A Phase 0 Study Assessing the Intracranial Activity of a Metabolic Radiosensitizer in Patients with Glioblastoma

PURPOSE/OBJECTIVE(S)

Efforts to overcome treatment resistance in glioblastoma (GBM) have been unsuccessful due to tumor heterogeneity and poor intracranial drug penetration. Targeting altered metabolism is a promising approach to improve GBM therapy despite this heterogeneity. Mycophenolate mofetil (MMF) is an inhibitor of purine synthesis that sensitizes GBM to radiation and temozolomide (TMZ) in vitro and in vivo, but its ability to cross the blood brain barrier and inhibit GBM metabolism in patients is unknown. NCT04477200 is a phase 0/1 dose escalation study of MMF combined with radiation and temozolomide in GBM. Here we report the phase 0 results of this study assessing the intracranial activity of MMF.

MATERIALS/METHODS

Purine (GTP and IMP) and mycophenolic acid (MPA, the active metabolite of MMF) concentrations were determined using mass spectrometry in flash-frozen tumor (enhancing and non-enhancing) and normal cortex obtained from 8 patients with recurrent GBM who received MMF (500, 1000, 1500 and 2000 mg BID, N = 2 patients each dose level) for 1 week prior to re-resection and 5 control patients who did not receive MMF prior to re-resection. Plasma MPA concentration was similarly quantified to calculate the enhancing tumor, non-enhancing tumor and normal cortex to plasma MPA ratios.

RESULTS

Patients who received MMF had a mean MPA concentration of 2.2 ± 0.7 µM in the enhancing tumor samples, 1.2 ± 0.5 µM in the non-enhancing tumor samples and 1.3 ± 0.5 µM in normal cortex. MPA concentration was negligible in control patients. This corresponded to tissue/plasma MPA ratios of 0.31, 0.17 and 0.10 for enhancing tumor, non-enhancing tumor and normal cortex, respectively. The GTP/IMP ratio was decreased by 75% in enhancing tumor in MMF-treated patients compared to untreated controls (p = 0.009), indicating effective target engagement and inhibition of purine synthesis. The GTP/IMP ratio was also decreased in cortex and non-enhancing tumor, though a paucity of control samples prevented statistical analysis.

CONCLUSION

Twice daily MMF treatment yields intracranial drug concentrations above 1 µM and lowers the GTP/IMP ratio in GBMs, consistent with target engagement. As we have previously observed radiosensitization in vitro with MPA concentrations of 1 µM, these data suggest that MMF may achieve adequate CNS penetration for therapeutic benefit. The Phase 1 component of this study to determine the dose limiting toxicity and maximally tolerated dose of MMF when combined with reirradiation in recurrent GBM and radiation and TMZ in newly diagnosed GBM is ongoing.

Identification of Excellent Prognosis IDH Wildtype Glioblastomas Using Genomic and Metabolic Profiling

PURPOSE/OBJECTIVE(S)

High grade gliomas (HGGs) are aggressive brain tumors with altered cellular metabolism. HGGs can carry mutations in the tricarboxylic acid (TCA) cycle enzyme isocitrate dehydrogenase 1 (IDH1), conferring distinct biology and improved patient prognosis compared to IDH wildtype (wt) tumors. Using metabolomic analyses of tumor tissue, we previously showed that IDH wt and IDH mutant (IDH mut) tumors have unique metabolomic signatures that correlate with different survival outcomes. Among this cohort of 69 HGG samples, we identified two unique patient tumors that metabolically clustered with IDH mut tumors, but lacked both the IDH mutation and its product 2-hydroxyglutarate. We aimed to discover unique mutations in these two tumors that may impart an IDH mutant-like phenotype in the absence of an IDH1 or IDH2 mutation.

MATERIALS/METHODS

Whole exome sequencing (WES) was performed on frozen tumor samples from two patients diagnosed as glioblastoma (GBM), IDH wt via Agilent v5 + IncRNA platform. Alignment to the hg38 genome and variant calling were completed using an accelerated implementation of GATK's BWA and MuTect2 algorithms from Sentieon. Variants were filtered based on supporting reads and variant allele thresholds, with synonymous variants and common SNPs removed. High-confidence variants were further filtered by membership in the four KEGG pathways associated with IDH1 and IDH2. Identified variants were corroborated with metabolomics data from the two unique IDH wt tumors compared with classical GBM IDH wt, oligodendrogliomas IDH mut and astrocytomas IDH mut to identify putative drivers of an IDH mutant-like metabolomic phenotype in these unique IDH wt tumors.

RESULTS

Despite the lack of an IDH mutation, one patient survived 45.6 months and the other patient remains alive at last follow up 64 months post diagnosis, much longer than the 16-18-month median survival typical of patients with GBM IDH wt. WES of outlier IDH wt tumor samples revealed 65 unique mutations in the queried KEGG pathways, of which 34 had a variant allele frequency > = 0.15. These variants were processed in Gprofiler, confirming expected enrichment of the carboxylic acid metabolic biologic process, a functional gene set consisting of TCA genes, among these variants (p = 0.002, 3.6-fold enrichment). Accordingly, metabolite levels of intermediates of the TCA cycle, including malate and isocitrate were decreased in the outlier tumor samples compared to classic GBMs IDH wt (p<0.001). Presence of genetic alterations in key variants of the carboxylic acid metabolic biologic process (including ME1, GYP4F3, PTGIS, PFKL, PSPH, AKR1A1, HK2, NOS1) correlated with improved overall survival among GBM patients in the TCGA (p = 0.04). Laboratory validation of these findings in preclinical GBM models is ongoing.

CONCLUSION

Disruption of the TCA cycle independent of an IDH mutation is associated with favorable survival in GBM. Pharmacologic inhibition of these pathways may be a promising strategy to improve GBM outcomes.

Subclonal evolution and expansion of spatially distinct THY1-positive cells is associated with recurrence in glioblastoma

PURPOSE

Glioblastoma(GBM) is a lethal disease characterized by inevitable recurrence. Here we investigate the molecular pathways mediating resistance, with the goal of identifying novel therapeutic opportunities.

EXPERIMENTAL DESIGN

We developed a longitudinal in vivo recurrence model utilizing patient-derived explants to produce paired specimens(pre- and post-recurrence) following temozolomide(TMZ) and radiation(IR). These specimens were evaluated for treatment response and to identify gene expression pathways driving treatment resistance. Findings were clinically validated using spatial transcriptomics of human GBMs.

