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Health & Wellness: A Triple Threat Cancer
Aggressive cancer affects African-Americans disproportionately.
by Ruth O'Regan, M.D., Director, Translational Breast Cancer Research, Emory Winship Cancer Institute
July 1, 2008
M
ortality from breast cancer has been slowly decreasing because of earlier detection and
more effective therapies. Despite these improved outcomes,African-American women continue to be
more likely to die from breast cancer, compared with their white counterparts.
Over the past ten years, we have learned that breast cancer is not a single entity, but is
made up of at least four different types, each with distinct prognoses. The types are determined by
the presence or absence of three target proteins, called estrogen receptor, progesterone receptor
and human epidermal growth factor receptor 2 or HER2.
The presence or absence
of these proteins within breast cancers determines what treatment a patient needs to prevent her
cancer from coming back. For example, tamoxifen is an agent that has been used for more than 30
years for breast cancers that contain estrogen and progesterone receptors to prevent the cancers
from coming back. Trastuzumzab (Herceptin), an antibody that targets the HER2, has dramatically
improved outcomes for patients with breast cancers containing that receptor.
Unfortunately there are a group of cancers that do not express any of these three important
target ] proteins, and therefore, cannot be treated with these curative therapies. These
"triple-negative" cancers run a highly aggressive course and have a high propensity for recurrence
over the first two to five years after diagnosis. Currently, the only approved treatment to prevent
triple negative cancers from coming back ischemotherapy, which unfortunately is not as effective as
targeted therapies.
Here at Emory, a team of researchers led by Mary Jo Lund, Ph.D., assistant professor of
epidemiology at Emory's Rollins School of Public Health, as well as colleagues from Emory's Winship
Cancer Institute, the Fred Hutchinson Cancer Research Center in Seattle, and the Centers for
Disease Control and Prevention, found the incidence of triple negative cancers in African-American
women to be more than twice that of white women.
To assess racial differences in the prevalence of triple negative breast cancer, Dr. Lund
and her colleagues in Atlanta combined data from a study of racial differences in progression of
breast cancer among Atlanta women under the age of 55 with tumor factors analyzed by collaborator
Peggy Porter, M.D., of the Fred Hutchinson Cancer Research Center in Seattle.
The team found that 47 percent of tumors in African-American women younger than 55 were
triple negative compared with 22 percent in white women in the same age range. After adjusting for
age and stage at diagnosis, African-American women were almost threefold more likely than white
women to have triple negative tumors. Similar findings have been reported in other states. A
similar increased incidence of triple negative cancers in African-Americans, compared with whites,
was reported in the Carolinas, for example.
Over all ages, African-American women are at lower risk for breast cancer compared with
white women. For women younger than 50, however, African-American women are at increased risk over
white women of the same age.
What is being done?
We are currently working to learn why this susceptibility exists. A multidisciplinary study
that is currently under way includes a questionnaire, blood tests, and collection of tumor samples.
It is ongoing at three Emory-affiliated hospitals in Atlanta among African-American and white
female patients who live in Fulton and DeKalb counties. These two counties account for the majority
of breast cancers diagnosed among African-American women, particularly those younger than 50, in
metro Atlanta.
Our team of researchers is analyzing tumors and searching for other protein markers, besides
the existing receptors, which occur consistently in triple negative breast cancers. Our hope is to
find other protein markers that occur consistently enough to open doors for new, protein-targeted
treatments. We are also looking at ways to turn target proteins, such as the estrogen receptor,
back on in triple negative cancers. This approach could be good news because it will target the
tumor independently, unlike chemotherapy, which indiscriminately attacks both tumor and normal
cells. Another question being addressed is why some triple negative cancers get extensive benefit
from chemotherapy, but others get absolutely no benefit.
We clearly need additional studies to examine the molecular profiles and risk profiles for
triple negative tumors to better understand why these tumors are resistant to targeted therapies
and why premenopausal African-American women have this increased risk.
The Jean Sindab Project for Breast Cancer Research was established at Emory’s Winship Cancer
Institute in April 2005, through a generous gift from an anonymous donor.
The purpose of the Sindab Project is to develop innovative research into breast cancer in
African-American women. Of the anticipated 40,000 female deaths from breast cancer in the United
States, a disproportionate number will be African-American.
Major reasons for the disparity have been attributed in part to the increased number of
African-American women diagnosed with early or premenopausal breast cancer, later staged disease,
or more aggressive cancers, which, consequently, leads to poorer outcomes. Potential reasons for
these racial variations can be attributed to sociodemographic and lifestyle factors, access to and
utilization of health care services, response to treatment and health status.
Another example of work supported by the endowment is a collaborative project between Emory
Winship and Georgia Tech on the use of quantum dot-based nanotechnology. Quantum dots are tiny
semiconductor particles that have unique electronic and light emitting properties. Their extremely
small size and highly compact structure enable them to be used as biological markers targeted to
specific proteins and cells. Nanotechnology is an important advance in the early detection of
breast and other cancers and in the development of targeted drugs for personalized treatments.
Dr. Ruth O’R egan comes to
the Emory Winship Cancer Institute from Northwestern University in Chicago where she was an
assistant professor of medicine at Northwestern Hospital specializing in breast cancer.
A native of Dublin, Ireland, Dr. O’Regan earned her medical degree at University College in Dublin and conducted a residency in internal medicine and a fellowship in oncology at the Mater Hospital, in Dublin. She did her U.S. residency and fellowship at Northwestern University in Chicago.
Since joining the faculty at the Emory Winship Cancer Institute, she has continued her research in SERM-resistance. She is the principal investigator of the first trial to be run through Georgia Cancer Coalition’s innovative Georgia CORE (Center for Oncology Research and Education).
