Risk factors for meningioma in adults: a case-control study in northeast China

Impact of Heavy Metals on Glioma Tumorigenesis

Recently, an increase in the incidence of brain tumors has been observed in the most industrialized countries. This event triggered considerable interest in the study of heavy metals and their presence in the environment (air, water, soil, and food). It is probable that their accumulation in the body could lead to a high risk of the onset of numerous pathologies, including brain tumors, in humans. Heavy metals are capable of generating reactive oxygen, which plays a key role in various pathological mechanisms. Alteration of the homeostasis of heavy metals could cause the overproduction of reactive oxygen species and induce DNA damage, lipid peroxidation, and the alteration of proteins. A large number of studies have shown that iron, cadmium, lead, nickel, chromium, and mercury levels were significantly elevated in patients affected by gliomas. In this study, we try to highlight a possible correlation between the most frequently encountered heavy metals, their presence in the environment, their sources, and glioma tumorigenesis. We also report on the review of the relevant literature.

Prognostic biomarker prediction for glioma induced by heavy metals and their mixtures: An in-silico study

Although there is an association between heavy metals and glioma, the molecular mechanisms involved in glioma development remain unclear. Therefore, this study aimed to assess the molecular mechanisms implicated in glioma development induced by heavy metals and their mixtures using various methodologies and databases (CTD, Google Scholar, PubMed, ScienceDirect, SpringerLink, miRNAsong, GeneMANIA, Metascape, MIENTURNET, UALCAN). I found that heavy metals, particularly arsenic, mercury, lead, and cadmium, as well as their mixtures, have substantial influences on the etiology of gliomas. "glioblastoma signaling pathways," "integrated cancer pathway," "central carbon metabolism in cancer," "microRNAs in cancer," "p53 signaling pathway," "chemical carcinogenesis-DNA adducts," "glioma," "TP53 network," and "MAPK signaling pathway" were the predominant molecular pathways implicated in the glioma development induced by the studied heavy metals and their mixtures. Five genes (SOD1, CAT, GSTP1, PTGS2, TNF), two miRNAs (hsa-miR-26b-5p and hsa-miR-143-3p), and transcription factors (DR1 and HNF4) were identified as key components related to combined heavy metal and glioma development. Physical interactions were found to be the most common among the heavy metals and their mixtures studied (ranging from 45.2% to 77.6%). The expression level of SOD1 was significantly lower in glioblastoma multiforma samples compared to normal samples, whereas GSTP1 and TP53 expression levels were significantly higher. Brain lower and grade glioma patients who had higher levels of TP53, hsa-miR-25, hsa-miR-34, hsa-miR-222, and hsa-miR-143 had a reduced likelihood of survival. Our findings suggest that further priority should be given to investigating the impact of specific heavy metals or their mixtures on these molecular processes.

Alcohol intake and the risk of glioma: a systematic review and updated meta-analysis of observational study

The association between alcohol intake and the risk of glioma has been widely studied, but these results have yielded conflicting findings. Therefore, we conducted this systematic review and updated meta-analysis to systematically evaluate the association between alcohol intake and the risk of glioma. A systematic literature search of relevant articles published in PubMed, Web of Science, CNKI and Wan fang databases up to December 2021 was conducted. Pooled estimated of relative risk (RR) and 95 % CI were calculated using fixed-effects models. A total of eight articles with three case-control studies involving 2706 glioma cases and 2 189 927 participants were included in this meta-analysis. A reduced risk of glioma was shown for the low-moderate alcohol drinking v. non-drinking (RR = 0·87; 95 % CI (0·78, 0·97); P = 0·014). In addition, there was no evidence of an increased risk of glioma in the heavy alcohol drinking compared with non-drinking (RR = 0·89; 95 % CI (0·67, 1·18); P = 0·404). The findings suggest an inverse association between low-moderate alcohol drinking and the risk of glioma, in the absence, however, of a dose-response relationship. More prospective studies are needed to provide further insight into the association between alcohol drinking and glioma risk.

Diagnostic radiological examinations and risk of intracranial tumours in adults-findings from the Interphone Study

BACKGROUND

Exposure to high doses of ionizing radiation is among the few well-established brain tumour risk factors. We used data from the Interphone study to evaluate the effects of exposure to low-dose radiation from diagnostic radiological examinations on glioma, meningioma and acoustic neuroma risk.

METHODS

Brain tumour cases (2644 gliomas, 2236 meningiomas, 1083 neuromas) diagnosed in 2000-02 were identified through hospitals in 13 countries, and 6068 controls (population-based controls in most centres) were included in the analysis. Participation across all centres was 64% for glioma cases, 78% for meningioma cases, 82% for acoustic neuroma cases and 53% for controls. Information on previous diagnostic radiological examinations was obtained by interviews, including the frequency, timing and indication for the examinations. Typical brain doses per type of examination were estimated based on the literature. Examinations within the 5 years before the index date were excluded from the dose estimation. Adjusted odds ratios were estimated using conditional logistic regression.

RESULTS

No materially or consistently increased odds ratios for glioma, meningioma or acoustic neuroma were found for any specific type of examination, including computed tomography of the head and cerebral angiography. The only indication of an elevated risk was an increasing trend in risk of meningioma with the number of isotope scans, but no such trends for other examinations were observed. No gradient was found in risk with estimated brain dose. Age at exposure did not substantially modify the findings. Sensitivity analyses gave results consistent with the main analysis.

CONCLUSIONS

There was no consistent evidence for increased risks of brain tumours with X-ray examinations, although error from selection and recall bias cannot be completely excluded. A cautious interpretation is warranted for the observed association between isotope scans and meningioma.

A decreased risk of meningioma in women smokers was only observed in American studies rather than studies conducted in other countries: a systematic review and meta-analysis

Background

Whether smoking is related to a decreased risk of meningioma in women is still controversial. We conducted a systematic review and meta-analysis examining the association between smoking and risk of meningiomas in women.

