High-risk black women need breast cancer gene test (Reuters)

NEW YORK (Reuters Health) - Genetic mutations in the breast cancer susceptibility genes -- BRCA1 and BRCA2 -- occur with "appreciable frequency" in African-American women with a family history of the disease, with more than one quarter testing positive for a mutation in one of these genes that indicates high risk, a study shows.

This finding supports genetic testing for BRCA1 and BRCA1 mutations in high-risk African American families, study investigators report in this week's issue of the Journal of the American Medical Association.

"Ten years after BRCA1 and BRCA2 were first identified as major breast cancer susceptibility genes, the spectrum of mutations and modifiers of risk among many ethnic minorities remain undefined," Dr. Olufunmilayo I. Olopade from the University of Chicago Medical Center and colleagues note in the article. This is particularly true of African Americans, in whom there is a high incidence of breast cancer at a young age.

Using a unique, ethnically diverse group of high-risk families, Olopade and colleagues characterized the predictors of BRCA1 and BRCA2 mutations among high-risk individuals of European and African ancestry.

They included a comparative analysis of white, Ashkenazi Jewish, African American, Hispanic and Asian families having at least two cases of breast and/or ovarian cancer among close or moderately close relatives.

The spectrum of BRCA1 and BRCA2 mutations was "vastly different" between families of African and European ancestry, the investigators report.

While rates of high-risk mutations were lower among African Americans compared with non-Hispanic, non-Jewish whites (27.9 percent vs 46.2 percent), sequence variations of "unknown significance" were significantly more common than in whites (44.2 percent vs 11.5 percent). Ashkenazi Jewish families had the highest rate of BRCA1 and BRCA2 mutations (69.0 percent), as expected.

According to Olopade and colleagues, young age at diagnosis of breast cancer and a family history of breast and ovarian cancer are "the most powerful predictors of mutation status and should be used to guide clinical decision making."

In a telephone interview with Reuters Health, Olopade said: "Women of all ethnic backgrounds with a family history of breast cancer should be referred for genetic counseling because prevention is better than cure."

"But if you look at who is getting genetic testing," she added, "it's Ashkenazi Jewish women. The rest of the women who have family history of the disease --they are still worried about genetic discrimination and many doctors are still actively advising them against genetic testing."

Summing up, Olopade said, "There are so many novel interventions that could potentially save women's lives and doctors are still not adopting this new technology to help their patients individualize their risk."

SOURCE: JAMA, October 19, 2005.