Vascular endothelial growth/permeability factor expression in human glioma specimens: correlation with vasogenic brain edema and tumor-associated cysts

Proteomic Analysis on Sequential Samples of Cystic Fluid Obtained from Human Brain Tumors

Cystic formation in human primary brain tumors is a relatively rare event whose incidence varies widely according to the histotype of the tumor. Composition of the cystic fluid has mostly been characterized in samples collected at the time of tumor resection and no indications of the evolution of cystic content are available. We characterized the evolution of the proteome of cystic fluid using a bottom-up proteomic approach on sequential samples obtained from secretory meningioma (SM), cystic schwannoma (CS) and cystic high-grade glioma (CG). We identified 1008 different proteins; 74 of these proteins were found at least once in the cystic fluid of all tumors. The most abundant proteins common to all tumors studied derived from plasma, with the exception of prostaglandin D2 synthase, which is a marker of cerebrospinal fluid origin. Overall, the protein composition of cystic fluid obtained at different times from the same tumor remained stable. After the identification of differentially expressed proteins (DEPs) and the protein-protein interaction network analysis, we identified the presence of tumor-specific pathways that may help to characterize tumor-host interactions. Our results suggest that plasma proteins leaking from local blood-brain barrier disruption are important contributors to cyst fluid formation, but cerebrospinal fluid (CSF) and the tumor itself also contribute to the cystic fluid proteome and, in some cases, as with immunoglobulin G, shows tumor-specific variations that cannot be simply explained by differences in vessel permeability or blood contamination.

Conventional and Advanced Magnetic Resonance Imaging Assessment of Non-Enhancing Peritumoral Area in Brain Tumor

The non-enhancing peritumoral area (NEPA) is defined as the hyperintense region in T2-weighted and fluid-attenuated inversion recovery (FLAIR) images surrounding a brain tumor. The NEPA corresponds to different pathological processes, including vasogenic edema and infiltrative edema. The analysis of the NEPA with conventional and advanced magnetic resonance imaging (MRI) was proposed in the differential diagnosis of solid brain tumors, showing higher accuracy than MRI evaluation of the enhancing part of the tumor. In particular, MRI assessment of the NEPA was demonstrated to be a promising tool for distinguishing high-grade gliomas from primary lymphoma and brain metastases. Additionally, the MRI characteristics of the NEPA were found to correlate with prognosis and treatment response. The purpose of this narrative review was to describe MRI features of the NEPA obtained with conventional and advanced MRI techniques to better understand their potential in identifying the different characteristics of high-grade gliomas, primary lymphoma and brain metastases and in predicting clinical outcome and response to surgery and chemo-irradiation. Diffusion and perfusion techniques, such as diffusion tensor imaging (DTI), diffusional kurtosis imaging (DKI), dynamic susceptibility contrast-enhanced (DSC) perfusion imaging, dynamic contrast-enhanced (DCE) perfusion imaging, arterial spin labeling (ASL), spectroscopy and amide proton transfer (APT), were the advanced MRI procedures we reviewed.

Diffusion Microstructure Imaging to Analyze Perilesional T2 Signal Changes in Brain Metastases and Glioblastomas

Purpose: Glioblastomas (GBM) and brain metastases are often difficult to differentiate in conventional MRI. Diffusion microstructure imaging (DMI) is a novel MR technique that allows the approximation of the distribution of the intra-axonal compartment, the extra-axonal cellular, and the compartment of interstitial/free water within the white matter. We hypothesize that alterations in the T2 hyperintense areas surrounding contrast-enhancing tumor components may be used to differentiate GBM from metastases. Methods: DMI was performed in 19 patients with glioblastomas and 17 with metastatic lesions. DMI metrics were obtained from the T2 hyperintense areas surrounding contrast-enhancing tumor components. Resected brain tissue was assessed in six patients in each group for features of an edema pattern and tumor infiltration in the perilesional interstitium. Results: Within the perimetastatic T2 hyperintensities, we observed a significant increase in free water (p < 0.001) and a decrease in both the intra-axonal (p = 0.006) and extra-axonal compartments (p = 0.024) compared to GBM. Perilesional free water fraction was discriminative regarding the presence of GBM vs. metastasis with a ROC AUC of 0.824. Histologically, features of perilesional edema were present in all assessed metastases and absent or marginal in GBM. Conclusion: Perilesional T2 hyperintensities in brain metastases and GBM differ significantly in DMI-values. The increased free water fraction in brain metastases suits the histopathologically based hypothesis of perimetastatic vasogenic edema, whereas in glioblastomas there is additional tumor infiltration.

Sodium MRI at 7T for Early Response Evaluation of Intracranial Tumors following Stereotactic Radiotherapy Using the CyberKnife

BACKGROUND AND PURPOSE

Conventionally, early treatment response to stereotactic radiotherapy in intracranial tumors is often determined by structural MR imaging. Tissue sodium concentration is altered by cellular integrity and energy status in cells. In this study, we aimed to investigate the feasibility of sodium MR imaging at 7T for the preliminary evaluation of radiotherapeutic efficacy for intracranial tumors.

MATERIALS AND METHODS

Data were collected from 16 patients (12 men and 4 women, 24-75 years of age) with 22 intracranial tumors who were treated with stereotactic radiation therapy using CyberKnife at our institution between December 1, 2016, and August 15, 2019. Sodium MR imaging was performed at 7T before and 48 hours, 1 week, and 1 month after CyberKnife radiation therapy. Tissue sodium concentration (TSC) was calculated and analyzed based on manually labeled regions of tumors.

RESULTS

Ultra-high-field sodium MR imaging clearly showed the intratumoral signal, which is significantly higher than that of normal tissue (t = 5.250, P <.001)., but the edema zone has some influence. The average TSC ratios of tumor to CSF in the 22 tumors, contralateral normal tissues, edema zones, frontal cortex, and frontal white matter were 0.66 (range, 0.23-1.5), 0.30 (range, 0.15-0.43), 0.58 (range, 0.25-1.21), 0.25 (range, 0.17-0.42), and 0.30 (range, 0.19-0.49), respectively. A total of 12 tumors in 8 patients were scanned at 48 hours, 1 week, and 1 month after treatment. The average TSC at 48 hours after treatment was 0.06 higher than that before treatment and began to decrease at 1 week. The TSC ratios of 10 continued to decline and 2 tumors increased at 1 month, respectively. Tumor volume decreased by 2.4%-99% after 3 months.

CONCLUSIONS

Changes in the TSC can be quantified by sodium MR imaging at 7T and used to detect radiobiologic alterations in intracranial tumors at early time points after CyberKnife radiation therapy.

Influence of dexamethasone on visible 5-ALA fluorescence and quantitative protoporphyrin IX accumulation measured by fluorescence lifetime imaging in glioblastomas: is pretreatment obligatory before fluorescence-guided surgery?

