By Emily Miller
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 new study by the National Institutes of Health.
For years scientists have known that age is a leading risk factor for the developing of many types of cancer. However, the reasoning behind why aging increases cancer risk has remained unclear until recently.
Researchers at the NIEHS suspect that NDA methylation, of the binding of chemical tags, called methyl groups, onto DNA, may be involved. These groups may be affecting the interaction between DNA and the cell’s protein-making machinery.
“You can think of methlylation as dust settling on an unused switch, which then prevent the cell from turning on certain genes,” said Jack Taylor, M.D., Ph.D co-researcher at the National Institute of Environmental Health Sciences. “If a cell can no longer turn on critical developmental programs, it might be easier for it to become a cancer cell.”
The discovery was made by both Taylor and Zongli Xu, Ph.D co-researcher at the National Institute of Environmental Health Science. They used blood samples from participants in the sister study, a nationwide research effort to find the environmental and genetic causes of breast cancer and other diseases.
More than 50,000 sisters of women who have had breast cancer participated in the study.
The researchers analyzed blood samples from 1,000 women, using a micro array that contained 27,000 specific methylation sites. Nearly one-third of the sites showed increased DNA methylation in association with age. All of their research was checked with similar study to help discover why age is associated with a higher risk of developing certain types of cancer.
“DNA methlylation appears to be part of the normal aging process and occurs in genes involved in cell developing,” said Taylor.
Taylor also suggests that age-related methlylation may disable the expression of certain genes, making it easier for cells to transition to cancer.
“On your 50th birthday, you would have 50 of these sites [from the subset of 749] that have acquired methyl groups in each cell,” Xu said. “The longer you live, the more methylation you will have.”
According to both Xu and Taylor as well as the NIEHS, as we age, it is extremely important that you pay closer attention to body to help prevent any diseases or forms of cancer. Precautionary steps will also save you money on your health and life insurance premiums.
