Epidemiology of brain tumors

β-elemene induces glioma cell apoptosis by downregulating survivin and its interaction with hepatitis B X-interacting protein

β-elemene, extracted from the ginger plant, possesses antitumor activity against a broad range of cancers clinically. However, the mechanism underlying β-elemene-induced cytotoxicity remains incompletely understood. Here, we show that β-elemene promoted apoptotic cell death in human glioma cells, downregulated survivin gene expression, and induced caspase-9, -3 and -7 activities. Induction of apoptosis was associated with inhibition of survivin gene expression, and restoration of survivin levels remarkably attenuated β-elemene-induced glioma cell death. Moreover, we found that the interaction between surviving and HBXIP, a critical regulator of caspase-9 activity, was impaired by β-elemene treatment. The results, therefore, reveal a caspase-mediated apoptotic pathway induced by β-elemene in human glioma cells, which is associated with downregulation of survivin itself and the interaction between survivin and HBXP.

[Adjuvant radiochemotherapy in the elderly affected by glioblastoma: single-institution experience and literature review]

PURPOSE

Radiochemotherapy (RCT) is the standard adjuvant treatment for patients affected by glioblastoma (GBM). As there is no evidence in elderly patients with GBM, combined, single modality or best supportive care is used. The aim of this retrospective study was to evaluate acute toxicity and outcome of elderly patients with GBM treated with RCT with temozolomide (TMZ).

MATERIALS AND METHODS

Patients >65 years with newly diagnosed GBM who underwent surgery or biopsy and RCT were evaluated. Recursive Partitioning Analysis (RPA) class and National Cancer Institute--Common Toxicity Criteria (NCI-CTC) version 3 were used to classify patients and evaluate acute toxicity, respectively.

RESULTS

From April 2005 to January 2011, 35 patients (18 women and 17 men) with GBM were treated at our institution. Only 31.43% of cases underwent complete resection. Median progression-free survival (PFS) was 8 months and median overall survival (OS) 13 months. At univariate and multivariate analysis, only RPA class correlated with OS (p=0.01, p=0.03, respectively). During RCT, toxicity was mild (thrombocytopaenia G3-4, 11.43%; neurological toxicity, G3-4, 8.57%).

CONCLUSIONS

Our data suggest that RCT with TMZ seems to produce a better outcome with a mild toxicity profile in elderly patients affected by GBM.

Role of sleep in the regulation of the immune system and the pituitary hormones

Sleep is characterized by a reduced response to external stimuli and a particular form of electroencephalographic (EEG) activity. Sleep is divided into two stages: REM sleep, characterized by muscle atonia, rapid eye movements, and EEG activity similar to wakefulness, and non-REM sleep, characterized by slow EEG activity. Around 80% of total sleep time is non-REM. Although it has been intensely studied for decades, the function (or functions) of sleep remains elusive. Sleep is a highly regulated state; some brain regions and several hormones and cytokines participate in sleep regulation. This mini-review focuses on how pituitary hormones and cytokines regulate or affect sleep and how sleep modifies the plasma concentration of hormones as well as cytokines. Also, we review the effects of hypophysectomy and some autoimmune diseases on sleep pattern. Finally, we propose that one of the functions of sleep is to maintain the integrity of the neuro-immune-endocrine system.

Ionizing radiation and the risk of brain and central nervous system tumors: a systematic review

Although exposure to moderate-to-high doses of ionizing radiation is the only established environmental risk factor for brain and CNS tumors, it is not clear whether this relationship differs across tumor subtypes, by sex or age at exposure, or at the low-to-moderate range of exposure. This systematic review summarizes the epidemiologic evidence on the association between ionizing radiation exposure and risk of brain/CNS tumors. Articles included in this review estimated radiation exposure doses to the brain and reported excess relative risk (ERR) estimates for brain/CNS tumors. Eight cohorts were eligible for inclusion in the analysis. Average age at exposure ranged from 8 months to 26 years. Mean dose to the brain ranged from 0.07 to 10 Gy. Elevated risks for brain/CNS tumors were consistently observed in relation to ionizing radiation exposure, but the strength of this association varied across cohorts. Generally, ionizing radiation was more strongly associated with risk for meningioma compared with glioma. The positive association between ionizing radiation exposure and risk for glioma was stronger for younger vs older ages at exposure. We did not observe an effect modification on the risk for meningioma by sex, age at exposure, time since exposure, or attained age. The etiologic role of ionizing radiation in the development of brain/CNS tumors needs to be clarified further through additional studies that quantify the association between ionizing radiation and risk for brain/CNS tumors at low-to-moderate doses, examine risks across tumor subtypes, and account for potential effect modifiers.

Genetic polymorphisms in the DNA repair gene XRCC1 and susceptibility to glioma in a Han population in northeastern China: a case-control study

BACKGROUND

Several single nucleotide polymorphisms (SNPs) in the X-ray cross-complementing group 1 (XRCC1) gene have been shown to influence DNA repair and to modify cancer susceptibility. To investigate the role of these loci further, we examined the association of three XRCC1 polymorphisms with the risk of gliomas in a Han population in northeastern China.

METHODS

Using a PCR-RFLP method, XRCC1 Arg194Trp, Arg280His and Arg399Gln were genotyped in 624 glioma patients and 580 healthy controls.

RESULTS

Significant differences in the distribution of the Arg399Gln allele were detected between glioma patients and healthy controls by a logistic regression analysis (OR=1.35, 95%CI 1.17-1.68, P=0.001). Our data also revealed that the Arg399Gln variant (allele A) carriers had an increased glioma risk compared to the wild-type (allele G) homozygous carriers (OR=1.40, 95%CI 1.12-1.76, P=0.003).

CONCLUSIONS

These results suggest that the XRCC1 Arg399Gln might influence the risk of developing glioma in a Han population in northeastern Chinese.

Lack of association between GSTM1 and GSTT1 polymorphisms and brain tumour risk

OBJECTIVE

Glutathione S-transferases (GSTs) are important enzymes that are involved in detoxification of environmental carcinogens. Molecular epidemiological studies have been conducted to investigate the association between GSTM1 and GSTT1 homozygous deletion polymorphisms and brain tumours but results have been conflicting. The aim of this study was to clarify this problem using a meta-analysis.

METHODS

A total of 9 records were identified by searching the PubMed and Embase databases. Fixed- and random-effects models were performed to estimate the pooled odds ratios.

RESULTS

No significant association was found between the GSTM1 and GSTT1 homozygous deletion polymorphisms and risk of brain tumours, including glioma and meningioma. Similar negative results were also observed in both population-based and hospital-based studies.

