| 1. |
- Forsberg, Lars A., et al.
(författare)
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Age-related somatic structural changes in the nuclear genome of human blood cells
- 2012
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Ingår i: American Journal of Human Genetics. - : Elsevier BV. - 0002-9297 .- 1537-6605. ; 90:2, s. 217-228
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Tidskriftsartikel (refereegranskat)abstract
- Structural variations are among the most frequent interindividual genetic differences in the human genome. The frequency and distribution of de novo somatic structural variants in normal cells is, however, poorly explored. Using age-stratified cohorts of 318 monozygotic (MZ) twins and 296 single-born subjects, we describe age-related accumulation of copy-number variation in the nuclear genomes in vivo and frequency changes for both megabase- and kilobase-range variants. Megabase-range aberrations were found in 3.4% (9 of 264) of subjects ≥60 years old; these subjects included 78 MZ twin pairs and 108 single-born individuals. No such findings were observed in 81 MZ pairs or 180 single-born subjects who were ≤55 years old. Recurrent region- and gene-specific mutations, mostly deletions, were observed. Longitudinal analyses of 43 subjects whose data were collected 7-19 years apart suggest considerable variation in the rate of accumulation of clones carrying structural changes. Furthermore, the longitudinal analysis of individuals with structural aberrations suggests that there is a natural self-removal of aberrant cell clones from peripheral blood. In three healthy subjects, we detected somatic aberrations characteristic of patients with myelodysplastic syndrome. The recurrent rearrangements uncovered here are candidates for common age-related defects in human blood cells. We anticipate that extension of these results will allow determination of the genetic age of different somatic-cell lineages and estimation of possible individual differences between genetic and chronological age. Our work might also help to explain the cause of an age-related reduction in the number of cell clones in the blood; such a reduction is one of the hallmarks of immunosenescence.
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| 2. |
- Epstein, Mara M, et al.
(författare)
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Seasonal variation in expression of markers in the vitamin D pathway in prostate tissue
- 2012
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Ingår i: Cancer Causes and Control. - : Springer. - 0957-5243 .- 1573-7225. ; 23:8, s. 1359-1366
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: Recent studies suggest variation in genes along the vitamin D pathway, as well as vitamin D receptor (VDR) protein levels, may be associated with prostate cancer. As serum vitamin D levels vary by season, we sought to determine whether the expression of genes on the vitamin D pathway, assessed in prostate tumor tissue, do the same.METHODS: Our study incorporates mRNA expression data from 362 men in the Swedish Watchful Waiting cohort, diagnosed between 1977 and 1999, and 106 men enrolled in the US Physicians' Health Study (PHS) diagnosed between 1983 and 2004. We also assayed for VDR protein expression among 832 men in the PHS and Health Professionals Follow-up Study cohorts. Season was characterized by date of initial tissue specimen collection categorically and by average monthly ultraviolet radiation levels. One-way analysis of variance was used to examine variation in the expression levels of six genes on the vitamin D pathway-VDR, GC, CYP27A1, CYP27B1, RXRα, CYP24A1-and VDR protein by season, adjusted for age at diagnosis and Gleason grade. Variation was also examined separately among lethal and nonlethal cases.RESULTS: Tumor expression levels of the six genes did not vary significantly by season of tissue collection. No consistent patterns emerged from subgroup analyses by lethal versus nonlethal cases.CONCLUSIONS: Unlike circulating levels of 25(OH) vitamin D, expression levels of genes on the vitamin D pathway and VDR protein did not vary overall by season of tissue collection. Epidemiological analyses of vitamin D gene expression may not be biased by seasonality.
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| 3. |
- Sigurdardottir, Lara G., et al.
(författare)
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Circadian disruption, sleep loss, and prostate cancer risk : a systematic review of epidemiologic studies
- 2012
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Ingår i: Cancer Epidemiology, Biomarkers and Prevention. - Philadelphia, USA : American Association for Cancer Research. - 1055-9965 .- 1538-7755. ; 21:7, s. 1002-1011
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Forskningsöversikt (refereegranskat)abstract
- Disruption of the circadian system has been hypothesized to increase cancer risk, either because of direct disruption of the molecular machinery generating circadian rhythms or because of disruption of parameters controlled by the clock such as melatonin levels or sleep duration. This hypothesis has been studied in hormone-dependent cancers among women, but data are sparse about potential effects of circadian disruption on the risk of prostate cancer. This review systematically examines available data evaluating the effects of light at night, sleep patterns, and night shift work on prostate cancer risk.
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