Increased Risk Of Brain Tumors Research Articles

Genetic variants in mitochondrial sirtuins associated with brain tumor risk: a case-control study.

Previous studies on brain tumors have been performed on the nuclear genome, but limited studies have been reported on the mitochondrial genome. The mitochondrial sirtuin (SIRT3/SIRT4/SIRT5) has been mutated in different cancers. Limited studies have been performed on brain tumors. Isocitrate dehydrogenase (IDH) is an important marker, and polymorphism in the IDH gene has been reported to differentiate the brain tumor subtypes. The present study was designed to screen mitochondrial sirtuins and IDH polymorphisms in brain tumor patients. One thousand blood samples were collected (500 brain tumor patients and 500 controls). Two SNPs for each gene SIRT3 (rs12226697, rs570591), SIRT4 (rs184496260, 1925909), SIRT5 (rs2841522, rs2841523), and one SNP for IDH (rs11554137) was screened using Tetra-ARMS PCR. Logistic regression showed that the mutant genotype of selected SNPs was associated with increased disease incidence compared to wild type. Haplotype analysis and linkage disequilibrium (LD) showed a strong LD in brain tumor patients. Kaplan-Meier analysis showed that mutant allele frequency was found to be associated with a significant decrease in the survival of brain tumor patients. The present study showed that the mutant allele of selected mitochondrial sirtuins' SNP was associated with increased brain tumor risk.

Genetic interactions of mitochondrial sirtuins in brain tumorigenesis.

Purpose: The present study was designed to understand the role of expression variations of mitochondrial imported sirtuins in brain tumorigenesis. The expression levels of mitochondrial imported sirtuins were further analyzed for biomarker potential. Methods: Samples from 200 brain tumors and 200 healthy control tissues wereused for expression analysis using quantitative PCR and for DNA damage using LORD-Q analysis. Results: Significant deregulation of SIRT3 (p=0.002), SIRT4 (p=0.03) and SIRT5 (p=0.006) was observed in brain tumors versus controls. Co-expression analysis showed a significant correlation between the mitochondrial imported sirtuins versus apoptotic genes. LORD-Q analysis showed a significantly increased frequency of lesions/10kb of mitochondrial imported sirtuins (p<0.0001) in brain tumor tissue versus controls. Conclusion: The present study showed a correlation between variations of mitochondrial imported sirtuins and increased brain tumor risk.

The risk of childhood brain tumors associated with delivery interventions: A Danish matched case-control study

BackgroundHead trauma has been associated with increased brain tumor risk in adults. Instrument assisted delivery can be a cause of head trauma in newborns. The goal of this study was to determine if instrument-assisted deliveries influenced the odds of childhood brain tumors in Denmark. MethodsWe conducted a matched case-control study of childhood (<20 years) brain tumors in Denmark born between 1978 and 2013 and diagnosed 1978–2016. A total of 1678 brain tumor cases were identified and 25 controls were matched to each case based on the child’s sex and birth date (N = 40,934). Conditional logistic regression was used to estimate effects (odds ratios (OR) and 95% confidence intervals (95%CI)) for variables of interest. ResultsCompared to children birthed by spontaneous vaginal delivery, children who later developed ependymomas (N = 118) had a greater likelihood of having experienced vacuum assisted deliveries (OR=1.74, 95% CI 1.02–2.96). Forceps use was low, and declined across the study period. We did not observe an overall increase in all CNS tumors (combined) with either vacuum delivery (OR=0.99, 95% CI 0.84–1.18) or forceps delivery (OR=1.26, 95% CI 0.78–2.03). ConclusionOur findings suggest an association between vacuum assisted deliveries and ependymomas.

Occurrence of primary brain tumors in cochlear implant patients in Sweden between 1989 and 2014.

PurposeCochlear implants are widely used for hearing rehabilitation of deaf children with congenital deafness or adults with acquired severe-to-profound hearing loss. The sound processor antenna creates a radio frequency-electromagnetic field transmitting the sound signal to the implant, similar to that in a mobile phone. A recent case report suggested a relationship between cochlear implants and malignant glioma, and some epidemiological studies have suggested an increased glioma and acoustic neuroma risk associated with long hours of mobile phone use. An epidemiological study is warranted to evaluate such a relationship in patients with cochlear implants.Patients and methodsTo examine whether this chronic radio frequency-electromagnetic field signaling is associated with an increased brain tumor risk, a population-based cohort study was performed examining all 2,748 patients receiving a cochlear implant in Sweden during the years 1989–2014. In all, 3,169 surgeries were performed in the total cohort. The expected occurrence of glioma, meningioma, and acoustic neuroma in the patient cohort was calculated using specific national incidence rates in the Swedish population.ResultsFour patients were diagnosed with a brain tumor during follow-up, three of them having meningioma compared with 0.95 expected (standardized incidence ratio =3.16, 95% CI 0.65–9.24), and one had glioma compared with 1.34 expected (standardized incidence ratio =0.75, 95% CI 0.02–4.15). No case of acoustic neuroma was observed compared with 0.09 expected.ConclusionIn this study, we did not find support for concerns raised in a previous case report regarding a potentially higher risk of glioma. The number of brain tumors observed was well within the numbers expected from national incidence figures. Although this was a relatively small cohort with a limited follow-up time, it is the largest epidemiological study to date to address this concern.

