PROFILE

Prevention Is the Best Medicine

From the United States to Africa, Mary-Claire King has revolutionized the fight against breast cancer—again and again.

Photo courtesy of Mary-Claire King
Photo courtesy of Mary-Claire King

“I have a couple of hundred friends in this room,” Mary-Claire King warned me as we entered a Manhattan gathering of the Breast Cancer Research Foundation in October 2018. “I might lose you.” Seconds later, physicians, researchers, and philanthropists surrounded the petite scientist and swept her away in a whirlwind of admiration.

It was further evidence, as if any were needed, of the 72-year-old King’s legendary status as a geneticist. There are few aspects of breast cancer research over the last three decades that King or her University of Washington laboratory hasn’t had a hand in. King helped redefine the very concept of cancer, saving the lives of countless women along the way—and today, nearly 30 years after her first breakthrough in the field, she remains at the front lines of the battle.

King’s early work on breast cancer was motivated by a deadly puzzle that her research eventually helped solve: a particularly aggressive and incurable form of breast cancer that typically killed women in their 30s and 40s, leaving their children without mothers and families devastated.

By scouring the DNA of hundreds of women, King linked hereditary breast cancer to a gene she discovered in 1990 and would go on to name BRCA1. Its sister gene, BRCA2, was discovered in 1995. These genes encode proteins that act as janitors in certain tissues of the body, cleaning up sloppy mutations caused by ultraviolet rays, tobacco smoke, or just cellular wear and tear. But they also have a propensity to develop harmful mutations, after which they don’t make repairs, and cells—especially when they encounter estrogen—grow out of control.

King’s revolutionary finding made preventative measures possible for the up to 415,000 women in the United States at risk of this deadly form of cancer and possibly for millions more worldwide. Carriers of the defective genes could now potentially avoid the affliction by having their ovaries and fallopian tubes surgically removed so as to reduce estrogen levels.

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Many septuagenarians would be content to cut back their workloads after such success, but King continues to push forward. Together with the University of Chicago cancer specialist Olufunmilayo “Funmi” Olopade and colleagues at Nigeria’s University College Hospital, Ibadan, King is now trying to find a way to stop breast cancer deaths in Africa’s most populous country—which could in the process revolutionize preventative measures worldwide.

Their current project began after the Nigerian-born Olopade—who was working as a well-respected geneticist in the United States—noticed that breast cancer was rising in her homeland, especially among younger women who might have been carriers of the BRCA genes. In 2004, she organized a meeting in Lagos of women’s health advocates and learned that beneath Nigeria’s officially reported cancer statistics lay a mountain of deaths from undiagnosed breast cancer. She then reached out to her longtime friend, King, to begin brainstorming on research that could figure out why the cancer rates were so high and what to do about it.

Together with Nigerian collaborators, they discovered not only that many Nigerian women carried the BRCA1 and BRCA2 mutations but also that mortality rates among these women were far higher than those in Europe and the United States. Worse, they were getting sick at younger ages, leaving young children behind in a country where raising them was still considered to be almost entirely a female responsibility.

Even if a clear medical breakthrough makes it possible to cure such cancer (rather than simply prevent its occurrence), the treatment would likely be too costly to reach most women in the developing world; Nigeria, for example, lacks the financing and infrastructure necessary to support basic measures such as routine access to mammograms, CT scans, radiation treatment, and chemotherapy. That’s unlikely to change soon.

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So King and Olopade have taken a different approach, focusing on offering genetic testing to all young Nigerian women.

Olopade took the lead in setting up a training program for Nigerian genetic counselors through the University College Hospital, Ibadan, with the hope of conducting routine genetic testing of young Nigerian women. The idea is to advise carriers of the BRCA genes that if they want babies, they should consider doing so early and then have their ovaries and fallopian tubes removed. Genetic sequencing is relatively inexpensive, King says, and should be routine everywhere—it needs to be done only once in a lifetime. Mass genetic testing has the added benefit of allowing women to raise their children and watch them grow to adulthood.

The program is still evolving, but King and Olopade are confident that they’ve hit on a genuinely viable alternative to the costly approaches taken to breast cancer detection and treatment in North America.

Meanwhile, King is pushing for all women to have access to this method of cancer prevention. Routine genetic screening of all young women, in the United States and around the world, would allow them a chance to find the threat of cancer before it develops. No woman with a mutation in BRCA1 or BRCA2 should die of breast cancer, King says. “It is completely preventable and absolutely unnecessary.”

This article originally appeared in the Winter 2019 issue of Foreign Policy magazine.

Laurie Garrett is a former senior fellow for global health at the Council on Foreign Relations and a Pulitzer Prize winning science writer.

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