Breast Cancer Gene Mutation More Common in Hispanic, Young Black Women, Stanford/NCCC Study Finds
STANFORD, Calif.--(Business Wire)--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. It 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, which will be 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.
The information could help doctors decide which patients to refer
to genetic counseling, the researchers said. They added that they hope
the information prompts genetic counselors to develop materials for
discussing breast cancer risk in a culturally sensitive way and in
languages other than English.
"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."
The risk of a woman developing breast cancer sometime during her
life is about one in eight. Although death rates from the disease are
dropping, the American Cancer Society estimates that 40,000 women will
die from the disease this year.
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.
Without the information from this study, doctors have treated all
women other than Ashkenazi Jews as having the same risk level for the
mutation. 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.
"The message is that these minority breast cancer patients may
need screening in ways that we hadn't appreciated before," Whittemore
said. She noted that Hispanic women in Northern California, where this
study was conducted, derive from different countries than Hispanic
women from the East Coast. For that reason, the findings may not apply
to Hispanic people in other parts of the country.
The research team found a few other surprises in the data. One is
that although mutations can occur throughout the BRCA1 gene, the
Hispanic women in the study were more likely to carry a particular
mutation that's also common in Ashkenazi Jewish women. Other ethnic
groups carried a wide range of different mutations.
John and Whittemore think the Hispanic women may have this
mutation because of their Spanish ancestry. Spain was the home of
Sephardic Jews who could have shared the mutation with Ashkenazi Jews
of Eastern European origin.
The prevalence of the mutation in young African-American women
with breast cancer also came as a surprise, given that the rate is low
in the overall African-American population. The researchers say the
finding is consistent with a long-known pattern that when young
African-American women get breast cancer it tends to be a particularly
aggressive form of the disease, which is a hallmark of tumors that
arise from BRCA1 mutations. Whittemore said this information doesn't
change how doctors treat those tumors, but it could help prompt more
doctors to recommend genetic counseling for those young
African-American breast cancer patients.
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.
Stanford University Medical Center integrates research, medical
education and patient care at its three institutions -- Stanford
University School of Medicine, Stanford Hospital & Clinics and Lucile
Packard Children's Hospital at Stanford. For more information, please
visit the Web site of the medical center's Office of Communication &
Public Affairs at http://mednews.stanford.edu.
The Northern California Cancer Center is a nationally recognized
leader in understanding the causes and prevention of cancer and in
improving the quality of life for individuals living with cancer. The
organization has been working with scientists, educators, patients,
clinicians and community leaders since 1974. For more information,
visit http://www.nccc.org.
(NOTE TO REPORTERS: Because of the Christmas holiday, the
researchers will only be available for interviews through the
afternoon of Friday, Dec. 21. They will not be available during the
week of Dec. 24-28. Please contact our office for assistance in
arranging pre-embargo interviews with the researchers. For broadcast
media, JAMA will post footage of the researchers at
http://www.thejamareport.org after the embargo lifts.)
Stanford University Medical Center
Amy Adams, 650-723-3900 (Media)
amyadams@stanford.edu
Ruthann Richter, 650-723-8222 (Media)
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