Heredity

In 5% of breast cancer cases, there is a strong inherited familial risk. Two autosomal dominant genes, BRCA1 and BRCA2, account for most of the cases of familial breast cancer. Family members who harbor mutations in these genes have a 60% to 80% risk of developing breast cancer in their lifetimes. Other associated malignancies include ovarian cancer and pancreatic cancer. If a mother or a sister was diagnosed breast cancer, the risk of a hereditary ‘’’BRCA1’’’ or ‘’’BRCA2’’’ gene mutation is about 2-fold higher than those women without a familial history. In addition to the BRCA genes associated with breast cancer, the presence of NBR2, near breast cancer gene 1, has been discovered, and research into its contribution to breast cancer pathogenesis is ongoing. Commercial testing for ‘’’BRCA1’’’ and ‘’’BRCA2’’’ gene mutations has been available since at least 2004. Genetic testing for BRCA gene mutations is conducted exclusively by Myriad Genetics, located in Salt Lake City.