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Genetic breast cancer detection


In a 25-year career of research, education and activism, Mary-Claire King has succeeded not only in scientific innovation but in making the world a better place.

Born in a Chicago suburb in 1946, King earned a B.A. in Mathematics at Carleton College (in Minnesota) at the age of 19. She then went directly to the University of California at Berkeley to study Genetics. King left school to protest the Vietnam War, but returned and earned a Ph.D. (1973).

King's doctoral thesis revolutionized evolutionary biology: through comparative study of proteins, she proved that human and chimpanzee genomes are 99% identical. This places the divergence of the two species from a common ancestor at about 5 million years ago, rather than 10 million years ago as was previously thought.

King's postdoctoral and professorial research has had more immediate ramifications. In 1974, she began to study the DNA of families in an attempt to find out whether breast cancer might be hereditary. Her colleagues were skeptical, believing instead that an indefinable combination of various genes and environment were the cause. Over years of painstaking research, King searched for a genetic "marker"---that is, an identified gene that tends to accompany the gene being searched for---that would flag the presence of the hereditary breast cancer gene in a chromosome. In 1990, after assessing 183 possible markers, King and her research team found the right one, on chromosome 17; in fact, they found that the marker was linked to a gene responsible for a number of different inhereited breast and ovarian cancers.

King's discovery made it possible for others to pinpoint the cancer-causing gene itself, now known as BRCA1, in 1994. The isolation of BRCA1 has led in turn to direct diagnosis of the 5-10% of all breast cancer that is hereditary. Just as importantly, King's research has given geneticists insights into the nature of cancer-caused genetic mutations in general. King herself has used BRCA1 to develop a number of cancer testing, screening and therapeutic procedures; for these, she has earned one patent (#5,622,829; 1997) and has others pending.

During most of her search for BRCA1, King was a Professor of Genetics at Berkeley (1976-95). But she was also applying her expertise outside the academic realm. In 1984, King traveled to Argentina, to take up the cause of the Abuelas de Plaza de Mayo. These were grandmothers of children who were kidnapped, and whose mothers were murdered, during the civil war of the 1970s in that country. The dictatorship would not grant these grandparents custody of their grandchildren without "proof" of kinship. To give those families that proof, King helped create a blood test, using genetic markers and mitochondrial DNA sequencing, that established with 99.9% certainty whether a given grandparent was in fact related to a given child. As a result of King's work, over 50 families have been formally reunited.

In 1995, King became American Cancer Society Professor of Medicine and Genetics at the University of Washington. Her current research includes breast cancer genetics, as well as mapping and cloning the gene for inherited deafness and analyzing the radically different effects that HIV has on different infected persons' immune systems. She also continues her humanitarian work: for example, her laboratory has become the DNA identification base for the United Nations War Crimes Tribunal.

Mary-Claire King thoroughly deserves the admiration she has won as an educator and an innovator, a scientist and a humanist.

For an article on Mary-Claire King with more specific scientific detail, see The Women, Medicine & Biology Web Site sponsored by Haverford College.

For a speech by Mary-Claire King on Biology at Berkeley visit Gifts of Speech: Women's Speeches from Around the World:

[Oct. 1998]

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