High-grade Brain Tumors Research Articles

Thyroid transcription factor-1 distinguishes subependymal giant cell astrocytoma from its mimics and supports its cell origin from the progenitor cells in the medial ganglionic eminence

Subependymal giant cell astrocytoma is a benign brain tumor mostly associated with tuberous sclerosis complex. However, it may be misinterpreted as other high-grade brain tumors due to the presence of large tumor cells with conspicuous pleomorphism and occasional atypical features, such as tumor necrosis and endothelial proliferation. In this study, we first investigated thyroid transcription factor-1 (TTF-1) expression in a large series of subependymal giant cell astrocytomas and other histologic and locational mimics to validate the diagnostic utility of this marker. We then examined TTF-1 expression in non-neoplastic brain tissue to determine the cell origin of subependymal giant cell astrocytoma. Twenty-four subependymal giant cell astrocytoma specimens were subjected to tissue microarray construction. For comparison, a selection of tumors, including histologic mimics (21 gemistocytic astrocytomas and 24 gangliogliomas), tumors predominantly occurring at the ventricular system (50 ependymomas, 19 neurocytomas, and 7 subependymomas), and 134 astrocytomas (3 pleomorphic xanthoastrocytomas, 45 diffuse astrocytomas, 46 anaplastic astrocytomas, and 40 glioblastomas) were used. Immunohistochemical stain for TTF-1 was positive in all 24 subependymal giant cell astrocytomas, whereas negative in all astrocytomas, gangliogliomas, ependymomas, and subependymomas. Neurocytomas were positive for TTF-1 in 4/19 (21%) of cases using clone 8G7G3/1 and in 9/19 (47%) of cases using clone SPT24. In the three fetal brains that we examined, TTF-1 expression was seen in the medial ganglionic eminence, a transient fetal structure between the caudate nucleus and the thalami. There was no BRAFV600E mutation identified by direct sequencing in the 20 subependymal giant cell astrocytomas that we studied. In conclusion, TTF-1 is a useful marker in distinguishing subependymal giant cell astrocytoma from its mimics. Expression of TTF-1 in the fetal medial ganglionic eminence indicates that subependymal giant cell astrocytoma may originate from the progenitor cells in this region.

Incidence trends in high-grade primary brain tumors in males and females.

The focus of the present review is to investigate whether there is a variation in the incidence rates between male and female patients with high-grade primary brain tumors and if there are altered incidence rates associated with the time at which they were diagnosed. Previous studies identified in internationally peer-reviewed journals were identified using a systematic search of the PubMed database. Due to the difficulties in data interpretation, studies that exclusively included patient data classified prior to the 2nd edition of the World Health Organization histological classification system of brain tumors were excluded. The overall incidence rates and incidence trends of male and female patients were analyzed separately. The mean age-adjusted overall incidence rate in the male population was 1.27 per 100,000 compared with 0.89 per 100,000 in the female population. The variance between the two genders differed and a Wilcoxon rank-sum test indicated that there was no significant difference in the incidence rate of high-grade primary brain tumors between males and females (P=0.3658). Furthermore, there was no significant difference in incidence rate trend between 1996-2004 and 2005-2010 for male or female populations (P=0.101 and P=0.472, respectively). The results from the present systematic review did not demonstrate a significant difference in incidence rate between the two genders. Therefore, the results from the current study are considered to be preliminary and further studies are required to elucidate this issue.

Deceased donor liver transplantation from donors with central nervous system malignancy: Experience of the Inonu University.