OBJECTIVE

Fluorescence-guided surgery using 5-aminolevulinic acid (5-ALA) is nowadays widely applied for improved resection of glioblastomas (GBMs). Initially, pretreatment with dexamethasone was considered to be essential for optimal fluorescence effect. However, recent studies reported comparably high rates of visible fluorescence in GBMs despite absence of dexamethasone pretreatment. Recently, the authors proposed fluorescence lifetime imaging (FLIM) for the quantitative analysis of 5-ALA-induced protoporphyrin IX (PpIX) accumulation. The aim of this study was thus to investigate the influence of dexamethasone on visible fluorescence and quantitative PpIX accumulation.

METHODS

The authors prospectively analyzed the presence of visible fluorescence during surgery in a cohort of patients with GBMs. In this study, patients received dexamethasone preoperatively only if clinically indicated. One representative tumor sample was collected from each GBM, and PpIX accumulation was analyzed ex vivo by FLIM. The visible fluorescence status and mean FLIM values were correlated with preoperative intake of dexamethasone.

RESULTS

In total, two subgroups with (n = 27) and without (n = 20) pretreatment with dexamethasone were analyzed. All patients showed visible fluorescence independent from preoperative dexamethasone intake. Furthermore, the authors did not find a statistically significant difference in the mean FLIM values between patients with and without dexamethasone pretreatment (p = 0.097).

CONCLUSIONS

In this first study to date, the authors found no significant influence of dexamethasone pretreatment on either visible 5-ALA fluorescence during GBM surgery or PpIX accumulation based on FLIM. According to these preliminary data, the authors recommend administering dexamethasone prior to fluorescence-guided surgery of GBMs only when clinically indicated.

Medical and Neurological Management of Brain Tumor Complications

PURPOSE OF REVIEW

The diagnosis of brain tumors often leads to complications that are either related to the tumor itself or the tumor-directed and supportive therapies, increasing the burden on the patients' quality of life and even survival. This article reviews the medical and neurological conditions that commonly complicate the disease course of brain tumors patients.

RECENT FINDINGS

Various mechanisms have been newly identified to be involved in the pathophysiology of seizures and brain edema and can help advance the treatment of such complications. There have also been new developments in the management of thromboembolic disease and cognitive impairment. Medical and neurological complications are being identified more often in brain tumor patients with the improved survival provided by therapeutic advances. Early and proper identification and management of such complications are crucial for a better survival and quality of life.

Comparison of the Signal Intensity of Vestibular Schwannoma Between Growing and Nongrowing Tumors

OBJECTIVES/HYPOTHESIS

To determine the relationship between signal intensity on gadolinium (Gd)-enhanced magnetic resonance images and growth of vestibular schwannomas (VSs).

STUDY DESIGN

Cross-sectional study.

METHODS

In this cross-sectional study, we retrospectively reviewed the data of 31 patients with VSs who underwent magnetic resonance imaging (MRI). The mean signal intensities within the regions of interest in the tumor, pons, and temporal muscles were measured on Gd-enhanced T1-weighted MRI. Relative intensity ratios were calculated as follows: T/N pons ratio (T/Np) is the tumor signal intensity/pons signal intensity and T/N muscle ratio (T/Nm) is the tumor signal intensity/temporal muscle signal intensity. Volume measurements were used to assess the tumor size. Growth rate was determined by assessing previous imaging studies. Growing VS was defined as a tumor with a growth rate >100 mm³ /year.

RESULTS

The mean (standard deviation) T/Np and T/Nm were 1.47 (0.27) and 1.50 (0.24), respectively, in nongrowing tumors and 1.78 (0.17) and 1.90 (0.12), respectively, in growing tumors. The T/Np and T/Nm differed significantly between the two groups (T/Np, P < .001; T/Nm, P < .001). Receiver operating characteristic curve analysis showed that cutoffs of 1.56 and 1.76 for T/Np (93.33% sensitivity, 75.00% specificity) and T/Nm (100.00% sensitivity, 93.75% specificity), respectively, could be used to diagnose a growth rate of >100 mm³ /year. The area under the curve was 0.85 (95% confidence interval, 0.70-1.00) for T/Np and 0.94 (0.82-1.00) for T/Nm.

CONCLUSION

Growing VSs show higher signal intensities on Gd-enhanced MRI. Thus, measuring the signal intensity of VS on Gd-enhanced MRI may aid in predicting VS growth.

LEVEL OF EVIDENCE

3 Laryngoscope, 2021.

Vascular endothelial growth factor concentrations in the cerebrospinal fluid of dogs with neoplastic or inflammatory central nervous system disorders

Background

Vascular endothelial growth factor (VEGF) is a key molecular driver of angiogenesis and vascular permeability and is expressed by a wide variety of neoplasms. Although blood VEGF concentrations have been quantified in intracranial tumors of dogs, cerebrospinal fluid (CSF) VEGF concentration might be a more sensitive biomarker of disease.

Objective

Concentrations of VEGF in CSF are higher in dogs with central nervous system (CNS) neoplasia compared to those with meningoencephalomyelitis and other neurologic disorders.

Animals

One hundred and twenty‐six client‐owned dogs presented to a veterinary teaching hospital.

Methods

Case‐control study. Cerebrospinal fluid was archived from dogs diagnosed with CNS neoplasia and meningoencephalomyelitis. Control dogs had other neurological disorders or diseases outside of the CNS. A commercially available kit was used to determine VEGF concentrations.

Results

Detectable CSF VEGF concentrations were present in 49/63 (77.8%) neoplastic samples, 22/24 (91.7%) inflammatory samples, and 8/39 (20.5%) control samples. The VEGF concentrations were significantly different between groups (P < .0001), and multiple comparison testing showed that both neoplastic and inflammatory groups had significantly higher concentrations than did controls (P < .05), but did not differ from each other. Gliomas and choroid plexus tumors had significantly higher VEGF concentrations than did the control group (P < .05).

Conclusions and Clinical Importance

Cerebrospinal fluid VEGF concentrations may serve as a marker of neoplastic and inflammatory CNS disorders relative to other conditions.

Pregnancies after Childhood Craniopharyngioma: Results of KRANIOPHARYNGEOM 2000/2007 and Review of the Literature

BACKGROUND

Data on female fertility, pregnancy, and outcome of offspring after childhood-onset craniopharyngioma (CP) are rare.

STUDY DESIGN

Observational study on pregnancy rate and offspring outcome in female CP patients recruited in KRANIOPHARYNGEOM 2000/2007 since 2000.

