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Background IDH mutations are thought to represent an early oncogenic event in glioma evolution, found with high penetrance across tumor cells, however in rare cases IDH mutation may exist only in a small subset of the total tumor cells (subclonal IDH-mutation). Methods We present two institutional cases with subclonal IDH1 R132H mutation. In addition, two large publicly-available cohorts of IDH-mutant astrocytomas were mined for cases harboring subclonal IDH mutations (defined as tumor cell fraction (TCF) with IDH mutation ≤0.67) and the clinical and molecular features of these subclonal cases were compared to clonal IDH-mutant astrocytomas. Results Immunohistochemistry (IHC) performed on two institutional WHO grade 4 IDH-mutant astrocytomas revealed only a minority of tumor cells in each case with IDH1 R132H mutant protein, and next-generation sequencing (NGS) revealed remarkably low IDH1 variant allele frequencies compared to other pathogenic mutations, including TP53 and/or ATRX. DNA methylation classified the first tumor as high-grade IDH-mutant astrocytoma with high confidence (0.98 score). In the publicly-available datasets, subclonal IDH mutation was present in 3.9% of IDH-mutant astrocytomas (18/466 tumors). Compared to clonal IDH-mutant astrocytomas (n=156), subclonal cases demonstrated worse overall survival in grades 3 (p=0.0106) and 4 (p=0.0184). Conclusions While rare, subclonal IDH1 mutations are present in a subset of IDH-mutant astrocytomas of all grades, which may lead to a mismatch between IHC results and genetic/epigenetic classification. These findings suggest a possible prognostic role of IDH mutation subclonality, and highlight the potential clinical utility of quantitative IDH1 mutation evaluation by IHC and NGS.

Sex as a variable of survival

One-way ANOVA analysis comparing expression of cytokines between Avelumab treated and Avelumab combined with Bevacizumab

Purpose:The treatment of glioblastoma (GBM) poses challenges. The use of immune checkpoint inhibition (ICI) has been disappointing as GBM is characterized by low mutational burden and low T-cell infiltration. The combination of ICI with other treatment modalities may improve efficacy.Patient and Methods:Patients with recurrent GBM were treated with avelumab, a human IgG1 antibody directed against PD-L1 (part A), or avelumab within a week after laser interstitial thermal therapy (LITT) and continuation of avelumab (part B). Bevacizumab was allowed to be combined with ICI to spare steroid use. The primary objective was to characterize the tolerability and safety of the regimens. The secondary objectives included overall survival, progression-free survival (PFS), signatures of plasma analytes, and immune cells.Results:A total of 12 patients (median age 64; range, 37–73) enrolled, five in part A and seven in part B. Two serious adverse events occurred in the same patient, LITT treated, not leading to death. The median survival from enrollment was 13 months [95% confidence interval (CI), 4–16 months] with no differences for part A or B. The median PFS was 3 months (95% CI, 1.5–4.5 months). The decrease in MICA/MICB, γδT cells, and CD4+ T cell EMRA correlated with prolonged survival.Conclusions:Avelumab was generally well tolerated. Adding bevacizumab to ICI may be beneficial by lowering cytokine and immune cell expression. The development of this combinatorial treatment warrants further investigation. Exploring the modulation of adaptive and innate immune cells and plasma analytes as biomarker signatures may instruct future studies in this dismal refractory disease.Significance:Our phase I of PD-L1 inhibition combined with LITT and using bevacizumab to spare steroids had a good safety profile for recurrent GBM. Developing combinatory treatment may help outcomes. In addition, we found significant immune modulation of cytokines and immune cells by bevacizumab, which may enhance the effect of ICI.

Supplementary Data includes Supplementary Materials and Methods (cell culture protocols, methods for predicting BUB1BR/S status and extracting molecular profiles of GBM tumor cells, genome-wide shRNA screens, GBM cohort data, drug sensitivity measurement, and etc.) Supplementary Figures, Supplementary Tables, and references for the supplementary. Here is a list of Supplementary Figures and Tables: Fig. S1: Principal component analysis (PCA) of gene expression levels, related to Fig. 1. Fig. S2: Gene set enrichment analysis of the 838 BUB1BS/R-associated genes, related to Fig. 1. Fig. S3: Cross-validation of the elastic net classifier, related to Fig. 1. Fig. S4: Expression features based on tumor tissue and GSC, related to Fig. 2 and Fig. 5. Fig. S5: Association between predicted BUB1B-inhibition sensitivity values and clinical information, related to Fig. 2 and Table 1. Fig. S6: BUB1BS and BUB1BR-specific sub-networks, related to Fig. 3. Fig. S7: Expression difference between BUB1BS GSCs and BUB1BR GSCs, related to Fig. 3. Fig. S8: The Predicted BUB1B-inhibition sensitivity values of glioma cell lines, related to Fig. 4. Fig. S9: Boxplot of drug sensitivity for glioma cell lines, related to Fig. 4. Fig. S10: Application of BUB1BR/S classifier to single cell RNA-seq data of two stemlike tumor-propagating glioblastoma cells, related to Discussion. Fig. S11: Application of BUB1BR/S classifier to single cell RNA-seq data, related to Discussion. Fig. S12: The application of BUB1B classifier to population controls, related to Discussion. Table S1: Summary of GSC samples and prediction of BUB1B sensitivity for GSC cell lines based on expression levels, related to Fig. 1. Table S2: Composition of each cell type based on tumor tissue expression levels, related to Fig. 5. Table S3: Association between BUB1BS/R status and survival rate, related to Fig. 2 and Table 1. Table S4: Normalized cell growth (%) of 9217B and 10647B for etoposide treatment, related to Fig. 5.

