Cancer Risk: Is It in Your Genes?

By Beverly Mangerich, MSNc, Educator Nurse, Scripps Polster Breast Care Center

By now, you probably know that unhealthy lifestyle behaviors, such as smoking, making poor nutritional choices or not getting enough exercise, can increase your risk of developing some types of cancers. However, what if you have a genetic predisposition to developing cancer that has nothing to do with your diet or lifestyle?

Through the study of DNA, we have started to learn about the role of genetics and family history in diseases such as breast and ovarian cancer. We know that women who have a mother, sister or other close relative with breast cancer has an increased risk of being diagnosed with it herself. And, the existence of certain mutated genes may also signal a higher risk.

What exactly are genes? Think of them as DNA “blueprints” inherited from your parents that determine everything about who you are physically, such as your hair color, height, vision and so on. Every cell in your body has two copies of each gene, one from your mother and one from your father, that dictate how your body grows and functions.

An abnormality in a gene, known as a genetic mutation, prevents that gene from working the way it is supposed to. After a number of years, it may lead to a cell becoming cancerous. A mutation can happen by chance in a single cell, or can be inherited from either parent and be present in every cell in the body.

The BRCA genes

In the mid-1990s, researchers discovered that women who have inherited a specific type of gene mutation, known as the BRCA gene, may have a higher risk of developing breast cancer and ovarian cancer. Since then we have identified five genetic mutations that may increase the risk of these types of cancers; the most common are BRCA1 (breast cancer
1) and BRCA2 (breast cancer 2).

These mutations may lead to uncontrollable cell growth and replication, which can be trademarks of cancer, and increase a woman’s risk of both breast and ovarian cancer. If a man has these genetic mutations, his risk of developing breast cancer is increased as well.

The following is a list of the most common risk factors for the BRCA gene mutations. Keep in mind that, while breast and ovarian cancers are primarily women’s diseases, your risk may be inherited from your father’s side of the family as well as your mother’s.

  • Diagnosis of breast cancer before age 50
  • Multiple cancer diagnoses in the same individual
  • One or more family members with ovarian cancer (any age)
  • Two or more family members with breast cancer diagnosed before age 50
  • Male relative diagnosed with breast cancer
  • Known BRCA1/BRCA2 mutation in the family
  • Of Ashkenazi Jewish heritage

Testing for BRCA mutations

If you do have any of these risk factors, you may want to talk to your physician about being tested for a BRCA gene mutation. Although this is a simple blood test, before testing it is important to meet with a team of specialists, which may include a genetic counselor/educator, who will review your family history with you and explain the features of hereditary breast and ovarian cancer, how to interpret test results, medical treatment options, and the benefits and risks of testing.

After the results come in, the team will interpret the results given your family history and meet with you to review them. Keep in mind that a positive result does not mean that you have cancer; instead, it means you have an increased risk of developing it, and can consider steps toward prevention and early detection.

Even if you have a negative result or you choose not to take the blood test, your physician and other specialists may still be able to assess your risk of developing cancer based on your family history, and recommend strategies to minimize it.