operative management and application of adjuvant therapy. Although profiling of DNA methylation, copy number variants (CNVs), RNA sequencing, and exome sequencing have better elucidated meningioma biology, these approaches have not revealed clinically tractable biomarkers for radiotherapy responses. In this study, we develop and validate a targeted gene expression biomarker to predict meningioma outcomes and benefit from radiotherapy. Methods: Targeted gene expression profiling was performed on a development set of 173 meningiomas (median follow-up 8.1 years) and a validation set of 331 consecutive meningiomas (median follow-up 6.1 years) treated at independent institutions (70% WHO grade 1, 24% WHO grade 2, 6% WHO grade 3). All patients underwent surgery (n = 504) with or without postoperative radiotherapy (n = 73 with radiation). Regularized Cox regression within the development set resulted in a continuous gene expression risk score for local freedom from recurrence (LFFR). The model (34 genes and 7 housekeeping genes) and thresholds for low, intermediate, and high-risk scores were locked and applied to the validation set. Results: The gene expression risk score outperformed WHO grade (validation 5-year LFFR delta-AUC 0.15, 95% CI 0.076-0.229, p = 0.001) and DNA methylation grouping (delta-AUC 0.075, 95% CI 0.006-0.130, p = 0.01) for LFFR, disease-specific survival, and OS, achieving a negative predictive value for recurrence at 5-years of 93.2%. The biomarker reclassified 35.8% of WHO grade 1 tumors as intermediate or high risk (5-year LFFR/OS 62%/79%), and 18.3% of WHO grade 2-3 tumors as low risk (5-year LFFR/OS 78%/100%). The biomarker was independently prognostic after accounting for WHO grade, extent of resection, primary versus recurrent presentation, CNV status, DNA methylation group, and Ki67 labeling index, and was predictive for LFFR after postoperative radiotherapy, with a hazard ratio of 0.41 for intermediate to high risk propensity-matched meningiomas (95% CI 0.2-0.9, p = 0.0002) versus 0.79 for low risk meningiomas (95% CI 0.1-8.8, p = 0.5182). Conclusions: Targeted gene expression profiling of 504 meningiomas resulted in a biomarker which improved discrimination of meningioma local recurrence, disease-specific survival, and overall survival, and also predicted benefit from radiotherapy.

2039 Background: Immune checkpoint inhibition has not improved outcomes for glioblastoma patients, and single- cell approaches reveal the glioblastoma microenvironment is largely comprised of immunosuppressive cells. We hypothesized intratumor convection enhanced delivery (CED) of adenoviral gene therapy could recruit and activate anti-tumor immune cells in the glioblastoma microenvironment. Methods: Syngeneic GL261 (3x105 cells/mouse) or SB28 glioblastoma (3 x 104) cells were implanted into the frontal lobe of immunocompetent C57BL/6J mice (18 mice/arm). Intracranial bioluminescence (BLI) and body weight (BW) measurements were used to assess glioblastoma growth and treatment toxicity, respectively. After tumor engraftment, glioblastomas were treated with conformal ionizing radiation mimicking stereotactic radiosurgery (SRS) in human patients as a positive control for tumor inhibition (18Gy/1Fx). Attenuated adeno-associated virus 9 (AAV9) vectors encoding Gfp as a negative control, or encoding experimental cytokines driving recruitment and activation of anti-tumor immune cells in other intracranial tumors ( Ccl4, Il1b, or Apoa1) were delivered using CED (2x1011 vg/mouse). Glioblastomas were collected for histologic, single-cell, and molecular analyses 5 days after treatment (6 mice/arm) and at endpoints after monitoring for survival (12 mice/arm). CED targeting was validated using AAV9-GFP and confocal microscopy. Treatment responses were assessed using H&E, IHC, multiplexed cytokine assays, and single cell mass cytometry (CyTOF) to define immune cell types in the glioblastoma microenvironment. Results: Histologic analyses revealed AAV9-CCL4, AAV9-IL1B, or SRS induced glioblastoma macrophage infiltration, and AAV9-IL1B, AAV9-APOA1, or SRS induced glioblastoma T cell infiltration. AAV9-APOA1 (18.5 days versus 15 days, p < 0.001) or AAV9-IL1B (16.5 days versus 15 days, p = 0.001) CED treatments prolonged median survival from SB28 allografts. Glioblastoma cytokine analysis revealed inhibition of pro-tumor cytokines (IL6, LIF) after experimental CED treatments. Systemic cytokines were minimally changed by CED treatments. CyTOF showed decreased immunosuppressive macrophage infiltration and increased CD8+ T cell or microglia infiltration of the glioblastoma microenvironment after experimental CED treatments. There was no evidence of systemic or central toxicity in any treatment condition. Conclusions: Convection-enhanced delivered of adenoviral gene therapy reprograms the glioblastoma immune microenvironment and improves survival in an immunologically “cold” syngeneic glioblastoma model.