RESULTS

These studies reveal in replicate cohorts, a gene expression profile characterized by upregulation of mesenchymal and stem-like genes at recurrence. Analyses of clinical databases revealed significant association of this transcriptional profile with worse overall survival and upregulation at recurrence. Notably, gene expression analyses identified upregulation of TGFβ signaling, and more than one-hundred-fold increase in THY1 levels at recurrence. Furthermore, THY1-positive cells represented <10% of cells in treatment-naïve tumors, compared to 75-96% in recurrent tumors. We then isolated THY1-positive cells from treatment-naïve patient samples and determined that they were inherently resistant to chemoradiation in orthotopic models. Additionally, using image-guided biopsies from treatment-naïve human GBM, we conducted spatial transcriptomic analyses. This revealed rare THY1+ regions characterized by mesenchymal/stem-like gene expression, analogous to our recurrent mouse model, which co-localized with macrophages within the perivascular niche. We then inhibited TGFBRI activity in vivo which decreased mesenchymal/stem-like protein levels, including THY1, and restored sensitivity to TMZ/IR in recurrent tumors.

CONCLUSIONS

These findings reveal that GBM recurrence may result from tumor repopulation by pre-existing, therapy-resistant, THY1-positive, mesenchymal cells within the perivascular niche.

Association of Autologous Tumor Lysate-Loaded Dendritic Cell Vaccination With Extension of Survival Among Patients With Newly Diagnosed and Recurrent Glioblastoma: A Phase 3 Prospective Externally Controlled Cohort Trial

Importance

Glioblastoma is the most lethal primary brain cancer. Clinical outcomes for glioblastoma remain poor, and new treatments are needed.

Objective

To investigate whether adding autologous tumor lysate-loaded dendritic cell vaccine (DCVax-L) to standard of care (SOC) extends survival among patients with glioblastoma.

Design, Setting, and Participants

This phase 3, prospective, externally controlled nonrandomized trial compared overall survival (OS) in patients with newly diagnosed glioblastoma (nGBM) and recurrent glioblastoma (rGBM) treated with DCVax-L plus SOC vs contemporaneous matched external control patients treated with SOC. This international, multicenter trial was conducted at 94 sites in 4 countries from August 2007 to November 2015. Data analysis was conducted from October 2020 to September 2021.

Interventions

The active treatment was DCVax-L plus SOC temozolomide. The nGBM external control patients received SOC temozolomide and placebo; the rGBM external controls received approved rGBM therapies.

Main Outcomes and Measures

The primary and secondary end points compared overall survival (OS) in nGBM and rGBM, respectively, with contemporaneous matched external control populations from the control groups of other formal randomized clinical trials.

Results

A total of 331 patients were enrolled in the trial, with 232 randomized to the DCVax-L group and 99 to the placebo group. Median OS (mOS) for the 232 patients with nGBM receiving DCVax-L was 19.3 (95% CI, 17.5-21.3) months from randomization (22.4 months from surgery) vs 16.5 (95% CI, 16.0-17.5) months from randomization in control patients (HR = 0.80; 98% CI, 0.00-0.94; P = .002). Survival at 48 months from randomization was 15.7% vs 9.9%, and at 60 months, it was 13.0% vs 5.7%. For 64 patients with rGBM receiving DCVax-L, mOS was 13.2 (95% CI, 9.7-16.8) months from relapse vs 7.8 (95% CI, 7.2-8.2) months among control patients (HR, 0.58; 98% CI, 0.00-0.76; P < .001). Survival at 24 and 30 months after recurrence was 20.7% vs 9.6% and 11.1% vs 5.1%, respectively. Survival was improved in patients with nGBM with methylated MGMT receiving DCVax-L compared with external control patients (HR, 0.74; 98% CI, 0.55-1.00; P = .03).

Conclusions and Relevance

In this study, adding DCVax-L to SOC resulted in clinically meaningful and statistically significant extension of survival for patients with both nGBM and rGBM compared with contemporaneous, matched external controls who received SOC alone.

Trial Registration

ClinicalTrials.gov Identifier: NCT00045968.

Rapid Automated Analysis of Skull Base Tumor Specimens Using Intraoperative Optical Imaging and Artificial Intelligence

BACKGROUND

Accurate specimen analysis of skull base tumors is essential for providing personalized surgical treatment strategies. Intraoperative specimen interpretation can be challenging because of the wide range of skull base pathologies and lack of intraoperative pathology resources.

OBJECTIVE

To develop an independent and parallel intraoperative workflow that can provide rapid and accurate skull base tumor specimen analysis using label-free optical imaging and artificial intelligence.

METHODS

We used a fiber laser-based, label-free, nonconsumptive, high-resolution microscopy method (<60 seconds per 1 × 1 mm2), called stimulated Raman histology (SRH), to image a consecutive, multicenter cohort of patients with skull base tumor. SRH images were then used to train a convolutional neural network model using 3 representation learning strategies: cross-entropy, self-supervised contrastive learning, and supervised contrastive learning. Our trained convolutional neural network models were tested on a held-out, multicenter SRH data set.

RESULTS

SRH was able to image the diagnostic features of both benign and malignant skull base tumors. Of the 3 representation learning strategies, supervised contrastive learning most effectively learned the distinctive and diagnostic SRH image features for each of the skull base tumor types. In our multicenter testing set, cross-entropy achieved an overall diagnostic accuracy of 91.5%, self-supervised contrastive learning 83.9%, and supervised contrastive learning 96.6%. Our trained model was able to segment tumor-normal margins and detect regions of microscopic tumor infiltration in meningioma SRH images.

CONCLUSION

SRH with trained artificial intelligence models can provide rapid and accurate intraoperative analysis of skull base tumor specimens to inform surgical decision-making.

A customized 3D implant to target laser interstitial thermal therapy ablation of a posterior fossa mass

Laser interstitial thermal therapy (LITT) is a minimally invasive neurosurgical technique that has been demonstrated to successfully ablate intracranial tumors. While LITT for supratentorial lesions can often be straightforward, ablation of infratentorial lesions can be difficult with current targeting technologies and instrumentation. The anatomical difficulty of targeting posterior fossa masses can be further complicated in patients who have had a prior craniectomy or other procedure that removed the bone that is required to set the surgical trajectory. This article describes use of a three-dimensional (3D)-printed customized surgical implant to improve and enable targeting of posterior fossa lesions using LITT, particularly in the setting of prior craniectomy. A 3D-printed implant was customized for a patient with a history of metastatic lung cancer and prior posterior fossa craniectomy who presented for treatment of a progressively enlarging contrast-enhancing lesion in the right cerebellar hemisphere. The device included a built-in bolt trajectory for LITT ablation. The temporary implant was successfully fabricated for use with laser ablation of a right cerebellar mass. Three potential trajectories for the LITT bolt were incorporated into the temporary implant, but only the primary trajectory was utilized. Laser ablation was performed with the implant and a SideFire laser probe. Customized 3D-printed implants can enable the use of LITT for patients who would not otherwise be candidates.

