New York: Researchers have found that DNA sustains more damage and gets fixed less often when blood sugar levels are high compared to when blood sugar is at a normal, healthy level, thereby increasing one's cancer risk.
"It's been known for a long time that people with diabetes have as much as a 2.5-fold increased risk for certain cancers," said John Termini from City of Hope, a research and treatment center for cancer and diabetes in the US.
These cancers include ovarian, breast, kidney and others. But why people with Type-1 or Type-2 diabetes run higher risk of these cancers has been a mystery for a long time.
The new findings could offer a possible explanation for this double whammy.
Termini wondered if the elevated blood glucose levels seen in diabetes could harm DNA, making the genome unstable, which could lead to cancer.
So Termini and colleagues looked for a specific type of damage in the form of chemically modified DNA bases, known as adducts, in tissue culture and rodent models of diabetes.
Indeed, they found a DNA adduct, called N2-(1-carboxyethyl)-2'-deoxyguanosine, or CEdG, that occurred more frequently in the diabetic models than in normal cells or mice.
What's more, high glucose levels interfered with the cells' process for fixing it.
"Exposure to high glucose levels leads to both DNA adducts and the suppression of their repair, which in combination could cause genome instability and cancer," Termini said.
Termini and colleagues have recently completed a clinical study that measured the levels of CEdG, as well as its counterpart in RNA (CEG), in people with Type-2 diabetes.
As in mice, people with diabetes had significantly higher levels of both CEdG and CEG than people without the disease.
The findings are scheduled to be presented at the American Chemical Society (ACS) Fall 2019 National Meeting and Exposition being held in San Diego, California, from August 25-29.