Inherited susceptibility to breast and ovarian cancer.

Approximately 5-10% of breast and ovarian cancer cases are due to an inherited susceptibility. The majority of inherited breast and ovarian cancer susceptibility is due to mutations in the BRCA1 and BRCA2 genes; however, other genes responsible for inherited susceptibility to these diseases are yet to be identified. A small proportion of inherited breast and ovarian cancers are due to other genetic cancer susceptibility syndromes including Li-Fraumeni syndrome, Cowden disease and hereditary non-polyposis colorectal cancer. It is recommended that individuals at risk for inherited susceptibility to breast and/or ovarian cancer who are requesting DNA testing be provided with pre-test genetic counseling and education and post-test counseling and follow-up to ensure that all aspects of genetic testing have been disclosed and that the patient has truly given informed consent.