Researchers have identified specific genes associated with the increased risk for triple-negative breast cancer, providing the basis for better risk management.
Germline genetic testing can identify women at increased risk of breast cancer by evaluating if there are genetic changes, often inherited from a parent, that increase the risk of certain cancers.
However, it has been difficult to identify women at elevated risk of triple-negative breast cancer because only inherited mutations in BRCA1 (a human tumour suppressor gene discovered in 1990) have been linked to this subtype of breast cancer.
Triple-negative breast cancer is an aggressive type of cancer that cannot be treated using the most common therapies, says the study published in the Journal of the National Cancer Institute. It accounts for 35 percent in the African American population, while 15 percent of breast cancer in the Caucasian population. It is also associated with high recurrence risk and poor five-year survival rate, the researchers said.
“The results from our study showing that multiple genes cause increased risk of triple-negative breast cancer should help in the clinical management of women found to have inherited mutations in these genes,” said co-author Fergus J. Couch from Mayo Clinic in the US.
For the study, the research team performed genetic testing on 10,901 triple-negative breast cancer patients from two studies. For 8,753 patients, 21 genes were tested, and for the remaining 2,148 patients, 17 genes were tested.
Among the genes tested, the researchers found that alternations in BARD1, BRCA1, BRCA2, PALB2, and RAD51D genes were associated with high risk for triple-negative breast cancer and greater than 20 percent lifetime risk for overall breast cancer among Caucasians.
Researchers observed a similar trend among African Americans. In addition, mutations in BRIP1 and RAD51C were linked to more moderate risks of triple-negative disease.