Thirty-Day Hospital Readmission and Surgical Complication Rates for Shunting in Normal Pressure Hydrocephalus: A Large National Database Analysis

BACKGROUND

Research on age-related complications secondary to shunts in normal pressure hydrocephalus (NPH) is primarily limited to single-center studies and small cohorts.

OBJECTIVE

To determine the rates of hospital readmission and surgical complications, and factors that predict them, following shunt surgery for NPH in a large healthcare network.

METHODS

Surgical procedures, complications, and readmissions for adults undergoing ventricular shunting for NPH were determined using de-identified claims from a privately insured United States healthcare network in years 2007-2014. Univariate and multivariate statistics were used to determine factors that predict poor surgical outcomes. The primary outcome variable was surgical complications or readmissions (composite variable for any major perioperative complication or 30-d readmission).

RESULTS

The 30-d readmission rate for 974 patients with NPH who underwent ventricular shunting was 7.29%; the most common reasons for readmission were shunt-related complications, infection, hemorrhage, altered mental status, and cardiopulmonary and musculoskeletal problems. The perioperative complication rate was 21.15%, including intraparenchymal hemorrhage (5.85%) and extra-axial (subdural or epidural) hematoma (5.54%). The overall rate of having a surgical complication or 30-d readmission was 25.15%. Age did not predict surgical complication or 30-d readmission. Preoperative comorbidities independently associated with poor outcome were myocardial infarction within 1 yr (OR = 3.984, 95% CI = 1.105-14.368); existing cerebrovascular disease (odds ratio [OR] = 2.206, 95% CI = 1.544-3.152); and moderate/severe renal disease (OR = 2.000, 95% CI = 1.155-3.464).

CONCLUSION

The rate of complications or readmission within 30 d of ventricular shunting for NPH is 25.15%. Preoperative comorbidities of myocardial infarction within 1 yr, cerebrovascular disease, and moderate/severe renal disease are independent risk factors for poor outcome.

Rapid, label-free detection of diffuse glioma recurrence using intraoperative stimulated Raman histology and deep neural networks

BACKGROUND

Detection of glioma recurrence remains a challenge in modern neuro-oncology. Noninvasive radiographic imaging is unable to definitively differentiate true recurrence versus pseudoprogression. Even in biopsied tissue, it can be challenging to differentiate recurrent tumor and treatment effect. We hypothesized that intraoperative stimulated Raman histology (SRH) and deep neural networks can be used to improve the intraoperative detection of glioma recurrence.

METHODS

We used fiber-laser-based SRH, a label-free, non-consumptive, high-resolution microscopy method (<60 secs per 1 x 1 mm2) to image a cohort of patients (n = 35) with suspected recurrent gliomas who underwent biopsy or resection. The SRH images were then used to train a convolutional neural network (CNN) and develop an inference algorithm to detect viable recurrent glioma. Following network training, the performance of the CNN was tested for diagnostic accuracy in a retrospective cohort (n = 48).

RESULTS

Using patch-level CNN predictions, the inference algorithm returned a single Bernoulli distribution for the probability of tumor recurrence for each surgical specimen or patient. The external SRH validation dataset consisted of 48 patients (recurrent, 30; pseudoprogression, 18), and we achieved a diagnostic accuracy of 95.8%.

CONCLUSION

SRH with CNN-based diagnosis can be used to improve the intraoperative detection of glioma recurrence in near-real time. Our results provide insight into how optical imaging and computer vision can be combined to augment conventional diagnostic methods and improve the quality of specimen sampling at glioma recurrence.

Near real-time intraoperative brain tumor diagnosis using stimulated Raman histology and deep neural networks

Intraoperative diagnosis is essential for providing safe and effective care during cancer surgery1. The existing workflow for intraoperative diagnosis based on hematoxylin and eosin staining of processed tissue is time, resource and labor intensive2,3. Moreover, interpretation of intraoperative histologic images is dependent on a contracting, unevenly distributed, pathology workforce4. In the present study, we report a parallel workflow that combines stimulated Raman histology (SRH)5-7, a label-free optical imaging method and deep convolutional neural networks (CNNs) to predict diagnosis at the bedside in near real-time in an automated fashion. Specifically, our CNNs, trained on over 2.5 million SRH images, predict brain tumor diagnosis in the operating room in under 150 s, an order of magnitude faster than conventional techniques (for example, 20-30 min)2. In a multicenter, prospective clinical trial (n = 278), we demonstrated that CNN-based diagnosis of SRH images was noninferior to pathologist-based interpretation of conventional histologic images (overall accuracy, 94.6% versus 93.9%). Our CNNs learned a hierarchy of recognizable histologic feature representations to classify the major histopathologic classes of brain tumors. In addition, we implemented a semantic segmentation method to identify tumor-infiltrated diagnostic regions within SRH images. These results demonstrate how intraoperative cancer diagnosis can be streamlined, creating a complementary pathway for tissue diagnosis that is independent of a traditional pathology laboratory.

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

Background

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

Methods

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

Results

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

Conclusions

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

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

Serious adverse events following Normal Pressure Hydrocephalus surgery

OBJECTIVE

Recent Normal Pressure Hydrocephalus (NPH) practice guidelines describe a serious adverse event (SAE) rate following surgery of 11%.

PATIENTS & METHODS

We conducted a retrospective review of 162 consecutive patients who have undergone work-up at our center's multidisciplinary NPH clinic over a 47 month time period (2/2014-12/2017). Of these, 22 ultimately underwent neurosurgical ventricular shunt surgery as treatment for NPH. Clinical records were reviewed for SAEs categorized as possibly/probably/definitely related to NPH surgery.

RESULTS

In 10/22 (45.5%) operated subjects, there were 11 qualifying SAEs over this 3-year period: 1 central nervous system infections, 4 subdural hematomas, 2 seizures resulting in hospitalization, 1 catheter malfunction, 2 perioperative AEs, and 1 death of uncertain cause. Eight SAEs were coded as probably/definitely related. Six occurred >3 months from the time of surgery.

CONCLUSIONS

SAEs following NPH surgery are common. Additional studies are needed to determine the long-term safety of NPH surgery in older adults.

