Epidemiology of brain tumors

The worldwide incidence and prevalence of primary brain tumors: a systematic review and meta-analysis

BACKGROUND

Primary brain tumors are a heterogeneous group of benign and malignant tumors arising from the brain parenchyma and its surrounding structures. The epidemiology of these tumors is poorly understood. The aim of our study is to systematically review the latest literature on the incidence and prevalence of primary brain tumors.

METHODS

The systematic review and meta-analysis were conducted according to a predetermined protocol and established guidelines. Only studies reporting on data from 1985 onward were included. Articles were included if they met the following criteria: (i) original research, (ii) population based, (iii) reported an incidence or prevalence estimate of primary brain tumors.

RESULTS

From the 53 eligible studies overall, 38 were included in the meta-analysis. A random-effects model found the overall incidence rate of all brain tumors to be 10.82 (95% CI: 8.63-13.56) per 100 000 person-years. The incidence proportion estimates were heterogeneous, even among the same tumor subtypes, and ranged from 0.051 per 100 000 (germ cell tumors) to 25.48 per 100 000 (all brain tumors). There were insufficient data to conduct a meta-analysis of the prevalence of primary brain tumors.

CONCLUSIONS

There is a need for more accurate and comparable incidence and prevalence estimates of primary brain tumors across the world. A standardized approach to the study of the epidemiology of these tumors is needed to better understand the burden of brain tumors and the possible geographical variations in their incidence.

NF-κB and STAT3 in glioblastoma: therapeutic targets coming of age

Since we last addressed the roles of NF-κB and JAK/STAT3 signaling in glioblastoma (GBM) 5 years ago, tremendous strides have been made in the understanding of these two pathways in glioma biology. Contributing to prosurvival mechanisms, cancer stem cell maintenance and treatment resistance, both NF-κB and STAT3 have been characterized as major drivers of GBM. In this review, we address general improvements in the molecular understanding of GBM, the structure of NF-κB and STAT3 signaling, the ways in which these pathways contribute to GBM and advances in preclinical and clinical targeting of these two signaling cascades.

Gender-related protection from or vulnerability to severe CNS diseases: gonado-structural and/or gonado-activational? A meta-analysis of relevant epidemiological studies

BACKGROUND

A vast scientific literature has dealt with gender-specific risk for brain disorder. That field is evolving toward a consensus to the effect that the estrogen hormone family is outstandingly and uniquely neuroprotective. However, the epidemiology relevant to this general outlook remains piecemeal.

METHOD

The present investigation strategically formats the relevant epidemiological findings around the world in order to quantitatively meta-analyze gender ratio of risk for a variety of relevant severe central nervous system (CNS) diseases at all three gonadal stages of the life cycle, pre pubertal, post adolescent/pre menopausal, and post menopausal.

RESULTS

The data quantitatively establish that (1) no single epidemiological study should be cited as evidence of gender-specific neuroprotection against the most common severe CNS diseases because the gender-specific risk ratios are contradictory from one study to the other; (2) risk for severe CNS disease is indeed significantly gender-specific, but either gender can be protected: it depends on the disease, not at all on the age bracket.

CONCLUSION

Our assay of gender-specific risk for severe brain disease around the world has not been able to support the idea according to which any one gender-prevalent gonadal steroid hormone dominates as a neuroprotective agent at natural concentrations.

Brain tumours and cigarette smoking: analysis of the INTERPHONE Canada case-control study

BACKGROUND

There is conflicting evidence regarding the associations between cigarette smoking and glioma or meningioma. Our purpose is to provide further evidence on these possible associations.

METHODS

We conducted a set of case-control studies in three Canadian cities, Montreal, Ottawa and Vancouver. The study included 166 subjects with glioma, 93 subjects with meningioma, and 648 population-based controls. A lifetime history of cigarette smoking was collected and various smoking indices were computed. Multivariable logistic regression was used to estimate odds ratios (ORs) between smoking and each of the two types of brain tumours.

RESULTS

Adjusted ORs between smoking and each type of brain tumour were not significantly elevated for all smokers combined or for smokers with over 15 pack-years ((packs / day) x years) accumulated. We tested for interactions between smoking and several sociodemographic variables; the interaction between smoking and education on glioma risk was significant, with smoking showing an elevated OR among subjects with lower education and an OR below unity among subjects with higher education.

CONCLUSION

Except for an unexplained and possibly artefactual excess risk in one population subgroup, we found little or no evidence of an association between smoking and either glioma or meningioma.

Polymersomes as an effective drug delivery system for glioma--a review

Glioma is one of the most commonly occurring malignant brain tumours which need proper treatment strategy. The current therapies for treating glioma like surgical resection, radiotherapy, and chemotherapy have failed in achieving satisfactory results and this forms a rationale for the development of novel drug delivery systems. Among them, polymersomes are superior novel carriers with diverse functions like enhanced stability, low permeability, tunable membrane properties, surface functionality, and long blood circulation time which make them suitable for cancer therapy. These are bilayered vesicles capable of encapsulating both hydrophilic and hydrophobic drugs used to target glioma effectively. In this review, we have discussed on general preparation, characterization, and targeting aspects of surface modified polymersomes for effective delivery of therapeutic agents to glioma.