BACKGROUND Surgery is the mainstay of meningioma treatment, but improvements in meningioma risk stratification are needed and indications for postoperative radiotherapy are controversial. DNA methylation profiling, copy number variants (CNVs), exome sequencing, and RNA sequencing have improved understanding of meningioma biology, but have not superseded histologic grading, or revealed biomarkers for radiotherapy responses. To address these unmet needs, we optimized and validated a targeted gene expression biomarker predicting meningioma outcomes and responses to radiotherapy. METHODS Targeted gene expression profiling was performed on a discovery cohort of 173 meningiomas (median follow-up 8.1 years) and a validation cohort of 331 meningiomas (median follow-up 6.1 years) treated with surgery (n=504) and postoperative radiotherapy (n=73) at independent, international institutions (70% WHO grade 1, 24% WHO grade 2, 6% WHO grade 3). Optimized targeted gene expression models predicting clinical outcomes (34 genes) or radiotherapy responses (12 genes) were developed from the discovery cohort, and compared to histologic and molecular classification systems by performing DNA methylation profiling, CNV analysis, exome sequencing, and RNA sequencing on the same meningiomas. RESULTS Targeted gene expression profiling achieved a concordance-index of 0.75 ± 0.03 (SEM) for local freedom from recurrence (LFFR) and 0.72 ± 0.03 for overall survival (OS) in the validation cohort, outperforming WHO grade (5-year LFFR delta-AUC 0.15, 95% CI 0.076-0.229, p=0.001) and DNA methylation grouping (delta-AUC 0.075, 95% CI 0.006-0.130, p=0.01) for LFFR, disease-specific survival, and OS. The biomarker was independently prognostic after accounting for WHO grade, extent of resection, primary versus recurrent presentation, CNV status, DNA methylation group, and Ki67 labeling index, and identified meningiomas benefiting from radiotherapy (interaction p-value=0.0008), suggesting postoperative radiotherapy could be refined in 30.2% of cases. CONCLUSIONS Targeted gene expression profiling of 504 meningiomas improves discrimination of meningioma local recurrence, disease-specific survival, and overall survival, and predicts radiotherapy responses.

BACKGROUND The overall prognostic significance of maximal surgical resection in patients with diffuse low-grade glioma has been well established. Nonetheless, prior studies omit the combined importance of molecular subclass, patient characteristics, and chemoradiation. Similar to findings recently published in newly diagnosed glioblastoma, incorporation of these interactive factors may redefine the relative benefit of cytoreductive surgery. METHODS We examine the interactive effects of volumetric extent of resection with molecular and clinical factors to develop a new roadmap for cytoreductive surgery. Based on a 20-year retrospective cohort of 556 patients with WHO II diffuse low-grade glioma treated with surgery at UCSF 444 had complete records for survival modeling and recursive partitioning (RPA) to investigate multivariate relationships of overall and progression free survival. RESULTS Regardless of molecular subtype, patients with tumor volume under 55cm3 and postoperative volume of residual under 1.9cm3 experience the longest OS (median OS: not reached). Patients with volume of residual over 1.9cm3 experience a OS similar to that of patients with large (over 55cm3) oligodendrogliomas (median OS: not reached). Patients faring worst have large (over 55cm3) astrocytic gliomas (median OS: 84.8 months). Patients not treated with chemotherapy and either ATRX wild-type tumors or ATRX-mutant tumors with small (under 1cm3) volume of residual have the longest PFS together with chemotherapy treated patients who receive either no radiation or radiation for p53-mutant tumors under 30cm3 (median PFS 119 months). Patients with the shortest PFS are under 32-years with larger volume of residual (>1cm3), who receive no chemotherapy for ATRX-mutant tumors together with patients who receive both chemoradiation for larger (>30cm3) p53 mutant tumors (median PFS 30.8 months). CONCLUSION This is the first study to combine extent of resection with molecular and clinical information which paves the way for rethinking surgical strategies for individual patients with newly diagnosed low-grade gliomas.

INTRODUCTION: The treatment for glioblastoma (GBM) has remained unchanged for the past decade, with only minimal improvements in patient survival. As a result, novel treatments are needed to combat this devastating disease. Immunotherapies are treatments that stimulate the immune system to attack tumor cells and can be either local or systemically delivered. Viral treatments can lead to direct tumor cell death through their natural lifecycle or through the delivery of a suicide gene, with the potential to generate an anti-tumor immune response, making them interesting candidates for combinatorial treatment with immunotherapy. METHODS: We review the current literature surrounding the interactions between oncolytic viruses and the immune system as well as the use of oncolytic viruses combined with immunotherapies for the treatment of GBM. RESULTS: Viral therapies have exhibited preclinical efficacy as single-agents and are being investigated in that manner in clinical trials. Oncolytic viruses have significant interactions with the immune system, although this can also vary depending on the strain of virus. Combinatorial treatments using both oncolytic viruses and immunotherapies have demonstrated promising preclinical findings. CONCLUSIONS: Studies combining viral and immunotherapeutic treatment modalities have provided exciting results thus far and hold great promise for patients with GBM. Additional studies assessing the clinical efficacy of these treatments as well as improved preclinical modeling systems, safety mechanisms, and the balance between treatment efficacy and immune-mediated viral clearance should be considered.