RESULTS

A total of 451 CP patients (223 female) have been recruited, and 269 (133 female) were postpubertal at study. Six of 133 female CP patients (4.5%) with a median age of 14.9 years at CP diagnosis had 9 pregnancies, giving birth to 10 newborns. Three patients achieved complete surgical resections. No patient underwent postoperative irradiation. Five natural pregnancies occurred in 3 CP patients without pituitary deficiencies. Four pregnancies in 3 CP patients with hypopituitarism were achieved under assisted reproductive techniques (ART) (median 4.5 cycles, range: 3-6 cycles). Median maternal age at pregnancy was 30 years (range: 22-41 years). Six babies (60%) were delivered by caesarean section. Median gestational age at delivery was 38 weeks (range: 34-43 weeks); median birth weight was 2,920 g (range: 2,270-3,520 g), the rate of preterm delivery was 33%. Enlargements of CP cysts occurred in 2 women during pregnancy. Other complications during pregnancy, delivery, and postnatal period were not observed.

CONCLUSIONS

Pregnancies after CP are rare and were only achieved after ART in patients with hypopituitarism. Close monitoring by an experienced reproductive physician is necessary. Due to a potentially increased risk for cystic enlargement, clinical, ophthalmological, and MRI monitoring are recommended in patients at risk. Severe perinatal complications, birth defects, and postnatal morbidity of mothers and offspring were not observed.

Assessment of Prognostic Value of Cystic Features in Glioblastoma Relative to Sex and Treatment With Standard-of-Care

Glioblastoma (GBM) is the most aggressive primary brain tumor and can have cystic components, identifiable through magnetic resonance imaging (MRI). Previous studies suggest that cysts occur in 7–23% of GBMs and report mixed results regarding their prognostic impact. Using our retrospective cohort of 493 patients with first-diagnosis GBM, we carried out an exploratory analysis on this potential link between cystic GBM and survival. Using pretreatment MRIs, we manually identified 88 patients with GBM that had a significant cystic component at presentation and 405 patients that did not. Patients with cystic GBM had significantly longer overall survival and were significantly younger at presentation. Within patients who received the current standard of care (SOC) (N = 184, 40 cystic), we did not observe a survival benefit of cystic GBM. Unexpectedly, we did not observe a significant survival benefit between this SOC cystic cohort and patients with cystic GBM diagnosed before the standard was established (N = 40 with SOC, N = 19 without SOC); this significant SOC benefit was clearly observed in patients with noncystic GBM (N = 144 with SOC, N = 111 without SOC). When stratified by sex, the survival benefit of cystic GBM was only preserved in male patients (N = 303, 47 cystic). We report differences in the absolute and relative sizes of imaging abnormalities on MRI and the prognostic implication of cysts based on sex. We discuss hypotheses for these differences, including the possibility that the presence of a cyst could indicate a less aggressive tumor.

Gelfoam Padding, an innovative surgical technique improving the total resection rate of cystic gliomas

OBJECTIVE

The cystic gliomas are the special type of malignant tumors in the brain and often lead to unsatisfied prognosis, but the microsurgical resection is still the most important treatment. However, they are difficult to be totally removed with craniotomy, especially for those who have flimsy cyst walls. Recently, we attempted to resect them via an innovative surgical technique, "Gelfoam Padding", in order to improve the total resection rate of the tumors safely.

PATIENTS AND METHODS

Fifteen patients suffering intracerebral cystic gliomas underwent surgical intervention via "Gelfoam Padding" technique between 2015 and 2018, and the different histopathological results and their features of cyst walls were recorded. Then, the total resection rate of tumors as well as the complications after surgeries were analyzed to assess the applied value of this technique.

RESULTS

All the patients were improved in the clinical symptoms after the operations. According to the intraoperative assessment and MRI examinations performed within 72 h after surgery, total resection of the tumor was achieved in all patients. Besides, there were no serious postoperative complications in these cases with this technique.

CONCLUSION

The cystic glioma with the flimsy wall was the best applied indication of "Gelfoam Padding" technique, which could not only improve the total resection rate of tumors, but also be safe for the patients.

Fiber-tract localized diffusion coefficients highlight patterns of white matter disruption induced by proximity to glioma

Gliomas account for 26.5% of all primary central nervous system tumors. Recent studies have used diffusion tensor imaging (DTI) to extract white matter fibers and the diffusion coefficients derived from MR processing to provide useful, non-invasive insights into the extent of tumor invasion, axonal integrity, and gross differentiation of glioma from metastasis. Here, we extend this work by examining whether a tract-based analysis can improve non-invasive localization of tumor impact on white matter integrity. This study retrospectively analyzed preoperative magnetic resonance sequences highlighting contrast enhancement and DTI scans of 13 subjects that were biopsy-confirmed to have either high or low-grade glioma. We reconstructed the corticospinal tract and superior longitudinal fasciculus by applying atlas-based regions of interest to fibers derived from whole-brain deterministic streamline tractography. Within-subject comparison of hemispheric diffusion coefficients (e.g., fractional anisotropy and mean diffusivity) indicated higher levels of white matter degradation in the ipsilesional hemisphere. Novel application of along-tract analyses revealed that tracts traversing the tumor region showed significant white matter degradation compared to the contralesional hemisphere and ipsilesional tracts displaced by the tumor.

Machine-learning in grading of gliomas based on multi-parametric magnetic resonance imaging at 3T

OBJECTIVE

The objective of this study was to assess the contribution of multi-parametric (mp) magnetic resonance imaging (MRI) quantitative features in the machine learning-based grading of gliomas with a multi-region-of-interests approach.

MATERIALS AND METHODS

Forty-three patients who were newly diagnosed as having a glioma were included in this study. The patients were scanned prior to any therapy using a standard brain tumor magnetic resonance (MR) imaging protocol that included T1 and T2-weighted, diffusion-weighted, diffusion tensor, MR perfusion and MR spectroscopic imaging. Three different regions-of-interest were drawn for each subject to encompass tumor, immediate tumor periphery, and distant peritumoral edema/normal. The normalized mp-MRI features were used to build machine-learning models for differentiating low-grade gliomas (WHO grades I and II) from high grades (WHO grades III and IV). In order to assess the contribution of regional mp-MRI quantitative features to the classification models, a support vector machine-based recursive feature elimination method was applied prior to classification.

RESULTS

A machine-learning model based on support vector machine algorithm with linear kernel achieved an accuracy of 93.0%, a specificity of 86.7%, and a sensitivity of 96.4% for the grading of gliomas using ten-fold cross validation based on the proposed subset of the mp-MRI features.

CONCLUSION

In this study, machine-learning based on multiregional and multi-parametric MRI data has proven to be an important tool in grading glial tumors accurately even in this limited patient population. Future studies are needed to investigate the use of machine learning algorithms for brain tumor classification in a larger patient cohort.

Relationship between expression of vascular endothelial growth factor and intratumoral hemorrhage in human pituitary adenomas

Aims and background

Although pituitary adenoma is a primary brain tumor that occasionally accompanies intratumoral hemorrhage, there are little reports about the molecular mechanism of intratumoral bleeding in pituitary adenoma. Vascular endothelial growth factor (VEGF) plays an important role in angiogenesis and vascular permeability of various brain tumors. The authors studied the relationship between intratumoral hemorrhage and the expression of VEGF in human pituitary adenomas.