CONCLUSION

These findings indicate that the GSTM1 and GSTT1 polymorphisms may not be related to the development of brain tumours.

Nanotechnological advances for the delivery of CNS therapeutics

Effective non-invasive treatment of neurological diseases is often limited by the poor access of therapeutic agents into the central nervous system (CNS). The majority of drugs and biotechnological agents do not readily permeate into brain parenchyma due to the presence of two anatomical and biochemical dynamic barriers: the blood-brain barrier (BBB) and blood-cerebrospinal fluid barrier (BCSFB). Therefore, one of the most significant challenges facing CNS drug development is the availability of effective brain targeting technology. Recent advances in nanotechnology have provided promising solutions to this challenge. Several nanocarriers ranging from the more established systems, e.g. polymeric nanoparticles, solid lipid nanoparticles, liposomes, micelles to the newer systems, e.g. dendrimers, nanogels, nanoemulsions and nanosuspensions have been studied for the delivery of CNS therapeutics. Many of these nanomedicines can be effectively transported across various in vitro and in vivo BBB models by endocytosis and/or transcytosis, and demonstrated early preclinical success for the management of CNS conditions such as brain tumors, HIV encephalopathy, Alzheimer's disease and acute ischemic stroke. Future development of CNS nanomedicines need to focus on increasing their drug-trafficking performance and specificity for brain tissue using novel targeting moieties, improving their BBB permeability and reducing their neurotoxicity.

Recursive partitioning analysis of prognostic factors for glioblastoma patients aged 70 years or older

BACKGROUND

The most-used prognostic scheme for malignant gliomas included only patients aged 18 to 70 years. The purpose of this study was to develop a prognostic model for patients ≥70 years of age with newly diagnosed glioblastoma.

METHODS

A total of 437 patients ≥70 years of age with newly diagnosed glioblastoma, pooled from 2 tertiary academic institutions, was identified for recursive partitioning analysis (RPA). The resulting prognostic model, based on the final pruned RPA tree, was validated using 265 glioblastoma patients ≥70 years of age from a data set independently compiled by a French consortium.

RESULTS

RPA produced 9 terminal nodes, which were pruned to 4 prognostic subgroups with markedly different median survivals: subgroup I = patients <75.5 years of age who underwent surgical resection (9.3 months); subgroup II = patients ≥75.5 years of age who underwent surgical resection (6.4 months); subgroup III = patients with Karnofsky performance status of 70 to 100 who underwent biopsy only (4.6 months); and subgroup IV = patients with Karnofsky performance status <70 who underwent biopsy only (2.3 months). Application of this prognostic model to the French cohort also resulted in significantly different (P < .0001) median survivals for subgroups I (8.5 months), II (7.7 months), III (4.3 months), and IV (3.1 months).

CONCLUSIONS

This model divides elderly glioblastoma patients into prognostic subgroups that can be easily implemented in both the patient care and the clinical trial settings. This purely clinical prognostic model serves as a backbone for the future incorporation of the increasing number of potential molecular prognostic markers.

HMG CoA reductase inhibitors, NSAIDs and risk of glioma

3-Hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase inhibitors (statins) have shown inverse associations with cancer risks, but the results have been inconsistent. As there are no previous published data in brain tumors, we conducted a case-control study to investigate statin therapy and risk of glioma. We further evaluated the use of nonsteriodal anti-inflammatory drugs (NSAIDs) and risk of these tumors. We recruited newly diagnosed glioma cases and frequency matched controls at Columbia University and the University of California San Francisco. Standardized questions on statins and NSAIDs were used at both institutions. Intakes of these drugs were defined as >6 months of at least twice weekly use versus less than this amount or never use. From July 2007 to January 2010, we recruited a total of 517 cases and 400 controls. Simvastatin and lovastatin showed significant inverse associations with glioma (odds ratio [OR] = 0.49, 95% confidence interval [CI] 0.30, 0.81 and OR = 0.47, 95% CI 0.24, 0.93, respectively). For NSAIDs, aspirin use was also inversely related to glioma risk (OR = 0.68, 95% CI 0.49, 0.96). Both statins and NSAIDs showed significant inverse trends between the duration of drug use and glioma risk (trend tests p = 0.03 and p = 0.02, respectively), and drug intake for >120 months demonstrated the most significant associations for both types of medication. The inverse association between statin therapy and risk of glioma supports the roles of Ras/Rho GTPases or inflammatory cytokines in gliomagenesis, and a similar relationship between NSAIDs and glioma highlights the importance of cyclo-oxygenase 2 in glioma pathogenesis.

Towards personalized therapy for patients with glioblastoma

Combined therapy with temozolomide and radiotherapy is a standard treatment and improves the survival for patients with newly diagnosed glioblastoma. However, the prognosis remains poor, with a median survival time of 12-15 months. Currently, several clinical trials of dose-dense temozolomide regimen or molecular-targeting therapies have been performed to overcome the resistance of glioblastoma. In these therapies, rational prognostic biomarkers have also been investigated to predict their outcome and response to treatment. This advanced understanding of the biological markers can help to develop personalized therapies for glioblastoma patients. Generally, due to a reduced tolerance, elderly patients do not seem to benefit from intensive treatment. This population needs individual treatments depended on their age or performance status. In this article, we review the recent studies that can provide personalized therapy for glioblastoma, based on molecular tumor profiling or patients' physical status.

Helical tomotherapy simultaneous integrated boost provides a dosimetric advantage in the treatment of primary intracranial tumors

OBJECTIVE

The research quantitatively evaluates the dosimetric advantage of a helical tomotherapy (HT) intensity-modulated radiation therapy simultaneous integrated boost (SIB) compared to a conventional HT sequential (SEQ) boost for primary intracranial tumors.

METHODS

Hypothetical lesions (planning target volumes or PTVs) were contoured within computed tomography scans from normal controls. A dose of 50 Gy was prescribed to the larger PTV1, while the boost PTV2 received a total of 60 Gy. HT SEQ and HT SIB plans were generated and compared. We evaluated the mean brain dose, the volume of normal brain receiving 45 Gy (V45), the volume of normal brain receiving 5 Gy (V5), and the integral dose. In addition, patients who were treated with the HT SEQ technique were replanned with the HT SIB technique and compared.

RESULTS

The average reduction in mean brain dose with the HT SIB plan compared to the composite HT SEQ plan was 11·0% [standard error (SE): 0·5]. The reductions in brains V45 and V5 were 43·7% (SE: 2·3) and 3·9% (SE: 0·6), respectively. The reduction in the integral dose was 11·0% (SE: 0·5). When comparing the SIB plan to the first 50 Gy only of the SEQ plan, there was only a 2·5% increase in the mean brain dose and a 2·9% increase in brain V45. This increase was dependent on the relative volumes of PTV2 and PTV1. These results were confirmed for the patient plans compared.