Comparison of Diffusion Tensor Imaging and Magnetic Resonance Perfusion Imaging in Differentiating Recurrent Brain Neoplasm From Radiation Necrosis

RATIONALE AND OBJECTIVES

To compare differences in diffusion tensor imaging (DTI) and dynamic susceptibility-weighted contrast-enhanced (DSC) magnetic resonance (MR) perfusion imaging characteristics of recurrent neoplasm and radiation necrosis in patients with brain tumors previously treated with radiotherapy with or without surgery and chemotherapy.

MATERIALS AND METHODS

Patients with a history of brain neoplasm previously treated with radiotherapy with or without chemotherapy and surgery who developed a new enhancing lesion on posttreatment surveillance MRI were enrolled. DSC perfusion MRI and DTI were performed. Region of interest cursors were manually drawn in the contrast-enhancing lesions, in the perilesional white matter edema, and in the contralateral normal-appearing frontal lobe white matter. DTI and DSC perfusion MR indices were compared in recurrent tumor versus radiation necrosis.

RESULTS

Twenty-two patients with 24 lesions were included. Sixteen (67%) lesions were placed into the recurrent neoplasm group and eight (33%) lesions were placed into the radiation necrosis group using biopsy results as the gold standard in all but three patients. Mean apparent diffusion coefficient values, mean parallel eigenvalues, and mean perpendicular eigenvalues in the contrast-enhancing lesion were significantly lower, and relative cerebral blood volume was significantly higher for the recurrent neoplasm group compared to the radiation necrosis group (P < 0.01, P = 0.03, P < 0.01, and P < 0.01, respectively).

CONCLUSIONS

The combined assessment of DTI and DSC MR perfusion properties of new contrast-enhancing lesions is helpful in distinguishing recurrent neoplasm from radiation necrosis in patients with a history of brain neoplasm previously treated with radiotherapy with or without surgery and chemotherapy.

Lateral inhibition of Notch signaling in neoplastic cells

During normal development, heterogeneous expression of Notch ligands can result in pathway suppression in the signal-sending cell, a process known as lateral inhibition. It is unclear if an analogous phenomenon occurs in malignant cells. We observed significant induction of Notch ligands in glioblastoma neurospheres and pancreatic carcinoma cells cultured in low oxygen, suggesting that this phenomenon could occur around hypoxic regions. To model lateral inhibition in these tumors, the ligand Jagged1 was overexpressed in glioblastoma and pancreatic carcinoma cells, resulting in overall induction of pathway targets. However, when ligand high and ligand low cells from a single line were co-cultured and then separated, we noted suppression of Notch pathway targets in the former and induction in the latter, suggesting that neoplastic lateral inhibition can occur. We also found that repression of Notch pathway targets in signal-sending cells may occur through the activity of a Notch ligand intracellular domain, which translocates into the nucleus. Understanding how this neoplastic lateral inhibition process functions in cancer cells may be important in targeting ligand driven Notch signaling in solid tumors.

Detection of human brain tumor infiltration with quantitative stimulated Raman scattering microscopy

Differentiating tumor from normal brain is a major barrier to achieving optimal outcome in brain tumor surgery. New imaging techniques for visualizing tumor margins during surgery are needed to improve surgical results. We recently demonstrated the ability of stimulated Raman scattering (SRS) microscopy, a nondestructive, label-free optical method, to reveal glioma infiltration in animal models. We show that SRS reveals human brain tumor infiltration in fresh, unprocessed surgical specimens from 22 neurosurgical patients. SRS detects tumor infiltration in near-perfect agreement with standard hematoxylin and eosin light microscopy (κ = 0.86). The unique chemical contrast specific to SRS microscopy enables tumor detection by revealing quantifiable alterations in tissue cellularity, axonal density, and protein/lipid ratio in tumor-infiltrated tissues. To ensure that SRS microscopic data can be easily used in brain tumor surgery, without the need for expert interpretation, we created a classifier based on cellularity, axonal density, and protein/lipid ratio in SRS images capable of detecting tumor infiltration with 97.5% sensitivity and 98.5% specificity. Quantitative SRS microscopy detects the spread of tumor cells, even in brain tissue surrounding a tumor that appears grossly normal. By accurately revealing tumor infiltration, quantitative SRS microscopy holds potential for improving the accuracy of brain tumor surgery.

Silencing BMI1 eliminates tumor formation of pediatric glioma CD133+ cells not by affecting known targets but by down-regulating a novel set of core genes

Clinical outcome of children with malignant glioma remains dismal. Here, we examined the role of over-expressed BMI1, a regulator of stem cell self-renewal, in sustaining tumor formation in pediatric glioma stem cells. Our investigation revealed BMI1 over-expression in 29 of 54 (53.7%) pediatric gliomas, 8 of 8 (100%) patient derived orthotopic xenograft (PDOX) mouse models, and in both CD133⁺ and CD133⁻ glioma cells. We demonstrated that lentiviral-shRNA mediated silencing of suppressed cell proliferation in vitro in cells derived from 3 independent PDOX models and eliminated tumor-forming capacity of CD133⁺ and CD133⁻ cells derived from 2 PDOX models in mouse brains. Gene expression profiling showed that most of the molecular targets of BMI1 ablation in CD133⁺ cells were different from that in CD133- cells. Importantly, we found that silencing BMI1 in CD133⁺ cells derived from 3 PDOX models did not affect most of the known genes previously associated with the activated BMI1, but modulated a novel set of core genes, including RPS6KA2, ALDH3A2, FMFB, DTL, API5, EIF4G2, KIF5c, LOC650152, C20ORF121, LOC203547, LOC653308, and LOC642489, to mediate the elimination of tumor formation. In summary, we identified the over-expressed BMI1 as a promising therapeutic target for glioma stem cells, and suggest that the signaling pathways associated with activated BMI1 in promoting tumor growth may be different from those induced by silencing BMI1 in blocking tumor formation. These findings highlighted the importance of careful re-analysis of the affected genes following the inhibition of abnormally activated oncogenic pathways to identify determinants that can potentially predict therapeutic efficacy.

