Researchers have identified the location of a genetic risk factor for a type of breast cancer that disproportionately affects women of African descent and carries a worse prognosis than other forms of the disease

Researchers have identified the location of a genetic risk factor for a special type of breast cancer. The investigative team was searching for genetic risk factors associated with what is known as estrogen receptor (ER)-negative breast cancer, a form of the disease that is deficient in expressing the estrogen receptor and therefore does not respond to drug treatments targeting the receptor in breast tissue. Women of African descent are more likely to have this type of breast cancer than women from other racial and ethnic backgrounds, according to the researchers. They also are more at risk for triple-negative breast tumors, which are deficient in expressing progesterone receptor and human epidermal growth factor-2 receptor, as well as the estrogen receptor. Triple negative breast cancer is an even more aggressive tumor subtype associated with a poor prognosis and decreased survival rates. The researchers found a common allele [an inherited variation in the DNA sequence] near the TERT gene on chromosome 5, which was significantly associated with an increased risk of ER-negative breast cancer. This genetic variant showed a greater association with triple-negative tumors, especially among women under age 50. This shows that there are susceptibility regions for triple-negative breast cancer. These and other regions may help to explain the greater risk of estrogen receptor-negative and triple-negative disease in women of African ancestry.