OBJECTIVE:Liver transplantation from deceased donors with a central nervous system (CNS) malignancy has some risk of tumor transmission to the recipient. Though the risk is small, this group of donors is regarded as marginal. The use of marginal grafts may be an acceptable alternative practice in order to expand the donor pool in countries where there is a shortage of donated organs. The aim of this study was to examine and present the outcomes of liver transplantations performed using donors with a CNS tumor.METHODS:Between March 2002 and July 2017, 1990 (deceased donor: n=399, 20%; living donor: n=1591, 80%) liver transplantations were performed at the center. Of the 399 deceased donors, 17 (4.2%) had a CNS tumor. The data of donors with a CNS tumor and of recipients who survived for more than 1 month (n=11) were retrospectively reviewed. Demographic data, the grade of the CNS tumor, tumor transmission to recipient data, and survival rates were analyzed.RESULTS:Only 2 (18%) grafts were provided locally, 6 (54%) were offered to the transplantation center after all of the national centers had declined them, and 3 (37%) were made available to us by the national coordination center for patients with a documented notification of urgency. High-grade (grade III-IV) brain tumors were detected in 7 (64%) donors, while low-grade (grade I-II) tumors were found in 2 patients. The remaining 2 donors were not pathologically graded because the diagnosis was made radiologically. The 1-, 3-, and 5-year overall and tumor-free survival of the patients was estimated at 100%, 70%, and 45%, respectively.CONCLUSION:A median survival of 40 months (range: 13-62 months) was achieved in recipients of grafts from a donor with a CNS tumor and no donor-related malignant transformation was observed.

INTRAOPERATIVE FLUORESCENCE-GUIDED RESECTION OF HIGH-GRADE GLYOBLASTOMA USING 5-AMINOLEVULINIC ACID: A META-ANALYSIS

Background. Glioblastoma (GBM) is a high-grade primary brain tumor characterized by resistance to modern treatment modalities. Intraoperative fluorescence-guided resection using 5-aminolevulinic acid (5-ALA) is one of the most innovative techniques to improve the local control rate in GBM surgery. Objective: to assess the diagnostic accuracy, sensitivity and specificity of 5-ALA fluorescence- guided resection (5-ALA-FGR) in patients with GBM. Material and methods. Surgical outcomes of 5-ALA-FGR in patients with GBM were studied in a meta-analysis of clinical series published from 2000 to 2017. Results. The meta-analysis included 26 studies. Gross total tumor resection was achieved in 74.8 % of patients (95 % CI: 67.4–83.5 %). The use of 5-ALA-FGR increased the disease-free survival time in patients with GBM by an average of 8.14 months (95 % CI: 4.36–12.02). The difference in the overall survival of GBM patients in favor of 5-ALA-FGR was 4.35–6.17 months (95 % CI: 0.9–13.23). The specificity and sensitivity of 5-ALA-FGR was high, being 86.6–87.5 % (95 % CI: 81.6–91.7) and 79.8–82.2 % (95 % CI: 73.5–91.07), respectively. Conclusion. The meta-analysis of 26 clinical series showed the high sensitivity and specificity of 5-ALA-FGR. Moreover, the use of 5-ALA-FGR in GBM was reported to increase the disease-free survival and the extent of surgical resection in patients with GBM.

PP36. IMPROVED GLIOBLASTOMA SURVIVAL FOLLOWING THE INTRODUCTION OF A SUBSPECIALISED SURGICAL HIGH GRADE BRAIN TUMOUR SERVICE

AIM: Glioblastoma (GBM) is a highly aggressive primary brain tumour. Whilst the prognosis remains poor, it has been noted in our centre that the three year survival of patients with GBM has improved over time. The aim of this study is to quantify the improved survival and identify causative factors. METHODS: We performed a retrospective analysis of all patients in our centre who were histologically proven to have GBM following surgery between 2008–2012 (n=353, 5 lost to follow up and excluded). Temozolomide was available throughout this time-period. We analysed survival trends and the effect of different factors including the type of surgery (biopsy vs debulking) and the introduction of a subspecialised surgical high grade brain tumour service. RESULTS: Better outcomes were seen with patients who underwent surgical debulking (median survival 11.4 months, 3 year survival 13.9%) compared to biopsy alone (median survival 3.9 months, 3 year survival 3.1%, p=0.00). There was also a survival difference between patients who were treated before and after the introduction of a high grade brain tumour service. Median survival improved from 7.0 to 8.8 months and 3 year survival improved from 7.8% to 13.1% (p=0.03). The survival of patients undergoing biopsy changed little before and after the service was introduced but the median survival of patients undergoing debulking increased from 9.7 months (3 year survival 11.5%) to 13.9 months (3 year survival 17.7%, p=0.01). CONCLUSION: Debulking confers significant benefit compared to biopsy alone. The introduction of a subspecialised high grade brain tumour service has led to improvement in survival. This is especially true for patients fit enough to undergo surgical debulking. A subspecialised high grade brain tumour service should be established in all neurosurgical units.

