Medical Health Encyclopedia

Family history plays a role in between 5% and 10% of women who have ovarian cancer. Certain genes are being investigated and identified that are responsible for some of these cases. Depending on the particularly genetic type, the lifetime risk for ovarian cancer in women who carry these genes ranges from 16% to 65%.

BRCA1 and 2 Genes. Inherited mutations in genes known as BRCA1 or BRCA2 are now believed to be responsible for 30% to 50% of breast cancers, ovarian cancers, or both in patients with a strong family history of these cancers.

According to some studies, the risk each carries appears to be as follows:

• Studies indicate that about 25% to 40% of women who carry the abnormal BRCA1 gene may develop ovarian cancer.
• The risk for women with the BRCA2 gene mutation is generally believed to be lower, about 9% to 15%.

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The mutated genes are linked to an even higher risk for developing breast cancer. These mutations are present in only about 0.5 of the US or UK population overall but occur in about 2.5% of all Jewish women of Eastern European (Ashkenazi) descent. This prevalence in a relatively large population makes mutations to BRCA1 and BRCA2 the most common serious genetic disease known in any population group. These mutations are not restricted to the Ashkenazi population and may occur in women of any ethnicity, including women of Asian and African descent.

The BRCA mutations can be passed down to the daughter by either the mother or the father. It should be noted that these mutations may occur in 5% to 10% of ovarian cancer patients who have no family history of breast or ovarian cancer. A number of studies have suggested that women with BRCA-mutated ovarian cancers tend to have better survival rates than others.

Other Genetic Mutations. Women who carry the hereditary nonpolyposis colorectal cancer (HNPCC) gene have about a 9% chance of developing ovarian cancer.