Research on hereditary breast cancer has not included as many women with African ancestry as women with European ancestry. For that reason, less is known about the risk for women from these ethnic groups to have a genetic mutation that increases the risk of breast cancer.
A study by one of the larger genetics laboratories found that 15.9% of African American women with breast cancer had a BRCA mutation, but only 12.1% of Europeans, leading the researchers to conclude that the rate of BRCA mutations in African Americans is at least equal to the European rate and may be higher.
One of the complications of studying high-risk breast cancer genes is the significant genetic variety among African Americans. So a study of mutations in African American women is, in reality, of study of many different ethnic groups. When researchers are able to identify specific subgroups, differences are seen. One study reported a higher incidence of BRCA mutations among women from Nigeria and the Bahamas than among women with ancestry from other African countries.
Note: BRCA1 (BReast CAncer gene 1) and BRCA2 (BReast CAncer gene 2) are genes that produce proteins that help repair damaged DNA. People who inherit harmful mutations in one of these genes have increased risks of several cancers, most notably breast and ovarian cancer, and tend to develop cancer at younger ages than people who do not have such a mutation.
See “BRCA Gene Testing: What African American Women Need To Know” by Melanie McDermet on the non-profit Maurer Foundation website (November 13, 2020)