Methods

Two authors independently performed a systematic literature review in the PubMed, Cochrane Library, and EMBASE databases. We identified case-control and cohort studies quantifying associations between smoking and risk of meningioma in women. A meta-analysis by pooling studies was performed according to the multivariate-adjusted risk estimates and 95% confidence intervals (CIs) preferentially. We further conducted additional subgroup and sensitivity analyses to explore possible explanations of the results.

Results

A total of seven observational studies were included, with a total of 2132 female patients diagnosed with meningiomas. Ever smoking was associated with a significantly reduced risk of meningioma in women, with pooled odds ratio (OR) of 0.83 (95% CI 0.70–0.98). Similar findings were noted for current (OR 0.78, 95% CI 0.66–0.93) and past (OR 0.82, 95% CI 0.71–0.94) smokers. However, considering the areas, the OR of ever smoking was 0.77 (95% CI 0.68–0.87) in three American studies, but 0.99 (95% CI 0.73–1.35) in four studies conducted in other countries.

Conclusions

Based on limited epidemiological evidence, a decreased risk of meningioma in women smokers was only observed in American studies rather than studies conducted in other countries.

A meta-analysis of active smoking and risk of meningioma

INTRODUCTION

Cigarette smoking has been hypothesized to be a risk factor for meningioma. However, the results of studies exploring the relationship between smoking exposure and the occurrence of meningioma are inconsistent.

METHODS

A search of PubMed, Medline, Embase, and Science Direct (up to June 2020) databases was performed. Two authors independently extracted the data. The Newcastle–Ottawa Scale was employed for judging the quality of articles. A random-effects model was utilized for meta-analysis. Association analysis between smoking and meningioma was based on the adjusted RR and the 95% CI, as reported by eligible studies. Subgroup and sensitivity analyses were performed and publication bias was assessed. Subgroup analysis was conducted by geographical region, study design, sex, study quality, and adjustments of RR score. Begg’s and Egger’s tests were employed for detecting publication bias.

RESULTS

Twelve articles, including 2 cohort studies and 10 case–control studies, and a total of 1210167 participants were identified. The pooled relative risk (RR) with 95% confidence interval (95% CI) implied that smoking was not associated with increased risk of meningioma in men and women combined (RR=1.09; 95% CI: 0.90–1.33). From the sex-stratified subgroup analysis, the risk of meningioma was significant in men (RR=1.42; 95% CI: 1.16–1.74). Risk of meningioma in women did not remain significant (RR=0.92; 95% CI: 0.73–1.16). There was a high heterogeneity in the results (I²=58.4%, p=0.002). Sensitivity analyses showed stable results and there was no evidence of publication bias.

CONCLUSIONS

Cigarette smoking is not associated with a significantly increased risk of meningioma in the whole population, but there is a positive association in men but not in women.

Systematic review of the epidemiology of a single physical trauma and cancer

Background

A systematic review of single physical trauma and cancer was carried out, with a meta-analysis where deemed appropriate.

Methods

A comprehensive search of the literature including databases such as Medline and Embase identified 1529 potentially relevant papers for inclusion. A further 89 potentially relevant studies were identified from bibliographies. After review of titles and abstracts and then full papers, a total of 77 studies were included in the broader review of trauma and cancer, and 31 of these studies considered single physical trauma and cancer. The searches were carried out in June 2016.

Results

Although physical trauma as a cause of cancer has been an issue of clinical interest for decades, the epidemiological evidence was sparse. Only for traumatic brain injury and brain cancer was there considered a sufficient number of epidemiological studies for a meta-analysis. A random effects meta-relative risk for glioma from cohort studies was 0.96 (95% CI: 0.49 to 1.88) and 1.53 (95% CI: 1.02 to 2.27) for case-control studies. The equivalent results for meningioma were 1.22 (95% CI: 0.85 to 1.76) and 1.88 (95% CI: 0.84 to 1.49) respectively.

Conclusions

Further work is required to clarify whether physical trauma has a role in cancer development, perhaps by exploiting trauma registries.

Occupational Lead Exposure and Brain Tumors: Systematic Review and Meta-Analysis

(1) Background: Due to inconsistencies in epidemiological findings, there has been uncertainty regarding the association of lead compounds with brain tumors. We performed a meta-analysis of published case-control and cohort studies exploring lead compound exposure and brain tumor risk. (2) Methods: We searched PubMed, Embase^®, and Cochrane to find eligible studies. Eighteen studies were selected for assessment of occupational exposure to lead compound and brain tumor. Pooled estimates of odds ratios (ORs) were obtained using random effects models. We assessed the differences through subgroup analysis according to tumor type, study design, measurements of exposure, and tumor outcome. Statistical tests for publication bias, heterogeneity, and sensitivity analysis were applied. (3) Results: Our systematic review and meta-analysis showed a not significant association with lead exposure and risk of benign and malignant brain tumors (pooled OR = 1.11, 95% Confidence Interval (CI): 0.95–1.29). Including only malignant brain tumors, the risk of brain tumor was significantly increased (pooled OR = 1.13, 95% CI: 1.04–1.24). (4) Conclusions: This meta-analysis provides suggestive evidence for an association between lead compound exposure and brain tumor. In future studies, it will be necessary to identify the effect of lead compounds according to the types of brain tumor.

The INTEROCC case-control study: risk of meningioma and occupational exposure to selected combustion products, dusts and other chemical agents

BACKGROUND

Little is known about occupational risk factors for meningioma.

OBJECTIVES

To study whether risk of meningioma is associated with several occupational exposures, including selected combustion products, dusts and other chemical agents.

METHODS

The INTEROCC study was an international case-control study of brain cancer conducted in seven countries. Data collection by interview included lifetime occupational histories. A job exposure matrix was used to derive estimates of exposure for the 12 agents. ORs for ever versus never exposed and for exposure-response using duration of exposure and cumulative exposure were derived using conditional logistic regression stratified by sex, age group, country/region, adjusted for education.

