African American women at high-risk of breast cancer have genetic mutations that would make genetic testing feasible, according to a study in the October 19 issue of JAMA: The Journal of the American Medical Association.
Because of recent advances in the understanding of breast cancer risk factors and the promise of prevention, women from high-risk families are encouraged to consider genetic testing to quantify their risk, according to background information in the article. An estimated 5 percent to 10 percent of breast cancer cases occur in individuals with inherited mutations in breast cancer susceptibility genes. Germline mutations in BRCA1 and BRCA2 are by far the most common and account for 80 percent to 90 percent of families containing multiple cases of breast and ovarian cancer. The proportion of breast cancer attributed to mutations in BRCA1 or BRCA2 has varied widely among different studies and different ethnic groups. Of note, one of the largest ethnic minorities in the United States, the African American population, remains understudied, despite having a proportionately higher incidence of early-onset breast cancer. Many of the risk-assessment tools used in cancer risk clinics, such as the BRCAPRO statistical model, were developed based on mutation rates observed primarily in Ashkenazi Jewish and other white women of European descent.
Rita Nanda, M.D., of the University of Chicago Medical Center, Chicago, and colleagues conducted a study to characterize the clinical predictors of BRCA1 and BRCA2 mutations among high-risk individuals of European and African ancestry, highlighting the similarities and differences.
The study included a comparative analysis of families (white, Ashkenazi Jewish, African American, Hispanic, Asian) with 2 or more cases of breast and/or ovarian cancer among first- and second-degree relatives. Families were identified at U.S. sites between February 1992 and May 2003; in each family, the individual with the highest probability of being a mutation carrier was genetically tested.