Methods

VEGF expression was assessed by reverse transcriptase polymerase chain reaction (RT-PCR) in 71 pituitary adenomas. Clinical factors to investigate were age, gender, hormonal functioning, and radiological findings of pituitary adenomas. Radiological findings which were investigated by magnetic resonance (MR) images were intratumoral hemorrhage, cystic change, tumor size, and cavernous sinus invasion. The relationship between these factors and VEGF expression was statistically analyzed.

Results

VEGF was expressed in 25 cases (35.2%). Functioning tumors, hemorrhage, cystic change, and cavernous sinus invasion were 32 (45.1%), 18 (25.4%), 12 (16.9%), and 21 (29.6%) respectively. The expression of VEGF showed a significant relationship with the intratumoral hemorrhage of the adenomas (P <0.001). However, age, gender, tumor size, hormonal functioning, cyst formation, and cavernous sinus invasion had no relationship with VEGF expression (P >0.05).

Conclusions

This study suggests that VEGF expression may be responsible for intratumoral hemorrhage of pituitary adenomas. Therefore, VEGF can be a novel target to prevent a catastrophic apoplexy in pituitary adenomas and to establish roles in angiogenesis-based therapeutics of pituitary adenomas.

Clinical Relevance of Steroid Use in Neuro-Oncology

BACKGROUND

Corticosteroids are commonly used in the management of primary central nervous system (CNS) tumors and CNS metastases to treat cancer- and treatment-related cerebral edema and improve neurologic function. However, they are also associated with significant morbidity and mortality, given their wide range of adverse effects.

PURPOSE OF REVIEW

To review the mechanism of action, pharmacology, and toxicity profile of corticosteroids and to critically appraise the evidence that supports their use in neuro-oncologic practice based on the latest scientific and clinical data.

RECENT FINDINGS

Recent data suggest that corticosteroids may negatively impact survival in glioma patients. In addition, corticosteroids should be incorporated as a standard criterion to assess a patient's clinical and radiographic response to treatment. Corticosteroids should be used judiciously in neuro-oncologic patients, given the potential deleterious effects on clinical outcome and patient survival. Anti-angiogenic agents, which lack these adverse effects, may be a reasonable alternative to corticosteroids.

Posttreatment Evaluation of Brain Gliomas

The imaging of treated gliomas is complicated by a variety of treatment related effects, which can falsely simulate disease improvement or progression. Distinguishing between disease progression and treatment effects is difficult with standard MR imaging pulse sequences and added specificity can be gained by the addition of advanced imaging techniques.

Systemic Expression of Vascular Endothelial Growth Factor in Patients with Cerebral Cavernous Malformation Treated by Stereotactic Radiosurgery

OBJECTIVE

Increased expression of angiogenic factors, such as vascular endothelial growth factor (VEGF), is associated with the pathogenesis of cerebral cavernous malformations (CCMs). The purpose of this study was to investigate plasma levels of VEGF in normal subjects and in patients with CCM and to evaluate change in these levels following stereotactic radiosurgery (SRS).

METHODS

Peripheral venous blood was collected from 6 patients with CCM before SRS using Gamma Knife and at the 1 week, 1 month, 3month, and 6 month follow-up visits. Plasma VEGF levels were measured using commercially available enzyme-linked immunosorbent assay kits. Peripheral blood samples were obtained from 10 healthy volunteers as controls.

RESULTS

Mean plasma VEGF level of 41.9 pg/mL (range, 11.7-114.9 pg/mL) in patients with CCM at baseline was higher than that of the healthy controls (29.3 pg/mL, range, 9.2-64.3 pg/mL), without significant differences between CCM patients and controls (p=0.828). Plasma VEGF level following SRS dropped to 24.6 pg/mL after 1 week, and decreased to 18.5 pg/mL after 1 month, then increased to 24.3 pg/mL after 3 months, and 32.6 pg/mL after 6 months. Two patients suffering from rebleeding after SRS showed a higher level of VEGF at 6 months after SRS than their pretreatment level.

CONCLUSION

Plasma VEGF levels in patients with CCM were elevated over controls at baseline, and decreased from baseline to 1 month after SRS and increased further for up to 6 months. Theses results indicated that anti-angiogenic effect of SRS might play a role in the treatment of CCMs.

Rapid increase in cystic volume of an anaplastic astrocytoma misdiagnosed as neurocysticercosis: A case report

Reports describing a rapid increase in the cystic volume of anaplastic astrocytoma (AA) in a short time frame are rare. The present study reports the case of a 68-year-old male who was admitted to the No. 9 People's Hospital, Shanghai Jiaotong University School of Medicine (Shanghai, China), with a small cystic brain lesion and positive immunological testing for cysticercosis. Head magnetic resonance imaging (MRI) showed a cystic lesion, 6 mm in diameter, in the left frontal lobe. Neurocysticercosis was suspected and the patient was treated with a clinical trial of albendazole and steroids. A period of 25 days later, the patient's condition had deteriorated, and MRI revealed a cystic lesion in the left frontal lobe; thereafter, the cystic lesion was removed and a diagnosis of AA was established. The tumor was soft, ivory white and gelatinous due to myxoid degeneration. In this case, tumor-related angiogenesis and microvascular extravasation (blood-brain barrier disruption) may have been the main cause of the rapid increase in the cystic volume in such a short time frame. The similarity of the glioma and cysticercus antigens may have been the cause of the positive reactions in the cystic fluid. The present study reports the rare occurrence of a rapid increase of cystic volume and potential diagnostic difficulties.

Targeted toxins

Objective. Current modalities used in the treatment of cancer often cause unacceptable damage to normal tissue. Toxins targeted toward tumor cells by antibodies or growth factors have the potential to selectively kill tumor cells while leaving normal tissue intact. The purpose of this review is to provide background information on targeted toxins and current clinical studies for this new class of anti-cancer compounds.

Data sources. A MEDLINE search was conducted using the term “immunotoxins.” Relevant articles were also obtained by the systematic examination of article references.

Data synthesis. The toxins Pseudomonas exotoxin, diphtheria toxin, and ricin toxin are often used as targeted toxins. Deletion or mutation of the binding domains of these toxins decreased binding of the toxins to normal tissues. Antibodies or growth factors can be used as targeting moiety, and the resulting agents are called immunotoxins or fusion proteins, respectively. DNA technology and chemical modifications of the toxin as well as the antibody moiety led to smaller and less immunogenic targeted toxins. Smaller targeted toxins are less toxic and penetrate further into the tumor. The summary of several targeted toxins elicited during clinical trials in this review makes it clear that several targeted toxins are potential agents for the treatment of various cancers, although some problems still need to be overcome. These problems include toxicity, immunogenicity, cross-reactivity of the targeted toxin with life-sustaining tissue, heterogenicity of tumor cells, and limited tumor penetration.