RESULTS

These analyses included 1906 cases and 5565 controls. For 11 of the 12 agents, no excess risk was found for ever exposed. For ever exposure to oil mists, an elevated OR of 1.57 (95% CI 1.10 to 2.22, 51 exposed cases) was found. Statistically significant exposure-response relationships were observed with cumulative exposure (p=0.01) and duration of exposure (p=0.04). Among women, there were also significant trends for cumulative and duration of exposure to asbestos and excesses in the highest exposure categories for formaldehyde.

CONCLUSIONS

Most agents examined did not provoke excess risks of meningioma. The main finding from this study is that it is the first study to identify a statistical association between exposure to oil mists and meningioma. This may be a chance finding or could be due to confounding with iron exposure and further research is required to understand whether the relationship is causal.

Pathophysiology of Meningioma Growth in Pregnancy

Meningioma is among the most frequent brain tumours predominantly affecting elderly women. Epidemiological studies have shown that at the age of fertility the incidence is relatively low. The biological behaviour of meningioma in pregnancy is different from other meningiomas. The possible explanation is rooted in the complex physiological changes and hormonal differences during pregnancy. The increased meningioma growth observed in pregnancy is presumably the result of endocrine mechanisms. These include increase in progesterone, human placental lactogen (hPL) and prolactin (PRL) serum levels. In contrast, levels of pituitary hormones such as follicle stimulating hormone (FSH), luteinizing hormone (LH) and human chorionic gonadotropin (hCG) produced by the placenta are decreasing in the mother prior to childbirth. Besides, vascular factors also play a crucial role. Peritumoral brain edema (PTBE), with well-known causative association with vascular endothelial growth factor (VEGF), can often be seen both with imaging and in the surgical specimens. Our aim is to assess published research on this topic including diagnostic and therapeutic guidelines, and to provide a clinically useful overview on the pathophysiology and biological behaviour of this rare complication of pregnancy.

Meningioma recurrence

Meningioma accounts for more than 30% of all intracranial tumours. It affects mainly the elderly above the age of 60, at a female:male ratio of 3:2. The prognosis is variable: it is usually favourable with no progression in tumour grade and no recurrence in WHO grade 1 tumours. However, a minority of tumours represent atypical (grade 2) or anaplastic (grade 3) meningiomas; this heterogeneity is also reflected in histopathological appearances. Irrespective of the grade, the size of the tumour and the localisation may have severe, sometimes lethal consequences. Following neurosurgical interventions to remove the tumour, recurrence and progression in WHO grade may occur. Our knowledge on predisposing histomorphological and molecular factors of recurrence is rather limited. These can be classified as I) demographic II) environmental, III) genetic and epigenetic IV) imaging, V) neuropathological, and VI) neurosurgical. In view of the complex background of tumour recurrence, the recognition of often subtle signs of increased risk of recurrence requires close collaboration of experts from several medical specialties. This multidisciplinary approach results in better therapy and fewer complications related to tumour recurrence.

Heavy metals and epigenetic alterations in brain tumors

Heavy metals and their derivatives can cause various diseases. Numerous studies have evaluated the possible link between exposure to heavy metals and various cancers. Recent data show a correlation between heavy metals and aberration of genetic and epigenetic patterns. From a literature search we noticed few experimental and epidemiological studies that evaluate a possible correlation between heavy metals and brain tumors. Gliomas arise due to genetic and epigenetic alterations of glial cells. Changes in gene expression result in the alteration of the cellular division process. Epigenetic alterations in brain tumors include the hypermethylation of CpG group, hypomethylation of specific genes, aberrant activation of genes, and changes in the position of various histones. Heavy metals are capable of generating reactive oxygen assumes that key functions in various pathological mechanisms. Alteration of homeostasis of metals could cause the overproduction of reactive oxygen species and induce DNA damage, lipid peroxidation, and alteration of proteins. In this study we summarize the possible correlation between heavy metals, epigenetic alterations and brain tumors. We report, moreover, the review of relevant literature.

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.

5,10-Methylenetetrahydrofolate reductase (MTHFR), methionine synthase (MTRR), and methionine synthase reductase (MTR) gene polymorphisms and adult meningioma risk

The causes of meningiomas are not well understood. Folate metabolism gene polymorphisms have been shown to be associated with various human cancers. It is still controversial and ambiguous between the functional polymorphisms of folate metabolism genes 5,10-methylenetetrahydrofolate reductase (MTHFR), methionine synthase (MTRR), and methionine synthase reductase (MTR) and risk of adult meningioma. A population-based case–control study involving 600 meningioma patients (World Health Organization [WHO] Grade I, 391 cases; WHO Grade II, 167 cases; WHO Grade III, 42 cases) and 600 controls was done for the MTHFR C677T and A1298C, MTRR A66G, and MTR A2756G variants in Chinese Han population. The folate metabolism gene polymorphisms were determined by using a polymerase chain reaction–restriction fragment length polymorphism assay. Meningioma cases had a significantly lower frequency of MTHFR 677 TT genotype [odds ratio (OR) = 0.49, 95 % confidence interval (CI) 0.33–0.74; P = 0.001] and T allele (OR = 0.80, 95 % CI 0.67–0.95; P = 0.01) than controls. A significant association between risk of meningioma and MTRR 66 GG (OR = 1.41, 95 % CI 1.02–1.96; P = 0.04) was also observed. When stratifying by the WHO grade of meningioma, no association was found. Our study suggested that MTHFR C677T and MTRR A66G variants may affect the risk of adult meningioma in Chinese Han population.

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.

Alcohol consumption and risk of glioma: a meta-analysis of 19 observational studies

The relationship between risk of glioma and alcohol consumption has been widely studied, but results have been conflicting. We therefore conducted a meta-analysis of observational studies to systematically assess the relationship between alcohol drinking and risk of glioma. Two electronic databases (PubMed and EMBASE) were searched from inception to 8 August 2013 to identify pertinent studies that linked alcohol drinking with glioma risk. We used a random-effects model to calculate the overall relative risk (RR) with corresponding 95% confidence intervals (CIs). Fifteen case-control and four cohort studies were identified for this analysis. The combined RR for total alcohol drinkers versus non-drinkers was 0.96 (95% CI: 0.89–1.04). In the subgroup analysis by geographic area, a significant association was observed in North American studies (RR = 0.78, 95% CI: 0.65–0.93), but not in European or Asian/Australian studies. In the subgroup analysis by study design, a borderline significant association emerged in population-based case-control studies (RR = 0.82, 95% CI: 0.68–0.99), but not in hospital-based case-control studies (RR = 1.00, 95% CI: 0.99–1.01) or cohort group (RR = 1.03, 95% CI: 0.88–1.20). Our results show no material association between alcohol consumption and risk of glioma existed. Further prospective evidences are needed to confirm this association.