CONCLUSIONS

Treating primary brain tumors with the HT SIB technique provides significant sparing of normal brain parenchyma compared to a conventional HT SEQ boost.

Matrix metalloproteinase-1 expression enhances tumorigenicity as well as tumor-related angiogenesis and is inversely associated with TIMP-4 expression in a model of glioblastoma

Herein we continue the study of matrix metalloproteinase-1 (MMP-1) with respect to glioblastoma multiforme (GBM) cell tumorigenicity and angiogenesis. A model of tumorigenicity with cells stably altered to over-express or knock-down MMP-1 revealed that it significantly increases tumor incidence and size. Organized endothelial growth in human umbilical vein endothelial cell (HUVEC)-GBM co-cultures was significantly increased in the presence of MMP-1. CD31 analysis of model tumors elucidated a substantial recruitment of endothelium in MMP-1 enhanced samples. Antibody arrays indicated an inverse expression of certain anti-angiogenic factors with respect to MMP-1, the most notable of which was a significant increase in tissue inhibitor of metalloproteinases-4 (TIMP-4) in the absence of MMP-1, as validated by immunoblot.

Evaluation of brain tumor vessels specific contrast agents for glioblastoma imaging

A mouse model of glioblastoma multiforme was used to determine the accumulation of a targeted contrast agent in tumor vessels. The contrast agent, consisting of superparamagnetic iron oxide coated with dextran, was functionalized with an anti-insulin-like-growth-factor binding protein 7 (anti-IGFBP7) single domain antibody. The near infrared marker, Cy5.5, was also attached for an in vivo fluorescence study. A 9.4T magnetic resonance imaging (MRI) system was used for in vivo studies on days 10 and 11 following tumor inoculation. T(2) relaxation time was used to measure the accumulation of the contrast agent in the tumor. Changes in tumor to brain contrast because of active targeting were compared with a nontargeted contrast agent. Effective targeting was confirmed with near infrared measurements and fluorescent microscopic analysis. The results showed that there was a statistically significant (P < .01) difference in normalized T(2) between healthy brain and tumor tissue 10 min, 1 h, and 2 h point postinjection of the anti-IGFBP7 single domain antibody targeted and nontargeted iron oxide nanoparticles. A statistical difference remained in animals treated with targeted nanoparticles 24 h postinjection only. The MRI, near infrared imaging, and fluorescent microscopy studies showed corresponding spatial and temporal changes. We concluded that the developed anti-IGFBP7-iron oxide single domain antibody-targeted MRI contrast agent selectively binds to abnormal vessels within a glioblastoma. T(2)-weighted MRI and near infrared imaging are able to detect the targeting effects in brain tumors.

MiRNA expression patterns predict survival in glioblastoma

Background

In order to define new prognostic subgroups in patients with glioblastoma a miRNA screen (> 1000 miRNAs) from paraffin tissues followed by a bio-mathematical analysis was performed.

Methods

35 glioblastoma patients treated between 7/2005 - 8/2008 at a single institution with surgery and postoperative radio(chemo)therapy were included in this retrospective analysis. For microarray analysis the febit biochip "Geniom^® Biochip MPEA homo-sapiens" was used. Total RNA was isolated from FFPE tissue sections and 1100 different miRNAs were analyzed.

Results

It was possible to define a distinct miRNA expression pattern allowing for a separation of distinct prognostic subgroups. The defined miRNA pattern was significantly associated with early death versus long-term survival (split at 450 days) (p = 0.01). The pattern and the prognostic power were both independent of the MGMT status.

Conclusions

At present, this is the first dataset defining a prognostic role of miRNA expression patterns in patients with glioblastoma. Having defined such a pattern, a prospective validation of this observation is required.

Neuroimaging findings in the initial phase of development of high grade cortical astrocytomas

OBJECTIVES

To describe the neuroradiological characteristics of a series of high grade cortical astrocytomas in the initial phase of development and their pattern of growth during a short time period.

MATERIAL AND METHODS

This was a retrospective observational study of the neuroradiological findings in six patients diagnosed with high grade astrocytoma. All presented with a new onset epileptic seizure and focal supratentorial cortical lesions. The diagnosis was established after a short period of clinical and radiological follow-up.

RESULTS

Magnetic resonance imaging (MRI) detected a small cortical lesion that was hyperintense in T2-weighted sequences in all six patients. This lesion showed slight or moderate enhancement after the administration of a contrast agent in five patients. All six patients underwent follow-up MRI within six months of the initial MRI examination (mean 79 days). Follow-up MRI showed marked growth of the lesions in all cases, and the histological diagnosis of high grade astrocytoma (glioblastoma in five patients and anaplastic oligoastrocytoma in one) was established after surgical debulking.

CONCLUSION

High grade astrocytomas originating in the supratentorial cortex can have an atypical neuroradiological presentation in the early stages. High grade astrocytoma should be included in the differential diagnosis of a cortical lesion that enhances slightly or moderately after the administration of contrast material in a patient with a new onset epileptic seizure.

Glioblastoma mimicking herpes simplex encephalitis

We report a case of 70-year-old man with glioblastoma presenting as acute encephalitic illness. The patient exhibited sudden onset of cognitive impairment and headache for 2 days. Initial brain MRI showed left temporal lobe hyperintensity, and cerebrospinal fluid cytology revealed a mild pleocytosis. The patient had initially improved after medical treatment with a presumptive diagnosis of herpes simplex encephalitis (HSE). After 8 months, the patient complained of recurrent seizures. A follow-up brain MRI revealed marked increases in size and surrounding perilesional edema in the left temporal lesion on T2-weighted images and a new contrast-enhancing lesion on gadolinium-enhanced T1-weighted images. Stereotactic brain biopsy revealed a glioblastoma. The atypical encephalitic presentation of glioblastoma should be considered if definitive evidence for the diagnosis of HSE cannot be obtained.

Heat-shock protein 70-dependent dendritic cell activation by 5-aminolevulinic acid-mediated photodynamic treatment of human glioblastoma spheroids in vitro

BACKGROUND

T-cell responses contribute to the anti-tumoural effect of photodynamic therapy (PDT). For such responses to occur, dendritic cells (DCs) have to migrate to the tumour, take up tumour antigens and respond to danger signals with maturation, before they engage in T-cell activation. Here, we have studied the effect of 5-aminolevulinic acid (ALA)-mediated PDT on DCs in vitro in a human spheroid model of glioblastoma (GB).