Neuroimaging

Imaging is integral to the management of patients with brain tumors. Conventional structural imaging provides exquisite anatomic detail but remains limited in the evaluation of molecular characteristics of intracranial neoplasms. Quantitative and physiologic biomarkers derived from advanced imaging techniques have been increasingly utilized as problem-solving tools to identify glioma grade and assess response to therapy. This chapter provides a comprehensive overview of the imaging strategies used in the clinical assessment of patients with gliomas and describes how novel imaging biomarkers have the potential to improve patient management.

Magnetic resonance diffusion metrics indexing high focal cellularity and sharp transition at the tumour boundary predict poor outcome in glioblastoma multiforme

AIM

To investigate the prognostic power of intra-tumoural and gradient magnetic resonance imaging (MRI) diffusion metrics in patients with glioblastoma multiforme (GBM).

MATERIALS AND METHODS

Forty-six consecutive patients with histologically confirmed GBM who had undergone preoperative diffusion tensor imaging at 3 T were included. Mean diffusivity (MD) and MD gradient maps were computed. Regions of interest were analysed to determine the minimum MD within the enhancing tumour (minMD). MD gradients were calculated along the enhancing tumour boundary and subjected to histogram analysis. Overall survival (OS) and time to progression (TTP) were derived and survival analysis was undertaken.

RESULTS

There were 31 deaths and 37 patients progressed during the study period. Multivariate survival analysis, controlling for treatment and gender, showed that minMD values<6.1×10(-4) mm(2)/s predicted shorter OS (hazard ratio [HR]=2.82, 1.25-6.34; p=0.012) and TTP (HR=5.43, 1.96-15.05; p=0.001). Higher MD gradient values of the tumour boundary predicted shorter survival: MD gradient values >4.7×10(-5) mm(2)/s (10(th) centile) had a significantly shorter OS with a HR of 0.43 (0.19-0.96; p=0.04). Similarly, a value above 1.4×10(-4) mm(2)/s (75(th) centile) was a significant predictor for shorter OS (HR=0.39, 0.17-0.89; p=0.03).

CONCLUSIONS

Lower minMD and higher MD gradient values for the 10(th) and 75(th) percentile of the tumour boundary demonstrated prognostic value in preoperative GBM. This suggests that MRI diffusion metrics indicative of higher focal cellularity and steeper transition from high cellular tumour edge to low cellular oedema define more aggressive glioblastoma subtypes with a poorer prognosis.

Depot delivery of dexamethasone and cediranib for the treatment of brain tumor associated edema in an intracranial rat glioma model

Treatments of brain tumor associated edema with systemically delivered dexamethasone, the standard of care, and cediranib, a novel anti-edema agent, are associated with systemic toxicities in brain tumor patients. A tunable, reservoir-based drug delivery device was developed to investigate the effects of delivering dexamethasone and cediranib locally in the brain in an intracranial 9L gliosarcoma rat model. Reproducible, sustained releases of both dexamethasone and solid dispersion of cediranib in polyvinylpyrrolidone (AZD/PVP) from these devices were achieved. The water-soluble AZD/PVP, which exhibited similar bioactivity as cediranib, was developed to enhance the release of cediranib from the device. Local and systemic administration of both dexamethasone and cediranib was equally efficacious in alleviating edema but had no effect on tumor growth. Edema reduction led to modest but significant improvement in survival. Local delivery of dexamethasone prevented dexamethasone-induced weight loss, an adverse effect seen in animals treated with systemic dexamethasone. Local deliveries of dexamethasone and cediranib via these devices used only 2.36% and 0.21% of the systemic doses respectively, but achieved similar efficacy as systemic drug deliveries without the side effects associated with systemic administration. Other therapeutic agents targeting brain tumor can be delivered locally in the brain to provide similar improved treatment outcomes.

Recurrent ascites in a patient with low-grade astrocytoma and ventriculo-peritoneal shunt treated with the multikinase inhibitor sorafenib

This report describes a 6-year-old boy with disseminated low-grade astrocytoma and ventriculo-peritoneal shunt, who developed recurrent ascites while receiving sorafenib on a clinical trial. Laboratory analysis of the peritoneal fluid showed no elevation of protein content and no evidence of underlying infection or tumor dissemination. This report highlights ascites as a previously unrecognized adverse reaction to sorafenib in a patient with a ventriculo-peritoneal shunt. We conclude that such patients should be closely monitored for this complication when treated with sorafenib.

Peritumoral brain edema in intracranial meningiomas: the emergence of vascular endothelial growth factor-directed therapy

Meningioma is the second most common type of adult intracranial neoplasm. A substantial subset of patients present with peritumoral brain edema (PTBE), which can cause significant morbidity via mass effect, complicate surgical management, and impact the safety of stereotactic radiosurgery. Recent studies suggest a close relationship between vascular endothelial growth factor-A (VEGF-A) expression and PTBE development in meningiomas. The authors performed a systematic review of the literature on the pathogenesis of PTBE in meningiomas, the effectiveness of steroid therapy, the role played by VEGF-A, and the current clinical evidence for antiangiogenic therapy to treat peritumoral brain edema. Mounting evidence suggests VEGF-A is secreted directly by meningioma cells to induce angiogenesis and edemagenesis of tumoral as well as peritumoral brain tissue. The VEGF-A cascade results in recruitment of cerebral-pial vessels and disruption of the tumor-brain barrier, which appear to be requisite for VEGF-A to have an edemagenic effect. Results of preliminary clinical studies suggest VEGF-directed therapy has modest activity against recurrent and progressive meningioma growth but can alleviate PTBE in some patients. A comprehensive understanding of the VEGF-A pathway and its modulators may hold the key to an effective therapeutic approach to treating PTBE associated with meningiomas. Further clinical trials with larger patient cohorts and longer follow-up periods are warranted to confirm the efficacy of VEGF-directed therapy.

Astragalus membranaceus as a cause of increased CA19-9 and liver and kidney cysts: a case report

WHAT IS KNOWN AND OBJECTIVE

Astragalus membranaceus, one of the most common Chinese herbs, is widely used to prevent and treat a variety of diseases. Very few adverse reactions, caused by A. membranaceus, have been reported in the literature. The purpose of this article was to report a case of marked increase in carbohydrate antigen 19-9 (CA19-9) and the formation of liver and kidney cysts following oral administration of A. membranaceus.

CASE SUMMARY

A 38-year-old woman was found to have a high serum CA19-9 level (156 U/mL) at her routine annual examination. On follow-up, several small cysts were found in her left kidney and liver by CT scan. Her medical history showed that she had taken Astragalus tea every day for 1 month. One month after she stopped taking it, the CA19-9 level decreased to 40·19 U/mL. Ten months later, PET-CT showed that there were no liver and kidney cysts. However, she took Astragalus powder again in the second year and 1 month later her CA19-9 level increased again to more than 1000 U/mL. Several small cysts were again seen in her left kidney and liver by enhanced CT. Her CA19-9 level gradually became normal after she stopped taking the Astragalus powder.

