U.S. Department of Health and Human Services
NATIONAL INSTITUTES OF HEALTH
NIH News
EMBARGOED FOR RELEASE: Tuesday, August 15, 2006; 12:01 a.m. ET
CONTACT: Geoff Spencer (NHGRI), 301-402-0911, spencerg@xxxxxxxxxxxx;
Robert Bock (NICHD), 301-496-5133, bockr@xxxxxxxxxxxx; Kristen Woodward
(Fred Hutchinson Cancer Research Center), 206-667-5095,
kwoodwar@xxxxxxxxx
NEW FINDINGS OFFER MORE COMPLETE VIEW OF BREAST CANCER GENE MUTATIONS IN
U.S. POPULATION
NIH-Supported Study Among The First to Include African Americans, Older
Women
A large study funded by the National Institutes of Health today provided
the clearest picture yet of the prevalence in the U.S. population of
mutations in two genes associated with an increased risk of breast
cancer. The genes are called Breast Cancer 1 ("BRCA1") and Breast Cancer
2 ("BRCA2"). In addition, the study identified key predictors for
assessing which women are most likely to carry these genetic mutations.
Each year, approximately 200,000 women in the United States are
diagnosed with breast cancer. The majority of breast cancer cases are
caused by genetic changes that occur during a woman's lifetime and not
by genetic mutations inherited from her parents. However, researchers
estimate that inherited mutations play a role in anywhere from 5 to 27
percent of all breast cancer cases. In the mid 1990s, researchers found
that mutations in the "BRCA1" and "BRCA2" genes are a major cause of the
hereditary form of the disease. Women inheriting these mutations have a
40 to 85 percent lifetime risk of developing breast cancer, as well as
an increased risk of ovarian cancer.
To date, most of the studies on "BRCA1" and "BRCA2" mutations have
focused on families known to be at high risk for breast cancer and on
women who develop breast cancer at a relatively young age. The new
study, published today in the journal "Cancer Research", looked at the
prevalence and predictors of "BRCA1" and "BRCA2" mutations in
under-studied groups of women, such as African Americans and older
women.
"Studies of any notable size have focused almost exclusively on white
women and young women. This research clearly was needed to improve our
means of assessing the likelihood of carrying "BRCA1" and "BRCA2"
mutations in a wider spectrum of women," said one of the study's lead
investigators, Elaine Ostrander, Ph.D., chief of the Cancer Genetics
Branch in the National Human Genome Research Institute's Division of
Intramural Research. Dr. Ostrander was previously head of the genetics
program at the Fred Hutchinson Cancer Research Center, which is the
institution that led the study.
The researchers examined the prevalence and predictors of "BRCA1" and
"BRCA2" mutations in 1,628 women with breast cancer and 674 similar
women without breast cancer, all of whom were participants in the
National Institute of Child Health and Human Development's (NICHD's)
Women's Contraceptive And Reproductive Experiences (CARE) study. The
women involved in the study were white and African American women, ages
35 to 64, who lived in the Atlanta, Detroit, Los Angeles, Philadelphia
and Seattle metropolitan areas.
"The advantages of this study include its large sample size, inclusion
of under-studied groups of women and the fact that the results are
population based," said one of the study's co-authors, Robert Spirtas,
Dr. P.H., former chief of NICHD's Contraception and Reproductive Health
Branch and now retired.
Researchers found that 2.4 percent of the breast cancer patients had
"BRCA1" mutations and 2.3 percent had "BRCA2" mutations. "BRCA1"
mutations were more common among white breast cancer patients, 2.9
percent, than among African American patients, 1.4 percent. Breast
cancer patients of Jewish ancestry were also significantly more likely
to have "BRCA1" mutations than non-Jewish patients, 10.2 percent
compared to 2.0 percent. For "BRCA2", African American patients were
slightly more likely to have mutations, 2.6 percent, than were white
patients, 2.1 percent.
Based on their findings, the researchers went on to calculate the
prevalence of "BRCA1" and "BRCA2" mutations in the general U.S.
population. Among white and African American women ages 35 to 64, the
prevalence of "BRCA1" mutations is 0.06 percent and the prevalence of
"BRCA2" mutations is 0.4 percent, the researchers estimated.
"These findings from our large, population-based study are compatible
with earlier estimates made by extrapolating from smaller studies.
However, we found a slightly lower frequency of "BRCA1" mutations and
higher frequency of "BRCA2" mutations," said the study's other lead
investigator, Kathleen Malone, Ph.D., Member of the Public Health
Sciences Division at the Fred Hutchinson Cancer Center. "We think the
difference lies in the fact that earlier studies were confined mainly to
whites, and that African American women carry "BRCA2" mutations more
often than white women."
The researchers also identified key predictors of whether a woman with
breast cancer is likely to carry a "BRCA1" or "BRCA2" mutation. Such
information is important because it can help to improve means of
assessing which women may benefit the most from genetic testing,
increased breast cancer screening and other measures aimed at early
detection, treatment or prevention. The most significant predictors for
"BRCA1" mutations were: Jewish ancestry, a family history of ovarian
cancer and a family history of breast cancer occurring before age 45.
For "BRCA2" mutations, researchers uncovered fewer predictors and they
had more modest effects. Among the breast cancer patients studied, the
only significant predictors of a "BRCA2" mutation were early age of
onset (before age 45) in the patient herself or early onset of breast
cancer in mother, sisters, grandmothers or aunts.
"These findings underscore why women need to learn as much as they can
about their family health history and then share that information with
their health-care professionals. However, it must be emphasized that the
presence or absence of a predictive factor does not automatically equate
with a high or low likelihood of carrying a breast cancer gene
mutation," said NIH Director Elias A. Zerhouni, M.D. "The majority of
women with breast cancer -- even those with a family history of the
disease -- do not carry mutations in these genes. These predictors need
to be considered in the context of each woman's complete family health
history."
In addition to the Fred Hutchinson Cancer Center, NHGRI, and NICHD, the
team included researchers from the National Cancer Institute; Bay State
Medical Center, Springfield, MA; the University of Pennsylvania,
Philadelphia; University of Southern California, Los Angeles; and Wayne
State University, Detroit.
HOW TO CREATE A FAMILY HEALTH HISTORY
To help people in the task of creating their family health histories,
HHS offers a free, computerized tool that organizes health information
into a printout that can be can taken to health-care professionals. The
tool, called "My Family Health Portrait," is available at
https://familyhistory.hhs.gov/.
NHGRI is one of 27 institutes and centers at the NIH, an agency of the
Department of Health and Human Services (DHHS). Additional information
about NHGRI can be found at its Web site, www.genome.gov.
The NICHD sponsors research on development, before and after birth;
maternal, child, and family health; reproductive biology and population
issues; and medical rehabilitation. For more information, visit the Web
site at http://www.nichd.nih.gov/.
For more information about cancer, please visit the NCI Web site at
http://www.cancer.gov, or call NCI's Cancer Information Service at
1-800-4-CANCER (1-800-422-6237).
The National Institutes of Health (NIH) -- "The Nation's Medical
Research Agency" -- includes 27 Institutes and Centers and is a
component of the U.S. Department of Health and Human Services. It is the
primary federal agency for conducting and supporting basic, clinical and
translational medical research, and it investigates the causes,
treatments, and cures for both common and rare diseases. For more
information about NIH and its programs, visit www.nih.gov.
This NIH News Release is available online at:
http://www.nih.gov/news/pr/aug2006/nhgri-15.htm.
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