WEDNESDAY, Dec. 26 (HealthDay News) -- The gene mutation BRCA1, which is known to increase the risk of breast cancer, is prevalent among Hispanics and young black women with breast cancer, researchers report.
The mutation is known to heighten the risk for Ashkenazi Jews, so the new ethnic findings are something of a surprise, the California researchers noted.
"We found that the Hispanic women had a higher prevalence of the harmful BRCA1 mutation than white women, and the highest prevalence was among young African-American women," said study author Esther John, a research scientist at the Northern California Cancer Center in Fremont and a consulting associate professor of health research and policy at Stanford University. "The prevalence of the BRCA1 mutation is different in different racial and ethnic groups."
In the study, which appears in the Dec. 26 issue of the Journal of the American Medical Association, John's team looked for the prevalence of the BRCA1 mutation among 3,181 women with breast cancer.
The researchers found that Ashkenazi women with breast cancer had the highest rate of the BRCA1 mutation, at 8.3 percent. For Hispanic women with breast cancer, the rate was 3.5 percent. Among non-Hispanic whites, the rate was 2.2 percent, and among Asian women it was 0.5 percent.
For all black women, the rate of the mutation was 1.3 percent, but for those under 35 who had breast cancer, the rate was 16.7 percent, John's group found.
Among the surprises in the study was that Hispanic women were more likely to have a particular mutation that is also common in Ashkenazi Jews, John said. Spanish ancestry may account for this, John noted. The researchers speculate that Sephardic Jews, who settled in Spain, could have shared the mutation with Ashkenazi Jews, who settled in central and Eastern Europe.
The prevalence of the BRCA1 mutation in young black women with breast cancer was also unexpected, since the overall rate of the mutation is low among black women of all ages, John said.
However, this finding could explain why when young black women get breast cancer it tends to be an aggressive form of the disease, which is consistent with cancers that involve BRCA1 mutations.
John noted that, because BRCA1 mutations are rare, not all women need to be tested for mutations. However, women who have a family history of breast cancer or who are diagnosed with breast cancer when they are under 35 might want to be tested, she said. "Women in all ethnic/racial populations would benefit from testing," she added.
One expert believes the findings in the study mirror what she has been seeing in a diverse urban population of women with breast cancer.
"This study supports what I've been finding in my clinical practice," said Dr. Christine Pellegrino, a breast cancer specialist at Montefiore Medical Center in New York City.
Pellegrino believes in genetic screening for all women who develop breast cancer early. "There should be a vigorous, well-defined, screening procedure for the female relatives of these women," she said. "There should be widespread use of genetic counseling in these young patients."
Young women who have the BRCA1 mutation and have had breast cancer are at risk for a recurrence of their cancer and also of developing ovarian cancer, Pellegrino said. "These women need to be closely monitored," she added.
Another expert agrees that most younger women with breast cancer have a genetic mutation, regardless of their ethnic or racial background.
"Whatever your ethnicity or your race, if you have a high-risk profile -- that is, early breast cancer -- it predicts the likelihood of genetic mutations across all ethnicities and races," said Dr. Jeffrey N. Weitzel, director of the department of clinical cancer genetics at the City of Hope Comprehensive Cancer Center, in Duarte, Calif.
However, Weitzel noted that this latest study does not take BRCA2 mutations into account, which also increase the risk for breast cancer.
"So some of these numbers are underestimates," he said. "BRCA2 usually accounts for about a third more cases in each group," he said.
For more information on breast cancer, visit the U.S. National Cancer Institute.
SOURCES: Esther John, Ph.D., research scientist, Northern California Cancer Center, Fremont, and associate professor, health research and policy, Stanford University; Christine Pellegrino, M.D., breast cancer specialist, Montefiore Medical Center, New York City; Jeffrey N. Weitzel, M.D., director, department of clinical cancer genetics, City of Hope Comprehensive Cancer Center, Duarte, Calif.; Dec. 26, 2007, Journal of the American Medical Association