WHAT IS NEW AND CONCLUSION

This case strongly suggests that oral administration of A. membranaceus may lead to increase in CA19-9 and the formation of liver and kidney cysts.

Perfusion MRI: the five most frequently asked clinical questions

OBJECTIVE

This article addresses questions that radiologists frequently ask when planning, performing, processing, and interpreting MRI perfusion studies in CNS imaging.

CONCLUSION

Perfusion MRI is a promising tool in assessing stroke, brain tumors, and neurodegenerative diseases. Most of the impediments that have limited the use of per-fusion MRI can be overcome to allow integration of these methods into modern neuroimaging protocols.

Tumor-associated edema in brain cancer patients: pathogenesis and management

The long-term treatment of peritumoral edema remains a major challenge in clinical neuro-oncology. Steroids have been and will remain the backbone of any anti-edematous therapy because of their striking activity, convenient oral administration and also because of their cost-effectiveness. Their side effects, however, can compromise quality of life, particularly upon continuous administration. Therapeutic alternatives which may replace or - at least - help to reduce the steroid dose are limited. However, with the development of new agents such as corticorelin acetate, there is a hope that steroid-induced side effects can be delayed and reduced. The administration of anti-angiogenic agents with steroid-sparing effects, for example, bevacizumab, is limited due to their costs. Increased knowledge on boswellic acids and cyclooxygenase-2 inhibitors which are available for clinical application may help to exploit their anti-edema activity more efficiently in the future.

Complications of brain tumors and their treatment

The diverse medical and neurologic complications of central nervous system (CNS) neoplasms or their treatment cause significant morbidity and mortality. Thus, their recognition and appropriate management by all members of the interdisciplinary team engaged in the care of patients with brain tumors is essential in optimizing quality of life and extending survival. Recognition of the acute, early delayed, and late complications of brain irradiation is essential to optimize management and mitigate their clinical impact.

Hydrocephalic holoprosencephaly: An oxymoron? Insights into etiology and management

Holoprosencephaly is usually associated with microcephaly, although macrocephaly is not uncommonly seen. However, the cause of hydrocephalus in holoprosencephaly remains ill-defined. Here, the authors report a case of CSF ascites following ventriculoperitoneal shunt placement in a five month-old child with alobar holoprosencephaly, and hypothesize that the excessive CSF production which occurs in this condition may be responsible for the formation of CSF ascites. Further research is required to assess whether the gene responsible for holoprosencephaly is also responsible for upregulating CSF production in patients with concomitant hydrocephalus.

Heparanase expression in periapical granulomas and radicular cysts

Heparanase is an endo-β-D-glucuronidase enzyme which degrades heparan sulfate glycosaminoglycan side chains of proteoglycans in the extracellular matrix and in basement membranes. The aim of this study was to evaluate the expression of heparanase in periapical granulomas (PGs) and radicular cysts (RCs). Immunohistochemistry was used to assess heparanase expression in PGs and RCs. Parameters including stain intensity, location and cell type were used to characterize heparanase expression in the periapical lesions. Ordered categories (from weak to strong) were used to compare the level of heparanase staining in the PG and RC groups. Both epithelial cells and inflammatory cells were positive for heparanase. The relative staining of the epithelial cells was strong, whereas the relative staining of the inflammatory cells was weak. Significant differences in immunohistochemical staining of epithelial cells were observed between RCs and PGs (p = 0.002). The relative expression of heparanase in epithelial cells in RCs was strong. In PGs, lesions with few or no epithelial cells, heparanase was predominantly expressed weakly by inflammatory cells. PGs and RCs have the same infectious origin. Therefore, the different cellular sources of heparanase in these periapical lesions may imply that this enzyme has specific pathogenetic functions in RCs and PGs.

A critical evaluation of cystic features in primary glioblastoma as a prognostic factor for survival

Object

The presence of cystic features in glioblastoma (GBM) has been described as a favorable prognostic factor. The aim of this study was to determine the survival outcome in patients undergoing surgery for newly diagnosed primary GBM with a large cystic component as compared with a large cohort of patients with noncystic GBM, while controlling for well-characterized prognostic factors.

Methods

A retrospective review of 354 consecutive patients treated with resection of primary GBM was performed using medical records and imaging information obtained at the University of California, San Francisco from 2005 to 2009. Within this cohort, 37 patients with large cysts (≥ 50% of tumor) were identified. Clinical presentations and surgical outcomes were statistically compared between the cystic and noncystic patients.

Results

There were no statistically significant differences in clinical presentation between groups, including differences in age, sex, presenting symptoms, tumor location, or preoperative functional status, with the exception of tumor size, which was marginally larger in the cystic group. Surgical outcomes, including extent of resection and postoperative functional status, were equivalent. The median actuarial survival for the patients with cystic GBM was 17.0 months (95% CI 12.6–21.3 months), and the median survival for patients with noncystic GBM was 15.9 months (95% CI 14.6–17.2 months). There was no significant between-groups difference in survival (p = 0.99, log-rank test). A Cox multivariate regression model was constructed, which identified only age and extent of resection as independent predictors of survival. The presence of a cyst was not a statistically significant prognostic factor.

Conclusions

This study, comprising the largest series of cases of primary cystic GBM reported in the literature to date, demonstrates that the presence of a large cyst in patients with GBM does not significantly affect overall survival as compared with survival in patients without a cyst. Preoperative discussions with patients with GBM should focus on validated prognostic factors. The presence of cystic features does not confer a survival advantage.

Does age matter? - A MRI study on peritumoral edema in newly diagnosed primary glioblastoma

Background

Peritumoral edema is a characteristic feature of malignant glioma related to the extent of neovascularisation and to vascular endothelial growth factor (VEGF) expression.

The extent of peritumoral edema and VEGF expression may be prognostic for patients with glioblastoma. As older age is a negative prognostic marker and as VEGF expression is reported to be increased in primary glioblastoma of older patients, age-related differences in the extent of peritumoral edema have been assessed.

Methods

In a retrospective, single-center study, preoperative magnetic resonance imaging (MRI) scans of steroid-naïve patients (n = 122) of all age groups were analysed. Patients with clinically suspected, radiologically likely or known evidence of secondary glioblastoma were not included.

Extent of brain edema was determined in a metric quantitative fashion and in a categorical fashion in relation to tumor size. Analysis was done group-wise related to age. Additionally, tumor size, degree of necrosis, superficial or deep location of tumor and anatomic localization in the brain were recorded.

