263 research outputs found

    Epidemiology and etiology of meningioma.

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    Although most meningiomas are encapsulated and benign tumors with limited numbers of genetic aberrations, their intracranial location often leads to serious and potentially lethal consequences. They are the most frequently diagnosed primary brain tumor accounting for 33.8% of all primary brain and central nervous system tumors reported in the United States between 2002 and 2006. Inherited susceptibility to meningioma is suggested both by family history and candidate gene studies in DNA repair genes. People with certain mutations in the neurofibromatosis gene (NF2) have a very substantial increased risk for meningioma. High dose ionizing radiation exposure is an established risk factor for meningioma, and lower doses may also increase risk, but which types and doses are controversial or understudied. Because women are twice as likely as men to develop meningiomas and these tumors harbor hormone receptors, an etiologic role for hormones (both endogenous and exogenous) has been hypothesized. The extent to which immunologic factors influence meningioma etiology has been largely unexplored. Growing emphasis on brain tumor research coupled with the advent of new genetic and molecular epidemiologic tools in genetic and molecular epidemiology promise hope for advancing knowledge about the causes of intra-cranial meningioma. In this review, we highlight current knowledge about meningioma epidemiology and etiology and suggest future research directions

    Epithelial cells in nipple aspirate fluid and subsequent breast cancer risk: A historic prospective study

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    <p>Abstract</p> <p>Background</p> <p>Past studies have shown that women with abnormal cytology or epithelial cells in nipple aspirate fluid (NAF) have an increased relative risk (RR) of breast cancer when compared to women from whom NAF was attempted but not obtained (non-yielders). This study analyzed NAF results from a group of women seen in a breast clinic between 1970–1991 (N = 2480). Our analysis presented here is an aggregate of two sub-groups: women with questionnaire data (n = 712) and those with NAF visits beginning in 1988 (n = 238), the year in which cancer case information was uniformly collected in California.</p> <p>Methods</p> <p>Cytological classification was determined for a group of 946 women using the most abnormal epithelial cytology observed in fluid specimens. Breast cancer incidence and mortality status was determined through June 2006 using data from the California Cancer Registry, California Vital Statistics and self-report. We estimated odd ratios (ORs) for breast cancer using logistic regression analysis, adjusting for age. We analyzed breast cancer risk related to abnormality of NAF cytology using non-yielders as the referent group and breast cancer risk related to the presence or absence of epithelial cells in NAF, using non-yielders/fluid without epithelial cells as the referent group.</p> <p>Results</p> <p>Overall, 10% (93) of the 946 women developed breast cancer during the follow-up period. Age-adjusted ORs and 95% confidence intervals (C.I.) compared to non-yielders were 1.4 (0.3 to 6.4), 1.7 (0.9 to 3.5), and 2.0 (1.1 to 3.6) for women with fluid without epithelial cells, normal epithelial cells and hyperplasia/atypia, respectively. Comparing the presence or absence of epithelial cells in NAF, women with epithelial cells present in NAF were more likely to develop breast cancer than non-yielders or women with fluid without epithelial cells (RR = 1.9, 1.2 to 3.1).</p> <p>Conclusion</p> <p>These results support previous findings that 1) women with abnormal epithelial cells in NAF have an increased risk of breast cancer when compared to non-yielders or women with normal epithelial cells in NAF and 2) women with epithelial cells present in NAF have an increased risk of breast cancer when compared to non-yielders or women who had NAF without epithelial cells present.</p

    Aging and Environmental Exposures Alter Tissue-Specific DNA Methylation Dependent upon CpG Island Context

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    Epigenetic control of gene transcription is critical for normal human development and cellular differentiation. While alterations of epigenetic marks such as DNA methylation have been linked to cancers and many other human diseases, interindividual epigenetic variations in normal tissues due to aging, environmental factors, or innate susceptibility are poorly characterized. The plasticity, tissue-specific nature, and variability of gene expression are related to epigenomic states that vary across individuals. Thus, population-based investigations are needed to further our understanding of the fundamental dynamics of normal individual epigenomes. We analyzed 217 non-pathologic human tissues from 10 anatomic sites at 1,413 autosomal CpG loci associated with 773 genes to investigate tissue-specific differences in DNA methylation and to discern how aging and exposures contribute to normal variation in methylation. Methylation profile classes derived from unsupervised modeling were significantly associated with age (P,0.0001) and were significant predictors of tissue origin (P,0.0001). In solid tissues (n = 119) we found striking, highly significant CpG island–dependent correlations between age and methylation; loci in CpG islands gained methylation with age, loci not in CpG islands lost methylation with age (P,0.001), and this pattern was consistent across tissues and in an analysis of blood-derived DNA. Our data clearly demonstrate age- and exposure-related differences in tissue-specific methylation and significant age-associated methylation patterns which are CpG island context-dependent. This work provides novel insight into the role of aging and the environment in susceptibility to diseases such as cancer and critically informs the field of epigenomics by providing evidence of epigenetic dysregulation by age-related methylation alterations. Collectively we reveal key issues to consider both in the construction of reference and disease-related epigenomes and in the interpretation of potentially pathologically important alterations

    Breast Cancer DNA Methylation Profiles Are Associated with Tumor Size and Alcohol and Folate Intake