Tenascin-C: a novel candidate marker for cancer stem cells in glioblastoma identified by tissue microarrays

Glioblastoma multiforme (GBM) is a highly aggressive brain tumor, with dismal survival outcomes. Recently, cancer stem cells (CSCs) have been demonstrated to play a role in therapeutic resistance and are considered to be the most likely cause of cancer relapse. The identification of CSCs is an important step toward finding new and effective ways to treat GBM. Tenascin-C (TNC) protein has been identified as a potential marker for CSCs in gliomas based on previous work. Here, we have investigated the expression of TNC in tissue microarrays including 17 GBMs, 18 WHO grade III astrocytomas, 15 WHO grade II astrocytomas, 4 WHO grade I astrocytomas, and 7 normal brain tissue samples by immunohistochemical staining. TNC expression was found to be highly associated with the grade of astrocytoma. It has a high expression level in most of the grade III astrocytomas and GBMs analyzed and a very low expression in most grade II astrocytomas, whereas it is undetectable in grade I astrocytomas and normal brain tissues. Double-immunofluorescence staining for TNC and CD133 in GBM tissues revealed that there was a high overlap between theses two positive populations. The results were further confirmed by flow cytometry analysis of TNC and CD133 in GBM-derived stem-like neurospheres in vitro. A limiting dilution assay demonstrated that the sphere formation ability of CD133⁺/TNC⁺ and CD133^–/TNC⁺ cell populations is much higher than that of the CD133⁺/TNC^– and CD133^–/TNC^– populations. These results suggest that TNC is not only a potential prognostic marker for GBM but also a potential marker for glioma CSCs, where the TNC⁺ population is identified as a CSC population overlapping with part of the CD133^– cell population.

Restoration of the orbital aesthetic subunit with the thoracodorsal artery system of flaps in patients undergoing radiation therapy

Objectives To demonstrate the advantages of the thoracodorsal artery scapular tip autogenous transplant (Tdast) for patients requiring restoration of the orbital aesthetic subunit. Design Prospective case series. Setting Tertiary center. Participants Ten patients (M:F,6:4) with a mean age of 56 years (range, 21 to 78 years) underwent restoration of the orbital aesthetic subunit and radiation therapy between 2001 and 2008. Main Outcome Measures The two reconstructive advantages of the thoracodorsal artery system of flaps for orbital reconstruction are a long pedicle and the suitability of the scapula tip to meet the three-dimensional requirements of the orbit. Patients were assessed 1 year or more after treatment for cosmetic outcome, work status, and socialization. Results Eight of 10 patients benefited from the three-dimensional nature of the scapula tip bone and 7 of 10 avoided vein grafting. Four of five evaluable patients reported "frequently" socializing outside their home. Four of five evaluable patients working before undergoing their treatment were able to return to work posttreatment. Seven of nine patients with postoperative photographs had minimal or no facial contour deformity. Conclusions The Tdast can restore orbital contour without osteotomy, and the thoracodorsal artery system of flaps has a long vascular pedicle that reduces vein grafting. Patients have an acceptable cosmetic result and return to preoperative work status and socialization.

Immunohistochemical staining, laser capture microdissection, and filter-aided sample preparation-assisted proteomic analysis of target cell populations within tissue samples

An important problem involves isolating subpopulations of cells defined by protein markers in clinical tissue samples for proteomic studies. We describe a method termed Immunohistochemical staining, laser capture microdissection (LCM) and filter-aided sample preparation (FASP)-Assisted Proteomic analysis of Target cell populations within tissue samples (ILFAPT). The principle of ILFAPT is that a target cell population expressing a protein of interest can be lit up by immunohistochemical staining and isolated from tissue sections using LCM for FASP and proteomic analysis. Using this method, we isolated a small population of CD90(+) stem-like cells from glioblastoma multiforme tissue sections and identified 674 high-confidence (false discovery rate < 0.01) proteins from 32 nL of CD90(+) cells by LC-MS/MS using an Orbitrap Elite mass spectrometer. We further quantified the relative abundance of proteins identified from equal volumes of LCM-captured CD90(+) and CD90(-) cells, where 109 differentially expressed proteins were identified. The major group of these differentially expressed proteins was relevant to cell adhesion and cellular movement. This ILFAPT method has demonstrated the ability to provide in-depth proteome analysis of a very small specific cell population within tissues. It can be broadly applied to the study of target cell populations within clinical specimens.

CD90 is identified as a candidate marker for cancer stem cells in primary high-grade gliomas using tissue microarrays

Although CD90 has been identified as a marker for various kinds of stem cells including liver cancer stem cells (CSCs) that are responsible for tumorigenesis, the potential role of CD90 as a marker for CSCs in gliomas has not been characterized. To address the issue, we investigated the expression of CD90 in tissue microarrays containing 15 glioblastoma multiformes (GBMs), 19 WHO grade III astrocytomas, 13 WHO grade II astrocytomas, 3 WHO grade I astrocytomas and 8 normal brain tissues. Immunohistochemical analysis showed that CD90 was expressed at a medium to high level in all tested high-grade gliomas (grade III and GBM) whereas it was barely detectable in low-grade gliomas (grade I and grade II) and normal brains. Double immunofluorescence staining for CD90 and CD133 in GBM tissues revealed that CD133(+) CSCs are a subpopulation of CD90(+) cells in GBMs in vivo. Flow cytometry analysis of the expression of CD90 and CD133 in GBM-derived stem-like neurospheres further confirmed the conclusion in vitro. The expression levels of both CD90 and CD133 were reduced along with the loss of stem cells after differentiation. Furthermore, the limiting dilution assay demonstrated that the sphere formation ability was comparable between the CD90(+)/CD133(+) and the CD90(+)/CD133(-) populations of GBM neurospheres, which is much higher than that of the CD90(-)/CD133(-) population. We also performed double staining for CD90 and a vascular endothelial cell marker CD31 in tissue microarrays which revealed that the CD90(+) cells were clustered around the tumor vasculatures in high-grade glioma tissues. These findings suggest that CD90 is not only a potential prognostic marker for high-grade gliomas but also a marker for CSCs within gliomas, and it resides within endothelial niche and may also play a critical role in the generation of tumor vasculatures via differentiation into endothelial cells.

Endothelial cells create a stem cell niche in glioblastoma by providing NOTCH ligands that nurture self-renewal of cancer stem-like cells

One important function of endothelial cells in glioblastoma multiforme (GBM) is to create a niche that helps promote self-renewal of cancer stem-like cells (CSLC). However, the underlying molecular mechanism for this endothelial function is not known. Since activation of NOTCH signaling has been found to be required for propagation of GBM CSLCs, we hypothesized that the GBM endothelium may provide the source of NOTCH ligands. Here, we report a corroboration of this concept with a demonstration that NOTCH ligands are expressed in endothelial cells adjacent to NESTIN and NOTCH receptor-positive cancer cells in primary GBMs. Coculturing human brain microvascular endothelial cells (hBMEC) or NOTCH ligand with GBM neurospheres promoted GBM cell growth and increased CSLC self-renewal. Notably, RNAi-mediated knockdown of NOTCH ligands in hBMECs abrogated their ability to induce CSLC self-renewal and GBM tumor growth, both in vitro and in vivo. Thus, our findings establish that NOTCH activation in GBM CSLCs is driven by juxtacrine signaling between tumor cells and their surrounding endothelial cells in the tumor microenvironment, suggesting that targeting both CSLCs and their niche may provide a novel strategy to deplete CSLCs and improve GBM treatment.

