A researcher key in understanding the role the BRCA1 and BRCA2 genes play in breast and ovarian cancer, Mary-Claire King of the University of Washington, has called for women to be screened for these genes at around age 30 as part of routine care. Her latest research suggests that these genetic markers offer as much insight as a family cancer history into the risk faced by a particular woman.
About half of the women who carry mutations in BRCA1 or BRCA2 have no family history of breast or ovarian cancer, according to King's latest research. Mutations in these genes expose women to extremely high risk for these kinds of cancer, according to King. But physicians currently only recommend testing for these variations in women who have a family history of these cancers.
"The women turned out to have the same high risks of developing either breast or ovarian cancer that we see among those who are identified by virtue of their family history," King told National Public Radio about the research findings she published last week in the Proceedings of the National Academy of Sciences (PNAS).
She argues that women who are aware that they have mutations in these genes can opt for preventative surgical intervention. Now, women often do not know that they are carriers until after they get a breast cancer diagnosis.
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| Mary Claire King--Courtesy of University of Washington |
The PNAS study found that Ashkenazi Jewish women with BRCA1 mutations had a 60% chance of developing either breast or ovarian cancer by age 60 and 83% by age 80. Those with BRCA2 mutations had a 33% risk at age 60 and a 76% risk at age 80.
In the U.S. as a whole, King estimates the BRCA1 and BRCA2 carrier rate as 1 in 300 women and 1 in 500 women, respectively. That translates into 250,000 to 415,000 American women for whom breast and ovarian cancer is highly likely and potentially preventable.
King specifically advocates for the surgical removal of the ovaries, fallopian tubes and/or breasts as successfully minimizing cancer risk for women with these genetic mutations.
But if all the women with BRCA mutations were to have surgery, huge numbers of patients who would not go on to develop cancer would also have preventive surgery. King's position also remains controversial because other cancer advocates worry that women who have these mutations would opt en masse for preventive surgery without an accurate assessment of the risk.
In the PNAS paper, King calls for BRCA screening among Ashkenazi Jewish women--who carry a particularly high risk and upon whom the paper is focused. But she expands that call more broadly to the general population in an opinion piece in The Journal of the American Medical Association (JAMA).
Myriad Genetics ($MYGN) tried to lay claim to the BRCA gene testing segment, but the U.S. Supreme Court validated some of its claims while invalidating others. Several other companies have entered BRCA genetic testing including Quest ($DGX) and LabCorp ($LH).
- here is the National Public Radio story
- here is the PNAS study and the JAMA viewpoint