Glioblastoma multiforme (GBM) remains a mainly incurable disease in desperate need of more effective treatments. In this study, we develop evidence that the mitotic spindle checkpoint molecule BUB1B may offer a predictive marker for aggressiveness and effective drug response. A subset of GBM tumor isolates requires BUB1B to suppress lethal kinetochore–microtubule attachment defects. Using gene expression data from GBM stem-like cells, astrocytes, and neural progenitor cells that are sensitive or resistant to BUB1B inhibition, we created a computational framework to predict sensitivity to BUB1B inhibition. Applying this framework to tumor expression data from patients, we stratified tumors into BUB1B-sensitive (BUB1BS) or BUB1B-resistant (BUB1BR) subtypes. Through this effort, we found that BUB1BS patients have a significantly worse prognosis regardless of tumor development subtype (i.e., classical, mesenchymal, neural, proneural). Functional genomic profiling of BUB1BR versus BUB1BS isolates revealed a differential reliance of genes enriched in the BUB1BS classifier, including those involved in mitotic cell cycle, microtubule organization, and chromosome segregation. By comparing drug sensitivity profiles, we predicted BUB1BS cells to be more sensitive to type I and II topoisomerase inhibitors, Raf inhibitors, and other drugs, and experimentally validated some of these predictions. Taken together, the results show that our BUB1BR/S classification of GBM tumors can predict clinical course and sensitivity to drug treatment. Cancer Res; 77(20); 5518–29. ©2017 AACR.

Supplementary Figure 3 from Human Bone Marrow–Derived Mesenchymal Stem Cells for Intravascular Delivery of Oncolytic Adenovirus Δ24-RGD to Human Gliomas

Supplementary Figure Legends 1-7 from Human Bone Marrow–Derived Mesenchymal Stem Cells for Intravascular Delivery of Oncolytic Adenovirus Δ24-RGD to Human Gliomas

Supplementary Figure 5 from Human Bone Marrow–Derived Mesenchymal Stem Cells for Intravascular Delivery of Oncolytic Adenovirus Δ24-RGD to Human Gliomas

Supplementary Figure 7 from Human Bone Marrow–Derived Mesenchymal Stem Cells for Intravascular Delivery of Oncolytic Adenovirus Δ24-RGD to Human Gliomas

Supplementary Figure 6 from Human Bone Marrow–Derived Mesenchymal Stem Cells for Intravascular Delivery of Oncolytic Adenovirus Δ24-RGD to Human Gliomas

Supplementary Figure 2 from Human Bone Marrow–Derived Mesenchymal Stem Cells for Intravascular Delivery of Oncolytic Adenovirus Δ24-RGD to Human Gliomas

Supplementary Figure 1 from Human Bone Marrow–Derived Mesenchymal Stem Cells for Intravascular Delivery of Oncolytic Adenovirus Δ24-RGD to Human Gliomas

Supplementary Figure 4 from Human Bone Marrow–Derived Mesenchymal Stem Cells for Intravascular Delivery of Oncolytic Adenovirus Δ24-RGD to Human Gliomas

Δ24-RGD is an infectivity-augmented, conditionally replicative oncolytic adenovirus with significant antiglioma effects. Although intratumoral delivery of Δ24-RGD may be effective, intravascular delivery would improve successful application in humans. Due to their tumor tropic properties, we hypothesized that human mesenchymal stem cells (hMSC) could be harnessed as intravascular delivery vehicles of Δ24-RGD to human gliomas. To assess cellular events, green fluorescent protein–labeled hMSCs carrying Δ24-RGD (hMSC-Δ24) were injected into the carotid artery of mice harboring orthotopic U87MG or U251-V121 xenografts and brain sections were analyzed by immunofluorescence for green fluorescent protein and viral proteins (E1A and hexon) at increasing times. hMSC-Δ24 selectively localized to glioma xenografts and released Δ24-RGD, which subsequently infected glioma cells. To determine efficacy, mice were implanted with luciferase- labeled glioma xenografts, treated with hMSC-Δ24 or controls, and imaged weekly by bioluminescence imaging. Analysis of tumor size by bioluminescence imaging showed inhibition of glioma growth and eradication of tumors in hMSC-Δ24-treated animals compared with controls (P < 0.0001). There was an increase in median survival from 42 days in controls to 75.5 days in hMSC-Δ24-treated animals (P < 0.0001) and an increase in survival beyond 80 days from 0% to 37.5%, respectively. We conclude that intra-arterially delivered hMSC-Δ24 selectively localize to human gliomas and are capable of delivering and releasing Δ24-RGD into the tumor, resulting in improved survival and tumor eradication in subsets of mice. [Cancer Res 2009;69(23):8932–40]

