There has never been a scientific career quite like Mary-Claire King’s. Years ago, her doctoral thesis concluded that humans and chimpanzees were, genetically speaking, 99 percent the same — a revolutionary thought. Her later work on human cancers resulted in the discovery of the so-called breast cancer gene, BRCA1, which transformed the diagnosis and treatment of the disease.
Besides her traditional scientific pursuits, Dr. King created genetic tests to help ascertain the identities of victims of political violence in places like Rwanda and El Salvador. And she did all this as a single mother raising a daughter.
Dr. King, 68, is now a geneticist at the University of Washington. We spoke in New York last fall, after she was awarded the prestigious Lasker Prize. A condensed and edited version of the interview follows.
Q. HOW DID YOU BEGIN STUDYING THE GENETICS OF BREAST CANCER?
A. Through a roundabout route. I studied statistics in graduate school in Berkeley in the late 1960s. It was there that I took a genetics course, fell in love with it, changed fields and never looked back. Just after I finished my Ph.D., I went to Chile to teach, but the military coup of September 1973 ended all that. Some of my students didn’t survive. I soon left. Back in the Bay Area in early 1974, I needed a job and was very lucky to be offered one at the University of California, San Francisco, studying breast cancer.
Of course, breast cancer wasn’t my field. But I thought genetics, evolutionary biology and statistics might add something to the newly launched War on Cancer. And my closest childhood friend had died of cancer. I wanted to try.
IN THE 1970S, WHAT WAS THE PREVAILING THEORY ABOUT BREAST CANCER’S CAUSE?
The dominant theory was that cancer was viral. I thought that inheritance had to be involved in at least some families. Luckily for me, the National Cancer Institute was studying oral contraceptives and was interviewing 1,500 women with breast cancer. I asked to add questions about family history to the study. Did the patients have close relatives with breast cancer? Ovarian cancer?
Then I asked a statistical question: “Does breast cancer cluster in families more than we’d expect by chance?” The answer was yes. Of all possible explanations, the statistically most likely was a gene with mutations responsible for breast cancer in about 4 percent of patients.
But the gene was hypothetical. The best way to prove that it existed was to find it. In 1990, my group published evidence that the gene we named BRCA1 mapped to human chromosome 17. My paper triggered a race in public and private laboratories, including my own, to clone the gene.
AFTER CLONING THE GENE, MYRIAD GENETICS GOT A PATENT ON IT. HOW DID YOU FEEL ABOUT THAT?
I was enormously relieved when BRCA1 was cloned. It meant we could get on with understanding how mutations in it led to breast cancer. But over the next months, the patent issue became a real bear. Myriad demanded exclusive use of BRCA1.
Previous genetic patents had been licensed nonexclusively and hadn’t made a ripple in how genes were used in research or diagnostics. But Myriad’s test cost more than $3,000, and there was only one place to obtain it. For many women, it was not covered by insurance and was too high to manage out of pocket.
DID THIS EXCLUSIVE PATENT INHIBIT RESEARCH?
At one point, I received a cease-and-desist letter from Myriad’s legal department demanding that I stop studying BRCA1. By then, my lab was at the University of Washington in Seattle. Our state attorney general’s office wrote the company that I had been working on the problem since 1974, was carrying out publicly funded research and was not marketing a test — or anything else. The A.G.’s office also wrote that they would represent me if the company persisted. I heard nothing more.
HOW DID YOU FEEL WHEN THE SUPREME COURT RULED IN 2013...
To end the patent! I felt terrific! The court ruled, 9-0, that genes are natural products and cannot be patented. Since then, testing is far more widely available and the price has fallen significantly.
YOU RECENTLY PUBLISHED A PIECE IN JAMA SUGGESTING THAT EVERY WOMAN OLDER THAN 30 SHOULD GET THIS TEST.
I believe that every woman should be offered testing of BRCA1 and BRCA2 at about age 30 as part of routine medical care. About half of women who inherit mutations in BRCA1 or BRCA2 have no family history of breast or ovarian cancer and have no idea they are carrying cancer-causing mutations.
Most of inherited breast and ovarian cancer can be prevented, if mutation carriers know who they are. Granted, the solution is not pretty. It requires removing the ovaries and fallopian tubes by about age 40 in order to eliminate almost all of the ovarian cancer risk and to reduce breast cancer risk by about half.
Some women opt also for prophylactic mastectomy to reduce the breast cancer risk almost to zero.
YOU HELPED PIONEER THE USE OF GENE TESTING TO HELP RECTIFY HUMAN RIGHTS VIOLATIONS.
In 1983, I was contacted by a group of Argentinian women — the Grandmothers of the Plaza de Mayo — who wanted to find their kidnapped grandchildren. During the military dictatorship in Argentina between 1975 and 1983, thousands of young leftists were “disappeared.” Some of these young adults had infants, and some of the young women were pregnant when they were taken. The infants were given to couples connected to the military.
The grandmothers wanted to identify these children.
HOW WERE YOU ABLE TO DO THAT?
Mitochondrial DNA is inherited only through mothers and is highly variable. It was the perfect tool to link a child to his or her maternal family. The grandmothers have reunited more than a hundred children with their families, the most recent only a few months ago.