Adenoviral vector-mediated gene therapy for gliomas: coming of age

INTRODUCTION

Glioblastoma multiforme (GBM) is the most common primary brain tumor in adults and it carries a dismal prognosis. Adenoviral vector (Ad)-mediated gene transfer is being developed as a promising therapeutic strategy for GBM. Preclinical studies have demonstrated safety and efficacy of adenovirus administration into the brain and tumor mass in rodents and into the non-human primates' brain. Importantly, Ads have been safely administered within the tumor resection cavity in humans.

AREAS COVERED

This review gives background on GBM and Ads; we describe gene therapy strategies for GBM and discuss the value of combination approaches. Finally, we discuss the results of the human clinical trials for GBM that have used Ads.

EXPERT OPINION

The transduction characteristics of Ads, and their safety profile, added to their capacity to achieve high levels of transgene expression have made them powerful vectors for the treatment of GBM. Recent gene therapy successes in the treatment of retinal diseases and systemic brain metabolic diseases encourage the development of gene therapy for malignant glioma. Exciting clinical trials are currently recruiting patients; although, it is the large randomized Phase III controlled clinical trials that will provide the final decision on the success of gene therapy for the treatment of GBM.

Adenoviral vector-mediated gene therapy for gliomas: coming of age

INTRODUCTION

Glioblastoma multiforme (GBM) is the most common primary brain tumor in adults and it carries a dismal prognosis. Adenoviral vector (Ad)-mediated gene transfer is being developed as a promising therapeutic strategy for GBM. Preclinical studies have demonstrated safety and efficacy of adenovirus administration into the brain and tumor mass in rodents and into the non-human primates' brain. Importantly, Ads have been safely administered within the tumor resection cavity in humans.

AREAS COVERED

This review gives background on GBM and Ads; we describe gene therapy strategies for GBM and discuss the value of combination approaches. Finally, we discuss the results of the human clinical trials for GBM that have used Ads.

EXPERT OPINION

The transduction characteristics of Ads, and their safety profile, added to their capacity to achieve high levels of transgene expression have made them powerful vectors for the treatment of GBM. Recent gene therapy successes in the treatment of retinal diseases and systemic brain metabolic diseases encourage the development of gene therapy for malignant glioma. Exciting clinical trials are currently recruiting patients; although, it is the large randomized Phase III controlled clinical trials that will provide the final decision on the success of gene therapy for the treatment of GBM.

Malignant gliomas: current perspectives in diagnosis, treatment, and early response assessment using advanced quantitative imaging methods

Malignant gliomas consist of glioblastomas, anaplastic astrocytomas, anaplastic oligodendrogliomas and anaplastic oligoastrocytomas, and some less common tumors such as anaplastic ependymomas and anaplastic gangliogliomas. Malignant gliomas have high morbidity and mortality. Even with optimal treatment, median survival is only 12–15 months for glioblastomas and 2–5 years for anaplastic gliomas. However, recent advances in imaging and quantitative analysis of image data have led to earlier diagnosis of tumors and tumor response to therapy, providing oncologists with a greater time window for therapy management. In addition, improved understanding of tumor biology, genetics, and resistance mechanisms has enhanced surgical techniques, chemotherapy methods, and radiotherapy administration. After proper diagnosis and institution of appropriate therapy, there is now a vital need for quantitative methods that can sensitively detect malignant glioma response to therapy at early follow-up times, when changes in management of nonresponders can have its greatest effect. Currently, response is largely evaluated by measuring magnetic resonance contrast and size change, but this approach does not take into account the key biologic steps that precede tumor size reduction. Molecular imaging is ideally suited to measuring early response by quantifying cellular metabolism, proliferation, and apoptosis, activities altered early in treatment. We expect that successful integration of quantitative imaging biomarker assessment into the early phase of clinical trials could provide a novel approach for testing new therapies, and importantly, for facilitating patient management, sparing patients from weeks or months of toxicity and ineffective treatment. This review will present an overview of epidemiology, molecular pathogenesis and current advances in diagnoses, and management of malignant gliomas.

Hydrocephalus after resection and adjuvant radiochemotherapy in patients with glioblastoma

OBJECTIVE

Glioblastomas are the most common primary malignant brain tumors in adults with a poor prognosis. The current study sought to identify risk factors in glioblastoma patients that are closely associated with communicating hydrocephalus.

METHODS

We retrospectively analyzed data from 151 patients who were diagnosed with a glioblastoma between 2007 and 2011 and underwent complete surgical resection closely followed by adjuvant radiochemotherapy.

RESULTS

We observed a significant tendency toward communicating hydrocephalus in cases of ventricular opening during surgical tumor resection (Fisher's exact test p<0.001) and a noticeable, although not statistically significant, correlation between the onset of communicating hydrocephalus and evidence of leptomeningeal tumor dissemination (Fisher's exact test p=0.067). Additionally, there was a trend toward frontal tumor location and a larger tumor volume in patients with communicating hydrocephalus. The majority of patients suffering from communicating hydrocephalus received a cerebrospinal fluid (CSF) shunt implantation after radiation therapy (63.6%, Fisher's exact test p=0.000).

