A genetic mutation already known to be more common in Ashkenazi Jewish breast cancer patients is also prevalent in Hispanic and young African-American women with breast cancer, according to one of the largest, multiracial studies of the mutation to date.
Researchers at the Stanford University School of Medicine and the Northern California Cancer Center reported the finding from a study of 3,181 breast cancer patients in Northern California.
The study revealed that although Ashkenazi Jewish women with breast cancer had the highest rate of the BRCA1 mutation at 8.3 percent, Hispanic women with breast cancer were next most likely, with a rate of 3.5 percent. Non-Hispanic whites with breast cancer showed a 2.2 percent rate, followed by 1.3 percent of African-American women of all ages and 0.5 percent in Asian-American women. Of the African-American breast cancer patients under age 35, 16.7 percent had the mutation.
The work, published in the Dec. 26 issue of the Journal of the American Medical Association, marks the largest study to date to look at the prevalence of BRCA1 mutations among patients in the four ethnic and racial groups, said lead author Esther John, PhD, research scientist at the Northern California Cancer Center and consulting associate professor of health research and policy at Stanford.
“If a woman has breast cancer she may ask the question, ?Could I be a carrier for a BRCA1 mutation? If I am, my daughters and sons need to know it,'” said senior author Alice Whittemore, PhD, professor of health research and policy at Stanford. She said that until now, doctors knew only that Ashkenazi Jewish women were more likely to carry a mutation, and therefore frequently referred these women to genetic counseling. What they didn’t know is how women of different ethnic groups needed to be treated in terms of their BRCA1 status.
“Traditionally studies have focused on white women,” said John. “There is a great need to study racial minorities in the United States.”
All people have the BRCA1 gene, which makes a protein that helps the cell repair its DNA. Women who inherit a mutation in that gene from either parent are less able to fix DNA damage and tend to accumulate mutations that lead to cancer. They have a roughly 65 percent risk of developing breast cancer and 39 percent risk of ovarian cancer. If one family member tests positive for a mutation, it can alert other women in the family to also get tested and to take preventive measures.
Now doctors who see Hispanic or young African-American breast cancer patients have more information to guide their decisions about referring those women to genetic counseling or testing.
Other Stanford researchers who participated in this study include Gail Gong, PhD, a research associate; Anna Felberg, a programmer in health research and policy; Dee West, PhD, professor of health research and policy at Stanford and chief scientific officer at the Northern California Cancer Center, and Amanda Phipps, epidemiologist at the NCCC.
The work was funded by the National Cancer Institute.
Source: Stanford University School of Medicine, USA