A study has identified five genes that are associated with an aggressive form of breast cancer.
Triple-negative breast cancers (TNBC) account for around 15 percent of all breast cancers (up to 35 percent in African-American women). They tend to have lower survival rates than other breast cancers: triple negative tumours grow faster and are more likely to recur after treatment, and because they do not have receptors for estrogen, progesterone or HER2 they do not respond to targeted therapies, limiting treatment options.
'This study is the first to establish which genes are associated with high lifetime risks of triple-negative breast cancer,' said lead author Dr Fergus Couch, a geneticist at the Mayo Clinic Cancer Centre in Rochester, Minnesota.
The study – published in the Journal of the National Cancer Institute – included over 10,000 US patients with TNBC. They were screened for a panel of up to 21 genes already known to be linked to breast cancer generally. Of those, five were shown to be strongly linked to TNBC: BRCA1 and BRCA2, as well as BARD1, PALB2, and RAD51D. The presence of certain mutations in these genes could increase the lifetime risk of breast cancer by 20 percent. Two other genes were associated with a moderate increase in TNBC risk. Results were similar among Caucasian and African-American women.
The authors hope that being able to test for increased risk of TNBC can help women access more preventative care, screening and early interventions.
'The results… should help in the clinical management of women found to have inherited mutations in these genes,' said Dr Couch.