Feasibility and Safety of a Home Exercise Program for Patients With High Grade Brain Tumors

Feasibility and Safety of a Home Exercise Program for Patients With High Grade Brain Tumors

Coculture Assays to Study Macrophage and Microglia Stimulation of Glioblastoma Invasion.

Glioblastoma multiforme (grade IV glioma) is a very aggressive human cancer with a median survival of 1 year post diagnosis. Despite the increased understanding of the molecular events that give rise to glioblastomas, this cancer still remains highly refractory to conventional treatment. Surgical resection of high grade brain tumors is rarely complete due to the highly infiltrative nature of glioblastoma cells. Therapeutic approaches which attenuate glioblastoma cell invasion therefore is an attractive option. Our laboratory and others have shown that tumor associated macrophages and microglia (resident brain macrophages) strongly stimulate glioblastoma invasion. The protocol described in this paper is used to model glioblastoma-macrophage/microglia interaction using in vitro culture assays. This approach can greatly facilitate the development and/or discovery of drugs that disrupt the communication with the macrophages that enables this malignant behavior. We have established two robust coculture invasion assays where microglia/macrophages stimulate glioma cell invasion by 5 - 10 fold. Glioblastoma cells labelled with a fluorescent marker or constitutively expressing a fluorescent protein are plated without and with macrophages/microglia on matrix-coated polycarbonate chamber inserts or embedded in a three dimensional matrix. Cell invasion is assessed by using fluorescent microscopy to image and count only invasive cells on the underside of the filter. Using these assays, several pharmacological inhibitors (JNJ-28312141, PLX3397, Gefitinib, and Semapimod), have been identified which block macrophage/microglia stimulated glioblastoma invasion.

PS1 - 163 Engaging in Difficult Discussions with Neuro-Oncology Patients: A Case Conference Based Quality Improvement Initiative

Due to the non-curative nature of high grade brain tumours “difficult discussions” about goals of care, advance care planning, palliative care, and end of life are inherent to the practice of the neuro-oncology team. Clinician and patient barriers are common and may include anxiety about destroying hope, lack of readiness to discuss end of life topics, difficulty managing emotional responses, and concerns over competency in facilitating difficult discussions. Nonetheless, clinician comfort and skill in facilitating these discussions is critical and can impact patient perception of illness, coping response, and ability to make decisions about care. Methods At our regional cancer centre, a novel quality improvement initiative was designed to bring monthly case presentation of “difficult discussions” into a pre-existing weekly multi-disciplinary case conference (MCC). We will describe the rationale and developmental processes behind this initiative. Roughly 15 neuro-oncology clinicians attended each case conference, with guest attendance from palliative care and psychosocial oncology. Clinician groups represented included physicians (77%), nurses (8%), nurse practitioners (10 %), and occupational therapists (5%). Baseline and monthly surveys were administered to determine clinicians’ self- rated practices, skills, and attitudes towards “difficult discussions”. Results Early findings indicate that the initiative has been well-received. Physicians indicated highest levels of agreement with the statement “I feel that having difficult discussions is part of my responsibility”. Non physician groups indicated the greatest agreement that the intervention is beneficial to their practice. Discussion: Our challenges and successes may help guide others to incorporate a similar initiative at disease-site meetings.

Investigating intracranial tumour growth patterns with multiparametric MRI incorporating Gd-DTPA and USPIO-enhanced imaging.