Objective: In this study, we identify clinical, radiographic, and histopathologic prognosticators of overall, early, and post-median recurrence in World Health Organization (WHO) grade I meningiomas. We also determine a clinically relevant cutoff for MIB-1 to identify patients at high risk for recurrence. Method: A retrospective review of WHO grade I meningioma patients with available MIB-1 index data who underwent treatment at our institution from 2007 to 2017 was performed. Univariate and multivariate analyses, and recursive partitioning analysis (RPA), were used to identify risk factors for overall, early (within 24 months), and post-median (>24 months post-treatment) recurrence. Result: A total of 239 patients were included. The mean age was 60.0 years, and 69.5% of patients were female. The average follow-up was 41.1 months. All patients received surgery and 2 patients each received either adjuvant radiotherapy (2/239) or gamma knife treatment (2/239). The incidence of recurrence was 10.9% (26/239 patients), with an average time to recurrence of 33.2 months (6-105 months). Posterior fossa tumor location (p = 0.004), MIB-1 staining (p = 0.008), nuclear atypia (p = 0.003), and STR (p < 0.001) were independently associated with an increased risk of recurrence on cox-regression analysis. RPA for overall recurrence highlighted extent of resection, and after gross total resection (GTR), a MIB-1 index cutoff of 4.5% as key prognostic factors for recurrence. Patients with a GTR and MIB-1 >4.5% had a similar incidence of recurrence as those with STR (18.8 vs. 18.6%). Variables independently associated with early recurrence on binary logistic regression modeling included STR (p = 0.002) and nuclear atypia (p = 0.019). RPA confirmed STR as associated with early recurrence. Conclusion: STR, posterior fossa location, nuclear atypia, and elevated MIB-1 index are prognostic factors for WHO grade I meningioma recurrence. Moreover, MIB-1 index >4.5% is prognostic for recurrence in patients with GTR. Verification of our findings in larger, multi-institutional studies could enable risk stratification and recommendations for adjuvant radiotherapy following resection of WHO grade I meningiomas.

Multiple studies have demonstrated that improved extent of resection is associated with longer overall survival for patients with both high and low grade glioma. Awake craniotomy was developed as a technique for maximizing resection whilst preserving neurological function. We performed a comprehensive review of the literature describing the history, indications, techniques and outcomes of awake craniotomy for patients with glioma. The technique of awake craniotomy evolved to become an essential tool for resection of glioma. Many perceived contraindications can now be managed. We describe in detail our preferred technique, the testing paradigms utilized, and critically review the literature regarding functional and oncological outcome. Awake craniotomy with mapping has become the gold standard for safely maximizing extent of resection for tumor in or near eloquent brain. Cortical and subcortical mapping methods have been refined and the technique is associated with an extremely low rate of complications.

Importance Per the World Health Organization 2016 integrative classification, newly diagnosed glioblastomas are separated into isocitrate dehydrogenase gene 1 or 2 (IDH)–wild-type andIDH-mutant subtypes, with median patient survival of 1.2 and 3.6 years, respectively. Although maximal resection of contrast-enhanced (CE) tumor is associated with longer survival, the prognostic importance of maximal resection within molecular subgroups and the potential importance of resection of non–contrast-enhanced (NCE) disease is poorly understood. Objective To assess the association of resection of CE and NCE tumors in conjunction with molecular and clinical information to develop a new road map for cytoreductive surgery. Design, Setting, and Participants This retrospective, multicenter cohort study included a development cohort from the University of California, San Francisco (761 patients diagnosed from January 1, 1997, through December 31, 2017, with 9.6 years of follow-up) and validation cohorts from the Mayo Clinic (107 patients diagnosed from January 1, 2004, through December 31, 2014, with 5.7 years of follow-up) and the Ohio Brain Tumor Study (99 patients with data collected from January 1, 2008, through December 31, 2011, with a median follow-up of 10.9 months). Image accessors were blinded to patient groupings. Eligible patients underwent surgical resection for newly diagnosed glioblastoma and had available survival, molecular, and clinical data and preoperative and postoperative magnetic resonance images. Data were analyzed from November 15, 2018, to March 15, 2019. Main Outcomes and Measures Overall survival. Results Among the 761 patients included in the development cohort (468 [61.5%] men; median age, 60 [interquartile range, 51.6-67.7] years), younger patients withIDH–wild-type tumors and aggressive resection of CE and NCE tumors had survival similar to that of patients withIDH-mutant tumors (median overall survival [OS], 37.3 [95% CI, 31.6-70.7] months). Younger patients withIDH–wild-type tumors and reduction of CE tumor but residual NCE tumors fared worse (median OS, 16.5 [95% CI, 14.7-18.3] months). Older patients withIDH–wild-type tumors benefited from reduction of CE tumor (median OS, 12.4 [95% CI, 11.4-14.0] months). The results were validated in the 2 external cohorts. The association between aggressive CE and NCE in patients withIDH–wild-type tumors was not attenuated by the methylation status of the promoter region of the DNA repair enzyme O6-methylguanine-DNA methyltransferase. Conclusions and Relevance This study confirms an association between maximal resection of CE tumor and OS in patients with glioblastoma across all subgroups. In addition, maximal resection of NCE tumor was associated with longer OS in younger patients, regardless ofIDHstatus, and among patients withIDH–wild-type glioblastoma regardless of the methylation status of the promoter region of the DNA repair enzyme O6-methylguanine-DNA methyltransferase. These conclusions may help reassess surgical strategies for individual patients with newly diagnosed glioblastoma.