CONCLUSION

We identified the following risk factors associated with the onset of communicating hydrocephalus in glioblastoma patients: ventricular opening during tumor resection and leptomeningeal tumor dissemination. Shunt implantation seems to be safe and effective in these patients.

Lentiviral Vector Mediated Delivery of RHBDD1 shRNA down Regulated the Proliferation of Human Glioblastoma Cells

Rhomboid domain containing 1 (RHBDD1) gene, a new member of rhomboid family of proteins is highly responsible for the regulation of apoptosis by cleaving pro-apoptotic Bcl-2 family protein BIK. Therefore, the higher expression levels of RHBDD1 in cancer tissues may have a direct influence on cancer progression by arresting apoptosis. With this background this study was focused to find out the effect of RHBDD1 silencing on the progression of human brain glioblastoma cells, U251 and U87MG. The results indicated that both cell lines show a higher expression level of RHBDD1 and RNA interference (RNA) mediated gene silencing successfully down regulated the RHBDD1 gene expression. As a result of RHBDD1 silencing the proliferation of both cell types was reduced by over 50%, 5 days after silencing. Moreover the colony formation was completely inhibited and there were no cells present following two week RHBDD1 gene silencing. The cell proliferation was inhibited as a result of cell cycle arrest due to RHBDD1 absence. Therefore, these results clearly indicate that, RHBDD1 is essential for the progression of glioblastoma cells and silencing of it is resulting in significant inhibition of cell cycle progression and cell proliferation. Collectively, this study shows that RHBDD1 gene engineering could be used as an effective tool in malignant brain tumor therapy.

Occupational solvent exposure and risk of meningioma: results from the INTEROCC multicentre case-control study

OBJECTIVE

To examine associations between occupational exposure to selected organic solvents and meningioma.

METHODOLOGY

A multicentre case-control study conducted in seven countries, including 1906 cases and 5565 controls. Occupational exposure to selected classes of organic solvents (aliphatic and alicyclic hydrocarbons, aromatic hydrocarbons, chlorinated hydrocarbons and 'other' organic solvents) or seven specific solvents (benzene, toluene, trichloroethylene, perchloroethylene, 1,1,1-trichloroethylene, methylene chloride and gasoline) was assessed using lifetime occupational histories and a modified version of the FINJEM job-exposure matrix (INTEROCC-JEM). Study participants were classified as 'exposed' when they had worked in an occupation for at least 1 year, with a 5-year lag, in which the estimated prevalence of exposure was 25% or greater in the INTEROCC-JEM. Associations between meningioma and each of the solvent exposures were estimated using conditional logistic regression, adjusting for potential confounders.

RESULTS

A total of 6.5% of study participants were ever exposed to 'any' solvent, with a somewhat greater proportion of controls (7%) ever exposed compared with cases (5%), but only one case was ever exposed to any chlorinated hydrocarbon (1,1,1-trichloroethane). No association was observed between any of the organic solvents and meningioma, in either men or women, and no dose-response relationships were observed in internal analyses using either exposure duration or cumulative exposure.

DISCUSSION

We found no evidence that occupational exposure to these organic solvents is associated with meningioma.

Glioblastoma: approach to treat elderly patients

Treating elderly cancer patients is a challenge for oncologists, especially considering the several therapeutic modalities in glioblastoma. Extensive tumor resection offers the best chance of local control. Adequate radiotherapy should always be given to elderly patients if they have undergone gross total resection and have maintained a good performance status. Rather than being ruled out, chemotherapy should be considered, and temozolomide is the chosen drug. A comprehensive geriatric assessment is a valuable tool to help guiding treatment decisions in elderly patients with glioblastoma.

Investigation of ICAM-1 and β3 integrin gene variations in patients with brain tumors

BACKGROUND

Primary brain tumors constitute a small percent of all malignant cancers, but their etiology remains poorly understood. β3 integrin (ITGB3) has been recognized to play influential roles in angiogenesis, tumor growth and metastasis. Intercellular adhesion molecule-1 (ICAM-1) is a surface glycoprotein important for tumor invasion and angiogenesis. The aim of this study was to investigate whether specific genetic polymorphisms of ICAM-1 and ITGB3 could be associated with brain cancer development and progression in a Turkish population. Our study is the first to our knowledge to investigate the relationship between brain tumor risk and ICAM-1 and β3 integrin gene polymorphisms.

MATERIALS AND METHODS

The study covered 92 patients with primary brain tumors and 92 age-matched healthy control subjects. Evaluation of β3 integrin (Leu33Pro (rs5918)) and ICAM-1 (R241G (rs1799969) and K469E (rs5498)) gene polymorphisms was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).

RESULTS

According to results of our research, the A allele of the ICAM-1 R241G gene polymorphism appeared to be a risk factor for primary brain tumors (p<0.001). Similarly, the frequency of the A mutant allele of ICAM-1 R241G was statistically significant in patients with brain tumors classified as glioma (p<0.001). When allele and genotype distributions of ICAM- 1 K469E, ICAM-1 R241G and β3 integrin Leu33Pro gene polymorphisms were evaluated with age, sex, and smoking, there were no statistically significant differences. Haplotype analysis revealed that the frequencies of GAC (rs1799969-rs5498-rs5918) and GAT (rs1799969-rs5498-rs5918) haplotypes were significantly lower in patients as compared with controls (p=0.001; p=0.036 respectively).

