What causes hereditary breast and ovarian cancer, and why is it important in the Ashkenazi Jewish population?

Approximately 5%-10% of all breast and ovarian cancers have a hereditary component. Hereditary breast and ovarian cancers are most often associated with mutations in one of two tumor suppressor genes, BRCA 1 and BRCA 2. Women, who inherit a BRCA 1 or a BRCA 2 gene mutation, face increased risks for breast and ovarian cancer. Mutations in these genes confer as high as a 90% lifetime risk for breast cancer and up to a 40% lifetime risk for ovarian cancer*.

Individuals of Ashkenazi Jewish descent are more likely than individuals in the non-Jewish population to carry a BRCA 1 or BRCA 2 mutation.

Approximately 1 in 40 women and men, or 2.5% of the Ashkenazi Jewish population, will be found to carry a BRCA 1 or BRCA 2 mutation**.

The BRCA 1 and BRCA 2 mutations are estimated to occur in 1 in 400 to 1 in 1000 individuals in the general population***.

* Tung N. Management of Women with BRCA Mutations. JAMA. 2011;305(21)2212.
** Struewing JP., et al. The risk of cancer associated with specific mutations of BRCA 1 and BRCA 2 among Ashkenazi Jews. N Engl J Med. 1997;336(20):1401-1408.
***Antoniou AC., et al. A comprehensive model for familial breast cancer incorporating BRCA 1, BRCA 2 and other genes. Br J Cancer. 2002;86(1):76-83.