You are here

Mary-Claire King, PhD

American Cancer Society Professor
Departments of Medicine and Genome Sciences
University of Washington
Seattle, Washington

Current Research

  • Seeking to characterize the genetic susceptibility to breast cancer in high-risk groups to improve screening and risk stratification strategies.
  • The NYBCS team will examine genetic profiles of Jewish families severely affected with breast cancer, but who have no mutations in any known breast cancer gene.
  • These collaborative efforts continue to inform our understanding of inherited risks of breast cancer in diverse populations.

Individuals who inherit a deleterious mutation in the breast cancer genes, BRCA1 or BCRA2 have a significantly high risk of getting breast or ovarian cancer. BRCA mutations are much more common in families of Eastern European (Ashkenazi) Jewish descent, than the general population, even when there is no known family history of cancer. Dr. King is leading studies to understand the inherited susceptibility of breast cancer in women and men of Ashkenazi Jewish heritage. These studies have revealed the involvement of other genes and stress the need for genetic screening in this high-risk population.

Full Research Summary

Dr. King is working with several BCRF colleagues on studies that are focused on understanding the genetic susceptibility to breast cancer. The New York Breast Cancer Study (NYBCS) is a study to identify all genes responsible for inherited predisposition to breast cancer among women of Ashkenazi Jewish ancestry and, by extension, among women of all ancestries.

The first goal of the NYBCS, more than a decade ago, was to determine the risks of breast cancer due to “founder mutations” in the BRCA1 and BRCA2 genes among women of Jewish ancestry.  Dr. King and her colleagues determined that 10 percent of breast cancer patients of Jewish ancestry carried one of three relatively common “founder mutations” in BRCA1 or BRCA2, that risks of breast and ovarian cancer to mutation carriers are very high, and that risk has increased with time for non-genetic reasons. 

As part of the NYBCS, they also discovered that among all breast cancer patients of Ashkenazi Jewish ancestry, 14 percent carry an inherited mutation very likely responsible for their breast cancer, including mutations in genes other than BRCA1 or BRCA2. About half of patients with a breast cancer-causing mutation have no suggestive family history of breast or ovarian cancer.

Next year they will study NYBCS Jewish families severely affected with breast cancer, but with no mutations in the protein coding sequences of any gene. They believe that breast cancer in these patients is due to mutations in DNA that regulates the timing of expression of genes, rather than mutations that directly alter the sequences of genes. 

A sister project of the NYBCS is the Middle East Breast Cancer Study (MEBCS). MEBCS is directed jointly by Drs. Ephrat Levy-Lahad, Moien Kanaan and Mary-Claire King.

Through the MEBCS, the team has established a modern genomics laboratory where routine genetic testing for breast cancer patients is being conducted. They have enrolled and carried out genetic testing for the largest cohort of breast cancer patients of Arab ancestry in the world. They have created, and sustained, training programs in cancer genetics for Palestinian nurses and social workers, who now offer genetic counseling for high-risk women. They have characterized the distinctive genetic risk profile in Arab women, including mutations specific to this population that will inform characterization of these mutations in women of all ancestries.


Mary-Claire King, PhD, is American Cancer Society Professor at the University of Washington, Seattle. She was the first to show that breast cancer is inherited in some families, as the result of mutations in the gene that she named BRCA1. In addition to inherited breast and ovarian cancer, her research interests include the genetic bases of schizophrenia, genetic disorders in children, and human evolution. She pioneered the use of DNA sequencing for human rights investigations. Dr. King has been elected to the National Academy of Sciences, the American Academy of Arts and Sciences, the Institute of Medicine, the American Philosophical Society, and as a foreign member of the French Academy of Sciences. She has served on the Advisory Committee to the Director of NIH; the National Commission on Breast Cancer of the President’s Cancer Panel, multiple councils and study sections of the NIH, and as past president of the American Society of Human Genetics.In 2014, she received the Lasker Special Achievement Award for Medical Research and in 2016 the United States National Medal of Science.

Grid Researcher Headshot -  King Mary Clairec

BCRF Investigator Since


Donor Recognition

The Roslyn and Leslie Goldstein Award