CONCLUSIONS

This study provides the first evidence that ICAM-1 R241G SNP significantly contributes to the risk of primary brain tumors in a Turkish population. In addition, our results suggest that ICAM-1 R241G in combination ICAM-1 K469E may have protective effects against the development of brain cancer.

Selection of appropriate tumour data sets for Benchmark Dose Modelling (BMD) and derivation of a Margin of Exposure (MoE) for substances that are genotoxic and carcinogenic: considerations of biological relevance of tumour type, data quality and uncertainty assessment

This article addresses a number of concepts related to the selection and modelling of carcinogenicity data for the calculation of a Margin of Exposure. It follows up on the recommendations put forward by the International Life Sciences Institute - European branch in 2010 on the application of the Margin of Exposure (MoE) approach to substances in food that are genotoxic and carcinogenic. The aims are to provide practical guidance on the relevance of animal tumour data for human carcinogenic hazard assessment, appropriate selection of tumour data for Benchmark Dose Modelling, and approaches for dealing with the uncertainty associated with the selection of data for modelling and, consequently, the derived Point of Departure (PoD) used to calculate the MoE. Although the concepts outlined in this article are interrelated, the background expertise needed to address each topic varies. For instance, the expertise needed to make a judgement on biological relevance of a specific tumour type is clearly different to that needed to determine the statistical uncertainty around the data used for modelling a benchmark dose. As such, each topic is dealt with separately to allow those with specialised knowledge to target key areas of guidance and provide a more in-depth discussion on each subject for those new to the concept of the Margin of Exposure approach.

The adolescent and young adult with cancer: state of the art--brain tumor

The management of adolescents and young adults with brain tumors, which consist of many different histologic subtypes, continues to be a challenge. Better outcome with a decrease of the side effects of the disease and therapy and improvement of quality of life has been demonstrated in recent decades for some tumors. Significant differences in survival and cure are also observed between adult and pediatric tumors of the same histologic grade. Genetic, developmental, and environmental factors likely influence the type of tumor and response observed, even though no clear pathologic features differentiate these lesions among children, adolescents, and adults. Similarly, treatment strategies are not identical among these populations; most patients receive surgery, followed by radiation therapy and multiagent chemotherapy. Advances in understanding the biology underlying the distribution of tumors in adolescents and young adults may influence the development of prospective trials. A more individualized view of these tumors will likely influence stratification of patients in future studies as well as selection for targeted agents. Accordingly, outcomes may improve and long-term morbidities may decrease.

Hormone replacement therapy and risk of glioma: a nationwide nested case-control study

AIM

Several studies indicate that use of hormone replacement therapy (HRT) is associated with an increased risk of intracranial meningioma, while associations between HRT use and risk of other brain tumors have been less explored. We investigated the influence of HRT use on the risk of glioma in a nationwide setting.

METHODS

Using population-based registries we conducted a case-control study nested in the Danish female population. We identified all women aged 55-84 years with a first diagnosis of histologically verified brain glioma during 2000-2009. Using risk-set sampling, each case was matched on birth year to eight population controls. Ever use of HRT was defined as ≥2 HRT prescriptions and categorized according to type (oestrogens only, combined oestrogen-progestagen and progestagen only) and duration of use (<1, ≥1 to <5, ≥5 to <10, and ≥10 years). We used conditional logistic regression to compute odds ratios (ORs), with 95% confidence intervals (CIs), for glioma associated with HRT use, adjusting for potential confounders.

RESULTS

We identified 658 cases and 4350 controls. Ever use of HRT was associated with an OR of 0.9 (95% CI: 0.8-1.1) for glioma. For long-term use (≥10 years) we found ORs of 1.1 (95% CI: 0.7-1.7) for HRT overall, 1.6 (95% CI: 0.9-2.6) for oestrogen only, 0.8 (0.4-1.6) for combined oestrogen-progestagen, and 2.2 (0.9-5.5) for progestagen. Tests for trends were statistically non-significant in all strata.

CONCLUSION

Use of HRT overall was not associated with an increased risk of glioma. However, our findings indicate that prolonged use of oestrogen only or progestagen may be associated with an increased risk of glioma.

Delayed growth of glioma by a polysaccharide from Aster tataricus involve upregulation of Bax/Bcl-2 ratio, activation of caspase-3/8/9, and downregulation of the Akt

In this study, a homogeneous polysaccharide (ATP-II), with a molecular weight of 3.4 × 10(4) Da, was successfully purified from Aster tataricus by DEAE-Sepharose CL-6B ion exchange and Sepharose CL-6B gel filtration chromatography. Monosaccharide component analysis indicated that ATP-II was composed of glucose, galactose, mannose, rhamnose, and arabinose in molar ratios of 2.1:5.2:2.1:1.0:1.2. We evaluated the anticancer efficacy and associated mechanisms of ATP-II on glioma C6 cells in vitro and in vivo. The results showed that treatment of C6 cells with ATP-II inhibited cell proliferation and this biological response came from induction of DAN damage and consequent inducing apoptosis. Likewise, oral ATP-II administration resulted in consistent regression of glioma tumors and induced apoptosis of transplanted tumor tissues by increasing the ratio of Bax/Bcl-2 and activation of caspase-3, caspase-8, and caspase-9 cascade. Importantly, the efficient downregulation of Akt, which is successfully detected in tumor tissues, is a unique contribution to retard the tumor growth by ATP-II. These data suggest that ATP-II may be a potential candidate for glioma treatment.