Glioblastoma (GBM) leads to severe systemic and local immunosuppression, and immunotherapies have had limited clinical success. Here, we evaluated the treatment efficacy of RLI, a superagonist of T-cell activator IL-15, delivered to tumor cells using a tumor-selective retroviral replicating vector (RRV) in the syngeneic murine SB28 and Tu2449 GBM models, which are both engineered to be poorly immunogenic with low-mutational burden and known resistance to immunotherapy, and hence more accurate biomimetic models of human GBM. RRV-RLI replicated and spread effectively in cultured murine GBM cells with robust production of functional RLI (165.4 ± 5.3 ng/mL). Stereotactic injection of RRV-RLI into pre-established intracerebral SB28 tumors significantly reduced tumor growth on bioluminescent imaging, and increased median survival compared to control mice (55 vs. 19 days, p=0.002), leading to long-term survival in 12% of treated mice. In the Tu2449 model, imaging results showed complete eradication of intracerebral tumors after RRV-RLI treatment, with long-term survival (median not reached) in > 85% of treated mice, compared to a median survival of 12.5 days in control mice (p=0.001). RRV-RLI treated tumors showed significantly increased CD8 T-cell infiltration, without altering immunosuppressive cell populations. Similarly, broad anti-tumor inflammatory changes, including increased expression of genes involved in T-cell activation and killing, were observed in the NanoString nCounter platform using a 770-gene panel representing various immune cell types. Notably, RLI was not detected in the blood of treated mice, and tumor-localized RRV-RLI gene delivery showed no adverse systemic immune effects in either model. In summary, RRV-mediated RLI immunotherapy results in immunostimulatory and pro-inflammatory changes to the tumor microenvironment and achieves a significant survival benefit in two poorly immunogenic syngeneic murine models of GBM. This tumor-localized immunomodulatory gene therapy has the potential to safely reverse the T-cell depleted immunophenotype of GBM.

INTRODUCTION The supplemental motor area (SMA) is an eloquent region that is frequently a site for gliomas or the region is included in the resection trajectory to deeper lesions. METHODS Patient, tumor and outcome data were collected retrospectively from the UCSF tumor registry for patients who underwent surgical resection for newly diagnosed supratentorial diffuse glioma (WHO Grade II - IV) between 2010 and 2019 in the SMA region and the extent of SMA resection was determined by volumetric assessment. Tumors were registered to a standard brain atlas to create a frequency heat map of tumor volumes and resection cavities. RESULTS Although the volume of tumor within the SMA region did not correlate with the development of SMA syndrome, patients with SMA syndrome had larger resection cavities in the SMA region (25.4% SMA resection vs. 14.2% SMA resection, p = 0.039). The size of the resection cavity in the SMA region did not correlate with the severity of the SMA syndrome. Patients who developed SMA syndrome had cavities that were located more posteriorly in the SMA region and in the cingulate. When the frontal aslant tract (FAT) was preserved, 50% of patients developed SMA syndrome post-operatively; whereas 100% of patients who had disruption of the FAT during surgery developed SMA syndrome (p = 0.06). There was no difference in the overall survival for newly diagnosed glioblastoma patients with SMA syndrome compared to those without SMA syndrome (1.6 years vs. 3.0 years, p = 0.33). CONCLUSION For patients with SMA gliomas, larger resections and resections involving the posterior SMA region and posterior cingulate gyrus increased the likelihood of a post-operative SMA syndrome. Although SMA syndrome occurred in all cases where the FAT was resected, FAT preservation does not reliably avoid SMA syndrome post-operatively.

Oncolytic virotherapy is a treatment approach with increasing clinical relevance, as indicated by the marked survival benefit seen in animal models and its current exploration in human patients with cancer. The use of an adenovirus vector for this therapeutic modality is common, has significant clinical benefit in animals, and its efficacy has recently been linked to an anti-tumor immune response that occurs following tumor antigen presentation. Here, we analyzed the adaptive immune system’s response following viral infection by comparing replication-incompetent and replication-competent adenoviral vectors. Our findings suggest that cell death caused by replication-competent adenoviral vectors is required to induce a significant anti-tumor immune response and survival benefits in immunocompetent mice bearing intracranial glioma. We observed significant changes in the repertoire of immune cells in the brain and draining lymph nodes and significant recruitment of CD103+ dendritic cells (DCs) in response to oncolytic adenoviral therapy, suggesting the active role of the immune system in anti-tumor response. Our data suggest that the response to oncolytic virotherapy is accompanied by local and systemic immune responses and should be taken in consideration in the future design of the clinical studies evaluating oncolytic virotherapy in patients with glioblastoma multiforme (GBM).

INTRODUCTION Glioblastoma carries a high economic burden for patients and caregivers. We investigated drivers of hospital costs of surgery for newly-diagnosed glioblastoma. METHODS Retrospective review of GBM patients undergoing first resection at UCSF (2010–2015) and corresponding hospital charges. Our cohort was divided into low (LC) and high cost (HC) groups for total surgical cost. Multivariate regression was used to identify factors driving cost of surgery. RESULTS Of 242 patients, 36.7% (n=86) were females (median age=62 years). The mean total hospital cost for surgery among our patient cohort was $40,384. When comparing the LC and HC groups, mean total hospital cost for surgery for HC patients was almost twice as much as LC group ($51,744 vs $29,023, p< 0.001). Kaplan-Meier analysis revealed that having higher cost of surgery worsened patient prognosis, with a 21% longer overall survival in the LC cohort versus the HC cohort (14.7 vs 17.9 months, p=0.02; HR=1.41 [1.05–1.91], p= 0.023). Tumor diameter at diagnosis was largest for HC group (4.7 cm) versus LC patients (3.9 cm, p=0.002). Multivariate analysis revealed longer hospital stay (F-ratio=8.87; p=0.01), longer ICU stay (F-ratio= 12.34, p< 0.001), younger age at surgery (F-ratio=6.71, p=0.02) and multifocal disease (F-ratio=6.26, p=0.02) to be independent predictors of higher cost of surgery, while having PCP at diagnosis (F-ratio=6.92, p=0.02), health insurance coverage (F-ratio= 4.23, p=0.03) and being married (F-ratio=3.71, p=0.04) were independent predictors of lower cost of surgery. CONCLUSIONS Higher costs of surgery correlate with worse survival outcomes in glioblastoma patients. Beyond the anticipated finding that greater disease burden drives some of this inverse correlation between cost and survival, correctable socioeconomic factors such as PCP and insurance status also drive higher hospital charges for GBM surgery. Manipulation of these factors is necessary to minimize the economic burden of disease and adopt cost-effective surgical treatments for GBM patients.