BACKGROUND Cladophialophora bantiana is a dematiaceous, saprophytic fungus and a rare but reported cause of intracranial abscesses due to its strong neurotropism. Although it predominantly affects immunocompetent individuals with environmental exposure, more recently, its significance as a highly lethal opportunistic infection in transplant recipients has been recognized. Successful treatment requires timely but often challenging diagnosis, followed by complete surgical excision. Next-generation sequencing of microbial cell-free DNA (cfDNA) from plasma is a novel diagnostic method with the potential to identify invasive fungal infections more rapidly and less invasively than conventional microbiological testing, including brain biopsy. OBSERVATIONS The authors described the case of a recipient of a liver transplant who presented with seizures and was found to have innumerable ring-enhancing intracranial lesions. The Karius Test, a commercially available method of next-generation sequencing of cfDNA, was used to determine the causative organism. Samples from the patient’s plasma identified C. bantiana 6 days before culture results of the surgical specimen, allowing optimization of the empirical antifungal regimen, which led to a reduction in the size of the abscesses. LESSONS The authors’ findings suggest that microbial cfDNA sequencing may be particularly impactful in improving the management of brain abscesses in which the differential diagnosis is wide because of immunosuppression.

OBJECTIVE Greater extent of resection (EOR) is associated with longer overall survival in patients with high-grade gliomas (HGGs). 5-Aminolevulinic acid (5-ALA) can increase EOR by improving intraoperative visualization of contrast-enhancing tumor during fluorescence-guided surgery (FGS). When administered orally, 5-ALA is converted by glioma cells into protoporphyrin IX (PPIX), which fluoresces under blue 400-nm light. 5-ALA has been available for use in Europe since 2010, but only recently gained FDA approval as an intraoperative imaging agent for HGG tissue. In this first-ever, to the authors’ knowledge, multicenter 5-ALA FGS study conducted in the United States, the primary objectives were the following: 1) assess the diagnostic accuracy of 5-ALA–induced PPIX fluorescence for HGG histopathology across diverse centers and surgeons; and 2) assess the safety profile of 5-ALA FGS, with particular attention to neurological morbidity. METHODS This single-arm, multicenter, prospective study included adults aged 18–80 years with Karnofsky Performance Status (KPS) score > 60 and an MRI diagnosis of suspected new or recurrent resectable HGG. Intraoperatively, 3–5 samples per tumor were taken and their fluorescence status was recorded by the surgeon. Specimens were submitted for histopathological analysis. Patients were followed for 6 weeks postoperatively for adverse events, changes in the neurological exam, and KPS score. Multivariate analyses were performed of the outcomes of KPS decline, EOR, and residual enhancing tumor volume to identify predictive patient and intraoperative variables. RESULTS Sixty-nine patients underwent 5-ALA FGS, providing 275 tumor samples for analysis. PPIX fluorescence had a sensitivity of 96.5%, specificity of 29.4%, positive predictive value (PPV) for HGG histopathology of 95.4%, and diagnostic accuracy of 92.4%. Drug-related adverse events occurred at a rate of 22%. Serious adverse events due to intraoperative neurological injury, which may have resulted from FGS, occurred at a rate of 4.3%. There were 2 deaths unrelated to FGS. Compared to preoperative KPS scores, postoperative KPS scores were significantly lower at 48 hours and 2 weeks but were not different at 6 weeks postoperatively. Complete resection of enhancing tumor occurred in 51.9% of patients. Smaller preoperative tumor volume and use of intraoperative MRI predicted lower residual tumor volume. CONCLUSIONS PPIX fluorescence, as judged by the surgeon, has a high sensitivity and PPV for HGG. 5-ALA was well tolerated in terms of drug-related adverse events, and its application by trained surgeons in FGS for HGGs was not associated with any excess neurological morbidity.

Maximal safe resection is the standard of care in the neurosurgical treatment of high-grade gliomas. To aid surgeons in the operating room, adjuvant techniques and technologies centered around improving intraoperative visualization of tumor tissue have been developed. In this review, we will discuss the most advanced technologies, specifically fluorescence-guided surgery, intraoperative imaging, neuromonitoring modalities, and microscopic imaging techniques. The goal of these technologies is to improve detection of tumor tissue beyond what conventional microsurgery has permitted. We describe the various advances, the current state of the literature that have tested the utility of the different adjuvants in clinical practice, and future directions for improving intraoperative technologies.