Germinoma in two brothers: case report

We present a third reported case of intracranial germinomas occurring in two brothers. They underwent chemotherapy and radiotherapy after biopsy and are doing well for 10 years and 20 months, respectively. The pertinent literatures are reviewed, and the possible role of heredity in the pathogenesis of familial occurrence of germinomas is discussed.

Antihistamine use and immunoglobulin E levels in glioma risk and prognosis

OBJECTIVE

An inverse association between personal history of allergies/asthma and glioma risk has been fairly consistently reported in the epidemiologic literature. However, the role of regular antihistamine use remains controversial due to a small number of studies reporting contradictory findings. We evaluated the association between regular use of oral antihistamines and glioma risk, adjusting for a number of relevant factors (e.g., immunoglobulin E levels and history of chickenpox).

METHODS

We used a subset of the Harris County Case-Control Study, which included 362 pathologically confirmed glioma cases and 462 cancer-free controls, to evaluate this association using unconditional multivariable logistic regression. These models were run among the overall study population and stratified by allergy status. Cox regression was utilized to examine whether antihistamine use was associated with mortality among all cases and separately among high-grade cases.

RESULTS

Antihistamine use was strongly associated with glioma risk among those with a positive allergy/asthma history (OR: 4.19, 95% CI: 2.06-8.51), but not among those with a negative history (OR: 1.59, 95% CI: 0.95-2.67). There were no significant associations between antihistamine use and survival among cases.

CONCLUSION

The current study implies that regular antihistamine use may increase glioma risk. However, several larger studies are necessary before definitive conclusions can be drawn.

Glioma and glioblastoma - how much do we (not) know?

Cancer is a heterogeneous disease, which provides a broad field for investigation, while simultaneously reducing the chances for a universal treatment. Malignant gliomas are the most common type of primary brain tumors. The heterogeneity of gliomas regarding clinical presentation, pathology and response to treatment makes this type of tumor a challenging area of research. As the clinical symptoms may be unspecific (e.g., seizures and headaches) it is often difficult to diagnose a patient in the early stages of the disease. Thus far, there are no known genetic patterns of inheritance of this disease. Currently, the treatment of glioblastoma involves surgery, whenever possible, followed by radiation and chemotherapy. Experimental procedures, such as passive and active immunotherapy, use of angiogenesis inhibitors in combination with chemotherapeutics and gene/antibody therapy, are additional treatment options. However, as the brain is difficult to access due to the presence of the blood-brain barrier (BBB), none of the above-mentioned therapies have been successful in curing this disease. The lack of knowledge regarding the mechanisms underlying the development and progression of gliomas further adds to the difficulties. Currently, investigations are focused on the development of novel methods for improving the outcome of this disease. However, despite the extensive investigations, 88% of all glioblastoma multiforme (GBM) patients succumb to the disease within 3 years. GBM remains one of the most challenging malignancies worldwide.

Aspergillosis in a patient receiving temozolomide for the treatment of glioblastoma

Leukopenia and selective CD4+ lymphopenia represent major adverse events associated with the use of temozolomide (TMZ), an oral alkylating agent incorporated in the treatment of glioblastoma (GBM). The increased risk of opportunistic infections, including those caused by Pneumocystis jiroveci and cytomegalovirus, has been previously described in the literature. Here we report the case, the first to our knowledge, of a patient with pulmonary invasive aspergillosis immediately after the completion of chemoradiation with TMZ for GBM. Diagnosis was confirmed through a CT-guided lung biopsy, and the patient had excellent response to systemic voriconazole. This case illustrates that TMZ can be associated with severe opportunistic infections, presumably associated with T lymphocyte immune dysfunction, and patients exposed to this agent should be carefully monitored.

Body mass index and the risk of meningioma, glioma and schwannoma in a large prospective cohort study (The HUNT Study)

BACKGROUND

Obesity increases the risk for a number of solid malignant tumours. However, it is not clear whether body mass index (BMI) and height are associated with the risk of primary tumours of the central nervous system (CNS).

METHODS

In a large population study (The Nord-Trøndelag Health Study (HUNT Study)) of 74 242 participants in Norway, weight and height were measured. During follow-up, incident CNS tumours were identified by individual linkage to the Norwegian Cancer Registry. Sex- and age-adjusted and multivariable Cox regression analyses were used to evaluate BMI and height in relation to the risk of meningioma, glioma and schwannoma.