High grade and metastatic brain tumours exhibit considerable spatial variations in proliferation, angiogenesis, invasion, necrosis and oedema. Vascular heterogeneity arising from vascular co‐option in regions of invasive growth (in which the blood–brain barrier remains intact) and neoangiogenesis is a major challenge faced in the assessment of brain tumours by conventional MRI.A multiparametric MRI approach, incorporating native measurements and both Gd‐DTPA (Magnevist) and ultrasmall superparamagnetic iron oxide (P904)‐enhanced imaging, was used in combination with histogram and unsupervised cluster analysis using a k‐means algorithm to examine the spatial distribution of vascular parameters, water diffusion characteristics and invasion in intracranially propagated rat RG2 gliomas and human MDA‐MB‐231 LM2–4 breast adenocarcinomas in mice.Both tumour models presented with higher ΔR 1 (the change in transverse relaxation rate R 1 induced by Gd‐DTPA), fractional blood volume (fBV) and apparent diffusion coefficient than uninvolved regions of the brain. MDA‐MB‐231 LM2–4 tumours were less densely cellular than RG2 tumours and exhibited substantial local invasion, associated with oedema, whereas invasion in RG2 tumours was minimal. These additional features were reflected in the more heterogeneous appearance of MDA‐MB‐231 LM2–4 tumours on T 2‐weighted images and maps of functional MRI parameters.Unsupervised cluster analysis separated subregions with distinct functional properties; areas with a low fBV and relatively impermeable blood vessels (low ΔR 1) were predominantly located at the tumour margins, regions of MDA‐MB‐231 LM2–4 tumours with relatively high levels of water diffusion and low vascular permeability and/or fBV corresponded to histologically identified regions of invasion and oedema, and areas of mismatch between vascular permeability and blood volume were identified.We demonstrate that dual contrast MRI and evaluation of tissue diffusion properties, coupled with cluster analysis, allows for the assessment of heterogeneity within invasive brain tumours and the designation of functionally diverse subregions that may provide more informative predictive biomarkers.

Automated Processing of Dynamic Contrast-Enhanced MRI: Correlation of Advanced Pharmacokinetic Metrics with Tumor Grade in Pediatric Brain Tumors.

Pharmacokinetic parameters from dynamic contrast-enhanced MR imaging have proved useful for differentiating brain tumor grades in adults. In this study, we retrospectively reviewed dynamic contrast-enhanced perfusion data from children with newly diagnosed brain tumors and analyzed the pharmacokinetic parameters correlating with tumor grade. Dynamic contrast-enhanced MR imaging data from 38 patients were analyzed by using commercially available software. Subjects were categorized into 2 groups based on pathologic analyses consisting of low-grade (World Health Organization I and II) and high-grade (World Health Organization III and IV) tumors. Pharmacokinetic parameters were compared between the 2 groups by using linear regression models. For parameters that were statistically distinct between the 2 groups, sensitivity and specificity were also estimated. Eighteen tumors were classified as low-grade, and 20, as high-grade. Transfer constant from the blood plasma into the extracellular extravascular space (Ktrans), rate constant from extracellular extravascular space back into blood plasma (Kep), and extracellular extravascular volume fraction (Ve) were all significantly correlated with tumor grade; high-grade tumors showed higher Ktrans, higher Kep, and lower Ve. Although all 3 parameters had high specificity (range, 82%-100%), Kep had the highest specificity for both grades. Optimal sensitivity was achieved for Ve, with a combined sensitivity of 76% (compared with 71% for Ktrans and Kep). Pharmacokinetic parameters derived from dynamic contrast-enhanced MR imaging can effectively discriminate low- and high-grade pediatric brain tumors.

Intranasal Oncolytic Virotherapy with CXCR4-Enhanced Stem Cells Extends Survival in Mouse Model of Glioma.

SummaryThe challenges to effective drug delivery to brain tumors are twofold: (1) there is a lack of non-invasive methods of local delivery and (2) the blood-brain barrier limits systemic delivery. Intranasal delivery of therapeutics to the brain overcomes both challenges. In mouse model of malignant glioma, we observed that a small fraction of intranasally delivered neural stem cells (NSCs) can migrate to the brain tumor site. Here, we demonstrate that hypoxic preconditioning or overexpression of CXCR4 significantly enhances the tumor-targeting ability of NSCs, but without altering their phenotype only in genetically modified NSCs. Modified NSCs deliver oncolytic virus to glioma more efficiently and extend survival of experimental animals in the context of radiotherapy. Our findings indicate that intranasal delivery of stem cell-based therapeutics could be optimized for future clinical applications, and allow for safe and repeated administration of biological therapies to brain tumors and other CNS disorders.