A meta-analysis of alcohol consumption and the risk of brain tumours

BACKGROUND

Alcohol is capable of traversing the blood-brain barrier and is thus a possible risk factor for brain cancer. Several epidemiological studies have been published on the issue, a number of those during recent years, with inconsistent findings.

MATERIALS AND METHODS

We performed a systematic literature search in the Medline and EMBASE databases. We found a total of 19 studies providing risk estimates for total alcohol or specific alcoholic beverages. Pooled estimates of the relative risks (RR) and 95% confidence intervals (CI) were calculated using random-effects models.

RESULTS

The pooled RR of brain cancer for alcohol drinkers versus non-drinkers was 0.97 (95% CI 0.82-1.15; based on 12 studies). Moderate (<2 drinks/day) and heavy alcohol drinkers had RRs of 1.01 (95% CI 0.81-1.25) and 1.35 (95% CI 0.85-2.15), respectively. With reference to specific alcoholic beverages, the RRs were 1.01 (95% CI 0.70-1.48) for wine, 0.96 (95% CI 0.82-1.12) for beer, and 1.20 (95% CI 1.01-1.42) for spirit consumption. The RRs for drinkers versus non-drinkers were 0.93 (95% CI 0.81-1.07) for glioma and 0.71 (95% CI 0.45-1.12) for meningioma.

CONCLUSIONS

Alcohol drinking does not appear to be associated with adult brain cancer, though a potential effect of high doses deserves further study.

Cigarette smoking and risk of meningioma: the effect of gender

BACKGROUND

A number of studies have reported on the association between smoking and meningioma risk, with inconsistent findings. We examined the effect of gender on the association between cigarette smoking and risk of intracranial meningioma in a large population-based, case-control study.

METHODS

The data include 1,433 intracranial meningioma cases aged 29 to 79 years diagnosed among residents of the states of Connecticut, Massachusetts, North Carolina, the San Francisco Bay Area and eight Texas counties between May 1, 2006 and April 28, 2011 as well as 1,349 controls that were frequency matched on age, sex, and geography. The data are analyzed separately and in a meta-analysis with six previously reported studies.

RESULTS

Female cases who reported having ever smoked were at significantly decreased risk of intracranial meningioma (OR, 0.8; 95% CI, 0.7-0.9) in contrast to male cases who were at increased risk (OR, 1.3; 95% CI, 1.0-1.7). Similar findings were noted for current and past smokers. Smoking-induced risk for females did not vary by menopausal status. For males, increased duration of use (P = 0.04) as well as increasing number of pack-years (P = 0.02) was associated with elevated risk. A meta-analysis including 2,614 cases and 1,179,686 controls resulted in an OR for ever smoking of 0.82 (95% CI, 0.68-0.98) for women and 1.39 (95% CI, 1.08-1.79) for men.

CONCLUSION

The association of cigarette smoking and meningioma case status varies significantly by gender with women at reduced risk and men at greater risk.

IMPACT

Whether the observed differences are associated with a hormonal etiology will require additional investigation.

Possible interaction between ionizing radiation, smoking, and gender in the causation of meningioma

Data on the association between smoking and meningioma are inconsistent. The aim of this study was to assess the role of smoking in radiation- and non-radiation-related meningiomas. The study was designed as a 4-group case-control study, balanced for irradiation, including 160 irradiated meningioma case patients, 145 irradiated control subjects, 82 nonirradiated case patients, and 135 nonirradiated control subjects. The sources of these groups included a cohort of individuals who underwent radiotherapy (mean dose, 1.5 Gy to the brain) during childhood for treatment of tinea capitis, claims filed for radiation damage in the framework of a compensation law, and the Israel Cancer Registry. All tests of statistical significance were 2-sided. A statistically significantly elevated risk of meningioma was found among men who had ever smoked, compared with those who were never smokers (odds ratio [OR], 2.13; 95% confidence interval [CI], 1.09-4.15), increasing with smoking pack-years from 1.67 to 2.69 for <10 to >20 pack-years, respectively. Among women, an interaction between radiation and smoking was observed, expressed by a significant protective effect for meningioma (OR, 0.32; 95% CI, 0.14-0.77), with a strong dose-response association (P < .01) in non-irradiated women and a nonsignificant increased risk of meningioma among those who were irradiated (OR, 1.23; 95% CI, 0.68-2.23). Variation in the association between smoking and meningioma may be explained by effects of distinct host factors, such as past exposure to ionizing radiation and/or hormonal factors.

Occupation and risk of glioma, meningioma and acoustic neuroma: results from a German case-control study (interphone study group, Germany)

BACKGROUND

Several epidemiological studies have investigated the association between occupation and brain tumour risk, but results have been inconclusive. We investigated the association between six occupational categories defined a priori: chemical, metal, agricultural, construction, electrical/electronic and transport, and the risk of glioma, meningioma and acoustic neuroma.

METHODS

In a population-based case-control study involving a total of 844 cases and 1688 controls conducted from 2000 to 2003, detailed information on life-long job histories was collected during personal interviews and used to create job calendars for each participant. Job title, job activity, job number, and the starting and ending dates of the activity were recorded for all activities with duration of at least 1 year. Reported occupational activities were coded according to the International Standard Classification of Occupations 1988 (ISCO 88). For the analyses we focused on six a priori defined occupational sectors, namely chemical, metal, agricultural, construction, electrical/electronic and transport. Multiple conditional logistic regression analysis was used to estimate odds ratios and their 95% confidence intervals.