Results

The extent of peritumoral edema in patients >65 years (ys) was not different from the edema extent in patients ≤ 65 ys (p = 0.261). The same was true if age groups ≤ 55 ys and ≥ 70 ys were compared (p = 0.308). However, extent of necrosis (p = 0.023), deep tumor localization (p = 0.02) and frontal localisation (p = 0.016) of the tumor were associated with the extent of edema. Tumor size was not linearly correlated to edema extent (Pearson F = 0.094, p = 0.303) but correlated to degree of necrosis (F = 0.355, p < 0.001, Spearman-Rho) and depth of tumor (p < 0.001). In a multifactorial analysis of maximum edema with the uncorrelated factors age, regional location of tumor and degree of necrosis, only the extent of necrosis (p = 0.022) had a significant effect.

Conclusion

Age at diagnosis does not determine degree of peritumoral edema, and tumor localization in the white matter is associated with greater extent of edema. The area of necrosis is reflective of volume of edema. In summary, the radiographic appearance of a glioblastoma at diagnosis does not reflect biology in the elderly patient.

Diffusion tensor-based tumor infiltration index cannot discriminate vasogenic edema from tumor-infiltrated edema

Diffusion tensor imaging (DTI) by magnetic resonance imaging (MRI) is now used not only for delineating white matter fiber tracts, but also for assessing the histological characteristics of pathological tissues. Among these uses, predicting the extent or existence of tumor cell invasion into white matter by DTI is under extensive investigation. The previously reported tumor infiltration index (TII) holds great potential for the discrimination of pure vasogenic edema from tumor-infiltrated edema. However, conflicting data are being reported questioning the clinical value of TII. The present investigation reevaluated the utility of TII in patients with meningioma or glioma. We found that TII was unable to discriminate vasogenic from tumor-infiltrated edema. Conversely, detailed voxel-by-voxel comparison of TII and (11)C-methionie PET in the T2-hyperintense area of gliomas showed that TII and (11)C-methionie PET has a positive correlation, suggesting that, although TII is unable to discriminate the cause of edema, the extent of tumor cell invasion into white matter is depicted in gliomas by TII. These data suggest that TII involves both vasogenic and tumor-infiltrated factors, rather than only a single factor. A more intensive investigation is required to reach a complete understanding of TII.

VEGF inhibitors in the treatment of cerebral edema in patients with brain cancer

Most brain tumors oversecrete vascular endothelial growth factor (VEGF), which leads to an abnormally permeable tumor vasculature. This hyperpermeability allows fluid to leak from the intravascular space into the brain parenchyma, which causes vasogenic cerebral edema and increased interstitial fluid pressure. Increased interstitial fluid pressure has an important role in treatment resistance by contributing to tumor hypoxia and preventing adequate tumor penetration of chemotherapy agents. In addition, edema and the corticosteroids needed to control cerebral edema cause significant morbidity and mortality. Agents that block the VEGF pathway are able to decrease vascular permeability and, thus, cerebral edema, by restoring the abnormal tumor vasculature to a more normal state. Decreasing cerebral edema minimizes the adverse effects of corticosteroids and could improve clinical outcomes. Anti-VEGF agents might also be useful in other cancer-related conditions that increase vascular permeability, such as malignant pleural effusions or ascites.

Quantitative imaging biomarkers in neuro-oncology

Conventional structural imaging provides limited information on tumor characterization and prognosis. Advances in neurosurgical techniques, radiotherapy planning and novel drug treatments for brain tumors have generated increasing need for reproducible, noninvasive, quantitative imaging biomarkers. This Review considers the role of physiological MRI and PET molecular imaging in understanding metabolic processes associated with tumor growth, blood flow and ultrastructure. We address the utility of various techniques in distinguishing between tumors and non-neoplastic processes, in tumor grading, in defining anatomical relationships between tumor and eloquent brain regions and in determining the biological substrates of treatment response. Much of the evidence is derived from limited case series in individual centers. Despite their 'added value', the effect of these techniques as an adjunct to structural imaging in clinical research and practice remains limited.

The differences of water diffusion between brain tissue infiltrated by tumor and peritumoral vasogenic edema

The differences between peritumoral brain tissue infiltrated by tumor and vasogenic edema were prospectively evaluated by comparing the apparent diffusion coefficient (ADC) of peritumoral areas of infiltrative tumors (anaplastic astrocytomas and glioblastomas) to that of peritumoral areas of noninfiltrative tumors (metastatic carcinomas) on 54 patients. Peritumoral ADCs indicated the possibility of differentiation between tumor infiltration and vasogenic edema, as well as between primary gliomas and metastases.

Brain tumors and epilepsy: pathophysiology of peritumoral changes

Epilepsy commonly develops among patients with brain tumors, frequently even as the presenting symptom, and such patients consequently experience substantial morbidity from both the seizures and the underlying disease. At clinical presentation, these seizures are most commonly focal with secondary generalization and conventional medical management is often met with less efficacy. The molecular pathophysiology of these seizures is being elucidated with findings that both the tumoral and peritumoral microenvironments may exhibit epileptogenic phenotypes owing to disordered neuronal connectivity and regulation, impaired glial cell function, and the presence of altered vascular supply and permeability. Neoplastic tissue can itself be the initiation site of seizure activity, particularly for tumors arising from neuronal cell lines, such as gangliogliomas or dysembryoblastic neuroepithelial tumors. Conversely, a growing intracranial lesion can both structurally and functionally alter the surrounding brain tissue with edema, vascular insufficiency, inflammation, and release of metabolically active molecules, hence also promoting seizure activity. The involved mechanisms are certain to be multifactorial and depend on specific tumor histology, integrity of the blood brain barrier, and characteristics of the peritumoral environment. Understanding these changes that underlie tumor-related epilepsy may have roles in both optimal medical management for the seizure symptom and optimal surgical objective and management of the underlying disease.

Inhibition of tumor-induced edema by antisense VEGF is mediated by suppressive vesiculo-vacuolar organelles (VVO) formation

Vascular endothelial growth factor (VEGF) is an important regulator of angiogenesis, vasculogenesis and vascular permeability. Edema in glioma tumors is considered one of the most pathological characteristics, but the mechanism of regulating vascular permeability is still unclear. In the present study, tumorigenic mice were generated by subcutaneous injection of glioma cell lines, C6-null cells and stable transfected-C6 cells overexpressing mock vector (C6-mock) and antisense VEGF (C6-VEGF(-/-)). Overexpression of antisense VEGF (C6-VEGF(-/-) mice) significantly suppressed tumor growth, decreased angiogenesis and reduced tumoral edema. Further studies by electron microscope revealed that tumor-induced hyperpermeability was mediated by formation of vesiculo-vacuolar organelles (VVO), specifically reducing the number of vesicle and caveolae in VVO, and this effect was blocked, at least partially, by antisense VEGF. These data show a possible mechanism of tumor-induced hyperpermeability and indicate that blockage of VEGF might contribute to therapeutical strategies for tumor edema.

Magnetic resonance perfusion imaging in neuro-oncology

Recent advances in magnetic resonance imaging (MRI) have seen the development of techniques that allow quantitative imaging of a number of anatomical and physiological descriptors. These techniques have been increasingly applied to cancer imaging where they can provide some insight into tumour microvascular structure and physiology. This review details technical approaches and application of quantitative MRI, focusing particularly on perfusion imaging and its role in neuro-oncology.