OCT4 spliced variants are highly expressed in brain cancer tissues and inhibition of OCT4B1 causes G2/M arrest in brain cancer cells.

The new claim about the origin of cancer known as Cancer Stem Cell theory states that a somatic differentiated cell can dedifferentiated or reprogrammed for regaining the cancer cell features. It has been recently shown that expression of stemness factors such as Oct4, Sox2, Nanog and Klf4, in a variety of somatic cancers can leads to development of tumorogenesis. Here, the expression of Oct4 variants were evaluated in brain tumor tissues by quantitative RT-PCR and immunohistochemical (IHC) analysis. In next phase of our study, the expression of Oct4B1 was knock-down in brain cancer cell lines and its effect on cell cycle was assessed. Finally, in order to get insights into sequence-structure-function relationships of Oct4 isofroms, their sequences were analysed using bioinformatic tools. Our data revealed that all three variants of Oct4 are expressed in different types of brain cancer. The expression level of Oct4B1, in contast to Oct4B, was much higher in high-grade brain tumors compared with low-grade ones. In line with qPCR, the expression of Oct4A and B isofroms was confirmed with IHC in different types of brain tumors. Moreover, as a result of the suppression of Oct4B1 expression, the brain cancer cells were arrested in G2/M phase of cell cycle. Bioinfromatics data indicated that the predicted Oct4B1 protein have DNA binding properties. All together, our findings suggest that Oct4B1 has a potential role in tumorigenesis of brain cancer and can be considered asa new tumor marker with potential value in diagnosis and treatment of brain cancer.

Optimization of DCE-MRI protocol for the assessment of patients with brain tumors

The interstitium-to-plasma rate constant (kep), extracted from dynamic contrast enhancement (DCE-MRI) MRI data, seems to have an important role in the assessment of patients with brain tumors. This parameter is affected by the slow behavior of the system, and thus is expected to be highly dependent on acquisition duration. The aim of this study was to optimize the scan duration and protocol of DCE-MRI for accurate estimation of the kep parameter in patients with high grade brain tumors. The effects of DCE-MRI scan duration and protocol design (continuous vs integrated scanning) on the estimated pharmacokinetic (PK) parameters and on model selection, were studied using both simulated and patient data. Scan duration varied, up to 60min for simulated data, and up to 25min in 25 MRI scans obtained from patients with high grade brain tumors, with continuous and integrated scanning protocols.Converging results were obtained from simulated and real data. Significant effect of scan duration was detected on kep. Scan duration of 9min, with integrated protocol in which the data are acquired continuously for 5min, and additional volumes at 7 and 9min, was sufficient for accurate estimation of even low kep values, with an average error of 3%. Over-estimation of the PK parameters was detected for scan duration <12min, being more pronounced at low kep values (<0.1min−1). For the model selection maps, significantly lower percentage of the full extended-Tofts-model (ETM) was selected in patients at scan duration of 5min compared to >12min. An integrated protocol of 9min is suggested as optimal for clinical use in patients with high grade brain tumors. Lower acquisition time may result in over-estimation of kep when using ETM, and therefore care should be taken using model selection.

Dynamic susceptibility contrast perfusion imaging in biopsy-proved adult medulloblastoma

Medulloblastoma (MB) is a high-grade rare brain tumor in adults, with heterogeneous imaging features and variable enhancing patterns. Diffusion and spectroscopy multimodal imaging have already been described in adult MB, yet perfusion has not been explored. This study aimed to evaluate vascularity in adult classic and desmoplastic MB, using perfusion-weighted dynamic susceptibility contrast (DSC) MRI and histopathology. Six histologically proved MB patients were classified as classic (n=3) and desmoplastic (n=3). DSC perfusion MRI was performed in three centers and retrospectively evaluated. Postprocessing included automatic arterial input function, motion and contrast leakage correction. Region of interest (ROI) delineation was performed on three perfusion slices to obtain a total of three cerebral blood volume ratios (rCBV) that were averaged to serve as the main rCBV. Permeability was evaluated on K2 maps. Low rCBVs were observed in all cases (mean rCBV=1.19±0.39). rCBV values were lower than 2 for classic MB and lower than 1 for desmoplastic MB. All cases showed an increase of permeability on K2 maps. Our preliminary results suggest that MB exhibits rCBV values close to 1 and increased permeability on DSC perfusion imaging, especially in desmoplastic cases, which could be explained by fibrous matrix. This type of perfusion pattern contrasts with those given by other enhancing subtentorial tumors such as metastasis, high-grade gliomas or hemangioblastomas.