RESULTS

Most of the observed odds ratios were close to 1.0 for ever having worked in the six occupational sectors and risk of glioma, meningioma and acoustic neuroma. Sub-group analyses according to duration of employment resulted in two elevated odds ratios with confidence intervals excluding unity.

CONCLUSIONS

We did not observe an increased risk of glioma or meningioma for occupations in the agricultural, construction, transport, chemical, electrical/electronic and metal sectors. The number of 'significant' odds ratios is consistent with an overall 'null-effect'.

Lead exposure, polymorphisms in genes related to oxidative stress, and risk of adult brain tumors

There is some evidence that oxidative stress plays a role in lead-induced toxicity. Mechanisms for dealing with oxidative stress may be of particular relevance in the brain given the high rate of oxygen metabolism. Using a hospital-based case-control study, we investigated the role of oxidative stress in the potential carcinogenicity of lead through examination of effect modification of the association between occupational lead exposure and brain tumors by single nucleotide polymorphisms in genes with functions related to oxidative stress. The study included 362 patients with glioma (176 of which had glioblastoma multiforme), 134 patients with meningioma, and 494 controls. Lead exposure was estimated by expert review of detailed job history data for each participant. We evaluated effect modification with 142 single nucleotide polymorphisms using likelihood ratio tests that compared nested unconditional logistic regression models that did and did not include a cross-product term for cumulative lead exposure and genotype. When the analyses were restricted to cases with glioblastoma multiforme, RAC2 rs2239774 and two highly correlated GPX1 polymorphisms (rs1050450 and rs18006688) were found to significantly modify the association with lead exposure (P Collapse

Key Words

• glioma
• meningioma
• lead exposure
• oxidative stress
• polymorphism

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MESH Headings

• Adolescent
• Adult
• Aged
• Aged, 80 and over
• Brain Neoplasms/chemically induced
• Brain Neoplasms/genetics
• Female
• Genetic Predisposition to Disease
• Glutathione Peroxidase/genetics
• Humans
• Lead/adverse effects
• Male
• Middle Aged
• Occupational Diseases/genetics
• Occupational Exposure/adverse effects
• Oxidative Stress/genetics
• Polymerase Chain Reaction
• Polymorphism, Single Nucleotide
• Risk Factors
• Young Adult
• rac GTP-Binding Proteins/genetics
• Glutathione Peroxidase GPX1
• RAC2 GTP-Binding Protein

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Grants

• N01CO12400 NCI NIH HHS
• NIH0011946573 Intramural NIH HHS
• Z01 CP010135-12 Intramural NIH HHS
• N01-CO-12400 NCI NIH HHS

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Affiliation(s)

Parveen Bhatti Department of Health ad Human Services, Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, Bethesda, Maryland, USA.
Patricia A Stewart
Amy Hutchinson
Nathaniel Rothman
Martha S Linet
Peter D Inskip
Preetha Rajaraman

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Brain tumor epidemiology: consensus from the Brain Tumor Epidemiology Consortium

Epidemiologists in the Brain Tumor Epidemiology Consortium (BTEC) have prioritized areas for further research. Although many risk factors have been examined over the past several decades, there are few consistent findings, possibly because of small sample sizes in individual studies and differences between studies in patients, tumor types, and methods of classification. Individual studies generally have lacked samples of sufficient size to examine interactions. A major priority based on available evidence and technologies includes expanding research in genetics and molecular epidemiology of brain tumors. BTEC has taken an active role in promoting understudied groups, such as pediatric brain tumors; the etiology of rare glioma subtypes, such as oligodendroglioma; and meningioma, which, although it is not uncommon, has only recently been registered systematically in the United States. There also is a pressing need for more researchers, especially junior investigators, to study brain tumor epidemiology. However, relatively poor funding for brain tumor research has made it difficult to encourage careers in this area. In this report, BTEC epidemiologists reviewed the group's consensus on the current state of scientific findings, and they present a consensus on research priorities to identify which important areas the science should move to address.

Lifestyle factors and primary glioma and meningioma tumours in the Million Women Study cohort

Previous studies have reported inconsistent results on the effect of anthropometric and lifestyle factors on the risk of developing glioma or meningioma tumours. A prospective cohort of 1.3 million middle-aged women was used to examine these relationships. During 7.7 million women-years of follow-up, a total of 1563 women were diagnosed with a primary incident central nervous system tumour: 646 tumours were classified as glioma and 390 as meningioma. Our results show that height is related to the incidence of all central nervous system tumours with a risk of about 20% per 10 cm increase in height (relative risk=1.19, 95% CI=1.10–1.30 per 10 cm increase in height, P<0.001): the risks did not differ significantly between specified glioma and meningioma. Body mass index (BMI) was also related to central nervous system tumour incidence, with a risk of about 20% per 10 kg m⁻² increase in BMI (relative risk=1.17, 95% CI=1.03–1.34 per 10 kg m⁻² increase in BMI, P=0.02). Smoking status, alcohol intake, socioeconomic level, parity, age at first birth, and oral contraceptive use were not associated with the risk of glioma or meningioma tumours. In conclusion, for women in the United Kingdom, the incidence of glioma or meningioma tumours increases with increasing height and increasing BMI.

Comprehensive analysis of DNA repair gene variants and risk of meningioma

BACKGROUND

Meningiomas account for up to 37% of all primary brain tumors. Genetic susceptibility to meningioma is well established, with the risk among relatives of meningioma patients being approximately threefold higher than that in the general population. A relationship between risk of meningioma and exposure to ionizing radiation is also well known and led us to examine whether variants in DNA repair genes contribute to disease susceptibility.

METHODS

We analyzed 1127 tagging single-nucleotide polymorphisms (SNPs) that were selected to capture most of the common variation in 136 DNA repair genes in five case-control series (631 case patients and 637 control subjects) from four countries in Europe. We also analyzed 388 putative functional SNPs in these genes for their association with meningioma. All statistical tests were two-sided.

