White blood cell global methylation and IL-6 promoter methylation in association with diet and lifestyle risk factors in a cancer-free population

Abstract

Keywords: DNA methylation, diet, lifestyle factors, cancer As aberrant DNA methylation is associated with cancer and other human diseases, there are growing interests in determining how environmental exposures may affect patterns of DNA methylation. Previous studies found older monozygotic twins were more diverse in DNA methylation patterns than were younger monozygotic twins.17 There is also evidence that DNA methylation patterns in individuals change over time, 18 supporting aging and/or external environment factors affecting DNA methylation. However, which environmental exposures, among many that individuals are exposed to over the life course, affect patterns of DNA methylation remains elusive.Chronic inflammation constitutes an important mechanism for cancer. 19 The specific pathways by which inflammation causes cancer are not fully understood. Interleukin (IL-6) is a proinflammatory cytokine released by inflammatory cells and can activate intracellular transcription factors leading to tumorigenesis. There are some suggestions that IL-6 may stimulate tumor proliferation by altering patterns of DNA methylation, 20-22 and

Associations between genetic variation in one-carbon metabolism and LINE-1 DNA methylation in histologically normal breast tissues

“…29,31 Little is known about the association between variation in one-carbon metabolism genes and genome-wide methylation. Further, while there is evidence that dietary folate intake may be associated with genome-wide methylation in WBCs, [32][33][34] it remains to be elucidated whether an association also exists for methylation levels in breast tissues with folate concentrations in the breast.…”

Epigenetics and human obesity

“…All of the studies used BMI or changes in BMI to classify obesity, and two studies also used percentage body fat 32 33 . The majority of these investigations, including a large study combining four study populations, including up to 1254 individuals 34 , did not find an association between obesity and global methylation 33,[35][36][37][38][39][40] . Two studies that included only women 32 41 , found reduced global methylation with increasing BMI, however in one of these studies this only occurred in the presence of low concentrations of the methyl donor folate 32 .…”

Is There a Link Between Genome-Wide Hypomethylation in Blood and Cancer Risk?

“…A recent microarray-based study found that approximately 39% of CpG sites analyzed were differentially methylated between leukocyte subgroups (91). However, a recent report did not find any association between L1 methylation and blood cell count (115). Another potential caveat for all cancer biomarker studies is tumor subtype heterogeneity, where the biomarker under investigation is a feature of only 1 disease subtype.…”