Object Maximal safe tumor resection is part of the standard of care for patients with newly diagnosed glioblastoma. The role of reoperation in the care of patients with recurrent glioblastoma is less clear, and less than a quarter of patients undergo a second surgery. Previous studies have identified preoperative variables associated with the improved survival of patients following reoperation, and guidelines for the selection of patients for reoperation have been devised and validated. In this study, the authors analyzed the relative survival benefit of maximal safe tumor removal in a series of patients with recurrent glioblastoma who all underwent reoperation. Methods In this longitudinal study, the clinical and radiological data of 97 consecutive patients who underwent reoperation for recurrent glioblastoma were prospectively collected. Multiple regression analyses and Kaplan-Meier plotting were performed to identify pre- and postoperative clinical and radiological variables associated with increased survival following reoperation. Results The median postoperative survival of all patients following reoperation was 12.4 months (95% confidence interval [CI] 9.0–15.6 months). Multiple Cox regression analysis revealed that patients with large (> 3 cm3) residual tumors following reoperation had significantly decreased survival relative to those with residual tumors that were small (> 0–3 cm3; hazard ratio [HR] = 3.10, 95% CI 1.69–5.70; p < 0.001) or radiologically absent (0 cm3; HR = 5.82, 95% CI 2.98–11.37; p < 0.001). Large residual tumors had faster rates of subsequent regrowth than small (odds ratio [OR] = 4.22, 95% CI 1.19–14.97; p = 0.026) or radiologically absent (OR = 11.00, 95% CI 2.79–43.43; p = 0.001) residual tumors, and a faster regrowth rate was significantly associated with decreased survival (HR = 4.01, 95% CI 2.26–7.14; p < 0.001). Conclusions The overall survival of patients with recurrent glioblastoma who underwent reoperations increased with decreasing postoperative residual tumor volumes. For patients meeting prognostic criteria for reoperation, the surgical goal should be to minimize residual tumor volume to maximize overall survival. Clinical trial registration no.: NCT00060541 (ClinicalTrials.gov).

Object Tumor-initiating cells are uniquely resilient to current treatment modalities and play an important role in tumor resistance and recurrence. The lack of specific tumor-initiating cell markers to identify and target these cells presents a major obstacle to effective directed therapy. Methods To identify tumor-initiating cell markers in primary brain tumors, the authors compared the proteomes of glioma tumor-initiating cells to their differentiated progeny using a novel, nongel/shotgun-based, multidimensional liquid-chromatography protein separation technique. An in vivo xenograft model was used to demonstrate the tumorigenic and stem cell properties of these cells. Western blot and immunofluorescence analyses were used to confirm findings of upregulated ciliary neurotrophic factor receptor subunit–α (CNTFRα) in undifferentiated tumor-initiating cells and gliomas of increasing tumor grade. Sequencing of the CNTFRα coding regions was performed for mutation analysis. Finally, antibody-dependent cell-mediated cytotoxicity was used to establish the role of CNTFRα as a potential immunotherapeutic target. Results Ciliary neurotrophic factor receptor subunit–α expression was increased in tumor-initiating cells and was decreased in the cells' differentiated progeny, and expression levels increased with glioma grade. Mutations of CNTFRα are not common in gliomas. Functional studies using CNTF treatment in glioma tumor-initiating cells showed induction of differentiation through the CNTFRα pathway. Treatment with anti-CNTFRα antibody resulted in increased antibody-dependent cell-mediated cytotoxicity in CNTFRα expressing DAOY cells but not in cell lines that lack CNTFRα. Conclusions These data indicate that CNTFRα plays a role in the formation or maintenance of tumor-initiating cells in gliomas, is a marker that correlates with histological grade, may underlie treatment resistance in some cases, and is a potential therapeutic target.

Summary Characterization of non-neoplastic and malignant human stem cell populations in their native state can provide new insights into gliomagenesis. Here we developed a purification strategy to directly isolate EGFR+/− populations from human germinal matrix (GM) and adult subventricular zone autopsy tissues, and from de novo glioblastoma (GBM) resections, enriching for cells capable of binding EGF ligand (LBEGFR+), and uniquely compared their functional and molecular properties. LBEGFR+ populations in both GM and GBM encompassed all sphere-forming cells and displayed proliferative stem cell properties in vitro. In xenografts, LBEGFR+ GBM cells showed robust tumor initiation and progression to high-grade, infiltrative gliomas. Whole-transcriptome sequencing analysis confirmed enrichment of proliferative pathways in both developing and neoplastic freshly isolated EGFR+ populations, and identified both unique and shared sets of genes. The ability to prospectively isolate stem cell populations using native ligand-binding capacity opens new doors onto understanding both normal human development and tumor cell biology., Graphical Abstract, Highlights • Prospective purification of EGFR+ cells from fresh human neural tissues using EGF • In vitro stem cell properties are restricted to EGFR+ germinal matrix and GBM cells • EGFR+ GBM cells are tumor-initiating and re-form high-grade gliomas in mice • RNA-seq defines developmentally shared pathways in EGFR+ GBM cells, Understanding human brain development and gliomagenesis requires deeper analysis of stem cells in their native state. Here, Tsankova and colleagues employ EGF ligand to prospectively isolate proliferative EGFR+ stem-like populations from fresh germinal matrix and glioblastoma tissues, capturing sphere-forming and tumor-initiating cells in uncultured state. Comparative transcriptome analysis of these populations provides molecular insight into the dysregulated developmental pathways in GBM.