METHODS

Spheroids of the GB cell lines U87 and U251 were treated with ALA/PDT, and effects on attraction, uptake of tumour antigens and maturation of DCs were studied. To block heat-shock protein-70 (HSP-70) on the spheroids, neutralising antibodies were used.

RESULTS

5-Aminolevulinic acid /PDT-treated GB spheroids attracted DCs that acquired tumour antigens from the spheroids effectively. Moreover, co-culture with ALA/PDT-treated spheroids induced DC maturation as indicated by the upregulation of CD83 and co-stimulatory molecules as well as increased T-cell stimulatory activity of the DCs. Heat-shock protein-70 was upregulated on the spheroids after ALA/PDT treatment. Uptake of tumour antigens and DC maturation induced by the ALA/PDT-treated spheroids were inhibited when HSP-70 was blocked.

CONCLUSION

ALA/PDT treatment of glioma spheroids promotes the three initial steps of the afferent phase of adaptive immunity, which is at least partially mediated by HSP-70.

Modulation of migratory activity and invasiveness of human glioma spheroids following 5-aminolevulinic acid–based photodynamic treatment

Object

Five-aminolevulinic acid–mediated photodynamic therapy (ALA/PDT) can improve the clinical outcome in patients suffering from glioblastoma. Besides direct phototoxicity, additional mechanisms may contribute. Therefore, the authors studied the influence of ALA/PDT on glioblastoma's migratory and invasive behavior in a human glioma cell spheroid model.

Methods

Glioma spheroids were grown from human U373 and A172 cell lines. After ALA/PDT of spheroids, the authors assessed the migration of tumor cells and their capacity to invade a collagen matrix, as well as changes in their viability, morphology, and expression of matrix metalloproteinases (MMPs).

Results

The authors found that ALA/PDT caused long-lasting, nearly complete suppression of glioma cell migration and matrix invasion compared with nontherapeutic controls, including either irradiation or incubation with ALA only. Although ALA/PDT induced tumor cell apoptosis, suppression of migration/invasion was not simply due to phototoxicity because 50% of tumor cells remained vital throughout the observation period. Moreover, the morphology of ALA/PDT-treated cells changed significantly toward a polygonal, epithelial-like appearance, which was associated with alterations in the actin cytoskeleton. Furthermore, downregulation of MMP-7 and -8 was observed after treatment whereas other MMPs remained unchanged.

Conclusions

In addition to directly eliminating glioma cells through apoptosis, ALA/PDT alters their invasiveness, possibly due to the effects on the cytoskeletal organization and MMP expression.

Demographic variation in incidence of adult glioma by subtype, United States, 1992-2007

BACKGROUND

We hypothesized that race/ethnic group, sex, age, and/or calendar period variation in adult glioma incidence differs between the two broad subtypes of glioblastoma (GBM) and non-GBM. Primary GBM, which constitute 90-95% of GBM, differ from non-GBM with respect to a number of molecular characteristics, providing a molecular rationale for these two broad glioma subtypes.

METHODS

We utilized data from the Surveillance, Epidemiology, and End Results Program for 1992-2007, ages 30-69 years. We compared 15,088 GBM cases with 9,252 non-GBM cases. We used Poisson regression to calculate adjusted rate ratios and 95% confidence intervals.

RESULTS

The GBM incidence rate increased proportionally with the 4th power of age, whereas the non-GBM rate increased proportionally with the square root of age. For each subtype, compared to non-Hispanic Whites, the incidence rate among Blacks, Asians/Pacific Islanders, and American Indians/Alaskan Natives was substantially lower (one-fourth to one-half for GBM; about two-fifths for non-GBM). Secondary to this primary effect, race/ethnic group variation in incidence was significantly less for non-GBM than for GBM. For each subtype, the incidence rate was higher for males than for females, with the male/female rate ratio being significantly higher for GBM (1.6) than for non-GBM (1.4). We observed significant calendar period trends of increasing incidence for GBM and decreasing incidence for non-GBM. For the two subtypes combined, we observed a 3% decrease in incidence between 1992-1995 and 2004-2007.

CONCLUSIONS

The substantial difference in age effect between GBM and non-GBM suggests a fundamental difference in the genesis of primary GBM (the driver of GBM incidence) versus non-GBM. However, the commonalities between GBM and non-GBM with respect to race/ethnic group and sex variation, more notable than the somewhat subtle, albeit statistically significant, differences, suggest that within the context of a fundamental difference, some aspects of the complex process of gliomagenesis are shared by these subtypes as well. The increasing calendar period trend of GBM incidence coupled with the decreasing trend of non-GBM incidence may at least partly be due to a secular trend in diagnostic fashion, as opposed to real changes in incidence of these subtypes.

Incidence of adult brain cancers is higher in countries where the protozoan parasite Toxoplasma gondii is common

We explored associations between the common protozoan parasite Toxoplasma gondii and brain cancers in human populations. We predicted that T. gondii could increase the risk of brain cancer because it is a long-lived parasite that encysts in the brain, where it provokes inflammation and inhibits apoptosis. We used a medical geography approach based on the national incidence of brain cancers and seroprevalence of T. gondii. We corrected reports of incidence for national gross domestic product because wealth probably increases the ability to detect cancer. We also included gender, cell phone use and latitude as variables in our initial models. Prevalence of T. gondii explained 19 per cent of the residual variance in brain cancer incidence after controlling for the positive effects of gross domestic product and latitude among nations. Infection with T. gondii was associated with a 1.8-fold increase in the risk of brain cancers across the range of T. gondii prevalence in our dataset (4-67%). These results, though correlational, suggest that T. gondii should be investigated further as a possible oncogenic pathogen of humans.

Assessment of type of allergy and antihistamine use in the development of glioma

BACKGROUND

Allergies have been associated with decreased risk of glioma; but, associations between duration and timing of allergies, and antihistamine use and glioma risk have been less consistent. The objective was to investigate this association by analyzing types, number, years since diagnosis, and age at diagnosis of allergies, and information on antihistamine usage, including type, duration, and frequency of exposure.

METHODS

Self-report data on medically diagnosed allergies and antihistamine use were obtained for 419 glioma cases and 612 hospital-based controls from Duke University and NorthShore University HealthSystem.