Parkinson's disease and risk of brain tumor: a Meta-analysis

Objective To assess the correlation between Parkinson's disease (PD) and brain tumor. Methods Taking Parkinson's disease, tumor, cancer in Chinese, and PD, Parkinson's disease, tumor, cancer, neoplasm in English as the key words, prospective cohort studies and case -control studies on relation between PD and brain tumor were searched by using PubMed, Web of Science, EMBASE/SCOPUS, Cochrane Library, China National Knowledge Infrastructure (CNKI), Wanfang Data, and VIP database from January 1965 to July 2016, assisted by manual searching. Quality assessment and Mete-analysis were made by using Newcastle-Ottawa Scale (NOS) and Stata 12.1 software. Results A total of 11 studies with a total number of 350 632 PD patients were included in the overall analysis after excluding duplicate ones and those which did not meet the inclusion criteria from 1832 articles. Meta-analysis showed that compared with healthy people, PD patients had an increased risk of brain tumor ( OR = 1.370, 95%CI: 1.120-1.690; P = 0.003), and the result was consistent after excluding 2 low-quality articles ( OR = 1.360, 95% CI: 1.080-1.720; P = 0.008). Further stratified analyses according to disease onset time and regional difference showed that brain tumor occurrence in PD patients was significantly higher than healthy people only after the diagnosis of PD ( OR = 1.430, 95% CI: 1.120-1.830; P = 0.004). The geographical subgroup analyses showed a higher risk of brain tumor among PD patients in Europe ( OR = 1.420, 95%CI: 1.290-1.560; P = 0.000) and Taiwan area of China in Asia ( OR = 2.590, 95% CI: 1.730-3.880; P = 0.000) compared with healthy people. Funnel plot, Begg test ( P = 0.583) and Egger test ( P = 0.985) showed there was no bias. Conclusions PD patients have a higher risk of brain tumor. DOI: 10.3969/j.issn.1672-6731.2017.01.006

Air pollution from traffic and risk for brain tumors: a nationwide study in Denmark.

Air pollution is an established lung carcinogen, and there is increasing evidence that air pollution also negatively affects the brain. We have previously reported an association between air pollution and risk of brain tumors in a cohort study based on only 95 cases. We set out to replicate that finding in a large nationwide case-control study. We identified all 4,183 adult brain tumor cases in Denmark in the years 2000-2009 and 8,018 risk set sampled population controls matched on gender and year of birth. We extracted residential address histories and estimated mean residential nitrogen oxides (NO x ) concentrations since 1971 with a validated dispersion model. Categorical and linear odds ratios (OR) and confidence intervals (CI) were calculated with conditional logistic regression models. The highest risk estimates for any brain cancer were observed among subjects with the highest average exposure levels (80-99 µg/m(3): OR 1.27, 95% CI 0.82-1.96; ≥100 µg/m(3): 1.40, 95 % CI 0.87-2.26 as compared to <20 µg/m(3) NO x ), but there was no increased OR at NO x levels below 80 µg/m(3) and when modeled linearly there was no significant association with risk of brain cancer (OR 1.11, 95% CI 0.84-1.46 per 100 µg/m(3) NO x ). In sub-analysis the OR associated with exposures ≥100 µg/m(3) was 2.30 (95% CI 1.15-4.59) for non-glioma and 0.89 (95% CI 0.44-1.77) for glioma. This study did not support the relatively strong linear association between air pollution and risk of brain tumors which was found in our previous study. The suggestion of an increased brain tumor risk at high exposures merits further attention as does the differing results according to tumor morphology.

Birth Weight and Subsequent Risk of Childhood Primary Brain Tumors: A Meta-Analysis

The etiology of primary brain tumors is largely unknown. Since a peak of incidence occurs during childhood, factors operating very early in life might play a key role. Previous studies have suggested that high birth weight is associated with an increased brain tumor risk. The authors conducted a meta-analysis on the association between birth weight and risk of specific histologic types of primary brain tumors. They included published studies (1966-2007) that reported odds ratios and 95% confidence intervals for brain tumors associated with birth weight. The authors identified eight studies involving 1,748,964 children, of whom 4,162 suffered from brain tumors of three histologic types (astrocytoma, medulloblastoma, and ependymoma). For astrocytoma, high birth weight (>4,000 g) was associated with increased risk (odds ratio = 1.38, 95% confidence interval (CI): 1.07, 1.79), with each 1,000-g increase in birth weight being associated with a 19% (95% CI: 4, 36) increase in risk. For medulloblastoma, high birth weight was also positively associated with increased risk (odds ratio = 1.27, 95% CI: 1.02, 1.60). No association was found for ependymoma. These findings indicate that birth weight is related to the development of childhood brain tumors, with high birth weight being a risk factor for the two most common types of brain tumors.