RESULTS

A total of 138 meningiomas, 148 gliomas and 39 schwannomas occurred during 23.5 years (median, range 0-25) of follow-up. In obese women (BMI ≥ 30 kg m(-2)), meningioma risk was 67% higher (hazard ratio (HR)=1.68, 95% confidence interval (CI): 0.97-2.92, P-trend=0.05) than in the reference group (BMI 20-24.9 kg m(-2)), whereas no association with obesity was observed in males. There was no association of BMI with glioma risk, but there was a negative association of overweight/obesity (BMI ≥ 25 kg m(-2)) with the risk of schwannoma (HR=0.48, 95% CI: 0.23-0.99). However, the schwannoma analysis was based on small numbers. Height was not associated with the risk for any tumour subgroup.

CONCLUSION

These results suggest that BMI is positively associated with meningioma risk in women, and possibly, inversely associated with schwannoma risk.

Hormone replacement therapy increases the risk of cranial meningioma

AIM

We investigated the influence of hormone replacement therapy (HRT) use on the risk of meningioma in a population-based setting.

METHODS

We conducted a nationwide case-control study in Denmark based on population-based administrative and health registries. The study included all female patients aged 55-84 years with a first time diagnosis of meningioma during 2000-2009. The cases were matched on birth year with female population controls. Ever use of HRT since 1995 was defined as ≥2 HRT prescriptions and categorised according to HRT type (oestrogen only, combined oestrogen-progestagen, and progestagen only) and cumulated duration of use (<1, ≥1 to <5, ≥5 to <10, ≥10 years). We used conditional logistic regression to compute odds ratios (ORs), with 95% confidence intervals (CIs), for meningioma associated with HRT use, and adjusting for potential confounders.

RESULTS

We identified 924 cases and 6122 controls. Ever use of HRT was associated with an increased risk of meningioma (OR, 1.3; 95%CI, 1.1-1.5) compared with non-use (0-1 prescriptions). The risk increased with increasing duration of HRT use, reaching an OR of 1.7 (95% CI, 1.2-2.3) after more than 10 years of use. The risk of meningioma associated with long-term (≥10 years) HRT use was most pronounced for combined oestrogen-progestagen therapy (OR, 2.2; 95% CI, 1.4-3.3), especially when this regimen constituted the sole HRT therapy (OR, 2.7; 95% CI, 0.9-7.5), although the latter estimate was based on small numbers.

CONCLUSIONS

Long-term HRT use, particularly of combined oestrogen-progestagen therapy, may increase the risk of meningioma.

Therapeutic targeting of EGFR-activated metabolic pathways in glioblastoma

INTRODUCTION

The highly divergent histological heterogeneities, aggressive invasion and extremely poor response to treatment make glioblastoma (GBM) one of the most lethal and difficult cancers in humans. Among key elements driving its behavior is epidermal growth factor receptor (EGFR), however, neither traditional therapy including neurosurgery, radiation, temozolomide, nor targeted EGFR therapeutics in clinic has generated promising results to date. Strategies are now focusing on blocking the downstream EGFR-activated metabolic pathways and the key phosphorylated kinases.

AREAS COVERED

Here, we review two major EGFR-activated downstream metabolic pathways including the PI3K/AKT/mTOR and RAS/RAF/MAPK pathways and their key phosphorylated kinase alterations in GBMs. This review also discusses potential pharmacological progress from bench work to clinical trials in order to evaluate specific inhibitors as well as therapeutics targeting PI3K and RAS signaling pathways.

EXPERT OPINION

Several factors impede clinical progress in targeting GBM, including the high rates of acquired resistance, heterogeneity within and across the tumors, complexity of signaling pathways and difficulty in traversing the blood-brain barrier (BBB). Substantial insight into genetic and molecular pathways and strategies to better tap the potential of these agents include rational combinatorial regimens and molecular phenotype-based patient enrichment, each of which will undoubtedly generate new therapeutic approaches to combat these devastating disabilities in the near future.

Anaplastic oligodendroglioma: advances and treatment options

OPINION STATEMENT

The optimal treatment strategy for anaplastic oligodendroglial (AO) tumors is evolving. Molecular profiling of oligodendrogliomas have shown distinctive genetic patterns characterized by combined deletions of chromosome arms 1p and 19q, O(6)-methylguanine methyltransferase (MGMT) methylation, and isocitrate dehydrogenase 1 (IDH1) mutations; they are all prognostic factors for patients with AO. In addition, a strong association has also been found between the CpG island hypermethylation phenotype (CIMP) status and MGMT promoter methylation. Long term follow up data of the Radiation Therapy Oncology Group (RTOG) 9402 and the European Organisation for Research and Treatment of Cancer (EORTC) 26951 studies demonstrate clear evidence that for patients with codeleted 1p19q AO, early chemotherapy with radiation offers a significant improvement in overall survival compared with early radiation, even with salvage chemotherapy at tumor relapse, and thus establishes the 1p19q allelic loss as a predictive marker distinct from tumors without the chromosome change. Radiotherapy alone is no longer considered an adequate treatment for this patient population. In cases with no 1p19q deletion, most neuro-oncologists recommend incorporating radiotherapy into the upfront treatment strategy. However, there are still unanswered questions regarding whether upfront chemotherapy, omitting/deferring radiotherapy, in the desire to avoid late neurocognitive toxicity of radiotherapy should be the initial therapy for AO tumors with codeleted 1p19q, or whether temozolomide, an oral agent with a better toxicity profile, can be substituted for procarbazine, lomustine, and vincristine (PCV). Further studies are warranted and the increasing understanding of molecular pathways involved may lead to more selective therapeutic targets in the future.