RESULTS

High- and low-grade glioma cases were statistically significantly less likely to report any allergy than controls (OR = 0.66, 95% CI: 0.49-0.87 and OR = 0.44, 95% CI: 0.25-0.76, respectively). The number of types of allergies (seasonal, medication, pet, food, and other) was inversely associated with glioma risk in a dose-response manner (P value for trend < 0.05). Age at diagnosis and years since diagnosis of allergies were not associated with glioma risk. Oral antihistamine use was statistically significantly inversely associated with glioma risk, but when stratified by allergy status, remained significant only for those with high-grade glioma and no medically diagnosed allergy.

CONCLUSIONS

All types of allergies appear to be protective with reduced risk for those with more types of allergies. Antihistamine use, other than in relationship with allergy status, may not influence glioma risk.

IMPACT

A comprehensive study of allergies and antihistamine use using standardized questions and biological markers will be essential to further delineate the biological mechanism that may be involved in brain tumor development.

Secreted factors from brain endothelial cells maintain glioblastoma stem-like cell expansion through the mTOR pathway

Glioma stem-cells are associated with the brain vasculature. However, the way in which this vascular niche regulates stem-cell renewal and fate remains unclear. Here, we show that factors emanating from brain endothelial cells positively control the expansion of long-term glioblastoma stem-like cells. We find that both pharmacological inhibition of and RNA interference with the mammalian target of rapamycin (mTOR) pathway reduce their spheroid growth. Conversely, the endothelial secretome is sufficient to promote this mTOR-dependent survival. Thus, interfering with endothelial signals might present opportunities to identify treatments that selectively target malignant stem-cell niches.

Curcumin delivery by methoxy polyethylene glycol-poly(caprolactone) nanoparticles inhibits the growth of C6 glioma cells

As a potential anticancer agent, curcumin (Cum) has been reported for its chemopreventive and chemotherapeutic activity in a series of cancers through influencing cell cycle arrest, differentiation, apoptosis, etc. Therefore, the potential activity against various cancers of Cum raises the possibility of its application as a novel model drug in nanoparticle-based delivery systems. The current study reported a spherical core-shell structure curcumin-loaded nanoparticle (Cum-np) formed by amphilic methoxy polyethylene glycol-poly(caprolactone) (mPEG-PCL) block copolymers. Characterization tests indicated that Cum was incorporated into mPEG-PCL-based nanoparticles with high encapsulation efficiency due to its lipophilicity. The incorporated Cum could be released from Cum-np in a sustained manner. Cum was effectively transported into the cells by nanoparticles through endocytosis and localized around the nuclei in the cytoplasms. In vitro studies proved that the cytotoxicity of Cum-np would be pro-apoptosis effect against rat C6 glioma cell line in a dose-dependent manner. The present results suggest that Cum-np could be a potential useful chemotherapeutic formulation for malignant glioma therapy. Moreover, the development of traditional Chinese medicine with nanoscale drug formation warrants more intensive research for its clinical applications.

Annual report to the nation on the status of cancer, 1975-2007, featuring tumors of the brain and other nervous system

Background

The American Cancer Society, the Centers for Disease Control and Prevention (CDC), the National Cancer Institute, and the North American Association of Central Cancer Registries (NAACCR) collaborate annually to provide updated information on cancer occurrence and trends in the United States. This year’s report highlights brain and other nervous system (ONS) tumors, including nonmalignant brain tumors, which became reportable on a national level in 2004.

Methods

Cancer incidence data were obtained from the National Cancer Institute, CDC, and NAACCR, and information on deaths was obtained from the CDC’s National Center for Health Statistics. The annual percentage changes in age-standardized incidence and death rates (2000 US population standard) for all cancers combined and for the top 15 cancers for men and for women were estimated by joinpoint analysis of long-term (1992–2007 for incidence; 1975–2007 for mortality) trends and short-term fixed interval (1998–2007) trends. Analyses of malignant neuroepithelial brain and ONS tumors were based on data from 1980–2007; data on nonmalignant tumors were available for 2004–2007. All statistical tests were two-sided.

Results

Overall cancer incidence rates decreased by approximately 1% per year; the decrease was statistically significant (P < .05) in women, but not in men, because of a recent increase in prostate cancer incidence. The death rates continued to decrease for both sexes. Childhood cancer incidence rates continued to increase, whereas death rates continued to decrease. Lung cancer death rates decreased in women for the first time during 2003–2007, more than a decade after decreasing in men. During 2004–2007, more than 213 500 primary brain and ONS tumors were diagnosed, and 35.8% were malignant. From 1987–2007, the incidence of neuroepithelial malignant brain and ONS tumors decreased by 0.4% per year in men and women combined.

Conclusions

The decrease in cancer incidence and mortality reflects progress in cancer prevention, early detection, and treatment. However, major challenges remain, including increasing incidence rates and continued low survival for some cancers. Malignant and nonmalignant brain tumors demonstrate differing patterns of occurrence by sex, age, and race, and exhibit considerable biologic diversity. Inclusion of nonmalignant brain tumors in cancer registries provides a fuller assessment of disease burden and medical resource needs associated with these unique tumors.

Brain tumors and hormonal factors: review of the epidemiological literature

BACKGROUND

To date, the etiology of primary tumors of the central nervous system (mainly gliomas and meningiomas) is poorly understood. The role of sex hormones has been suggested, based on clinical, experimental, biological, and epidemiological data.

OBJECTIVE

To review the epidemiological studies on the relation between hormonal factors and the occurrence of glioma and meningioma, in order to identify new research developments.

METHODS

Articles published until September 2010 were selected by considering exogenous and endogenous exposures and specific brain tumors. Standardized information was collected from 20 articles: 15 concerning gliomas and 13 meningiomas.

RESULTS

An increased glioma risk was observed with later menarche and menopause, while a reduced glioma risk was observed with hormone replacement therapy (HRT) and oral contraceptive use, despite duration of use had no effect on risk. Meningioma risk increased after menopause and with HRT use. No clear association was found with pregnancy and breastfeeding.

CONCLUSION

Results are globally concordant with the biologic hypothesis assuming that female sex hormones are protective against glioma and may increase the risk of meningioma. However, new epidemiological studies should be conducted in order to confirm these associations and to refine the role of hormonal factors in brain etiology.

[Malignant gliomas]

Glial tumors represent 2000 to 3000 new cases per year in France and 75% of them are of high grade. Recent understanding of the molecular biology of these tumors revealed the importance of 1p19q codeletion and mgMT promotor methylation. Radiotherapy also recently evolved with the progress in medical imaging which allows a better definition of the target volumes. Even modest, therapeutic progress is based on chemoradiotherapy with temozolomide and on the development of non-coplanar conformational radiotherapy. Knowledge and precise evaluation of potential late effects of our treatments is necessary due to actual improvement of survival with chemoradiotherapy in glioblastoma.

