| 1. |
- Balassiano, Karen, et al.
(författare)
-
Aberrant DNA methylation of cancer-associated genes in gastric cancer in the European Prospective Investigation into Cancer and Nutrition (EPIC-EURGAST)
- 2011
-
Ingår i: Cancer Letters. - Amsterdam : Elsevier BV. - 1872-7980 .- 0304-3835. ; 311:1, s. 85-95
-
Tidskriftsartikel (refereegranskat)abstract
- Epigenetic events have emerged as key mechanisms in the regulation of critical biological processes and in the development of a wide variety of human malignancies, including gastric cancer (GC), however precise gene targets of aberrant DNA methylation in GC remain largely unknown. Here, we have combined pyrosequencing-based quantitative analysis of DNA methylation in 98 GC cases and 64 controls nested within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort and in cancer tissue and non-tumorigenic adjacent tissue of an independent series of GC samples. A panel of 10 cancer-associated genes (CHRNA3, DOK1, MGMT, RASSF1A, p14ARF, CDH1, MLH1, ALDH2, GNMT and MTHFR) and LINE-1 repetitive elements were included in the analysis and their association with clinicopathological characteristics (sex, age at diagnosis, anatomical sub-site, histological sub-type) was examined. Three out of the 10 genes analyzed exhibited a marked hypermethylation, whereas two genes (ALDH2 and MTHFR) showed significant hypomethylation, in gastric tumors. Among differentially methylated genes, we identified new genes (CHRNA3 and DOK1) as targets of aberrant hypermethylation in GC, suggesting that epigenetic deregulation of these genes and their corresponding cellular pathways may promote the development and progression of GC. We also found that global demethylation of tumor cell genomes occurs in GC, consistent with the notion that abnormal hypermethylation of specific genes occurs concomitantly with genome-wide hypomethylation. Age and gender had no significant influence on methylation states, but an association was observed between LINE-1 and MLH1 methylation levels with histological subtype and anatomical sub-site. This study identifies aberrant methylation patters in specific genes in GC thus providing information that could be exploited as novel biomarkers in clinics and molecular epidemiology of GC. (C) 2011 Elsevier Ireland Ltd. All rights reserved.
|
|
| 2. |
- Campa, Daniele, et al.
(författare)
-
Variation in genes coding for AMP-activated protein kinase (AMPK) and breast cancer risk in the European Prospective Investigation on Cancer (EPIC).
- 2011
-
Ingår i: Breast Cancer Research and Treatment. - : Springer. - 0167-6806 .- 1573-7217. ; 127:3, s. 761-767
-
Tidskriftsartikel (refereegranskat)abstract
- AMP-activated protein kinase (AMPK) is an energy sensing/signalling intracellular protein which is activated by an increase in the cellular AMP:ATP ratio after ATP depletion. Once activated, AMPK inhibits fatty acid synthesis and the Akt-mTOR pathway, and activates the p53-p21 axis. All these molecular mechanisms are thought to play a key role in breast carcinogenesis. We investigated the genetic variability of four genes encoding AMPK (PRKAA1, PRKAA2, PRKAB1 and PRKAB2). Using a tagging approach and selecting SNPs we covered all the common genetic variation of these genes. We tested association of tagging SNPs in our four candidate genes with breast cancer (BC) risk in a study of 1340 BC cases and 2536 controls nested into the European Prospective Investigation into Cancer and Nutrition (EPIC). Given the relevance of AMPK on fatty acid synthesis and the importance of body fatness as a BC risk factor, we tested association of SNPs and body-mass index as well. We observed no statistically significant association between the SNPs in the PRKAs genes and BC risk and BMI after correction for multiple testing.
|
|
| 3. |
- Kilpeläinen, Tuomas O, et al.
(författare)
-
Physical activity attenuates the influence of FTO variants on obesity risk: a meta-analysis of 218,166 adults and 19,268 children.
- 2011
-
Ingår i: PLoS medicine. - : Public Library of Science (PLoS). - 1549-1676 .- 1549-1277. ; 8:11
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The FTO gene harbors the strongest known susceptibility locus for obesity. While many individual studies have suggested that physical activity (PA) may attenuate the effect of FTO on obesity risk, other studies have not been able to confirm this interaction. To confirm or refute unambiguously whether PA attenuates the association of FTO with obesity risk, we meta-analyzed data from 45 studies of adults (n = 218,166) and nine studies of children and adolescents (n = 19,268). METHODS AND FINDINGS: All studies identified to have data on the FTO rs9939609 variant (or any proxy [r(2)>0.8]) and PA were invited to participate, regardless of ethnicity or age of the participants. PA was standardized by categorizing it into a dichotomous variable (physically inactive versus active) in each study. Overall, 25% of adults and 13% of children were categorized as inactive. Interaction analyses were performed within each study by including the FTO×PA interaction term in an additive model, adjusting for age and sex. Subsequently, random effects meta-analysis was used to pool the interaction terms. In adults, the minor (A-) allele of rs9939609 increased the odds of obesity by 1.23-fold/allele (95% CI 1.20-1.26), but PA attenuated this effect (p(interaction) = 0.001). More specifically, the minor allele of rs9939609 increased the odds of obesity less in the physically active group (odds ratio = 1.22/allele, 95% CI 1.19-1.25) than in the inactive group (odds ratio = 1.30/allele, 95% CI 1.24-1.36). No such interaction was found in children and adolescents. CONCLUSIONS: The association of the FTO risk allele with the odds of obesity is attenuated by 27% in physically active adults, highlighting the importance of PA in particular in those genetically predisposed to obesity.
|
|