Integration of epidemiology, immunobiology, and translational research for brain tumors

We recently identified a pivotal role for the host type I interferon (IFN) pathway in immunosurveillance against de novo mouse glioma development, especially through the regulation of immature myeloid cells (IMCs) in the glioma microenvironment. The present paper summarizes our published work in a number of areas. We have identified single-nucleotide polymorphisms (SNPs) in human IFN genes that dictate altered prognosis of patients with glioma. One of these SNPs (rs12553612) is located in the promoter of IFNA8 and influences its activity. Conversely, recent epidemiologic data show that chronic use of nonsteroidal anti-inflammatory drugs lowers the risk of glioma. We translated these findings back to our de novo glioma model and found that cyclooxygenase-2 inhibition enhances antiglioma immunosurveillance by reducing glioma-associated IMCs. Taken together, these findings suggest that alterations in myeloid cell function condition the brain for glioma development. Finally, in preliminary work, we have begun applying novel immunotherapeutic approaches to patients with low-grade glioma with the aim of preventing malignant transformation. Future research will hopefully better integrate epidemiological, immunobiological, and translational techniques to develop novel, preventive approaches for malignant gliomas.

The vitamin D receptor (VDR) gene polymorphisms in Turkish brain cancer patients

Objective. It has been stated that brain cancers are an increasingly serious issue in many parts of the world. The aim of our study was to determine a possible relationship between Vitamin D receptor (VDR) gene polymorphisms and the risk of glioma and meningioma. Methods. We investigated the VDR Taq-I and VDR Fok-I gene polymorphisms in 100 brain cancer patients (including 44 meningioma cases and 56 glioma cases) and 122 age-matched healthy control subjects. This study was performed by polymerase chain reaction-based restriction fragment length polymorphism (RF LP). Results. VDR Fok-I ff genotype was significantly increased in meningioma patients (15.9%) compared with controls (2.5%), and carriers of Fok-I ff genotype had a 6.47-fold increased risk for meningioma cases. There was no significant difference between patients and controls for VDR Taq-I genotypes and alleles. Conclusions. We suggest that VDR Fok-I genotypes might affect the development of meningioma.

INTEROCC case-control study: lack of association between glioma tumors and occupational exposure to selected combustion products, dusts and other chemical agents

Background

The aim was to investigate possible associations between glioma (an aggressive type of brain cancer) and occupational exposure to selected agents: combustion products (diesel and gasoline exhaust emissions, benzo(a)pyrene), dusts (animal dust, asbestos, crystalline silica, wood dust) and some other chemical agents (formaldehyde, oil mist, sulphur dioxide).

Methods

The INTEROCC study included cases diagnosed with glioma during 2000–2004 in sub-regions of seven countries. Population controls, selected from various sampling frames in different centers, were frequency or individually matched to cases by sex, age and center. Face-to-face interviews with the subject or a proxy respondent were conducted by trained interviewers. Detailed information was collected on socio-economic and lifestyle characteristics, medical history and work history. Occupational exposure to the 10 selected agents was assessed by a job exposure matrix (JEM) which provides estimates of the probability and level of exposure for different occupations. Using a 25% probability of exposure in a given occupation in the JEM as the threshold for considering a worker exposed, the lifetime prevalence of exposure varied from about 1% to about 15% for the different agents. Associations between glioma and each of the 10 agents were estimated by conditional logistic regression, and using three separate exposure indices: i) ever vs. never; ii) lifetime cumulative exposure; iii) total duration of exposure.

Results

The study sample consisted of 1,800 glioma cases and 5,160 controls. Most odds ratio estimates were close to the null value. None of the ten agents displayed a significantly increased odds ratio nor any indication of dose–response relationships with cumulative exposure or with duration of exposure.

Conclusion

Thus, there was no evidence that these exposures influence risk of glioma.

Area-based socioeconomic position and adult glioma: a hierarchical analysis of surveillance epidemiology and end results data

Background

Glioma rates vary by demographic factors and geo-political boundaries and this variation suggests higher glioma rates in groups of higher socioeconomic position. The primary goal of this analysis is to investigate the relationship between glioma and county socioeconomic position using U.S. Surveillance Epidemiology and End Results (SEER) data.

Methods

Cases were individuals 25+ years diagnosed with glioma between 2000 and 2006 and residing within the SEER-17 catchment area. County-, sex-, race-, age-specific rates were created in order to investigate individual-level associations (population data from U.S. Census 2000). A Bayesian hierarchical Poisson spatial conditionally autoregressive (CAR) model was utilized to simultaneously estimate individual- and county-level associations while controlling for county spatial dependence.