BACKGROUND Severe local and systemic immune suppression in glioblastoma (GBM) contributes to the failure of single-agent immunotherapies in clinical trials. In this study, we evaluated the efficacy of locally delivered combination immunotherapy in a poorly immunogenic murine GBM model. METHODS Immunomodulators used in these studies included: IL-15 and IL-7 (T cell activation), LIGHT (T cell tumor infiltration), FLT3L (dendritic cell maturation/proliferation), a surface T cell engager (T cell killing of tumor cells), and a bispecific PD-L1/T cell engager (T cell killing targeted to PD-L1-expressing cells). We first assessed T cell-mediated cytotoxicity in vitro against SB28, a poorly immunogenic murine GBM cell line, after expressing these immunomodulators in combination. Next, tumor growth inhibition in vivo was evaluated in syngeneic C57BL/6 mice, initially by establishment of intracranial tumors with pre-transduced SB28 cells, and subsequently by delivering these immunomodulators to pre-established naïve SB28 tumors using neural stem cells (NSCs) and retroviral replicating vectors (RRV). RESULTS SB28 cells transduced with immunomodulators activated dose-dependent T cell-mediated cytotoxicity in vitro. Mice with pre-transduced intracranial SB28 gliomas showed significantly longer survival (minimum survival: 60 days, long-term survival in 57% of mice) vs. control mice (median survival: 20 days) (p< 0.001), and significantly increased tumor infiltration of CD4+ and CD8+ T cells. NSC- and RRV-mediated immunomodulator delivery to pre-established SB28 gliomas also resulted in significantly increased survival of treated mice vs. controls (median survival: 31 days vs. 22 days, p< 0.001). Immunomodulator-treated tumors again showed significantly increased infiltration of CD4+ and CD8+ T cells, along with decreased CD11b+ cell infiltration. CONCLUSIONS A novel combination therapy for GBM immunotherapy activated T cell killing of SB28 GBM cells in vitro and achieved a significant survival benefit in vivo, associated with anti-tumor alterations to the GBM tumor microenvironment. Further studies to optimize the efficiency of combinatorial immunomodulator delivery are currently underway.

BACKGROUND In this study, we identify clinical, radiographic, and histopathologic prognosticators of overall, early, and post-median recurrence in World Health Organization (WHO) grade I meningiomas. We also determine a clinically relevant cutoff for MIB-1 to identify patients at high risk for recurrence. METHODS A retrospective review of WHO grade I meningioma patients with available MIB-1 index data who underwent treatment at our institution from 2007-2017 was performed. Univariate and multivariate analyses, and recursive partitioning analysis (RPA), were used to identify risk factors for overall, early (within 24 months), and post-median (greater than 24 months post-treatment) recurrence. RESULTS A total of 239 patients were included. The mean age was 60.0 years, and 69.5% of patients were female. The average follow-up was 41.1 months. All patients received surgery and 2 patients each received either adjuvant radiotherapy or gamma knife treatment. The incidence of recurrence was 10.9%, with an average time to recurrence of 33.2 months (6-105 months). Posterior fossa tumor location (p=0.004), MIB-1 staining (p=0.008), nuclear atypia (p=0.003), and STR (p< 0.001) were independently associated with an increased risk of recurrence on cox-regression analysis. RPA for overall recurrence highlighted extent of resection, and after gross total resection (GTR), a MIB-1 index cutoff of 4.5% as key prognostic factors for recurrence. Patients with a GTR and MIB-1 >4.5% had a similar incidence of recurrence as those with STR (18.8vs.18.6%). Variables independently associated with early recurrence on binary logistic regression modeling included STR (p=0.002) and nuclear atypia (p=0.019). RPA confirmed STR as associated with early recurrence. MIB-1 index (p=0.010) was identified as an independent predictor of post-median recurrence using similar methods. CONCLUSIONS STR, posterior fossa location, nuclear atypia, and elevated MIB-1 index are prognostic factors for WHO grade I meningioma recurrence. Moreover, MIB-1 index >4.5% is prognostic for recurrence in patients with GTR.

Although the overall prognostic significance of maximal surgical resection of contrast-enhancing tumor in glioblastoma patients is well established, prior studies have not evaluated the combined importance of resection, molecular markers, patient characteristics, and chemoradiation. Incorporation of these factors may redefine the relative benefit of cytoreductive surgery and establish differing thresholds for extent of resection in varying clinical presentations. In the first study of its kind, we examine the interactive effects of volumetric extent of resection with molecular and clinical factors to develop a new roadmap for cytoreductive surgery. Based on a 20-year retrospective cohort of 850 glioblastoma patients who had initial surgery at UCSF, we employed survival models and recursive partitioning (RPA) to investigate multivariate relationships of overall survival (OS), both in the entire cohort as well as a subset diagnosed since 2005 (Stupp-era) with IDH1 mutation status available (n=470). For the entire cohort and the Stupp-era subset, the RPAs elucidate the combinatorial consequence of treatment, age, IDH1 status (in the subset), and resection of both enhancing and non-enhancing tumor. In the Stupp-era, temozolomide-treated patients that are IDH-wildtype and >65 clearly benefit from a reduction of the enhancing tumor (median OS: 10.1 vs 15.8 months). IDH-wildtype, temozolomide-treated patients under 65 benefit from reduction of both enhancing and non-enhancing tumor with a median survival similar to that of IDH-mutant, temozolomide-treated patients (combined median OS: 33.7 months). The patients faring worst are those that did not receive temozolomide that are >65 and/or have ≥0.3 cm(3) residual enhancing tumor (median OS: 4 months). These risk models outperform all published prognostic models. This is the first study to combine resection of contrast-enhancing and non-enhancing tumor in conjunction with molecular and clinical information in a large single-institution study, and paves the way for rethinking surgical strategies for individual patients with newly diagnosed glioblastoma.

