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The majority of women who are diagnosed with breast cancer have already reached menopause, but for
young women, those who are diagnosed tend to have more aggressive forms of the disease. Now
researchers are beginning to understand why breast cancer may differ in young women. According
to new research, hundreds of sets of genes are more active in young women with breast
cancer compared to older women. The research could have implications for how young women are treated for breast cancer.
"Clinicians have long noted that the breast cancers we see in women under the age of 45 tend to
respond less well to treatment and have higher recurrence rates than the disease we see in
older women, particularly those over the age of 65," said Kimberly Blackwell, M.D., a
breast oncologist at Duke and senior investigator on the study, in a Duke Comprehensive
Cancer Center news release. "Now we're really understanding why this is the case, and by
understanding this, we may be able to develop better and more targeted therapies to treat these younger women."
To perform the research, Dr. Blackwell and her colleagues at Duke Comprehensive Cancer Center examined
breast cancer tissue samples from nearly 800 women in five countries. They divided the samples by the
women's age and found that more than 350 sets of genes that were active only in the breast cancer
tissue samples from women under age 45. Interestingly, the researchers also noted that in the
samples from women over age 65, these sets of genes were not active.
"The breast tumors that arose in younger women shared a common biology, and this discovery was
truly remarkable," Blackwell said in the Duke news release. "The genes that regulate things
like immune function, oxygen supply and mutations that we know are related to breast
cancer, such as BRCA1 [breast cancer gene 1], were preferentially expressed in the
tumors taken from younger women, but when we compared younger women's tumors to older
women's tumors, we found those same gene sets were not expressed in the 'older' tumors."
BRCA1 (breast cancer gene 1) and
BRCA2 (breast cancer gene 2), for example, are
two tumor suppressor genes that, when functioning normally, help repair damage to DNA (a process that
also prevents tumor development). Researchers have discovered that women who carry mutations of BRCA1
or BRCA2 are at higher risk of developing both breast and ovarian cancer than
women who do not have these genetic mutations. Women with BRCA1 mutations account for about 5% of breast cancer cases.
The researchers say their study could help better understand the characteristics of breast cancer in young
women and help develop targeted therapies that are more effective in treating these women. However, they
note that their research did not identify any certain characteristics of breast cancer tumors in older
women, which they point out is an area needing more research.
About 77% of women with breast cancer are over age 50 at the time of diagnosis. Three quarters of women
with breast cancer are over age 50 at the time of diagnosis. Women between the ages of 20 and 29 account
for only 0.3% of breast cancer cases.
Additional Resources and References
- Duke Comprehensive Cancer Center issued a news release about the study referenced above, Young Women's Breast
Cancers Have More Aggressive Genes, Worse Prognosis," http://www.cancer.duke.edu/
- The study, "Young Age at Diagnosis Correlates With Worse Prognosis and Defines a Subset of Breast Cancers With Shared
Patterns of Gene Expression" was published in the July 10, 2008 issue of the Journal of
Clinical Oncology, http://jco.ascopubs.org/
- To learn more about risk factors for breast cancer, please visit
http://www.imaginis.com/breasthealth/bc_risks.asp
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