“The accumulation of age-associated changes in a biochemical process that helps control genes may be responsible for some of the increased risk of cancer seen in older people, according to a National Institutes of Health study. Scientists have known for years that age is a leading risk factor for the development of many types of cancer, but why aging increases cancer risk remains unclear. Researchers suspect that DNA methylation, or the binding of chemical tags, called methyl groups, onto DNA, may be involved. Methyl groups activate or silence genes, by affecting interactions between DNA and the cell’s protein-making machinery. Zongli Xu, Ph.D., and Jack Taylor, M.D., Ph.D., researchers from the National Institute of Environmental Health Sciences (NIEHS), part of NIH, identified DNA methylation sites across the human genome that changed with age. They demonstrated that a subset of those sites — the ones that become increasingly methylated with advancing age — are also disproportionately methylated in a variety of human cancers. Their findings were published online in the journal Carcinogenesis.”

• See also the The Cancer Genome Atlas, a database funded by the National Cancer Institute and the National Human Genome Research Institute.