Overview of cellular immunotherapy for patients with glioblastoma

High grade gliomas (HGG) including glioblastomas (GBM) are the most common and devastating primary brain tumours. Despite important progresses in GBM treatment that currently includes surgery combined to radio- and chemotherapy, GBM patients' prognosis remains very poor. Immunotherapy is one of the new promising therapeutic approaches that can specifically target tumour cells. Such an approach could also maintain long term antitumour responses without inducing neurologic defects. Since the past 25 years, adoptive and active immunotherapies using lymphokine-activated killer cells, cytotoxic T cells, tumour-infiltrating lymphocytes, autologous tumour cells, and dendritic cells have been tested in phase I/II clinical trials with HGG patients. This paper inventories these cellular immunotherapeutic strategies and discusses their efficacy, limits, and future perspectives for optimizing the treatment to achieve clinical benefits for GBM patients.

Surgical outcomes for older patients with glioblastoma multiforme: preoperative factors associated with decreased survival. Clinical article

OBJECT

As the population ages, the incidence of glioblastoma multiforme (GBM) among older patients (age > 65 years) will increase. Older patients, unlike their younger counterparts, are not often offered aggressive surgery because of their age, comorbidities, and potential inability to tolerate surgery. The goal of this study was to identify preoperative factors associated with decreased survival for older patients who underwent resection of a GBM. The identification of these factors may provide insight into which patients would benefit most from aggressive surgery.

METHODS

All patients older than 65 years who underwent nonbiopsy resection of an intracranial GBM at a single institution between 1997 and 2007 were retrospectively reviewed. Factors associated with overall survival were assessed using multivariate proportional hazards regression analysis after controlling for peri- and postoperative factors known to be associated with outcome (extent of resection, carmustine wafer implantation, temozolomide chemotherapy, and radiation therapy). Variables with p < 0.05 were considered statistically significant.

RESULTS

A total of 129 patients with an average age of 73 ± 5 years met the inclusion/exclusion criteria. At last follow-up, all 129 patients had died, with a median survival of 7.9 months. The preoperative factors that were independently associated with decreased survival were Karnofsky Performance Scale (KPS) score less than 80 (p = 0.001), chronic obstructive pulmonary disease (p = 0.01), motor deficit (p = 0.01), language deficit (p = 0.005), cognitive deficit (p = 0.02), and tumor size larger than 4 cm (p = 0.002). Patients with 0-1 (Group 1), 2-3 (Group 2), and 4-6 (Group 3) of these factors had statistically different survival times, where the median survival was 9.2, 5.5, and 4.4 months, respectively. In log-rank analysis, the median survival for Group 1 was significantly longer than that for Group 2 (p = 0.004) and Group 3 (p < 0.0001), while Group 2 had longer survival than Group 3 (p = 0.02).

CONCLUSIONS

Older patients with an increasing number of these factors may not benefit as much from aggressive surgery as patients with fewer factors. This may provide insight into identifying which patients older than 65 years of age may benefit from aggressive surgery.

Links between private habits, psychological stress and brain cancer: a case-control pilot study in France

Numerous studies have increasingly suggested that medical history and lifestyle factors could be involved in the increase of cancer risk in adults. The issue whether psychological factors can influence the development of cancer has been discussed for many years. In the field of brain cancer, psychological stress has not so far been investigated. We conducted a French case-control pilot study with 122 adult incident cases and 122 controls free of any cancer diagnosis, matched for age and gender, to investigate links between malignant primitive brain tumours (MPBT) and medical history, private habits and psychological stress. Data were collected through self-administered questionnaires, and person-to-person interviews. To complete the psychological stress assessment, 100-mm visual analog scales were used. After adjustment for confounders, we found no significant effect of head trauma, aspartame, tobacco or alcohol consumption, place (rural or urban) of residence, sociodemographic data, and experience of psychological stress at work/home. Our results showed a significant association between MPBT risk and major life events over the past 5 years before diagnosis (OR = 1.90, 95% CI 1.13-3.20), family histories of cancer (OR = 1.90, 95% CI 1.12-3.22), fresh vegetable and fruit intake (OR = 0.29, 95% CI 0.09-0.95), and skipped meals several times per week (OR = 0.35, 95% CI 0.16-0.77). The present study suggests the role of genetic factors in glioma risk, and also suggests that an acute and sudden psychological stress might influence MPBT appearance. Additional large clinical studies are needed to confirm these findings.

Brain tumor stem cells as therapeutic targets in models of glioma

At this time, brain tumor stem cells remain a controversial hypothesis while malignant brain tumors continue to present a dire prognosis of severe morbidity and mortality. Yet, brain tumor stem cells may represent an essential cellular target for glioma therapy as they are postulated to be the tumorigenic cells responsible for recurrence. Targeting oncogenic pathways that are essential to the survival and growth of brain tumor stem cells represents a promising area for developing therapeutics. However, due to the multiple oncogenic pathways involved in glioma, it is necessary to determine which pathways are the essential targets for therapy. Furthermore, research still needs to comprehend the morphogenic processes of cell populations involved in tumor formation. Here, we review research and discuss perspectives on models of glioma in order to delineate the current issues in defining brain tumor stem cells as therapeutic targets in models of glioma.

The future role of personalized medicine in the treatment of glioblastoma multiforme

Glioblastoma multiforme (GBM) remains one of the most malignant primary central nervous system tumors. Personalized therapeutic approaches have not become standard of care for GBM, but science is fast approaching this goal. GBM's heterogeneous genomic landscape and resistance to radiotherapy and chemotherapy make this tumor one of the most challenging to treat. Recent advances in genome-wide studies and genetic profiling show that there is unlikely to be a single genetic or cellular event that can be effectively targeted in all patients. Instead, future therapies will likely require personalization for each patient's tumor genotype or proteomic profile. Over the past year, many investigations specifically focused simultaneously on strategies to target oncogenic pathways, angiogenesis, tumor immunology, epigenomic events, glioma stem cells (GSCs), and the highly migratory glioma cell population. Combination therapy targeting multiple pathways is becoming a fast growing area of research, and many studies put special attention on small molecule inhibitors. Because GBM is a highly vascular tumor, therapy that directs monoclonal antibodies or small molecule tyrosine kinase inhibitors toward angiogenic factors is also an area of focus for the development of new therapies. Passive, active, and adoptive immunotherapies have been explored by many studies recently, and epigenetic regulation of gene expression with microRNAs is also becoming an important area of study. GSCs can be useful targets to stop tumor recurrence and proliferation, and recent research has found key molecules that regulate GBM cell migration that can be targeted by therapy. Current standard of care for GBM remains nonspecific; however, pharmacogenomic studies are underway to pave the way for patient-specific therapies that are based on the unique aberrant pathways in individual patients. In conclusion, recent studies in GBM have found many diverse molecular targets possible for therapy. The next obstacle in treating this fatal tumor is ascertaining which molecules in each patient should be targeted and how best to target them, so that we can move our current nonspecific therapies toward the realm of personalized medicine.