Glioblastoma multiforme (GBM) is the most common primary intrinsic brain tumor in adults. Patients diagnosed with GBM have a median survival of approximately 15 months. Contributing to this poor prognosis is the high recurrence rate of tumors following initial treatment with surgical resection, radiation therapy and chemotherapy. Numerous therapies for recurrent GBM have been proposed, but their safety and efficacy have yet to be demonstrated in definitive clinical trials. Among the more promising treatments, however, is bevacizumab, a humanized mouse monoclonal antibody against vascular endothelial growth factor A (VEGFA) Bevacizumab has antiangiogenic activity and can cause dramatic improvements in tumor size and peritumoral edema as determined by contrast enhanced magnetic resonance imaging. The following is a review of the basic science, translational and clinical studies that have rendered bevacizumab one of the current treatment options for recurrent GBM. Also discussed are the still unanswered questions regarding the use of bevacizumab for this disease.

The tumor microenvironment of a glioblastoma is highly immunosuppressive. Overcoming this immunosuppressive activity seems imperative to a successful treatment. Like other cancers, glioblastoma is capable of generating tumor-specific peptides that can be recognized by the immune system, providing a specific target for antitumor therapy. Glioma vaccines including tumor lysate pulsed dendritic cell-based immunotherapy have proven safe and potentially of clinical value, suggesting that dead cells can confer tumor associated antigens for processing and presentation. Use of TTFields in newly diagnosed glioblastoma increases progression-free survival and overall survival. Among several mechanisms of action, TTFields induces an immunogenic cell death. Therefore, we combined this modality treatment with the standard of care and a personalized vaccine for newly diagnosed glioblastoma with the expectation of improved outcome for the patients. RNA and DNA are extracted from tumor specimens and blood and whole exome sequence and mRNASeq is performed. HLA typing is obtained for each patient. Mutation-derived tumor antigens are identified using computational predictions and ranked according to both predicted HLA binding affinity and expression. A maximum of 10 peptides is selected for each patient vaccine. The vaccine is administered subcutaneously using Poly-ICLC as adjuvant during Temozolomide treatment after radiotherapy with concurrent Temozolomide. We are reporting on the initial safety data for patients who received the mutation-derived tumor antigen vaccine without the use of the TTFields. We have encountered not only novel mutated tumor antigens but also well known driver mutations that are predicted to be immunogenic despite a low mutation load in the GBM patients. The trial is feasible and the vaccine seems well tolerated without unexpected adverse events.

Bone marrow-derived human mesenchymal stem cells (hMSCs) are capable of localizing to gliomas after systemic delivery and can be used in glioma therapy. However, the mechanism underlying the tropism of hMSCs for gliomas remains unclear. In vitro studies suggest that platelet-derived growth factor BB (PDGF-BB) may mediate this tropism. However, a causal role of PDGF-BB has not been demonstrated in vivo. Therefore, we tested the hypothesis that PDGF-BB mediates the attraction of hMSCs to gliomas in vitro and in vivo.U87 or LN229 glioma cells were transfected with plasmids encoding human PDGF-B. Stable transfected clones that secreted large amounts of PDFG-BB and clones that produced low levels of PDGF were chosen. In vitro migration of hMSCs toward PDGF-B or conditioned media from high- and low-secreting PDGF-B tumor cells was assessed using Matrigel invasion assays. For in vivo localization studies, hMSCs were tracked by bioluminescence imaging (BLI) after transduction with an adenovirus containing luciferase cDNA. In other studies, hMSCs were labeled with green fluorescent protein (gfp) and analyzed for intratumoral localization by immunohistochemistry.In vitro invasion assays showed that significantly more hMSCs migrated toward glioma cells engineered to secrete high levels of PDGF-BB compared with low-secreting gliomas. Anti-PDGF-BB-neutralizing antibody abrogated this increase in migration. Pretreatment of hMSCs with inhibitory antibodies against PDGF receptor-beta also reduced hMSC migration. To demonstrate that PDGF-BB mediates the localization of hMSCs in vivo, hMSCs-Ad-Luc were injected into the carotid artery of mice harboring orthotopic 7-day-old U87-PDGF-BB-high secreting or U87-PDGF-BB-low secreting xenografts and analyzed by BLI. Statistically significant increases in hMSCs were seen within PDGF-BB-high xenografts compared with PDGF-BB-low xenografts. To control for PDGF-BB-induced differences in tumor size and vascularity, gfp-labeled hMSCs were injected into the carotid arteries of animals harboring 4-day old PDGF-BB-high secreting xenografts or 7-day old PDGF-BB-low secreting xenografts. At these times tumors had similar size and vessel density. Statistically significant more hMSCs localized to PDGF-BB-high secreting xenografts compared with PDGF-BB-low secreting xenografts. Pretreatment of hMSCs with anti-PDGFR-beta-inhibitory antibodies decreased the localization of hMSCs in this intracranial model.PDGF-BB increases the attraction of hMSCs for gliomas in vitro and in vivo, and this tropism is mediated via PDGF-beta receptors on hMSCs. These findings can be exploited for advancing hMSC treatment.