Esthesioneuroblastoma: Results and Outcomes of a Single Institution's Experience

OBJECTIVES

Analysis of outcomes of a cohort of patients with esthesioneuroblastoma.

DESIGN

Retrospective cohort analysis.

SETTING

PATIENTS presenting with esthesioneuroblastoma from 1994 to 2006 in a tertiary care academic medical center.

PATIENTS

Fifteen consecutive patients diagnosed as having esthesioneuroblastoma were treated during this time period using a subcranial resection. The mean follow-up is 75 months (range, 2 to 240 mos).

RESULTS

The overall survival was 100% and the overall disease-free survival was 49% and 24% at 5 and 15 years, respectively. PATIENTS treated with radiation therapy following surgical resection had a 5- and 15-year disease-free survival of 83.3% compared with a 5- and 15-year disease-free survival of 26.7% and 0%, respectively, for patients whose initial treatment was surgery alone. The mean time to recurrence was 82.1 months. None of the patients had a decrease in Karnofsky Performance Score following subcranial resection.

CONCLUSIONS

PATIENTS with esthesioneuroblastoma whose initial treatment consists of surgical resection followed by radiation therapy have a longer disease-free survival than patients treated with surgery alone. However, initial treatment modality did not have an effect on survival. Long-term, close follow-up is necessary to identify recurrences, which can be treated with a high degree of success.

Abstract 3297: Endothelial cells function as a niche to cancer stem-like cells by providing notch ligands in glioblastoma

Recent data show that endothelial cells function as a stem cell niche to promote CD133-positive cancer stem-like cells (CSLCs) self-renewal in glioblastoma (GBM). However, the molecular mechanism by which endothelial cells function as a stem cell niche is largely unknown. We had demonstrated recently that activation of NOTCH signaling is required for GBM CSLC propagation both in vitro and in vivo. To investigate if the acquisition of NOTCH activation in GBM CSLCs results from adjacent endothelial cells, we first examined the expression of NOTCH ligands JAG/DLL in primary GBM frozen samples. We found that JAG1, JAG2 and DLL4 are expressed mostly in endothelial cells adjacent to NESTIN- and NOTCH receptor-positive cancer cells. Some tumor cells also express JAG1, JAG2, and DLL1, but not DLL4, adjacent to NESTIN- and NOTCH-receptor positive cells in primary GBMs. Furthermore, we found that forced differentiated GBM cells from GBM neurospheres express a higher level of NOTCH ligands and a lower level of stem cell marker CD133, have reduced NOTCH activity, and are less tumorigenic in mice compared to GBM neurospheres. In addition, when we co-cultured GBM neurospheres with human brain microvascular endothelial cells (hBMECs) which express NOTCH ligands JAG/DLL, we found that hBMECs promote GBM neurosphere growth, increase the CD133-positive CSLC population and clonogenicity in vitro, whereas knocking down JAG1 or DLL4 in hBMECs abrogates hBMEC-induced GBM growth both in vitro and in vivo. Finally, we found that knockdown of JAG1 or DLL4 in hBMECs decreases growth of GBM intracranial xenograft in mice through reducing the CD133-positive population. In summary, we have demonstrated that NOTCH activation in GBM CSLCs is driven by juxtacrine signaling between tumor cells and surrounding endothelial cells, suggesting that targeting both CSLCs and their niche may provide an effective strategy to deplete GBM CSLCs.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3297. doi:10.1158/1538-7445.AM2011-3297

KIT expression and methylation in medulloblastoma and PNET cell lines and tumors

The stem cell factor/kit tyrosine kinase receptor pathway is related to tumor growth and progression in several cancers including Ewing sarcoma, a peripheral PNET (pPNET). Identifying additional groups of tumors that may use the pathway is important as they might be responsive to imatinib mesylate treatment. MB and central PNET (cPNET) are embryonal tumors of the CNS that share similar undifferentiated morphology with Ewing sarcomas and display aggressive clinical behavior. cPNET outcome is significantly lower than MB outcome, even for localized tumors treated with high-risk MB therapy. The elucidation of signaling pathways involved in MB and cPNET pathogenesis, and the discovery of new therapeutic targets is necessary to improve the treatment of these neoplasms. We analyzed KIT expression in 2 MB, one pPNET, one cPNET and 2 rhabdomyosarcoma (RMS) cell lines. Also, in 13 tumor samples (12 MB and one cPNET), we found KIT overexpression in the most aggressive cell lines (metastatic MB and pPNET). Hypermethylation of KIT was clear in the RMS non-expressing cell lines. Among MB tumors, we could see variable levels of KIT expression; a subset of them (25%) might be related in its growth pattern to KIT up-regulation. No methylated KIT was detected in the tumors expressing the lowest levels of KIT. Our results point to methylation as an epigenetic regulatory mechanism for KIT inhibition only in the KIT non-expressing RMS cell lines, and neither in the rest of the cell lines nor in the tumor samples.

Abstract 4235: Notch ligand-dependent cancer stem cell niche in glioblastoma

Recent data shows that endothelial cells function as a stem cell niche to promote CD133-positive cancer stem-like cells (CSLCs) self-renewal in glioblastoma (GBM). However, the mechanism by which endothelial cells function as a stem cell niche is largely unknown. To test if endothelial cells and differentiated tumor cells could function as a niche by providing Notch ligands to CSLCs, first we co-cultured GBM neurospheres with primary human endothelial cells (PHECs) which express Notch ligand Jagged/Delta. We found that PHECs promote GBM neurosphere growth, CD133 expression and clonogenicity in vitro, whereas knocking down Notch ligand expression in PHECs abrogates PHEC-induced GBM growth. We also found that the CD133-negative GBM cells express a higher level of Jagged/Delta and glial differentiation marker GFAP compared with CD133-positive population. When GBM neurospheres were forced to differentiate and grow as mono-layer attached cells, CD133-positive population was reduced, whereas expression of GFAP (glial marker), GalC (oligodendrocyte marker), Tuj1 (neuronal marker) and Notch ligands were induced. Furthermore, treatment of GBM neurospheres with a Jagged peptide increases GBM growth in a dosage dependent fashion. In addition, Notch ligands are highly expressed in the blood vessels of GBM primary tumors and intracranial xenografts in mouse, and CSLCs accumulate around the blood vessels within the tumors. Finally, we found that knocking down Notch ligands in PHECs inhibits GBM xenograft propagation in mice through reducing CD133-positive population. In summary, we show that Notch activation in GBM CSLCs is driven by juxtacrine signaling between tumor cells replicating the classical process of lateral inhibition and by stromal niche signals, suggesting that targeting both CSLCs and their niche may provide a profound strategy to deplete GBM CSLCs.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4235.