PreSurgMapp: a MATLAB Toolbox for Presurgical Mapping of Eloquent Functional Areas Based on Task-Related and Resting-State Functional MRI.

The main goal of brain tumor surgery is to maximize tumor resection while minimizing the risk of irreversible postoperative functional sequelae. Eloquent functional areas should be delineated preoperatively, particularly for patients with tumors near eloquent areas. Functional magnetic resonance imaging (fMRI) is a noninvasive technique that demonstrates great promise for presurgical planning. However, specialized data processing toolkits for presurgical planning remain lacking. Based on several functions in open-source software such as Statistical Parametric Mapping (SPM), Resting-State fMRI Data Analysis Toolkit (REST), Data Processing Assistant for Resting-State fMRI (DPARSF) and Multiple Independent Component Analysis (MICA), here, we introduce an open-source MATLAB toolbox named PreSurgMapp. This toolbox can reveal eloquent areas using comprehensive methods and various complementary fMRI modalities. For example, PreSurgMapp supports both model-based (general linear model, GLM, and seed correlation) and data-driven (independent component analysis, ICA) methods and processes both task-based and resting-state fMRI data. PreSurgMapp is designed for highly automatic and individualized functional mapping with a user-friendly graphical user interface (GUI) for time-saving pipeline processing. For example, sensorimotor and language-related components can be automatically identified without human input interference using an effective, accurate component identification algorithm using discriminability index. All the results generated can be further evaluated and compared by neuro-radiologists or neurosurgeons. This software has substantial value for clinical neuro-radiology and neuro-oncology, including application to patients with low- and high-grade brain tumors and those with epilepsy foci in the dominant language hemisphere who are planning to undergo a temporal lobectomy.

Cost and resource utilization associated with glioblastoma among commercially insured adults in the United States (US).

2011Background: Few studies have evaluated the economic burden of GBM—the most common type of high-grade brain tumors in adults. We assessed healthcare costs and resource utilization in newly-diagnosed GBM patients in a commercially-insured US population. Methods: The analysis included subjects identified in the IMS Pharmetrics Lifelink Plus claims database from 01/2009 to 03/2014 who were aged ≥18 years; had ≥1 malignant brain cancer diagnosis (ICD9-CM, 191.xx) (with first diagnosis date = “index” date); were treated with temozolomide (TMZ); had brain surgery ≤90 days prior to TMZ initiation; and were continuously enrolled for ≥12 months pre-index and ≥1 month post-index. Per-patient per-month (PPPM) costs (i.e., average allowed charges for all claims) and cumulative costs from 3 months pre- to up to 6, 12, or 60 months post-index were calculated. Results: 2,981 patients were included (median age: 56 years; 60% male). During the post-index period, the per-patient median (interquartile range, IQR) number ...

Bevacizumab is superior to Temozolomide in causing mitochondrial dysfunction in human brain tumors

Objective: Current chemotherapy treatments available for treating high-grade brain tumors, Temozolomide (TMZ) or Bevacizumab (BEV), not only have specific anti-tumor mechanisms, but also have an effect on mitochondria. However, effects of both drugs on mitochondria isolated from human brain tumors have not been thoroughly investigated. This study determined the direct effects of TMZ and BEV as well as the neurotoxic condition (calcium overload), on the function of mitochondria and compared these effects on mitochondria isolated from low- and high-grade human brain tumors.Methods: Mitochondria were isolated from either low- or high-grade human primary brain tumors. Calcium overload conditions (100 or 200 μM), TMZ (300 μM), and BEV (2 mg/mL) were applied to isolated mitochondria from low- and high-grade brain tumors. Following the treatment, mitochondrial function, including reactive oxygen species production, membrane potential changes, and swelling, were determined. The mitochondrial morphology was also examined.Results: In calcium overload conditions, mitochondrial dysfunction was only found to have occurred in low-grade tumors. In TMZ and BEV treatment, BEV, rather than TMZ, caused greater membrane depolarization and mitochondrial swelling in both grades of brain tumors.Conclusions: TMZ and BEV can directly cause the dysfunction of mitochondria isolated from human brain tumors. However, BEV has a greater ability to disturb mitochondrial function in mitochondria isolated from human brain tumors than either TMZ or calcium overload conditions.