Inherited variation in immune genes and pathways and glioblastoma risk

To determine whether inherited variations in immune function single-nucleotide polymorphisms (SNPs), genes or pathways affect glioblastoma risk, we analyzed data from recent genome-wide association studies in conjunction with predefined immune function genes and pathways. Gene and pathway analyses were conducted on two independent data sets using 6629 SNPs in 911 genes on 17 immune pathways from 525 glioblastoma cases and 602 controls from the University of California, San Francisco (UCSF) and a subset of 6029 SNPs in 893 genes from 531 cases and 1782 controls from MD Anderson (MDA). To further assess consistency of SNP-level associations, we also compared data from the UK (266 cases and 2482 controls) and the Mayo Clinic (114 cases and 111 controls). Although three correlated epidermal growth factor receptor (EGFR) SNPs were consistently associated with glioblastoma in all four data sets (Mantel-Haenzel P values = 1 × 10⁻⁵ to 4 × 10⁻³), independent replication is required as genome-wide significance was not attained. In gene-level analyses, eight immune function genes were significantly (minP < 0.05) associated with glioblastoma; the IL-2RA (CD25) cytokine gene had the smallest minP values in both UCSF (minP = 0.01) and MDA (minP = 0.001) data sets. The IL-2RA receptor is found on the surface of regulatory T cells potentially contributing to immunosuppression characteristic of the glioblastoma microenvironment. In pathway correlation analyses, cytokine signaling and adhesion-extravasation-migration pathways showed similar associations with glioblastoma risk in both MDA and UCSF data sets. Our findings represent the first systematic description of immune genes and pathways that characterize glioblastoma risk.

Helianthin induces antiproliferative effect on human glioblastoma cells in vitro

A major focus of brain cancer research today is to translate understanding of glioma biology into advances in treatment, by exploring the potential of target therapy. Here we investigated the ability of three compounds belonging to the chemical class of azo dyes (methyl red, methyl yellow, and helianthin) to inhibit glioblastoma (GB) cell growth in vitro. Our results showed that helianthin induced cytotoxicity in two GB cell cultures, cell lines 18 and 38, whereas methyl red and methyl yellow were not cytotoxic. The effect of helianthin on EGFR, IGF-1R, and their common intracellular signaling via PI3-K and ERK1/2 was also analyzed. Treatment with helianthin down-regulated EGFR and IGF-1R activity in both cell lines. Helianthin treatment blocked ERK1/2 phosphorylation without affecting PI3K activity in cell line 18 and reduced both PI3K and ERK1/2 in GB 38 cell line. The cell death was accompanied by degradation of PARP without affecting BCL2 expression in both GB cell cultures. Because of the genetic heterogeneity of malignant gliomas, we tested the effect of helianthin on other two primary GB lines (11 and 15) and two early-passage GB cultures (BT1GB and BT2GB), to assess the general nature of the anti-tumor effect of the drug in GB cells. We found that helianthin treatment induced cell death in all the GB cell cultures analyzed. To our knowledge, this is the first report indicating that helianthin can reduce GB cell growth.

SPP1 promoter polymorphisms and glioma risk in a Chinese Han population

SPP1 was found to be significantly upregulated in many kinds of malignant tumors, including gliomas. Considering that gene polymorphisms have been implicated in the development of gliomas, we performed an association study between SPP1 functional promoter region polymorphisms and glioma risk in a Chinese population. We found significant evidence of an association between SPP1 promoter polymorphisms and glioma risk. For the -155_156insG variant, the -155_156GG allele was found to be significantly associated with an increased risk of glioma (P=0.020, odds ratio (OR)=1.202, 95% confidence interval (CI): 1.028-1.408). Individuals with the genotype containing the GG allele had a 1.372-fold increased risk (P=0.006, OR=1.372, 95% CI: 1.095-1.719). Further stratified analyses suggested that a significant association existed in adult glioma patients, male subjects and in cases without a family history of cancer. Alternatively, the study of single-nucleotide polymorphism -443C/T in a recessive model revealed that the genotype CC+CT significantly decreased the risk of glioma when compared with TT (P=0.023, OR=0.774, 95% CI: 0.621-0.966). After the analysis of haplotypes, the haplotype -155_156GG/-443T was represented at a significantly higher frequency in cases (P=0.029, OR=1.192, 95% CI: 1.018-1.395). Cellular assay indicated that the transcriptional activity of the SPP1 promoter containing the -155_156GG allele significantly increased in glioma cells. Thus, variants of the SPP1 promoter might influence the risk of glioma by regulating promoter activity. Further analyses are necessary to validate our observation in larger samples or in other ethnic groups.

Modulation of Radiation-Induced Genetic Damage by HCMV in Peripheral Blood Lymphocytes from a Brain Tumor Case-Control Study

Human cytomegalovirus (HCMV) infection occurs early in life and viral persistence remains through life. An association between HCMV infection and malignant gliomas has been reported, suggesting that HCMV may play a role in glioma pathogenesis and could facilitate an accrual of genotoxic damage in the presence of g-radiation; an established risk factor for gliomas. We tested the hypothesis that HCMV infection modifies the sensitivity of cells to γ-radiation-induced genetic damage. We used peripheral blood lymphocytes (PBLs) from 110 glioma patients and 100 controls to measure the level of chromosome damage and cell death. We evaluated baseline, HCMV-, γ-radiation and HCMV + γ-radiation induced genetic instability with the comprehensive Cytokinesis-Blocked Micronucleus Cytome (CBMN-CYT). HCMV, similar to radiation, induced a significant increase in aberration frequency among cases and controls. PBLs infected with HCMV prior to challenge with γ-radiation led to a significant increase in aberrations as compared to baseline, γ-radiation and HCMV alone. With regards to apoptosis, glioma cases showed a lower percentage of induction following in vitro exposure to γ-radiation and HCMV infection as compared to controls. This strongly suggests that, HCMV infection enhances the sensitivity of PBLs to γ-radiation-induced genetic damage possibly through an increase in chromosome damage and decrease in apoptosis.