Frontal-to-temporal horn shunt as treatment for temporal horn entrapment

In cases of temporal horn entrapment caused by primary malignant central nervous system tumors, the goal is to restore physiological flow of cerebrospinal fluid (CSF) while preventing the spread of malignant tumor cells to distant sites. This goal is usually accomplished by placement of a traditional ventriculoperitoneal, ventriculopleural, or ventriculoatrial shunt. In this study, the authors describe a novel treatment approach using placement of a frontal-to-temporal horn shunt as an alternative to distal CSF diversion. Stereotactic surgery was used for placement of frontal-to-temporal horn shunts in 3 patients who presented with focal compressive symptoms caused by temporal horn dilation. Serial imaging studies confirmed temporal horn decompression with symptom resolution after a maximum of 20 months of follow-up (minimum 2 months in 1 patient who died of tumor progression). The authors believe this simple technique may be considered for use in all patients with neurological symptoms resulting from temporal horn dilation caused by malignant central nervous system neoplasms in which seeding of distant sites by CSF diversion is a concern.

Frontal-to-temporal horn shunt as treatment for temporal horn entrapment

In cases of temporal horn entrapment caused by primary malignant central nervous system tumors, the goal is to restore physiological flow of cerebrospinal fluid (CSF) while preventing the spread of malignant tumor cells to distant sites. This goal is usually accomplished by placement of a traditional ventriculoperitoneal, ventriculopleural, or ventriculoatrial shunt. In this study, the authors describe a novel treatment approach using placement of a frontal-to-temporal horn shunt as an alternative to distal CSF diversion. Stereotactic surgery was used for placement of frontal-to-temporal horn shunts in 3 patients who presented with focal compressive symptoms caused by temporal horn dilation. Serial imaging studies confirmed temporal horn decompression with symptom resolution after a maximum of 20 months of follow-up (minimum 2 months in 1 patient who died of tumor progression). The authors believe this simple technique may be considered for use in all patients with neurological symptoms resulting from temporal horn dilation caused by malignant central nervous system neoplasms in which seeding of distant sites by CSF diversion is a concern.

Adeno-associated virus type 5 reduces learning deficits and restores glutamate receptor subunit levels in MPS VII mice CNS

A major challenge in treating lysosomal storage diseases with enzyme therapy is correcting symptoms in the central nervous system (CNS). This study used a murine model of mucopolysaccharidosis type VII (MPS VII) to test whether pathological and functional CNS defects could be corrected by expressing beta-glucuronidase via bilateral intrastriatal injection of adeno-associated virus type 5 (AAV5betagluc) vectors. After injecting AAV5betagluc, different brain regions expressed active beta-glucuronidase, which corrected lysosomal storage defects. Compared to age-matched littermates, adult MPS VII mice were impaired in spatial learning and memory, as measured by the repeated acquisition and performance chamber (RAPC) assay. AAV5betagluc-treated MPS VII mice improved significantly in the RAPC assay, relative to saline-injected littermates. Moreover, our studies reveal that cognitive changes in MPS VII mice correlate with decreased N-methyl-d-aspartate and alpha-amino-3-hydroxy-5-methyl-isoxazole-4-propionic acid receptor expression. Importantly, AAV5betagluc delivery restored glutamate receptor levels. Together, these data demonstrate that AAV5 vectors deliver a therapeutically effective beta-glucuronidase gene to the CNS and further suggest a possible mechanism underlying spatial learning defects in MPS VII mice.

EXTRACRANIAL NASOPHARYNGEAL CRANIOPHARYNGIOMA

OBJECTIVE

Craniopharyngiomas (CPs) are benign tumors that almost always occur in a suprasellar location, making complete resection difficult and often necessitating radiotherapy. A case of CP presenting in an unusual location in an 8-year-old boy highlights the goals of CP treatment.

CLINICAL PRESENTATION

An 8-year-old boy sought treatment for symptoms of nasal obstruction and snoring. He also had a history of mild developmental delay, and his father had a thyroglossal duct cyst resected in his own youth. After tonsillectomy and adenoidectomy failed to improve the patient's symptoms, nasal endoscopy and biopsy revealed an intranasal CP. After this treatment, he experienced chronic thin brown nasal discharge. Magnetic resonance imaging further revealed tumor invading the sphenoid body and the clivus and that the tumor had no intracranial extension.

INTERVENTION

The child underwent surgical resection via a Le Fort I osteotomy approach. Complete resection was accomplished based on intraoperative frozen section pathological examination and postoperative magnetic resonance imaging results.

CONCLUSION

CP with no intracranial extension is a very rare but benign tumor. We recommend vigorous attempts to resect such tumors completely to minimize the chance of recurrence and the possible need for radiotherapy. Although radiotherapy controls CP growth quite well, it has its own risks that should be avoided if possible. Cranial base techniques may facilitate total resection.

Cavernous sinus meningiomas

Cavernous sinus meningiomas were once considered unresectable. The development of microsurgical and skull base techniques as well as advances in anesthesia and neuroradiology have allowed safe and systematic treatment of these lesions. Proper evaluation and patient counseling are required. A thorough understanding of the anatomy and surgical approaches are crucial to success, as is knowledge of the possible adverse outcomes including cranial neuropathy and stroke. The authors discuss these issues in the treatment of cavernous sinus meningiomas.

Free tissue transfer and local flap complications in anterior and anterolateral skull base surgery

BACKGROUND

Advances in reconstructive techniques over the past two decades have allowed the resection of more extensive skull base tumors than had previously been possible. Despite this progress, complications related to these cases remain a concern.

METHODS

Univariate and multivariate analyses were used to determine the relationship of host, tumor, defect, treatment, and reconstructive variables to wound and systemic complications after anterior and anterolateral skull base resections. The study included 67 patients receiving local flap (LF) or free tissue transfer (FTT) reconstructions during an 8-year period.

RESULTS

Overall, 28% of patients had a major wound complication, and 19% had a major systemic complication. LF and FTT flaps had similar rates of wound complications. LF reconstructions were associated with late wound breakdown problems, and FTT flap complications were primarily acute surgery-related problems.