Gene therapy is a rapidly developing treatment modality that functions on its ability to deliver genes directly to the tumor site in order to yield antitumoral effects and thus prolong patient survival. The delivery of any gene(s) requires a delivery system that either involves the direct delivery of therapeutic gene(s) to the tumor site via viral or nonviral vectors, or through carriers that express the gene(s) in the tumor site via neural stem cells, mesenchymal stem cells, or other carriers. Four basic categories of gene therapy are currently being investigated for the treatment of brain tumors: (i) prodrug activation and suicide gene therapy; (ii) immunomodulatory and cytokine-based gene therapy; (iii) brain tumor hallmark targeting therapy; and (iv) oncolytic virotherapy. Preclinical studies of gene therapy for brain tumors have led to an array of human clinical trials, demonstrated to be remarkably safe and well tolerated with encouraging therapeutic results.

INTRODUCTION Microscopic residual disease at the tumor margin is the primary barrier to complete resection which impacts outcome. Stimulated Raman scattering microscopy (SRM) has proven effective to classify CNS tumor tissue and detect tumor cells within grossly normal post mortem glioma specimens. In this study, we use SRM for detection of residual glioma cells within the resection cavity margins. METHODS Patients with gliomas undergoing surgical resection were included. Margin samples were taken after the primary surgeon determined the resection cavity wall to be grossly normal and were analyzed using (1) true H&E, (2) SRM pseudo H&E, (3) immunohistochemical stains (IHC) for IDH1-R132H or p53. The sections were scored on a scale of 0–3 by a neuropathologist blinded to the corresponding results from each modality (0=no definite tumor cells; 1=rare tumor cells; 2=moderate tumor cells with preserved neuropil; 3 = abundant tumor cells). Positive and negative predictive values and Spearman correlation coefficients were calculated. RESULTS Ninety-one margin samples from 19 patients were included. Tumors were WHO grade II (29.7%), III (38.5%), and IV (31.8%). There was a strong correlation between SRM and H&E (Spearman correlation (r) = 0.76), SRM and IHC (r=0.81), and H&E and IHC scores (r=0.91). PPV of SRM score of 3 was 100%. The presence of tumor cells on SRM (scores 1–3) strongly correlated with the presence of tumor cells on H&E (PPV = 95%) and IHC (PPV = 91%). The absence of tumor cells on SRM correlated with absence of tumor on H&E and IHC only 10% and 50% (NPV) of the time, respectively. CONCLUSIONS The PPV of utilizing SRM to detect residual glioma cells in grossly normal resection cavity margins is high however the NPV is low. SRM may have utility as a rapid point-of-care intraoperative tool for identification of infiltrative glioma within resection cavity margins.

Surgical resection is standard of care for patients with lesions concerning for high-grade glioma on MRI scan. There is no consensus on the urgency of the procedure for patients with good clinical performance status. Treatment history and functional outcomes were collected retrospectively from the electronic medical record for 105 consecutive patients with newly diagnosed WHO Grade IV gliomas who underwent surgical resection at the University of California, San Francisco in 2014 and 2015 (41% female, average age = 61.25). Median preoperative KPS score was 80. Median wait time to surgery was 11 days after the initial MRI scan (range: 0–213 days). Mean tumor volume at the time of initial MRI scan was 29.0 cm3 (SD = 26.1 cm3), which did not significantly differ from the mean pre-operative tumor volume of 31.2 cm3 (SD = 27.3 cm3). In this retrospective cohort, patients with larger glioblastomas were taken to surgery more quickly. Patients who presented to the emergency room were more likely to wait less than 7 days (p < 0.001). Patients who waited less than 7 days had a larger initial and pre-operative tumor volume compared to patients who waited between 7–21 days and patients who waited over 21 days (p=< 0.001, p=< 0.001). Tumor growth occurred in 10% of patients who waited one week or less, 26% of patients who waited one to three weeks, and 55% of patients who waited over 3 weeks. Overall survival was not significantly affected by wait time until tumor resection (p=0.52). Additionally, Tumor growth was not associated with postoperative outcomes including postoperative KPS score, postoperative deficits, 3-month follow up KPS score, overall survival, and survival after surgery. In conclusion, longer wait time to surgery does not impact overall survival, pre-, and post-operative KPS, but the tumor is likely to grow in the interim.

