High-risk black women need breast cancer gene test

By Megan Rauscher

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.