Since 1994, many thousands of women with breast cancer from families severely affected with the disease have been tested for inherited mutations in BRCA1 and BRCA2 by the Myriad Genetics test. The vast majority of those patients were told that their gene sequences were normal. With the development of modern genomics sequencing tools, the discovery of additional genes implicated in breast cancer, and the change in the legal status of genetic testing for BRCA1 and BRCA2 due to the June 13, 2013 U.S. Supreme Court decision to bar the patenting of naturally occurring genes that ended Myriad’s monopoly on the testing for BRCA1 and BRCA2 mutations, it is now possible to determine how often families in these circumstances actually do carry cancer-predisposing mutations in BRCA1, BRCA2, or any of a number of breast cancer-associated genes, despite the results of their previous genetic tests. This was the challenge addressed by Mary-Claire King (photo), Ph.D., American Cancer Society Professor of Medicine and Genome Sciences at the University of Washington, Seattle, past President of the ASHG, and renowned breast cancer genetic researcher; and Tomas Walsh, Ph.D., Associate Research Professor of Medical Genetics, also at the University of Washington, Seattle. The researchers conducted complete genomic sequencing of all genes known to be implicated in breast cancer on DNA samples from breast cancer patients who had normal BRCA1 and BRCA2 commercial test results (Myriad testing). The commercial testing occurred because the patients had a severe family history of breast cancer, defined as a family with three or more relatives affected by breast or ovarian cancer. The results were presented today by Dr. Walsh at the American Society of Human Genetics 2013 annual meeting in Boston.
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