Anaplastic oligodendrogliomas are a type of high grade glioma defined molecularly by the 1p19q co-deletion. Currently, there is no curative therapy, and some studies have estimated median survival is estimated to be approximately 5 years. Current standard of care includes surgical resection followed by radiation and chemotherapy. However, the benefit of up-front radiation with chemotherapy compared to chemotherapy alone following surgical resection has not been shown in a randomized control trial. Given the long-term cognitive consequences of radiation therapy and the high percentage of patients who lives beyond 15 years with AO, there is an effort to balance longevity with radiation toxicity. As such we performed a retrospective single institution analysis of survival of patients with anaplastic oligodendroglioma over 20 years. 159 patients were identified as diagnosed with an anaplastic oligodendroglioma between 1996–2016. Of those, 57 patients were found to have anaplastic olidodendroglioma at original diagnosis and had long term follow-up. Sixty-six percent of patients were between the ages of 30–50 and mean KPS was 87.3. At the time of analysis, 33% of patients had died. In this cohort, 60% of patients were initially treated with radiation and chemotherapy (either temozolomide or CCNU) at diagnosis and 40% were treated with chemotherapy alone. Median overall survival for the entire cohort was 142 months. The related risk of progression in the upfront chemotherapy only group is approximately 5.87 times higher than the patients who received radiation and chemotherapy (Hazard ratio=5.87, 1.92–17.90, p=0.002). However, there was no significant difference in overall survival in patients treated with upfront chemotherapy compared to patients treated upfront with chemotherapy and radiation (p=0.14). On univariate analysis, there was no association between age, KPS, EOR, or upfront vs. delayed radiation and survival. As such initial treatment with chemotherapy alone may be an option for some patients with anaplastic oligodendroglioma.

The dismal clinical context of advanced-grade glioma demands the development of novel therapeutic strategies with direct patient impact. Adenovirus-mediated virotherapy represents a potentially effective approach for glioma therapy. In this research, we generated a novel glioma-specific adenovirus by instituting more advanced genetic modifications that can maximize the efficiency and safety of therapeutic adenoviral vectors. In this regard, a glioma-specific targeted fiber was developed through the incorporation of previously published glioma-specific, phage-panned peptide (VWT peptide) on a fiber fibritin-based chimeric fiber, designated as "GliomaFF." We showed that the entry of this virus was highly restricted to glioma cells, supporting the specificity imparted by the phage-panned peptide. In addition, the stability of the targeting moiety presented by fiber fibritin structure permitted greatly enhanced infectivity. Furthermore, the replication of this virus was restricted in glioma cells by controlling expression of the E1 gene under the activity of the tumor-specific survivin promoter. Using this approach, we were able to explore the combinatorial efficacy of various adenoviral modifications that could amplify the specificity, infectivity, and exclusive replication of this therapeutic adenovirus in glioma. Finally, virotherapy with this modified virus resulted in up to 70% extended survival in an in vivo murine glioma model. These data demonstrate that this novel adenoviral vector is a safe and efficient treatment for this difficult malignancy.

Malignant glioma is a relentless burden to both patients and clinicians, and calls for innovation to overcome the limitations in current management. Glioma therapy using viruses has been investigated to accentuate the nature of a virus, killing a host tumor cell during its replication. As virus mediated approaches progress with promising therapeutic advantages, combination therapy with chemotherapy and oncolytic viruses has emerged as a more synergistic and possibly efficacious therapy. Here, we will review malignant glioma as well as prior experience with oncolytic viruses, chemotherapy and combination of the two, examining how the combination can be optimized in the future.

Gene therapy offers a multidimensional set of approaches intended to treat and cure glioblastoma (GBM), in combination with the existing standard-of-care treatment (surgery and chemoradiotherapy), by capitalizing on the ability to deliver genes directly to the site of neoplasia to yield antitumoral effects. Four types of gene therapy are currently being investigated for their potential use in treating GBM: (i) suicide gene therapy, which induces the localized generation of cytotoxic compounds; (ii) immunomodulatory gene therapy, which induces or augments an enhanced antitumoral immune response; (iii) tumor-suppressor gene therapy, which induces apoptosis in cancer cells; and (iv) oncolytic virotherapy, which causes the lysis of tumor cells. The delivery of genes to the tumor site is made possible by means of viral and nonviral vectors for direct delivery of therapeutic gene(s), tumor-tropic cell carriers expressing therapeutic gene(s), and "intelligent" carriers designed to increase delivery, specificity, and tumoral toxicity against GBM. These vehicles are used to carry genetic material to the site of pathology, with the expectation that they can provide specific tropism to the desired site while limiting interaction with noncancerous tissue. Encouraging preclinical results using gene therapies for GBM have led to a series of human clinical trials. Although there is limited evidence of a therapeutic benefit to date, a number of clinical trials have convincingly established that different types of gene therapies delivered by various methods appear to be safe. Due to the flexibility of specialized carriers and genetic material, the technology for generating new and more effective therapies already exists.

Introduction: Oncolytic virotherapy is an interesting approach for the treatment of cancer, including glioblastoma. Recent studies in this area suggest a synergistic approach to combine oncolytic virotherapy with immunomodulatory approaches. In this study, we have examined the role of platelet-rich fibrin patch (PRF-P) to enhance anti-tumoral immune response in immune-competent murine model C57/BL when used in conjunction with tumor specific oncolytic Ad5RGD-CMV-E1Δ24. This PRF-P is derived from blood, enriched with lymphocytes, platelets, macrophages (M1), and pro-inflammatory cytokines. Application of PRF-P has been shown to enhance immune cell migration and proliferation. HYPOTHESIS: We hypothesize that PRF-P provides local immunomodulation by supplying pro-inflammatory chemokines, as well as recruiting and enhancing proliferation of cytotoxic T cells, which may lead to an enhanced anti-tumoral immune response when combined with oncolytic virotherapy. METHODS: Blood from donor mice bearing GL261-OVA, a murine glioma cell line expressing ovalbumin (OVA), as a model antigen was collected into non-anticoagulant tubes and processed according to platelet-rich fibrin protocol. Five days after tumor implantation, a stereotactic intra-tumor injection of Ad5RGD-CMVΔ24 viral vector was performed. 48 hours post viral vector administration, a craniotomy was performed and the autologous PRF-P was applied over the tumor. For immunological flow and immunohistochemical analyses, mice were sacrificed five days post treatment. Results: We first performed a survival analysis in immuno-competent murine model. Mice injected with oncolytic virus alone had a significantly prolonged survival compared to PBS treated group (P