Prevalence estimates for primary brain tumors in the United States by age, gender, behavior, and histology

Prevalence is the best indicator of cancer survivorship in the population, but few studies have focused on brain tumor prevalence because of previous data limitations. Hence, the full impact of primary brain tumors on the healthcare system in the United States is not completely described. The present study provides an estimate of the prevalence of disease in the United States, updating an earlier prevalence study. Incidence data for 2004 and survival data for 1985-2005 were obtained by the Central Brain Tumor Registry of the United States from selected regions, modeled under 2 different survival assumptions, to estimate prevalence rates for the year 2004 and projected estimates for 2010. The overall incidence rate for primary brain tumors was 18.1 per 100 000 person-years with 2-, 5-, 10-, and 20-year observed survival rates of 62%, 54%, 45%, and 30%, respectively. On the basis of the sum of nonmalignant and averaged malignant estimates, the overall prevalence rate of individuals with a brain tumor was estimated to be 209.0 per 100 000 in 2004 and 221.8 per 100 000 in 2010. The female prevalence rate (264.8 per 100 000) was higher than that in males (158.7 per 100 000). The averaged prevalence rate for malignant tumors (42.5 per 100 000) was lower than the prevalence for nonmalignant tumors (166.5 per 100 000). This study provides estimates of the 2004 (n = 612 770) and 2010 (n = 688 096) expected number of individuals living with primary brain tumor diagnoses in the United States, providing more current and robust estimates for aiding healthcare planning and patient advocacy for an aging US population.

Childhood brain tumors, residential insecticide exposure, and pesticide metabolism genes

BACKGROUND

Insecticides that target the nervous system may play a role in the development of childhood brain tumors (CBTs). Constitutive genetic variation affects metabolism of these chemicals.

METHODS

We analyzed population-based case-control data to examine whether CBT is associated with the functional genetic polymorphisms PON1C-108T, PON1Q192R, PON1L55M, BCHEA539T, FMO1C-9536A, FMO3E158K, ALDH3A1S134A, and GSTT1 (null). DNA was obtained from newborn screening archives for 201 cases and 285 controls, <or= 10 years of age, and born in California or Washington State between 1978 and 1990. Conception-to-diagnosis home insecticide treatment history was ascertained by interview.

RESULTS

We observed no biologically plausible main effects for any of the metabolic polymorphisms with CBT risk. However, we observed strong interactions between genotype and insecticide exposure during childhood. Among exposed children, CBT risk increased per PON1-108T allele [odds ratio (OR) = 1.8; 95% confidence interval (CI), 1.1-3.0] and FMO1-9536A (*6) allele (OR = 2.7; 95% CI, 1.2-5.9), whereas among children never exposed, CBT risk was not increased (PON1: OR = 0.7; 95% CI, 0.5-1.0, interaction p = 0.005; FMO1: OR = 1.0; 95% CI, 0.6-1.6, interaction p = 0.009). We observed a similar but statistically nonsignificant interaction between childhood exposure and BCHEA539T (interaction p = 0.08). These interactions were present among both Hispanic and non-Hispanic white children.

CONCLUSION

Based on known effects of these variants, these results suggest that exposure in childhood to organophosphorus and perhaps to carbamate insecticides in combination with a reduced ability to detoxify them may be associated with CBT. Confirmation in other studies is required.

Late recurrence in pediatric cancer: a report from the Childhood Cancer Survivor Study

BACKGROUND

An increasing percentage of childhood cancer patients are surviving their disease, but there is limited research on late recurrence. We sought to estimate late recurrence rates for the most common pediatric cancers and to determine risk factors for late recurrence.

METHODS

The incidence of late recurrences, or first recurrences that occurred more than 5 years after diagnosis, was analyzed for the most common pediatric cancers using data from the Childhood Cancer Survivor Study, a retrospective cohort of 5-year survivors of childhood and adolescent cancers who were diagnosed between 1970 and 1986. A total of 12,795 survivors with no history of recurrence within 5 years after their original cancer diagnosis were included in the analysis, with a total of 217,127 person-years of follow-up. Cumulative incidence of late recurrence at 5, 10, 15, and 20 years after diagnosis was calculated using death as a competing risk. Adjusted relative rates of late recurrence were obtained using multivariable Poisson regression. All statistical tests were two-sided.

RESULTS

Overall, 5-year survivors of pediatric cancers experienced a cumulative incidence of recurrent disease of 4.4%, 5.6%, and 6.2% at 10, 15, and 20 years, respectively. Cumulative incidence varied by diagnosis: Survivors of Ewing sarcoma and astrocytoma had the highest 20-year cumulative incidences at 13.0% (95% confidence interval [CI] = 9.4 to 16.5) and 14.4% (95% CI = 12.3 to 16.6), respectively. In multivariable analysis, the greatest risk factors for late recurrence included diagnosis, combination treatment with chemotherapy and radiation, earlier treatment era, and fewer years since diagnosis (P < .001 for all).

CONCLUSION

Late recurrence is a risk for some pediatric cancers. By understanding diagnosis-specific risks, patients, families, and their medical providers can be better informed of the probability of cure.

DNA repair gene polymorphisms and risk of adult meningioma, glioma, and acoustic neuroma

Although the etiology of primary brain tumors is largely unknown, prior studies suggest that DNA repair polymorphisms may influence risk of glioma. Altered DNA repair is also likely to affect the risk of meningioma and acoustic neuroma, but these tumors have not been well studied. We estimated the risk of glioma (n = 362), meningioma (n = 134), and acoustic neuroma (n = 69) in non-Hispanic whites with respect to 36 single nucleotide polymorphisms from 26 genes involved in DNA repair in a hospital-based, case-control study conducted by the National Cancer Institute. We observed significantly increased risk of meningioma with the T variant of GLTSCR1 rs1035938 (OR(CT/TT) = 3.5; 95% confidence interval: 1.8-6.9; P(trend) .0006), which persisted after controlling for multiple comparisons (P = .019). Significantly increased meningioma risk was also observed for the minor allele variants of ERCC4 rs1800067 (P(trend) .01); MUTYH rs3219466 (P(trend) .02), and PCNA rs25406 (P(trend) .03). The NBN rs1805794 minor allele variant was associated with decreased meningioma risk (P(trend) .006). Risk of acoustic neuroma was increased for the ERCC2 rs1799793 (P(trend) .03) and ERCC5 rs17655 (P(trend) .05) variants and decreased for the PARP1 rs1136410 (P(trend) .03). Decreased glioma risk was observed with the XRCC1 rs1799782 variant (P(trend) .04). Our results suggest that common DNA repair variants may affect the risk of adult brain tumors, especially meningioma.