Mammographic density measures that predict breast cancer are associated with at least two common genetic breast cancer susceptibility variants, according to a study published online in the February edition of the journal Cancer Research.
The study confirms the genetic link between mammographic breast density and breast cancer, according to lead author John Hopper, professor of the School of Population Health at the University of Melbourne in Victoria, Australia, and colleagues.
"Previous twin studies have suggested there is a genetic link between mammographic density and breast cancer,” said Hopper. “For the first time, we have been able to identify some of the breast cancer genetic variants involved."
By way of the Australian Twin Registry, the researchers recruited 830 twin pairs and 600 of their sisters between the ages of 30 and 80 years for their study. Using mammograms and blood tests that were administered to each of the participants, the researchers investigated 12 genetic variants known to be associated with breast cancer.
Hopper and colleagues measured mammographic dense area, percent dense area and nondense area utilizing a computer-thresholding technique and stratified the data according to age and body mass index.
The researchers found that two genetic variants associated with breast cancer genes are also associated with mammographic density. The authors wrote that this finding may indicate a biological reason why women of the same age differ in mammographic density.
“[The research] could also help unravel how these genetic variants are associated with breast cancer risk," said Hopper. “This is the beginning of a new research focus on how cancers begin and the role mammographic density plays."
Further research by the authors is currently under way and includes an international study aimed at identifying more genetic variants that are linked to mammographic density and breast cancer, according to Hopper.
"We hope our research on mammographic density will eventually help identify women at higher risk of getting breast cancer. That is still a way off, but for now women should follow national guidelines for screening," suggested the authors.
The current guidelines in Australia recommend women aged 50 to 69 years undergo breast cancer screening every two years.