Modern virotherapy for the potential treatment of a wide array of human diseases, including cancer, has been investigated for its capacity to elicit therapeutic benefits by way of alterable genetic modification. And while immediate gains in the field have demonstrated pronounced efficacy in therapeutic potential, endogenous and preexisting neutralizing antibody responses hinder the delivery of these vectors. Even more so in the case of cancer therapeutic potential, limited biodistribution of such viral particles within the bulk of the tumor mass is observed. To circumvent these adversities in the delivery of a viral vector to the site of pathology, mesenchymal stem/stromal cells may be used to avoid immune stimulation with resultant vector clearance, to maximize the effective delivery potential, and to augment biodistribution ability in neoplastic tumor masses.

A limitation of small molecule inhibitors, nanoparticles (NPs) and therapeutic adenoviruses is their incomplete distribution within the entirety of solid tumors such as malignant gliomas. Currently, cell-based carriers are making their way into the clinical setting as they offer the potential to selectively deliver many types of therapies to cancer cells.Here, we review the properties of stem cells, induced pluripotent stem cells and engineered cells that possess the tumor-tropic behavior necessary to serve as cell carriers. We also report on the different types of therapeutic agents that have been delivered to tumors by these cell carriers, including: i) therapeutic genes; ii) oncolytic viruses; iii) NPs; and iv) antibodies. The current challenges and future promises of cell-based drug delivery are also discussed.While the emergence of stem cell-mediated therapy has resulted in promising preclinical results and a human clinical trial utilizing this approach is currently underway, there is still a need to optimize these delivery platforms. By improving the loading of therapeutic agents into stem cells and enhancing their migratory ability and persistence, significant improvements in targeted cancer therapy may be achieved.

The generation of a targeting agent that strictly binds to IL13Rα2 will significantly expand the therapeutic potential for the treatment of IL13Rα2-expressing cancers. In order to fulfill this goal, we generated a single-chain antibody (scFv47) from our parental IL13Rα2 monoclonal antibody and tested its binding properties. Furthermore, to demonstrate the potential therapeutic applicability of scFv47, we engineered an adenovirus by incorporating scFv47 as the targeting moiety in the viral fiber and characterized its properties in vitro and in vivo. The scFv47 binds to human recombinant IL13Rα2, but not to IL13Rα1 with a high affinity of 0.9 · 10−9 M, similar to that of the parental antibody. Moreover, the scFv47 successfully redirects adenovirus to IL13Rα2 expressing glioma cells both in vitro and in vivo. Our data validate scFv47 as a highly selective IL13Rα2 targeting agent and justify further development of scFv47-modified oncolytic adenovirus and other therapeutics for the treatment of IL13Rα2-expressing glioma and other malignancies.

INTRODUCTION: Glioblastoma carries a high economic burden for patients and caregivers. We investigated the hospital costs of surgery for newly-diagnosed glioblastoma patients based on insurance status. METHODS: Retrospective review of GBM patients undergoing first resection at UCSF and corresponding hospital charges from 2010–2015. RESULTS: Of 227 patients (median age= 62; females= 37.9%), 31 (13.7%) had Medicaid, 94 (41.4%) had Medicare, and 102 (44.9%) had private insurance. Medicaid patients had 30% higher mean overall hospital costs for resecting GBM compared to non-Medicaid insurance patients ($50,285 vs $38,800; p= 0.015). Sub-cost analysis revealed Medicaid patients had higher ICU, OR and imaging costs versus non-Medicaid insured patients ($13,400/$16,470/$2,182 vs $9,700/$14,770/$1,357; p= 0.01/p= 0.03/p< 0.0001). Kaplan-Meier survival analysis showed Medicaid patients had the shortest overall survival (10.7 months, Medicare = 12.8 months, Private insurance = 15.8 months; p=0.02). Tumor diameter at diagnosis was largest for Medicaid (4.7 cm) versus Medicare (4.1 cm) and privately insured patients (4.2 cm; p=0.03). Only 67.74% of Medicaid patients had PCPs versus 91.5% and 86.27% of Medicare and privately insured patients, respectively (p=0.004), at their initial visit to our institution. Medicaid patients had longer overall and ICU lengths of stay (6.9 and 2.6 days) versus Medicare (4.0 and 1.5 days) and privately insured (3.9 and 1.8 days; p < 0.01) cohorts. Moreover, Medicaid patients had similar comorbidity rates as Medicare patients (67.8% vs. 67.18%), but both groups had higher comorbidity rates than privately insured patients (40.4%; p< 0.0001). CONCLUSIONS: Despite higher surgical costs and longer lengths of stay, GBM patients with Medicaid have poorer survival. This may reflect that these patients lacking PCPs and, thus, having more comorbidities and presenting later in the disease course with larger tumors consume more hospital resources such as OR time and confer increased operative risk.