Genetic Testing to Determine Cancer Risks

Genetic testing is a means by which your doctor identifies predispositions to certain types of cancer. During genetic testing, your doctor looks at specific gene sequences to determine if there is a possible mutation that could lead to cancer. BRCA1 and BRCA2 are two genes that have been closely linked to the risk of breast and ovarian cancers. A mutation in one or both of these genes can lead to a significantly increased risk of developing these cancers.

What Are BRCA1 and BRCA2?

The genes BRCA1 and BRCA2 help repair damaged DNA and reinforce genetic material in the blood cells. A mutation in one or both of the genes can mean that they are unable to function correctly, so they cannot repair DNA and support cell growth properly. In turn, this can lead to the development of cancer. There are certain inherited mutations that can occur in these genes, which specifically increase the risk for breast and ovarian cancers.

Studies show that a mutation in these genes accounts for up to 25% of hereditary breast cancers and up to 10% of all breast cancers. Additionally, the mutation is also responsible for roughly 15% of ovarian cancers. A mutation in these genes can be maternally or paternally linked in the genes, and it can be passed on to children as well. It is estimated that 55-65% of women who have a harmful mutation in BRCA1 and 45% who have one in BRCA2 will develop breast cancer by the age of 70.

Do These Genes Increase Other Cancer Risks?

In addition to increasing the risk for breast and ovarian cancer, BRCA1 and BRCA2 mutations are also indicated in the increase of other cancers for both males and females. Other cancer risks include:

• Fallopian tube cancer (women)
• Peritoneal cancer (women)
• Prostate cancer (men)
• Pancreatic cancer (men and women)

What Does Genetic Testing Involve?

Genetic testing scans for harmful mutations in these genes. Although mutations are rare, people who have the previously listed cancers in family histories are strongly encouraged to undergo testing. However, before taking one of these tests, genetic counseling is usually required.

Genetic counseling helps people understand hereditary risks, medical and emotional implications of the test, and the risk of passing a mutation on to children. While genetic testing only involves a simple blood test, potential results often cause emotional distress. In these cases, patients will need to understand how to handle the results. If you have a history of cancer in your family and would like to learn more about genetic testing, contact your OBGYN today.