✓ This 42-year-old man presented with an intradural extramedullary mass in his lower cervical spine. On imaging studies the lesion mimicked the appearance of a meningioma. At surgery, the mass was found to be an intradural extra-arachnoid tumor. An intraoperative pathological examination determined the lesion to be a Hodgkin lymphoma. The procedure was limited to biopsy sampling and the patient was treated further with adriamycin, bleomycin, vincristine, and dacarbazine chemotherapy, after which remission was demonstrated both clinically and on images. Analysis of a frozen section obtained during the procedure aided in the diagnosis of the tumor, thus preventing further resection and the potential neurological complications associated with more radical resection. To the authors’ knowledge this is the first reported case of a presumed primary intradural extraarachnoid Hodgkin lymphoma.

Maximal safe tumor resection is part of the standard of care for patients with newly diagnosed glioblastoma. The role of reoperation in the care of patients with recurrent glioblastoma is less clear, and less than a quarter of patients undergo a second surgery. Previous studies have identified preoperative variables associated with the improved survival of patients following reoperation, and guidelines for the selection of patients for reoperation have been devised and validated. In this study, the authors analyzed the relative survival benefit of maximal safe tumor removal in a series of patients with recurrent glioblastoma who all underwent reoperation.In this longitudinal study, the clinical and radiological data of 97 consecutive patients who underwent reoperation for recurrent glioblastoma were prospectively collected. Multiple regression analyses and Kaplan-Meier plotting were performed to identify pre- and postoperative clinical and radiological variables associated with increased survival following reoperation.The median postoperative survival of all patients following reoperation was 12.4 months (95% confidence interval [CI] 9.0-15.6 months). Multiple Cox regression analysis revealed that patients with large (3 cm(3)) residual tumors following reoperation had significantly decreased survival relative to those with residual tumors that were small (0-3 cm(3); hazard ratio [HR] = 3.10, 95% CI 1.69-5.70; p0.001) or radiologically absent (0 cm(3); HR = 5.82, 95% CI 2.98-11.37; p0.001). Large residual tumors had faster rates of subsequent regrowth than small (odds ratio [OR] = 4.22, 95% CI 1.19-14.97; p = 0.026) or radiologically absent (OR = 11.00, 95% CI 2.79-43.43; p = 0.001) residual tumors, and a faster regrowth rate was significantly associated with decreased survival (HR = 4.01, 95% CI 2.26-7.14; p0.001).The overall survival of patients with recurrent glioblastoma who underwent reoperations increased with decreasing postoperative residual tumor volumes. For patients meeting prognostic criteria for reoperation, the surgical goal should be to minimize residual tumor volume to maximize overall survival. Clinical trial registration no.: NCT00060541 ( ClinicalTrials.gov ).

Background Section of a tight filum terminale is a minimally invasive procedure compared with cord untethering procedures used for more complex spinal abnormalities. Anecdotal evidence suggests, however, that the risk of symptomatic retethering resulting from scarring might be higher than previously thought. Objective To determine the frequency of symptomatic retethering after section of a tight filum terminale and to explore possible risk factors. Methods We reviewed databases at 2 pediatric neurosurgery centers for all patients who had surgery for a suspected tight filum terminale between January 1982 and June 2009. Results We identified 152 patients. The median length of follow-up was 78 months. Thirteen patients (8.6%) went on to retether symptomatically at a median time of 23.4 months after the initial procedure. Eight had early retethering (within 2 years) and 5 had late retethering (after 7 years). Compared with late retetherers, early retetherers were older at initial surgery (median, 9.4 vs 0.9 years of age), had a higher level of the conus (median, L1/L2 vs L3/L4), had more arachnoiditis after initial surgery, and required more repeat untethering procedures. Late retetherers were younger at initial surgery than those who did not retether (median, 0.9 vs 4.5 years of age). Conclusion Symptomatic retethering is not uncommon after a simple filum snip, and long-term follow-up is warranted. Two distinct patterns of retethering were observed. Arachnoiditis caused by infection or a cerebrospinal fluid fistula may predispose to early retethering, whereas early surgery for prevention of tethered cord symptoms may predispose to late retethering.