CONCLUSIONS

The surgical reconstruction of skull base defects should be planned on the basis of the ability of the technique to attain safe closure and maintain integrity after radiation therapy.

In vivo gene transfer using a nonprimate lentiviral vector pseudotyped with Ross River Virus glycoproteins

Vectors derived from lentiviruses provide a promising gene delivery system. We examined the in vivo gene transfer efficiency and tissue or cell tropism of a feline immunodeficiency virus (FIV)-based lentiviral vector pseudotyped with the glycoproteins from Ross River Virus (RRV). RRV glycoproteins were efficiently incorporated into FIV virions, generating preparations of FIV vector, which after concentration attain titers up to 1.5 x 10(8) TU/ml. After systemic administration, RRV-pseudotyped FIV vectors (RRV/FIV) predominantly transduced the liver of recipient mice. Transduction efficiency in the liver with the RRV/FIV was ca. 20-fold higher than that achieved with the vesicular stomatitis virus G protein (VSV-G) pseudotype. Moreover, in comparison to VSV-G, the RRV glycoproteins caused less cytotoxicity, as determined from the levels of glutamic pyruvic transaminase and glutamic oxalacetic transaminase in serum. Although hepatocytes were the main liver cell type transduced, nonhepatocytes (mainly Kupffer cells) were also transduced. The percentages of the transduced nonhepatocytes were comparable between RRV and VSV-G pseudotypes and did not correlate with the production of antibody against the transgene product. After injection into brain, RRV/FIV preferentially transduced neuroglial cells (astrocytes and oligodendrocytes). In contrast to the VSV-G protein that targets predominantly neurons, <10% of the brain cells transduced with the RRV pseudotyped vector were neurons. Finally, the gene transfer efficiencies of RRV/FIV after direct application to skeletal muscle or airway were also examined and, although transgene-expressing cells were detected, their proportions were low. Our data support the utility of RRV glycoprotein-pseudotyped FIV lentiviral vectors for hepatocyte- and neuroglia-related disease applications.

A biomechanical comparison between anterior and transverse interbody fusion cages

STUDY DESIGN

Human cadaveric lumbar spines underwent placement of threaded fusion cages (TFCs) in either an anterior or transverse orientation. Spines underwent load testing and angular rotation measurement in the intact state, after diskectomy, after cage placement, and after fatiguing. Angular rotations were compared between cage orientations and interventions.

OBJECTIVE

To determine which cage orientation resulted in greater immediate stability.

SUMMARY OF BACKGROUND DATA

There has been extensive biomechanical study of interbody fusion cages. The lateral orientation has been increasingly used for intervertebral fusion, but a direct biomechanical comparison between cages implanted either anteriorly or transversely in human cadaveric spines has not been performed.

METHODS

Fourteen spines were randomized into the anterior group (anterior diskectomy and dual anterior cage placement) and the lateral group (lateral diskectomy and single transverse cage placement). Pure bending moments of 1.5, 3.0, 4.5, and 6.0 Nm were applied in flexion, extension, lateral bending, and axial rotation. Load testing was performed while intact, after diskectomy, after cage placement, and after fatiguing. Angular rotation was compared between anterior and lateral groups and, within each group, among the different interventions.

RESULTS

Segmental ranges of motion were similar between spines undergoing either anterior or lateral cage implantation.

CONCLUSIONS

These results demonstrate few differences between angular rotation after either anterior or lateral TFC implantation. These findings add to data that find few differences between orientation of implanted TFCs. Combined with a decreased risk of adjacent structure injury through a lateral approach, these data support a lateral approach for lumbar interbody fusion.

Paraparesis induced by inflammatory contents of a pneumonectomy cavity. Case report

The authors report on a patient who developed acute-onset paraparesis after underoing a thoracotomy 40 years earlier for a carcinoid adenoma. No infectious or neoplastic origin could be found to explain the patient's current clinical course and radiographic findings. The postoperative events in this case are discussed, as well as the literature regarding postthoracotomy complications.

Intraspinal familial clear cell meningioma in a mother and child. Case report

The authors present a case of familial clear cell meningioma in which the proband is a child with an intraspinal tumor. The clear cell meningioma variant has recently been studied. The literature regarding clear cell meningioma is reviewed.

Recombinant adeno-associated virus type 2, 4, and 5 vectors: transduction of variant cell types and regions in the mammalian central nervous system

Recombinant adeno-associated virus vectors based on serotype 2 (rAAV2) can direct transgene expression in the central nervous system (CNS), but it is not known how other rAAV serotypes perform as CNS gene transfer vectors. Serotypes 4 and 5 are distinct from rAAV2 and from each other in their capsid regions, suggesting that they may direct binding and entry into different cell types. In this study, we examined the tropisms and transduction efficiencies of beta-galactosidase-encoding vectors made from rAAV4 and rAAV5 compared with similarly designed rAAV2-based vectors. Injection of rAAV5 beta-galactosidase (betagal) or rAAV4betagal into the lateral ventricle resulted in stable transduction of ependymal cells, with approximately 10-fold more positive cells than in mice injected with rAAV2betagal. Major differences between the three vectors were revealed upon striatal injections. Intrastriatal injection of rAAV4betagal resulted again in striking ependyma-specific expression of transgene, with a notable absence of transduced cells in the parenchyma. rAAV2betagal and rAAV5betagal intrastriatal injections led to beta-gal-positive parenchymal cells, but, unlike rAAV2betagal, rAAV5betagal transduced both neurons and astrocytes. The number of transgene-positive cells in rAAV5betagal-injected brains was 130 and 5,000 times higher than in rAAV2betagal-injected brains at 3 and 15 wk, respectively. Moreover, transgene-positive cells were widely dispersed throughout the injected hemisphere in rAAV5betagal-transduced animals. Together, our data provide in vivo support for earlier in vitro work, suggesting that rAAV4 and rAAV5 gain cell entry by means of receptors distinct from rAAV2. These differences could be exploited to improve gene therapy for CNS disorders.

Hypoplastic internal carotid artery mimicking a classic angiographic "string sign". Case report

The authors report the case of a patient with transient ischemic attacks who was evaluated by duplex scanning, which demonstrated total carotid artery occlusion. Arteriography revealed what appeared to be a classic "string sign" in the cervical carotid artery, and a standard endarterectomy was planned. At surgery the internal carotid artery was found to be congenitally atretic, accounting for the string appearance of the arteriogram. The etiology, associated anomalies, differential diagnosis, and diagnostic evaluation of such lesions are discussed.