African-American Women: More Genetically Susceptible to Breast Cancer
A newly published study shows that African-American women are more likely than their white, Asian, or Hispanic counterparts to have the inherited gene mutations that increase breast cancer risk.
The recent flurry of media attention on Angelina Jolie and her double mastectomy alerted many women, perhaps for the first time, to the possibility of genetic susceptibility to breast cancer.
Sure, we’re all familiar with the “family history” connection to medical conditions: heart issues, high blood pressure, depression, all can be “passed along” from parents to children. As can breast cancer risk.
In recent years, researchers have begun identifying specific genes and gene combinations that increase breast cancer risk to sometimes astronomical levels: up to nearly 90%, for some unlucky women.
The BRCA1 and BRCA2 gene mutations are two genetic indicators that have been known to science for quite some time. And while they’re present in less than 1% of the general population (and about 2.4% of those diagnosed with breast cancer), their effect on breast cancer risk is so great that they get a lot of attention – especially since Angelina’s story hit the wires.
Now, a study published June 6 in the online Journal of Clinical Oncology reveals that African-American women are much, much more likely to carry these gene mutations than women of other races. The study adds to the growing body of evidence that points to African-American women being diagnosed with breast cancer at an earlier age, and suffering a worse outcome, than most other women.
The small but significant study, carried out on 249 African-American women diagnosed with breast cancer, revealed that fully 19% of them carried either or both of the BRCA genes. Compare this to 2.4% of all women diagnosed with breast cancer who carry the gene(s); clearly, the disparity is huge.
And potentially deadly. Triple negative breast cancer (TNBC), a type unresponsive to hormone therapy; and breast cancer diagnosed under age 45 have higher mortality rates than other diagnoses. And 30% of the women in the study who had TNBC also carried the mutant genes; while 27% of younger (under age 45) patients had the genes.
In addition, almost half of those who had two separate, unrelated breast cancer diagnoses; and 30% with a significant family history of breast or ovarian cancer were gene carriers.
The study’s conclusion? “These high carrier frequencies suggest the importance of screening for mutations in all breast cancer genes in all AA [African-American] breast cancer patients diagnosed at a young age, with a family history, or with TNBC as a way to identify at-risk family members for life-saving interventions.” (Churpek, 2013)
The study’s lead author, Jane Churpek, M.D., a hematologist/oncologist from the University of Chicago, commented that the genetic screening necessary to identify carriers of the known range of dangerous genes can be difficult.
She noted, at the time the study was published, “New techniques that allow us to comprehensively screen multiple genes… in a single test will allow cost-effective and efficient genetic testing… Right now, BRCA1 and BRCA2 cannot be included in those panels because there is a patent on those genes. Therefore, for many patients, genetic testing is a multi-step, multi-expense process.” (Johnson, 2013)
However, on June 14 the Supreme Court ruled that genes cannot be patented, thus breaking the stranglehold on BRCA genetic testing previously held by Myriad Genetics of Salt Lake City, Utah. The company charged upwards of $3,600 for genetic testing, an expense often not covered by insurance.
A number of labs have announced that they’re prepared to begin BRCA testing immediately, and this will no doubt drive down the test’s cost.
“I think this will allow more comprehensive cancer genetic testing for many more patients,” noted Elizabeth Swisher, MD, professor of gynecologic oncology at the University of Washington School of Medicine in Seattle. Swisher added, “This will also increase access to better tests… because of the competitive marketplace.” (Azvolinsky, 2013)
Are you an African-American woman? The bad news is, you’re probably more likely than you think to be carrying a genetic mutation that increases your risk for breast cancer.
The good news? The screening tests to determine whether you carry these genes are about to get a whole lot more affordable.
Azvolinsky, A. (2013, June 14). Supreme court ruling invalidates myriad’s brca gene patents. Retrieved from http://www.cancernetwork.com/display/article/10165/2146788
Churpek, J. (2013, June 03). Inherited mutations in breast cancer genes in African American breast cancer patients revealed by targeted genomic capture and next-generation sequencing.. Retrieved from http://meetinglibrary.asco.org/content/116465-132
Johnson, K. (2013, June 06). Breast cancer gene mutations more common in black women. Retrieved from http://www.medscape.com/viewarticle/805431