Breast & Ovarian Cancer Genetic Testing

Genetic Testing to Understand Breast & Ovarian Cancer Risk

Cancer Genetics specialists at Beth Israel Deaconess Medical Center (BIDMC) can help you and your family members determine if you may be at an increased risk for certain types of cancer. Together with a genetic counselor, you may choose to have genetic testing for cancer to better understand and plan for your personal risk.

Why Have Genetic Cancer Testing?

Knowing if you have a mutation in a gene related to one type of cancer could help predict what other cancers you might be at risk to develop in the future. For example, an individual with breast cancer who carries a specific genetic mutation may also be at increased risk for other cancers, such as ovarian cancer or pancreas cancer, even if there is no family history of these cancers.

Having this information allows your healthcare providers to recommend strategies to prevent or detect those cancers at an earlier stage. And, if you’ve been diagnosed with breast or ovarian cancer, knowing your genetic status might alter the treatment plan for you.

Learn what to expect if you choose to have genetic testing.

Breast Cancer Genes (BRCA1 and BRCA2)

While hereditary factors can play a role in the development of breast and ovarian cancer, in only approximately 5-15% of cases does genetic testing identify an abnormal gene that explains why cancer developed in an individual. The most common genes that cause high-risk hereditary breast cancer are known as BRCA1 and BRCA2. There are certain features of a family that indicate there may be a hereditary component to the cancer in the family. These include:

• Multiple family members affected with the same cancer or related cancers (e.g., breast and ovarian cancer or colon and uterine cancer)
• Cancer within multiple generations of a family
• Young age of onset
• Two or more primary cancers in one person
• The presence of less common cancers (such as pancreatic cancer or male breast cancer)
• Additionally, individuals of Ashkenazi Jewish ancestry are more likely to carry mutations in certain hereditary cancer genes due to founder mutations that have been passed on through many generations

Genetic Testing for BRCA1 & BRCA2 

Genetic testing for the BRCA1 and BRCA 2 genes can help you and your healthcare team make important decisions about your ongoing healthcare. There are many cancer screening and prevention options for those who have an elevated risk of developing cancer, including:

• Increased cancer screening
• Medications to lower cancer risk
• Preventive surgery (removing healthy tissue before cancer develops)

Hereditary Breast & Ovarian Cancer Syndrome

Hereditary Breast and Ovarian Cancer Syndrome (HBOC) is a hereditary cancer syndrome caused by mutations in the BRCA1 and BRCA2 genes. HBOC is associated with a significantly increased risk of developing breast, ovarian and prostate cancer. It’s also linked to an increased risk of developing other types of cancer such as melanoma, pancreatic cancer, male breast cancer and prostate cancer.

BRCA1 and BRCA2 mutations are inherited in an autosomal dominant pattern. This means that one copy of a mutated gene from one parent can cause increased risk of developing cancer. Both men and women can carry BRCA gene mutations and can pass them down to their children. An individual with HBOC has a 50% chance of passing the genetic mutation causing HBOC to children.

For women and men with HBOC:

• Women have a 55-72% lifetime chance of developing breast cancer.
• Women have a 13-58% chance of developing ovarian cancer.
• Men have a 1-7% lifetime risk of developing male breast cancer.
• Men have a 7-61% risk of developing prostate cancer.
• Men and women have about a <5–10% lifetime risk of developing pancreatic cancer.

Other Hereditary Breast Cancer Genes

Mutations in different genes can predispose to the same type of cancer. For example, there are many other genes besides BRCA1 and BRCA2 that can predispose an individual to develop breast (and other) cancers. A technology called next generation sequencing allows testing of many genes associated with hereditary cancer risk at the same time. By testing a number of genes all at once, it is more likely that we may identify the cause for hereditary cancer in a family.

Other, more rare, hereditary cancer syndromes associated with increased risk of developing breast cancer include:

• Cowden syndrome, caused by mutations in the PTEN gene (also known as PTEN hamartoma tumor syndrome)
• Hereditary diffuse gastric cancer (HDGC), caused by mutations in the  CDH1 gene
• Li Fraumeni syndrome, caused by mutations in the TP53 gene

Other moderate-risk genes associated with breast cancer include ATM CHEK2, BARD1, RAD51C and RAD51D. Both rare high-risk genes and more common moderate-risk genes are typically included on cancer gene panel tests.