Breast Cancer and Genetic Testing: It’s Different for Black Women
Even before Angelina Jolie made headlines about her decision to have a double mastectomy after discovering she carried the BRCA 1 and BRCA 2 genes – mutations that increase the chance of developing breast and ovarian cancers – I underwent genetic testing myself. I didn’t expect much from the test, but my doctor offered it during my first pregnancy, and my insurance covered it, so I agreed. I was shocked when testing revealed that I am a carrier of a rare disease gene that occurs in less than one percent of my ethnic population.
Since the Supreme Court unanimously decided last month that Myriad Genetics cannot hold patents on the BRCA 1 and BRCA 2 genes, it is believed that the availability of testing will increase ,and the cost will decrease from the current price tag of $3000 and $4000 dollars.
The debate now is: Who should test and when?
The death rate from breast cancer is 40% higher for black women than for white women, even though they are less likely than white women to develop breast cancer. Black women have the highest breast cancer death rate of all racial and ethnic groups. Doctors and researchers have long been aware of the disparities, and have identified several social and economic factors that have contributed to the difference. Yet these factors still don’t explain the fact that black women are being diagnosed, and often dying, at a younger age than other ethnic groups.
Shortly before the Supreme Court decision, a presentation was made at the American Society of Clinical Oncology in Chicago about the results of a comprehensive study, which links genetics to the rates of breast cancer among black women. The study was led by Dr. Jane Churpeck of the University of Chicago and funded by The National Cancer Institute, The Breast Cancer Research Foundation and Komen for the Cure.
The study involved 249 black breast cancer patients in the Chicago area, about half of whom had a family history of the disease. There are several genes that are linked to breast cancer, and the researchers looked at 18 of them. General testing, like the one created by Myriad Genetics, only looks for a few mutations on the BRCA1 and BRCA 2 genes.
22 percent of the study participants were found to have gene flaws. Less than half of those (46 percent) were found on the most commonly tested BRCA1 and BRCA2 genes. This means that about 10 percent had the commonly tested mutations. In comparison, the percentage among white women is estimated at 5 percent and Eastern European Jews at 12 percent. The rest of the gene flaws (54 percent) were found on less commonly mutated cancer-risk genes.
The researchers also noted that the mutations were all different, meaning that, for black women, tests that look at just a few mutations on a few genes are insufficient.
Many people criticized Angelina’s decision and her rally cry for increased testing. While the presence of a mutation on the BRCA1 or BRCA2 genes does significantly increase the likelihood of developing breast cancer, it is estimated that only 5-10 percent of breast cancers are from mutations on these genes. As this study of black women shows — which, it should be noted is the first study to be done of this population — focusing on just the mutations on these specific genes is not enough, and a more comprehensive approach is necessary when evaluating risk among black women.
The Agency for Healthcare Research and Quality — a division of the US Department of Health and Human Services — has national guidelines on genetic counseling, evaluation and risk assessment. In short, a personal and family history of suggested inherited cancers should be evaluated prior to considering genetic testing. Furthermore, consideration as to whether the results of the testing will influence treatment should also be done. The key element, however, is to refer people with a personal and family history to genetic counseling with professionals who can help them determine their risk factors and if testing is right for them.
Black women are less likely to be referred to genetic counseling.
My rare disease gene is not a risk unless I procreate with someone else who has the gene. Fortunately, that was not the case with my son, who is happy and healthy. However, being black, it would have been unlikely that I would have normally been screened for the gene, or even had reason to suspect that I would be a carrier. This could have been fatal for my son if his parentage had been different.
In a recent interview with Slate, Mary-Claire King, the University of Washington scientist that discovered the BRCA1 gene, was asked about how genetic research has changed since she began working in the field in the 1970s. She responded, “The questions people have been asking about genetics and ancestry and the relationship of genes to disease have been the same for hundreds of years. What has changed is our capacity to answer them.”
Let’s hope they remember to include people of all ancestries in those answers.
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