Results

Those residing in counties of the second, third, and fourth highest quartiles of socioeconomic position have glioma incidence rates that are 1.10 (95% CI: 1.02,1.19), 1.11 (95% CI: 1.02,1.20), 1.14 (95% CI: 1.05,1.23) times that of the first quartile, respectively. A CAR model properly controlled for error spatial dependence. Investigated lag times suggest year 2000 census data yields superior model fit.

Conclusion

Demographically adjusted rates of glioma are elevated in counties of higher socioeconomic position. More well-grounded theory concerning the glioma-socioeconomic position association along with socioeconomic data collected at multiple levels is recommended for future studies investigating this relationship.

Use of low-dose aspirin and non-aspirin nonsteroidal anti-inflammatory drugs and risk of glioma: a case-control study

Background:

Few studies have examined the association between use of aspirin or other non-steroidal anti-inflammatory drugs (NSAIDs) and risk of glioma and the results have been equivocal. We therefore investigated the influence of NSAID use on glioma risk in a nationwide setting.

Methods:

We used national registries in Denmark to identify all patients aged 20–85 years with a first diagnosis of histologically verified glioma during 2000–2009. Each case was matched on birth year and sex to eight population controls using risk-set sampling. We used prescription data to assess NSAID use and classified exposure to low-dose aspirin or non-aspirin (NA) NSAIDs into ever use or long-term use, defined as continuous use for ⩾5 years. Conditional logistic regression was used to compute odds ratios (ORs), with 95% confidence intervals (CIs), for glioma associated with NSAID use, adjusted for potential confounders.

Results:

A total of 2688 glioma cases and 18 848 population controls were included in the study. Ever use of low-dose aspirin (OR=0.90; 95% CI: 0.77–1.04) or NA-NSAIDs (OR=1.05; 95% CI: 0.96–1.14) was not associated with glioma risk. Compared with never use, long-term use of low-dose aspirin or of NA-NSAIDs was associated with ORs of 0.80 (95% CI: 0.53–1.21) and 1.11 (0.57–2.17), respectively. We observed no clear patterns of risk in stratified analysis according to estimated doses of low-dose aspirin (⩽100 mg, 150 mg).

Conclusion:

We did not find any apparent association between aspirin or NA-NSAID use and risk of glioma, although our results may be consistent with a slight reduction in glioma risk with long-term use of low-dose aspirin.

Migration of mesenchymal stem cells towards glioblastoma cells depends on hepatocyte-growth factor and is enhanced by aminolaevulinic acid-mediated photodynamic treatment

Hepatocyte-growth factor (HGF) is expressed by glioblastomas and contributes to their growth, migration and invasion. HGF also mediates migration of mesenchymal stem cells (MSC) to sites of apoptotic cell death. Moreover, MSC show tropism for glioblastomas, which is exploited in gene therapy to deliver the therapeutics to the tumor cells. Here, we have studied whether HGF contributes to the recruitment of MSC by glioblastoma cells and whether aminolaevulinic acid-mediated photodynamic therapy (ALA/PDT), a novel therapeutic approach that induces apoptosis in glioblastoma cells, affects HGF release and this migratory response. MSC expressed the HGF receptor MET and migrated towards U87 and U251 glioblastoma spheroids. Migration increased significantly when spheroids were subjected to ALA/PDT, which was associated with induction of apoptosis and up-regulation of HGF. Neutralizing HGF resulted in significant inhibition of MSC migration towards untreated as well as ALA/PDT-treated spheroids. Thus, glioblastoma cells express HGF, which contributes to the attraction of MSC. ALA/PDT induces apoptosis and augments HGF release causing enhanced MSC migration towards the tumor cells. ALA/PDT may therefore be exploited to improve targeting of MSC delivered gene therapy, but it may also constitute a risk in terms of beneficial effects for the tumor.

Use of statins and risk of glioma: a nationwide case-control study in Denmark

Background:

Laboratory studies and a single case–control study have suggested a protective effect of statins on the risk of glioma. We wished to investigate the influence of statin use on the risk of glioma in a population-based setting.

Methods:

We conducted a nationwide case–control study in Denmark based on population-based medical registries. We identified all patients aged 20 to 85 years with a first diagnosis of histologically verified glioma during 2000–2009. These cases were matched on birth year and sex with population controls. Prior use of statins since 1995 was classified into short-term use (<5 years) and long-term use (5+ years). We used conditional logistic regression to compute odds ratios (ORs), with 95% confidence intervals (CIs), for glioma associated with statin use, adjusted for potential confounders.

Results:

A total of 2656 cases and 18 480 controls were included in the study. The risk of glioma was reduced among long-term statin users (OR=0.76; 95% CI: 0.59–0.98) compared with never users of statins, and was inversely related to the intensity of statin treatment among users (OR=0.71; 95% CI: 0.44–1.15 for highest intensity). The inverse association between long-term statin treatment and glioma risk was more pronounced among men aged ⩽60 years (OR=0.40; 95% CI: 0.17–0.91) compared with men aged 60+ years (OR=0.71; 95% CI: 0.49–1.03). An inverse association was also observed among women aged ⩽60 years (OR=0.28; 95% CI: 0.06–1.25), but not among women over age 60 years (OR=1.23; 95% CI: 0.82–1.85).

Conclusion:

Long-term statin use may reduce the risk of glioma.

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.