RESULTS

The SNP rs4968451, which maps to intron 4 of the gene that encodes breast cancer susceptibility gene 1-interacting protein 1, was consistently associated with an increased risk of developing meningioma. Across the five studies, the association was highly statistically significant (trend odds ratio = 1.57, 95% confidence interval = 1.28 to 1.93; P(trend) = 8.95 x 10(-6); P = .009 after adjusting for multiple testing).

CONCLUSIONS

We have identified a novel association between rs4968451 and meningioma risk. Because approximately 28% of the European population are carriers of at-risk genotypes for rs4968451, the variant is likely to make a substantial contribution to the development of meningioma.

Epidemiology of brain tumors

Brain tumors seemed to have increased in incidence over the past 30 years, but the rise probably results from use of new neuroimaging techniques. Treatments have not improved prognosis for rapidly fatal brain tumors. Established brain tumor risk factors (exposure to ionizing radiation, rare mutations of penetrant genes, and familial history) explain only a small proportion of brain tumors, and only one of these potentially is modifiable. Genetic and environmental characteristics likely play a role in familial aggregation of glioma and these factors are not identified. New concepts in brain tumor etiology and clinical management are the goal of research, with an aim at eradicating this devastating disease.

Meningiomas: causes and risk factors

Meningiomas are among the most common primary intracranial tumors. Although the vast majority of these tumors are considered histologically benign, the incidence of complications can be high. Few studies have investigated the causes and risk factors for meningioma; this review highlights the current state of knowledge. Gaining a better understanding of the origin of this disease is essential so that treatments and outcomes can be improved and prevention strategies can be developed.

Lead, genetic susceptibility, and risk of adult brain tumors

BACKGROUND

Although few etiologic factors for brain tumors have been identified, limited data suggest that lead may increase the risk of brain tumors, particularly meningioma. The ALAD G177C polymorphism affects the toxicokinetics of lead and may confer genetic susceptibility to adverse effects of lead exposure.

METHODS

We examined occupational exposure to lead and risk of brain tumors in a multisite, hospital-based, case-control study of 489 patients with glioma, 197 with meningioma, and 799 non-cancer controls frequency matched on hospital, age, sex, race/ethnicity, and residential proximity to hospital. ALAD genotype was assessed by a Taqman assay for 355 glioma patients, 151 meningioma patients, and 505 controls. Exposure to lead was estimated using a rigorous questionnaire-based exposure assessment strategy incorporating lead measurement and other occupational data abstracted from published articles and reports.

RESULTS

Increased risk of meningioma with occupational lead exposure (estimated by odds ratios and 95% confidence intervals) was most apparent in individuals with the ALAD2 variant allele, for whom risk increased from 1.1 (0.3-4.5) to 5.6 (0.7-45.5) and 12.8 (1.4-120.8) for estimated cumulative lead exposures of 1 to 49 microg/m3-y, 50 to 99 microg/m3-y, and >or=100 microg/m3-y, respectively, compared with unexposed individuals (two-sided P trend = 0.06). This relationship became stronger after excluding occupational lead exposures characterized by a low confidence level or occurring in the 10 years before meningioma diagnosis. Occupational lead exposure was not associated with glioma risk.

CONCLUSIONS

Although our results indicate that lead may be implicated in meningioma risk in genetically susceptible individuals, these results need to be interpreted with caution given the small numbers of exposed cases with a variant genotype.

Association of meningioma with reproductive factors

Meningiomas occur more commonly in females. The coincidence between meningioma and breast cancer and case reports of tumor growth during pregnancy support a hormonal hypothesis. A case control study was conducted to investigate this. Female subjects treated between 1987 and 1992 were identified from 3 hospitals in the Chicago area. Female spouses of male back pain patients were recruited as controls. A self-administered mail questionnaire focused on exogenous, endogenous and other hormonal factors, personal and family medical history as well as radiation exposures. Odds ratios and 95% confidence intervals were estimated using crude, stratified and multivariable logistic models including 219 cases and 260 controls. Participation rates were 86% among cases and 75% among controls. An increased odds ratio (OR) was observed comparing African Americans to Caucasians [OR = 2.4, 95% confidence interval (CI) = 1.0-6.1]. A protective effect was observed for pregnancy, which increased with number and age at first pregnancy. The odds ratio for 3 or more pregnancies compared to none was 0.3 (95% CI = 0.2-0.6). Age at menarche or total period of hormonal activity was not protective. Ever smokers showed a decreased odds ratio for meningioma (OR = 0.6, 95% CI = 0.4-0.9). The increased odds ratios with African Americans was retained in post-menopausal women, while the protective odds ratios for pregnancy, smoking and oral contraceptives (OCs) became stronger in pre-menopausal women. The pattern by duration and timing of use does not suggest an etiologic role for OCs or hormone replacement therapy. These data add to the evidence that factors known to influence endogenous hormones (pregnancy and indirectly smoking) may have protective effects for meningiomas primarily in premenopausal women.

Brain cancer mortality and potential occupational exposure to lead: findings from the National Longitudinal Mortality Study, 1979-1989

We evaluated the association between potential occupational lead exposure and the risk of brain cancer mortality in the National Longitudinal Mortality Study (NLMS), which is a prospective census-based cohort study of mortality among the noninstitutionalized United States population (1979-1989). The present study was limited to individuals for whom occupation and industry were available (n = 317,968). Estimates of probability and intensity of lead exposure were assigned using a job-exposure matrix (JEM). Risk estimates for the impact of lead on brain cancer mortality were computed using standardized mortality ratio (SMR) and proportional hazards and Poisson regression techniques, adjusting for the effects of age, gender and several other covariates. Brain cancer mortality rates were greater among individuals in jobs potentially involving lead exposure as compared to those unexposed (age- and gender-adjusted hazard ratio (HR) = 1.5; 95% confidence interval (CI) = 0.9-2.3) with indications of an exposure-response trend (probability: low HR = 0.7 (95% CI = 0.2-2.2), medium HR = 1.4 (95% CI = 0.8-2.5), high HR = 2.2 (95% CI = 1.2-4.0); intensity: low HR = 1.2 (95% CI = 0.7-2.1), medium/high HR = 1.9 (95% CI = 1.0-3.4)). Brain cancer risk was greatest among individuals with the highest levels of probability and intensity (HR = 2.3; 95% CI = 1.3-4.2). These findings provide further support for an association between occupational lead exposure and brain cancer mortality, but need to be interpreted cautiously due to the consideration of brain cancer as one disease entity and the absence of biological measures of lead exposure.

