Landmark Breast Cancer Study


A landmark study of Ashkenazi Jewish women with inherited mutations in the genes BRCA1 and BRCA2, called The New York Breast Cancer Study, was published by the journal Science magazine on October 24, and reveals some surprising findings that will contribute significantly to the scientific knowledge in the field of breast cancer management. The study was the first to incorporate pre- and post-test genetic counseling, offered through the Sarah Lawrence College graduate program in Human Genetics, for enrolled subjects.

The study, which was based on one of the largest population samples ever collected in this area of research, provides the truest estimation to date of the lifetime risks of developing breast and ovarian cancer caused by mutations in the genes BRCA1 and BRCA2. Important scientific findings include:

  • New statistics about incidences of ovarian cancer among women with the gene mutation: Women who carry the BRCA1 gene have a 54% lifetime risk of developing ovarian cancer.
  • Groundbreaking information about the negative impact of obesity and lack of exercise among teenagers on breast cancer development as adult women: Exercise and appropriate weight during adolescence delayed the onset of breast cancer in women who carry the mutation.
  • Findings that relate the date of birth of the subjects to the risk of breast cancer: Women in this study who carried the breast cancer gene born before 1940 developed breast cancer later in life than those born after 1940.

Conducted by Dr. Mary-Claire King of the Departments of Medicine and Genome Sciences, University of Washington, Seattle and Joan H. Marks, MS and Jessica B. Mandell, MS, CGC, of the Graduate Program in Human Genetics at Sarah Lawrence College in Bronxville, NY, the study engaged over 1000 women of Ashkenazi Jewish background in the New York Metropolitan area.

More than 100 students in the Sarah Lawrence program served as research associates. Twelve hospitals and medical centers in New York, New Jersey and Connecticut enrolled participants in the study over a 5-year period.

Principal investigator Mary-Claire King, American Cancer Society Professor of Genome Sciences and Medicine at the University of Washington, commented: “This study is unique because it integrates molecular genetics, epidemiology and genetic counseling to identify genetic and environmental factors whose understanding can lead to the control of breast or ovarian cancer. Data about inherited cancer in Jewish families not only benefits those with mutation in the BRCA genes but can also be applied to the general population of American women who, although not at such extremely high risk, confront breast and ovarian cancer as devastating realities in their lives.”

The role of genetic counseling in the study provided the 1,008 participants and their families with:

  • Information and the opportunity to discuss risks associated with BRCA1 and BRCA2 gene mutations.
  • Medical options for prevention and early detection.

“The results of the study provide genetic counselors with validated information about the actual cancer risks related to BRCA gene mutations so that they can offer patients the most comprehensive information on genetic testing and preventive medical options,” said Joan H. Marks, one of the study’s principal investigators and co-author of the Science magazine article. “The environmental findings also enable younger women without breast cancer today to consider changing behavior to help modify their risks of developing breast cancer,” she said.

The field of genetic counseling, which now extends around the world, was born at Sarah Lawrence College in 1969 with the establishment of the first graduate program to train professionals in both the science of genetics and the psychology of working with patients and families at risk for inherited disease. Today, there are approximately 28 institutions providing graduate training in genetic counseling and over 1,000 professionals in the field, about half of who are graduates of the Sarah Lawrence program.

Jessica B. Mandell, genetic counselor and research coordinator, provided genetic counseling for the study participants along with over 30 genetic counselors from collaborating medical centers and 100 students in the Sarah Lawrence graduate program. “With the growth of knowledge about human genetics and expanded opportunities for genetic testing,” said Ms. Mandell, “the need and demand for trained genetic counselors has grown exponentially. Genetic counselors possess a unique ability to assist in disease diagnosis, prevention and management, and provide psychosocial and ethical guidance to help patients make informed, autonomous health care and reproductive decisions.”

The Sarah Lawrence program, which utilizes 50 hospitals in and around New York City for field placements, is a two-year program leading to a Master of Science degree. Students complete a clinical caseload required by the American Board of Genetic Counseling (ABGC) and upon graduation are eligible for board certification. The vast majority of the men and women who have successfully completed the program have found employment within two months of graduation. For more information on genetic counseling and the Sarah Lawrence graduate program, please visit the Human Genetics Graduate Program website as well as