Nonlinear ghost waves accelerate the progression of high-grade brain tumors

We study a reduced continuous model describing the evolution of high grade gliomas in response to hypoxic events through the interplay of different cellular phenotypes. We show that hypoxic events, even when sporadic and/or limited in space, may have a crucial role on the acceleration of high grade gliomas growth. Our modeling approach is based on two cellular phenotypes. One of them is more migratory and a second one is more proliferative. Transitions between both phenotypes are driven by the local oxygen values, assumed in this simple model to be uniform. Surprisingly, even very localized in time hypoxia events leading to transient migratory populations have the potential to accelerate the tumor’s invasion speed up to speeds close to those of the migratory phenotype. The high invasion speed persists for times much longer than the lifetime of the hypoxic event. Moreover, the phenomenon is observed both when the migratory cells form a persistent wave of cells located on the invasion front and when they form a evanescent “ghost” wave disappearing after a short time by decay to the more proliferative phenotype.Our findings are obtained through numerical simulations of the model equations both in 1D and higher dimensional scenarios. We also provide a deeper mathematical analysis of some aspects of the problem such as the conditions for the existence of persistent waves of cells with a more migratory phenotype.

Seizures in patients with primary brain tumors: what is their psychosocial impact?

Seizures occur in most patients with primary malignant tumors and are associated with poor quality of life. To our knowledge, no previous studies have sought descriptions of quality of life in patients' own words. Patients with a history of a malignant primary brain tumor and seizures participated in semi-structured interviews, which were analyzed with qualitative methodology. Twenty-seven patients participated, most with high grade brain tumors. Most were receiving anti-seizure medication. Three distinct themes emerged: (1) the first seizure as a sentinel event, as manifested in part by how patients described their first seizure in remarkable detail ("I clearly remember the date…"); (2) seizures as inextricably tied to the brain tumor itself; for example, one patient explained how he "always wondered what was happening with my brain tumor" with each seizure; and (3) adaptation and acceptance-or lack therefore-to seizures. With respect to this third theme, patients conveyed frustration from an inability to work, to drive, and to take care of their children ("It's like you are 15 all over again.") Others described frustration with taking antiseizure medications ("I felt like an 80year old, now taking her pills every day"). However, some patients had adapted or resigned themselves ("…so much of life is out of control-you just gotta take what you get."). These findings have future research implications but should also serve to make healthcare providers more aware of the heavy emotional burden that seizures thrust upon brain tumor patients.

Evaluation of PAX8 Expression in Brain Tissue and Related Neoplasms.

Undifferentiated brain tumors represent a diagnostic challenge, particularly in small biopsies, with regards to their primary versus metastatic origin. The latter may show overlapping morphologic features with primary high-grade brain tumors. In recent years several new antibodies have entered the realm of daily pathology practice. PAX8 (mammalian paired box genes 1 to 9 protein encoding gene) is among these new markers and is recognized as a differentiating marker of the primary site in epithelial tumors outside of the central nervous system. A review of the literature shows lack of site-specific studies with regards to the expression of PAX8 in the central nervous system and its neoplasms. Using this marker we investigated its immunohistochemical expression in normal brain tissue and glial tumors. The immunostain was performed on tissue microarrays of 71 cores from 24 cases. We also performed PAX8 immunostain on sections from cerebellum, pons, periventricular ependymal layer, choroid plexus, pituitary, and meninges of 3 autopsy cases. Our results indicate lack of PAX8 expression by benign brain tissue. Only 1 glioblastoma core (1/9 cores) showed focal nuclear reactivity with the antibody. Our results indicate that presence of PAX8 immunoreactivity in an undifferentiated brain tumor lacking gliofibrillary acidic protein expression should prompt consideration of a metastatic tumor.