Head injury and brain tumours in adults: A case–control study in Rio de Janeiro, Brazil

A hospital-based case-control study exploring the association between selected risk factors and head injury in adults, brain trauma included, was carried out in Greater Metropolitan Rio de Janeiro, Brazil. Cases included adults diagnosed with primary brain tumours (n = 231). Controls were matched for gender and age among in-patients hospitalized for various conditions unrelated to brain cancer (n = 261) identified in the same hospitals where cases were enrolled. Risk of having experienced head injury was more frequent among cases (46%) than controls (36%) (OR(adj) = 1.49; 95% CI = 1.03-2.15). A dose-response effect was observed according to the number of head injuries, and a statistically borderline association was observed for meningioma (OR(adj) = 1.63; 95% CI = 0.96-2.75). Although recall bias cannot be ruled out, our results suggest an association between prior head injury and the development of brain tumours in adults.

Ethnicity affects the distribution of delta-aminolevulinic acid dehydratase (ALAD) genetic variants

BACKGROUND

delta-Aminolevulinic acid dehydratase (ALAD) catalyzes the second step of heme synthesis. The ALAD gene shows a polymorphism (G-to-C transversion at position 177) leading to 2 alleles (ALAD1 and ALAD2) and 3 phenotypes (ALAD 1-1, ALAD 1-2 and ALAD 2-2). This polymorphism has been shown to affect lead toxicity and the risk of meningioma. In addition, there is little evidence showing interethnic differences in the distribution this polymorphism, especially in heterogeneous populations such as the present-day Brazilian population. We examined the distribution of genetic variants of the G177C ALAD polymorphism in black and white Brazilians.

METHODS

We studied 115 subjects self-reported as black and 119 subjects as white (total N=234; 135 men and 99 women; age range: 18-60 years). Genomic DNA was extracted from venous blood and the genotypes for the ALAD polymorphism were determined by PCR followed by RFLP digestion and gel electrophoresis.

RESULTS

We found a notable interethnic disparity in the distribution of G177C ALAD genotypes and alleles. The ALAD2 allele was more common in whites (12%) than in blacks (4%) (P<0.05). Correspondingly, the heterozygote (ALAD 1-2) or homozygote variant (ALAD 2-2) genotypes for this polymorphism were more common in whites than in blacks (P<0.05).

CONCLUSIONS

The significant interethnic differences in the distribution of G177C ALAD variants found in the Brazilian population is consistent with differences previously reported in other countries. These findings may help us understand the interethnic disparities in susceptibility to lead toxicity and brain tumors.

Predisposing conditions and risk factors for development of symptomatic meningioma in adults

BACKGROUND

Risk factors and predisposing factors for the development of symptomatic meningioma during adult life are not well known.

METHODS

Data from 306 consecutive patients with primary meningioma were collected retrospectively in a hypothesis-generating study. Factors studied included localisation of tumours, blood group typing, and risk factors, such as diabetes mellitus, coronary arterial disease, hypertension, rheumatoid arthritis, bronchial asthma, smoking, obesity, and second primary tumour. Case-control analysis of putative risk factors was carried out using a control data set from the German East-West Health Survey (n=7466, age range 25-69 years). Patients and controls were matched for age, gender, geographic area, and time of data collection.

RESULTS

Rh(D) positive cases were significantly less frequent in the patient group compared to controls (p=0.01). Pre-existing diabetes was associated with meningioma in middle-aged (40-69 years) patients (odds ratio, OR 13.94-4.30, p=0.001-0.05). In female patients, arterial hypertension was significantly associated with occurrence of meningioma in the age group 60-69 years (OR=2.23, p=0.041). Rheumatoid arthritis had a negative association with meningioma in both males and females in the age groups above 50 years (OR 0.19-0.27, p=0.02-0.034). Bronchial asthma, smoking, and obesity were not significantly associated with meningioma. A second primary tumour was present in 12 cases. The most frequent combination was meningioma and breast cancer (5/12).

CONCLUSIONS

This study shows statistically significant association of some co-morbidities with symptomatic meningioma in adults. Areas of interest have been identified where further research would be necessary.

Delta-aminolevulinic acid dehydratase polymorphism and risk of brain tumors in adults

The enzyme delta-aminolevulinic acid dehydratase (ALAD), which catalyzes the second step of heme synthesis, can be inhibited by several chemicals, including lead, a potential risk factor for brain tumors, particularly meningioma. In this study we examined whether the ALAD G177C polymorphism in the gene coding for ALAD is associated with risk of intracranial tumors of the brain and nervous system. We use data from a case-control study with 782 incident brain tumor cases and 799 controls frequency matched on hospital, age, sex, race/ethnicity, and residential proximity to the hospital. Blood samples were drawn and DNA subsequently sent for genotyping for 73% of subjects. ALAD genotype was determined for 94% of these samples (355 glioma, 151 meningioma, 67 acoustic neuroma, and 505 controls). Having one or more copy of the ALAD2 allele was associated with increased risk for meningioma [odds ratio (OR) = 1.6; 95% confidence interval (CI), 1.0-2.6], with the association appearing stronger in males (OR = 3.5; 95% CI, 1.3-9.2) than in females (OR = 1.2; 95% CI, 0.7-2.2). No increased risk associated with the ALAD2 variant was observed for glioma or acoustic neuroma. These findings suggest that the ALAD2 allele may increase genetic susceptibility to meningioma.