Bone marrow is a complex tissue and is a source of several stem/progenitor cell populations. In addition to hematopoietic stem cells and endothelial progenitors,1–4 the bone marrow is also a source of a less well-characterized stem cell/progenitor population referred to as mesenchymal stem cells (MSCs). This cell population was originally identified in the 1970s by Friedenstein et al,1,5 who placed whole bone marrow in plastic culture dishes and, after removing the nonadherent (hematopoietic) cells, was left with an adherent cell population that had the ability to differentiate into colonies resembling bone or cartilage. Castro-Malaspina et al6 used similar methods to isolate adherent bone marrow cells, which others showed could be induced to differentiate into a variety of mesenchymal elements, including fat, bone, cartilage, and bone marrow stroma.7–10 Most recently, Pittenger and Marshak4 and Pittenger et al9 isolated a bone marrow population, referred to as MSCs, that grew as adherent cells on plastic, could be expanded ex vivo to high passage numbers, and could be differentiated into multiple mature connective tissue cell types, particularly adipocytes, chondrocytes, and osteocytes. Although there is no specific surface marker that defines MSCs, human MSCs are negative for CD45 and CD31 and express CD105, CD73, CD90, CD44, and CD166.11 In the mouse, there is less consensus regarding the defining surface markers,12–14 but several studies indicate that mouse MSCs are negative for CD45, CD11b, and CD31 and positive for stem cell antigen-1 (Sca-1), and CD9.14,15 Physiologically, these cells are thought to give rise to the bone marrow stromal elements that provide the microenvironment and supporting structure necessary for marrow homeostasis.1,4,16–19 For the neurosurgeon, MSCs are of interest because of their potential use in the therapy of a variety of neurological disorders.12 In the field of neuro-oncology, we and others have reported that ex vivo expanded human bone marrow–derived MSCs (BM-MSCs) selectively localize to human gliomas after systemic administration and can be engineered to deliver antiglioma therapies to experimental human glioblastomas such as interferon-β and tumor necrosis factor-α–related apoptosis-inducing ligand.20,21 Exogenous MSCs also localize to areas of stroke,22 traumatic brain injury,23 and intracerebral hemorrhage,24 suggesting a potential role in these pathological processes. MSCs are also of interest because of the potential involvement of endogenous MSCs in normal physiological responses to injury and inflammation and because they may comprise the stroma of solid tumors, the milieu of which is much like a nonhealing wound.25 Recent evidence suggests that endogenous MSCs may be an important component of glioblastoma multiforme, the most common adult malignant brain tumor. Specifically, cells resembling MSCs can be isolated from fresh glioma specimens obtained at surgery.26,27 Like BM-MSCs, these tumor derived-MSCs grow as adherent cells in culture; differentiate into adipocytes, chondrocytes, and osteocytes; and express the requisite MSC surface markers.26,27 These tumor-derived MSCs are thought to contribute to the stroma of human gliomas. Although it is postulated that MSCs may be recruited into areas of inflammation, injury, and tumors from a pool of circulating BM-MSCs originating from the bone marrow, to date there is conflicting evidence supporting the notion that BM-MSCs actually circulate in the bloodstream. However, an alternative source of MSCs may be the local tissues within peripheral organs. Cells similar to MSCs have been reported to be found in tissues other than the bone marrow, including fat, dermis, muscle, liver, pancreas, lung, endometrium, kidney, vessels, and brain.28–36 It is suggested that MSCs may reside throughout the body in most postnatal organs.28,32 Although Rutka et al37 reported in the 1980s that nonglial, mesenchymal cells can be cultured from normal brain tissue, the isolation of cells with the specific characteristics of MSCs from the brain has only begun to be explored, and the existence of brain-derived MSCs (Br-MSCs) and their location within the brain remains unclear. Identifying MSCs in normal brain tissue would provide new insight into the capacity of central nervous system tissues to respond to inflammation and tumor formation. In this context, we sought to determine the extent to which cells with the features of MSCs exist in normal brain tissue and to determine the location of these cells in the brain. Consequently, we isolated and cultured cells from normal mouse brain using the same methods used to isolate BM-MSCs and thereby identified cells that were similar to BM-MSCs in terms of morphology, surface markers, and differentiation pattern, which we called brain-derived MSCs (Br-MSCs). Histological studies suggest that these Br-MSCs reside within the perivascular niche. We propose that these Br-MSCs may represent a pool of local stem cells that maintain normal homeostasis of the perivascular niche and are capable of responding to tissue stresses within the brain.

Δ24-RGD is an infectivity-augmented, conditionally replicative oncolytic adenovirus with significant antiglioma effects. Although intratumoral delivery of Δ24-RGD may be effective, intravascular delivery would improve successful application in humans. Due to their tumor tropic properties, we hypothesized that human mesenchymal stem cells (hMSC) could be harnessed as intravascular delivery vehicles of Δ24-RGD to human gliomas. To assess cellular events, green fluorescent protein–labeled hMSCs carrying Δ24-RGD (hMSC-Δ24) were injected into the carotid artery of mice harboring orthotopic U87MG or U251-V121 xenografts and brain sections were analyzed by immunofluorescence for green fluorescent protein and viral proteins (E1A and hexon) at increasing times. hMSC-Δ24 selectively localized to glioma xenografts and released Δ24-RGD, which subsequently infected glioma cells. To determine efficacy, mice were implanted with luciferase- labeled glioma xenografts, treated with hMSC-Δ24 or controls, and imaged weekly by bioluminescence imaging. Analysis of tumor size by bioluminescence imaging showed inhibition of glioma growth and eradication of tumors in hMSC-Δ24-treated animals compared with controls (P < 0.0001). There was an increase in median survival from 42 days in controls to 75.5 days in hMSC-Δ24-treated animals (P < 0.0001) and an increase in survival beyond 80 days from 0% to 37.5%, respectively. We conclude that intra-arterially delivered hMSC-Δ24 selectively localize to human gliomas and are capable of delivering and releasing Δ24-RGD into the tumor, resulting in improved survival and tumor eradication in subsets of mice. [Cancer Res 2009;69(23):8932–40]

