Led by researchers from the The Institute of Cancer Research in London, an international study of 100,000 women revealed that two genetic variants are associated with higher risks of breast cancer.
Published in the journal Human Molecular Genetics, the study involved DNA from 86,000 European women, 12,000 Asian women and 2,000 African women, about half of which have been diagnosed with breast cancer. By identifying two new genetic variants associated with breast cancer, researchers gained important clues that would help in further understanding the disease's causes.
Researchers were looking into one-letter differences in the DNA code that were likelier to manifest in women who have been diagnosed with breast cancer. Using a technique referred to as fine mapping, they explored a recently identified hotspot responsible for genetic breast cancer causes on chromosome 9, implicating a gene known as KLF4 in the process.
The two genetic variants identified by the study were "rs10816625" and "rs13294895." The presence of the first variant gave women 12 percent higher chances of developing cancer while the second variant led to 9-percent increased risk.
Additionally, those at higher risk were also 14 percent likelier to develop estrogen receptor positive breast cancer if they had the the first genetic variant while those with the second genetic variant were 11 percent likelier to acquire the same type of breast cancer.
For estrogen receptor negative breast cancer, no association was made when the genetic variants were present in women.
Both genetic variants are linked to higher breast cancer risk in European women but Asian women only faced increased risk when they harbored the first genetic variant.
The gene KLF4 is located far away from the genetic variants but it is believed that they can control how the gene behaves.
"The variants we identified are specifically associated with the most common form of breast cancer," explained Nick Orr, Complex Trait Genetics team leader from The Institute of Cancer Research and lead author for the study.
"The more genetic risk factors for breast cancer we discover, of which there are currently more than 80, the more accurately we will be able predict who is at risk of getting the disease," he added.
Breast cancer rates have dropped in the United States but still about 295,240 new cases were estimated to be diagnosed in 2014 in women. The disease is one of the leading causes of cancer deaths in women in the U.S., coming in behind only to lung cancer.