Active and Passive Cigarette Smoking and Risk of Intracranial Meningioma

Motivated by prior studies, we examined associations between cigarette smoking and risk of intracranial meningioma in a population-based case-control study, including 200 cases and 2 controls matched to each case on age and sex. Subjects were asked to recall their history of active and passive cigarette smoking occurring 10 or more years before the date of meningioma surgery. Ever active smoking was associated with an increased risk of meningioma in men (OR = 2.1; 95% CI 1.1-4.2) but not in women (OR = 0.7; 95% CI 0.5-1.1). The statistical interaction by gender was significant (p = 0.01). In men, risk increased with increasing number of cigarettes smoked daily (p for trend = 0.04). In women, the trend was opposite (p for trend = 0.08). Among never active smokers, passive smoking from a spouse was associated with increased risk in both sexes (OR 2.0; 95% CI 1.1-3.5), and risk increased with increasing duration of exposure (p for trend = 0.02). Uncertain is whether these findings reflect a true biological phenomenon or result from chance or uncontrolled confounding.

Rhabdoid meningioma occurring in an unrelated resection cavity with leptomeningeal carcinomatosis

✓ Rhabdoid meningioma (RM) is a recently described, aggressive variant of meningioma. The authors report a case of RM occurring in the resection cavity of an unrelated neurosurgical procedure, temporal lobectomy for intractable seizures. The patient presented with intractable headache 10 years after the temporal lobectomy. Imaging revealed a dura-based, uniformly enhancing lesion within the resection cavity. She underwent gross-total resection and the findings of the surgical pathological report were consistent with an RM, with a dramatically elevated MIB-1 index of approximately 50%. The patient's clinical course was complicated by severe pain and communicating hydrocephalus secondary to rapid dissemination of malignant cells throughout the CSF pathways. Despite aggressive measures, including tumor resection, ventriculoperitoneal shunt placement, and the initiation of conventional radiation therapy, the ensuing leptomeningeal carcinomatosis proved to be rapidly fatal.

Thymoma and multiple malignancies: a case of five synchronous neoplasms and literature review

The presence of five discrete synchronous or metachronous primary neoplasms in a single patient is an extremely rare event. This is a report of a patient with a malignant (invasive) thymoma and four other independent primary neoplasms including: gliosarcoma, papillary thyroid cancer, meningioma and metastatic adenocarcinoma of the colon, found synchronously at autopsy. Thymoma patients appear to have an inherent predisposition towards developing additional neoplasms. Other than the thymoma, the presented patient had no obvious risk factors for neoplasia. This case provides evidence for an unusual syndrome of thymoma and multiple primary neoplasms. Further research is required to elucidate the mechanism of this association. Meanwhile, heightened awareness of this association may allow earlier detection and treatment of additional cancers in patients with a history of thymoma.

History of head trauma and risk of intracranial meningioma: population-based case-control study

A population-based case-control study in western Washington state was performed to assess the relation between head trauma and meningioma. Based on 200 case and 400 control subjects, head trauma was associated with an increased risk of meningioma (odds ratio = 1.83; 95% CI = 1.28, 2.62), especially head traumas occurring 10 to 19 years before reference date (odds ratio = 4.33; 95% CI = 2.06, 9.10). A dose-response relationship was present for number, but not severity, of head traumas. Whether the associations observed in this study are causal remains unclear.

Occupational risk factors for small bowel carcinoid tumor: a European population-based case-control study

Small bowel carcinoid tumor (SBC) is a rare disease of unknown etiology but with an age-, sex-, and place-specific occurrence that may indicate an occupational origin. A European multicenter population-based case-control study was conducted from 1995 through 1997. Incident SBC cases between 35 and 69 years of age (n = 101) were identified, together with 3335 controls sampled from the catchment area of the cases. Histological review performed by a reference pathologist left 99 cases for study; 84 cases and 2070 population controls were interviewed. The industries most closely associated (a twofold or more odds ratio [OR]) with SBC, taking into account a 10-year time lag after exposure were, among women, employment in wholesale industry of food and beverages (OR, 8.2; 95% confidence interval [CI], 1.9 to 34.9]) and among men, manufacture of motor vehicle bodies (OR, 5.2; 95% CI, 1.2 to 22.4), footwear (OR, 3.9; 95% CI, 0.9 to 16.1), and metal structures (OR, 3.3; 95% CI, 1.0 to 10.4). The identified high-risk occupations with an OR above 2 were shoemakers, structural metal preparers, construction painters and other construction workers, bookkeepers, machine fitters, and welders (men). The OR for regular occupational use of organic solvents for at least half a year was 2.0 (95% CI, 1.0 to 4.2). Exposure to rust-preventive paint containing lead was suggested as another potential occupational exposure (OR, 9.1; 95% CI, 0.8 to 107). This explorative study suggests an association between certain occupational exposures and SBC, but some of these associations could be attributable to chance. All findings should be regarded as tentative.

Parental cigarette smoking, hard liquor consumption and the risk of childhood brain tumors--a case-control study in northeast China

In this study we examine the effect of parents' lifestyles on the risk of childhood brain tumors. Parents of 82 children newly diagnosed with primary malignant brain tumors and 246 individually matched hospital controls were interviewed in the hospital wards between September 1991 and December 1996. Data were collected on socioeconomic status, parental lifestyle prior to and during the pregnancy, and family history. Odds ratios and 95% confidence intervals were derived through conditional logistic regression. The risk of childhood brain tumors was associated with paternal use of hard liquor prior to the pregnancy: the odds ratios were 3.72 (95% CI = 1.91-7.26) for < or = 15 years of hard liquor consumption and 4.06 (95% CI = 1.09-15.21) for > or = 16 years of hard liquor consumption compared with never consuming hard liquor (test for trend p = 0.0001); the odds ratios increased with increasing lifetime hard liquor consumption. There is little evidence to support an association between childhood brain tumors and parents' smoking prior to or during pregnancy.

Epidemiology of brain tumors

Primary brain tumor incidence and survival patterns are emerging, assisted by progress in molecular classification. Evidence is accumulating to suggest that infectious diseases may affect the risk of developing a brain tumor, although data require clarification. Other promising research directions include evaluating the role of diet and allergic conditions in reducing brain tumor risk.