Object Tumor size is likely to be a major determinant of hearing preservation after surgery for vestibular schwannoma. Findings in some large case series have not supported this concept, possibly due to variation in the technique used for tumor measurement. The authors sought to determine if the length of tumor–cochlear nerve contact was predictive of hearing outcome in adults undergoing resection of a vestibular schwannoma. Methods Patients who underwent a hearing-preserving approach for resection of a vestibular schwannoma at one institution by a neurosurgeon/neurotologist team between 2001 and 2005 were screened. Patients with American Academy of Otolaryngology–Head and Neck Surgery (AAO-HNS) Class A or B hearing preoperatively were included. Magnetic resonance images were reviewed and used to calculate the length of tumor–cochlear nerve contact. Tumors were also measured according to AAO-HNS guidelines. Results Thirty-one patients were included, 8 (26%) of whom had hearing preservation. Univariate analysis revealed that extracanalicular length of tumor–cochlear nerve contact (p = 0.0365), preoperative hearing class (p = 0.028), I–V interpeak latency of the brainstem auditory evoked potential (p = 0.021), and the interaural I–V interpeak latency difference (p = 0.018) were predictive of hearing outcome. Multivariate analysis confirmed the predictive value of extra-canalicular length of contact and preoperative hearing class (p = 0.041 and p = 0.0235, respectively). Conclusions Vestibular schwannomas with greater lengths of tumor–cochlear nerve contact increase a patient's risk for hearing loss after surgery with attempted hearing preservation. Involvement of the internal auditory canal produces a constant risk of hearing loss. Data from the experience of a single surgical team can be used to estimate the probability of good hearing outcome for any given patient with serviceable hearing and a vestibular schwannoma.

Background: Medulloblastoma is the most common malignant central nervous system tumour in children but, in contrast, quite rare in adults. Hemispheric, rather than midline, cerebellar medulloblastomas are more common in older children and adults. We present the unusual case of a 71-year-old man who presented with a fourth ventricular mass that proved to be a medulloblastoma. Methods: A 71-year-old man presented with progressive balance problems, slurred speech and double vision. A CT scan of the brain revealed a hyperattenuating, partially calcified, avidly enhancing mass within the fourth ventricle. Diffusion weighted MRI showed restricted diffusion within the mass. The patient underwent a midline suboccipital craniotomy and a subtotal resection was achieved. Results: Histological examination showed a densely cellular neoplasm composed of small cells with a tendency towards neuroblastic rosette formation. Most cells were strongly positive for neuron-specific enolase and synaptophysin. Ultrastructurally, tumour cells showed evidence of neuronal differentiation. These findings were consistent with a classical medulloblastoma. Conclusion: Adult medulloblastoma should be considered in the differential diagnosis of a partially calcified hyperattenuating mass within the fourth ventricle.

To the Editor: A 42-year-old man who was in rehabilitation for intravenous substance abuse presented with a three-month history of seizures and incoordination. Other symptoms included dysarthria, a hesitant pattern of speech, myoclonic jerks, postural tremor, emotional lability, and fluctuating short-term memory. On questioning he admitted that for four years he had been concentrating his methadone preparation, which was diluted with a grape-flavored drink, by heating it in an uncoated aluminum pot. He would then reconstitute the residue for intravenous injection. His serum aluminum level was 6650 nmol per liter (reference interval

Aluminum toxicity first came to attention in the medical literature as a sequela of peritoneal or hemodialysis, where accumulation of aluminum in body tissues results from the use of aluminum-containing dialysate and phosphate binders. The most common clinical presentations of aluminum toxicity include anemia, bone disease, and a syndrome of encephalopathy known as the dialysis encephalopathy sydrome (DES). We present the unique case of a 42-year-old man who developed chronic aluminum toxicity from the intravenous injection of a methadone preparation intended for oral consumption. The methadone solution was concentrated for intravenous injection by heating in aluminum cookware. Experiments performed in our laboratory reproducing this technique, using weakly acidic solutions similar to popular drink mixes, confirmed that significant amounts of elemental aluminum can be leached from aluminum cookware when heated. The patient presented to medical attention with generalized seizures, profound cerebellar dysfunction, myoclonus, and speech apraxia, all of which are characteristic of DES. The peripheral blood film revealed bizarre red cell morphology, with clear features of iron deficiency and prominent coarse basophilic stippling, suggesting impaired iron utilization, which is at least one mechanism of aluminum related hematologic toxicity. A bone marrow biopsy demonstrated extensive osteosclerosis and myelosclerosis, compatible with significant metabolic bone disease. Subsequent investigations revealed a serum aluminum level of 7200 nmol/L, eighteen times the upper limit of normal (400 nmol/L). Chelation therapy with a continuous intravenous infusion of deferoxamine was started, and over a course of ten months the serum aluminum level was reduced to 2390 nmol/L with few side effects. The patient made a significant neurologic recovery and returned to life in the community. This is the first detailed account of the successful use of deferoxamine to chelate aluminum in a patient without dialysis-dependent renal insufficiency. This case also highlights heavy metal exposure as a diagnostic consideration in intravenous substance abusers presenting with multiorgan dysfunction, and the importance of performing a thorough inquiry into injection drug practices when evaluating these patients.