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    Although tumor size and lymph node involvement are the current cornerstones of breast cancer prognosis, they have not been extensively explored in relation to tumor methylation attributes in conjunction with other tumor and patient dietary and hormonal characteristics. Using primary breast tumors from 162 (AJCC stage I-IV) women from the Kaiser Division of Research Pathways Study and the Illumina GoldenGate methylation bead-array platform, we measured 1,413 autosomal CpG loci associated with 773 cancer-related genes and validated select CpG loci with Sequenom EpiTYPER. Tumor grade, size, estrogen and progesterone receptor status, and triple negative status were significantly (Q-values \u3c0.05) associated with altered methylation of 209, 74, 183, 69, and 130 loci, respectively. Unsupervised clustering, using a recursively partitioned mixture model (RPMM), of all autosomal CpG loci revealed eight distinct methylation classes. Methylation class membership was significantly associated with patient race (P\u3c0.02) and tumor size (P\u3c0.001) in univariate tests. Using multinomial logistic regression to adjust for potential confounders, patient age and tumor size, as well as known disease risk factors of alcohol intake and total dietary folate, were all significantly (P\u3c0.0001) associated with methylation class membership. Breast cancer prognostic characteristics and risk-related exposures appear to be associated with gene-specific tumor methylation, as well as overall methylation patterns

    Risk factors for breast cancer in a population with high incidence rates.

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    BackgroundThis report examines generally recognized breast cancer risk factors and years of residence in Marin County, California, an area with high breast cancer incidence and mortality rates.MethodsEligible women who were residents of Marin County diagnosed with breast cancer in 1997-99 and women without breast cancer obtained through random digit dialing, frequency-matched by cases' age at diagnosis and ethnicity, participated in either full in-person or abbreviated telephone interviews.ResultsIn multivariate analyses, 285 cases were statistically significantly more likely than 286 controls to report being premenopausal, never to have used birth control pills, a lower highest lifetime body mass index, four or more mammograms in 1990-94, beginning drinking after the age of 21, on average drinking two or more drinks per day, the highest quartile of pack-years of cigarette smoking and having been raised in an organized religion. Cases and controls did not significantly differ with regard to having a first-degree relative with breast cancer, a history of benign breast biopsy, previous radiation treatment, age at menarche, parity, use of hormone replacement therapy, age of first living in Marin County, or total years lived in Marin County. Results for several factors differed for women aged under 50 years or 50 years and over.ConclusionsDespite similar distributions of several known breast cancer risk factors, case-control differences in alcohol consumption suggest that risk in this high-risk population might be modifiable. Intensive study of this or other areas of similarly high incidence might reveal other important risk factors proximate to diagnosis

    Breast cancer incidence and mortality trends in an affluent population: Marin County, California, USA, 1990–1999

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    BACKGROUND: Elevated rates of breast cancer in affluent Marin County, California, were first reported in the early 1990s. These rates have since been related to higher regional prevalence of known breast cancer risk factors, including low parity, education, and income. Close surveillance of Marin County breast cancer trends has nevertheless continued, in part because distinctive breast cancer patterns in well-defined populations may inform understanding of breast cancer etiology. METHODS: Using the most recent incidence and mortality data available from the California Cancer Registry, we examined rates and trends for 1990–1999 for invasive breast cancer among non-Hispanic, white women in Marin County, in other San Francisco Bay Area counties, and in other urban California counties. Rates were age adjusted to the 2000 US standard, and temporal changes were evaluated with weighted linear regression. RESULTS: Marin County breast cancer incidence rates between 1990 and 1999 increased 3.6% per year (95% confidence interval, 1.8–5.5), six times more rapidly than in comparison areas. The increase was limited to women aged 45–64 years, in whom rates increased at 6.7% per year (95% confidence interval, 3.8–9.6). Mortality rates did not change significantly in Marin County despite 3–5% yearly declines elsewhere. CONCLUSION: Patterns of breast cancer incidence and mortality in Marin County are unlike those in other California counties, and they are probably explained by Marin County's unique sociodemographic characteristics. Similar trends may have occurred in other affluent populations for which available data do not permit annual monitoring of cancer occurrence

    Lack of association of rare alleles in the <I>HRAS</I> variable number of tandem repeats (VNTR) region with adult glioma

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    HRAS rare alleles have been associated with the increased susceptibility to a variety of cancers. In the present study we examined the hypothesis that HRAS rare alleles are a risk factor for adult glioma in a population-based case-control study of adult glioma in six San Francisco Bay Area counties. We compared the prevalence of rare alleles in the variable number of tandem repeats region of HRAS in the germline DNA from 73 white adults who had gliomas with that of 65 controls. Overall, the prevalence of rare alleles in cases was not different from the prevalence of those in controls according to two definitions of rare alleles. We found that 25 of 73 (34%) of cases versus 25 of 65 (38%) of controls had at least one allele that was not 30, 46, 69, or 87 repeats; 4 of 73 (5%) of cases versus 6 of 65 (9%) of controls carried one or more alleles with 33, 39, 42, 53, 59, 63, 68, 105, or 114 repeats. The proportion of rare alleles was somewhat higher among subjects with anaplastic astrocytoma. Among women, cases were less likely than controls to have HRAS rare alleles, whereas among men, cases were slightly more likely to have HRAS rare alleles, but none of these results approach statistical significance. Our data do not suggest an excess of HRAS rare alleles among adult glioma cases
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