Immunoexpression of vascular endothelial growth factor in periapical granulomas, radicular cysts, and residual radicular cysts

OBJECTIVE

Our aim was to assess and compare the immunoexpression of vascular endothelial growth factor (VEGF) in periapical granulomas (PGs), radicular cysts (RCs), and residual radicular cysts (RRCs), relating it to the angiogenic index and the intensity of the inflammatory infiltrate.

STUDY DESIGN

Twenty PGs, 20 RCs, and 10 RRCs were evaluated by immunohistochemistry using anti-VEGF antibody. Angiogenic index was determined by microvessel count (MVC) using anti-von Willebrand factor antibody.

RESULTS

The PGs and RCs showed higher expression of VEGF than the RRCs. Lesions presenting few inflammatory infiltrate revealed the lowest immunoexpression of VEGF (P < .05). Irrespective of the intensity of the inflammatory infiltrate, most of the RCs and RRCs showed moderate to strong epithelial expression of VEGF. Lesions showing dense inflammatory infiltrate presented higher MVC indices (P < .05). VEGF expression and MVC did not reveal a significant correlation (P > .05).

CONCLUSIONS

VEGF is present in periapical inflammatory lesions but at a lower level in RRCs. The expression of this proangiogenic factor is closely related to the intensity of the inflammatory infiltrate in these lesions.

Expression of AT1 and AT2 angiotensin receptors in astrocytomas is associated with poor prognosis

Astrocytomas develop intense vascular proliferation, essential for tumour growth and invasiveness. Angiotensin II (ANGII) was initially described as a vasoconstrictor; recent studies have shown its participation in cellular proliferation, vascularisation, and apoptosis. We conducted a prospective study to evaluate the expression of ANGII receptors – AT1 and AT2 – and their relationship with prognosis. We studied 133 tumours from patients with diagnosis of astrocytoma who underwent surgery from 1997 to 2002. AT1 and AT2 were expressed in 52 and 44% of the tumours, respectively, when determined by both reverse transcriptase–polymerase chain reaction and immunohistochemistry. Ten per cent of low-grade astrocytomas were positive for AT1, whereas grade III and IV astrocytomas were positive in 67% (P<0.001). AT2 receptors were positive in 17% of low-grade astrocytomas and in 53% of high-grade astrocytomas (P=0.01). AT1-positive tumours showed higher cellular proliferation and vascular density. Patients with AT1-positive tumours had a lower survival rate than those with AT1-negative (P<0.001). No association to survival was found for AT2 in the multivariate analysis. Expression of AT1 and AT2 is associated with high grade of malignancy, increased cellular proliferation, and angiogenesis, and is thus related to poor prognosis. These findings suggest that ANGII receptors might be potential therapeutic targets for high-grade astrocytomas.

Vascular endothelial growth factor mRNA expression and peritumoral edema in canine primary central nervous system tumors

Vascular endothelial growth factor (VEGF) is an important regulator of tumor angiogenesis and vascular permeability, and has been implicated both in progression of central nervous system (CNS) tumors and development of vasogenic peritumoral edema. A retrospective study was done to characterize the levels of expression of the 3 major canine VEGF isoforms (VEGF(120), VEGF(164), VEGF(188)) in a variety of spontaneous canine CNS tumors using quantitative TaqMan reverse transcription real-time polymerase chain reaction. Presence and degree of peritumoral edema also were determined in sampled tumors using magnetic resonance imaging (MRI). Increased expression of VEGF relative to normal cerebral cortex tissue was seen predominantly in high grade astrocytic (grade IV) and oligodendroglial (grade III) tumors, with lower expression in low grade astrocytomas (grade II) and meningiomas (grade I). All 3 major VEGF isoforms were present; VEGF(164) was the predominant isoform, particularly in the tumors with the highest VEGF expression. Peritumoral edema was present in all tumor types; however, a significant association between the extent of peritumoral edema and the level of VEGF expression was not apparent.

Proton MR spectroscopy of cerebral gliomas at 3 T: spatial heterogeneity, and tumour grade and extent

This study aimed to evaluate the usefulness of proton MR spectroscopic imaging ((1)H-MRSI) at 3 T in differentiating high- from low-grade gliomas, and tumour from necrosis, oedema or normal tissue. Forty-four patients with brain gliomas and four with meningiomas were retrospectively reviewed. The normalised metabolites choline (nCho), N-acetylaspartate (nNAA), creatine (nCr) and lactate/lipids (nLL), and the metabolite ratios Cho/NAA, NAA/Cr and Cho/Cr were calculated. Necrotic-appearing areas showed two spectroscopic patterns: "necrosis" with variable nCho and high nLL, and "cystic necrosis" with variable nLL or nonevident peaks. Peri-enhancing oedematous-appearing areas showed three spectroscopic patterns ("tumour" with abnormal Cho/NAA, "oedema" with normal Cho/NAA and "tumour/oedema" with normal nCho and abnormal Cho/NAA) in gliomas, and one ("oedema") in meningiomas. Peri-enhancing or peri-tumour normal-appearing areas showed two patterns ("infiltrated" with abnormal nCho and/or Cho/NAA and "normal" with normal spectra) in gliomas and one ("normal") in meningiomas. Discriminant analysis showed that classification accuracy between high- and low-grade glioma masses was better with normalised metabolites or all parameters together than metabolite ratios and that among peri-enhancing areas was much better with normalised metabolites. The analysis of spatial distribution of normalised metabolites by 3-T (1)H-MRSI helps to discriminate among different tissues, offering information not available with conventional MRI.

Increased expression of intracystic matrix metalloproteinases in brain tumors: relationship to the pathogenesis of brain tumor-associated cysts and peritumoral edema

Although several types of brain tumors are commonly associated with cyst formation, the pathogenesis of tumor-associated cysts (TAC) is unknown. We investigated the matrix metalloproteinase (MMP) expression of cyst fluids to elucidate the pathogenesis of TAC in brain tumors. We also examined the relationship between the severity of peritumoral edema and the expression of intracystic MMP. We collected 40 cyst fluid samples from 34 patients with TAC and studied the expression of MMP-2 and -9 in the cyst fluid using gelatin zymography. Radiological studies were used to estimate the severity of the peritumoral edema and to determine the presence of TAC. Although gelatin zymography of the cyst fluid showed high levels of MMPs, there was no correlation between the expression of MMPs in the cyst fluid and that in the tumor tissue. The level of MMP expression in the cyst fluid did not reflect the pathologic grade of the individual tumors. However, the total and activated MMP-9 levels were significantly associated with the severity of the peritumoral edema (p<0.05). These results suggest that MMPs may be partly involved in the pathogenesis of TAC and peritumoral edema in brain tumors.