Genetic testing for cancer

With the many breakthroughs in cancer research over the last several decades, one of the most significant is the ability to test a person’s risk of developing it. Since some kinds of cancer, including breast cancer, appear to be hereditary, genetic testing may serve as an advantage when thinking about specific health risks.


In recent years, tests have become available that allow doctors to screen patients and determine their risk for developing certain types of cancer, including breast cancer. These tests are by no means conclusive evidence that cancer will develop; however, they can supply an idea of the patient’s potential for developing cancer later in life based on various genetic factors. Therefore, many women choose to have genetic testing for cancer in order to start taking steps that may help them reduce the risk. For women looking to identify their risk for breast cancer, or any other form of cancer, an educational consultation with a general practitioner, clinical oncologist or a geneticist, is the first step in addressing hereditary concerns associated with heightened risks for developing cancer.


While having a family history of cancer cannot conclusively predict the likelihood of the future development of cancer, there are several important factors in determining the levels of risk associated with a particular family’s past incidence of any type of cancer, including breast cancer. Two key indicators that can predict the existence of a significant risk for developing breast cancer concern close family members and the age at which the disease developed.

A close family member is someone related by blood, within the first degree of familial relationships. For example, if your mother, father, grandparent, siblings, aunts or uncles have been affected by breast cancer they have an increased risk of developing the disease. If the breast cancer occurred in the close family member before the age of 50, you have an even greater genetic disposition toward developing breast cancer.


The genetic structure is the basic set of instructions that directs every facet of the human body, from a person’s eye color to their height. Some genes become altered during the development process, or are inherited in their altered state, and can affect the future health of a close family member by making them more susceptible to a particular disease. Such is the case with a wide percentage of families with a history of certain types of cancer, including breast cancer. Currently, the increased risk has been narrowed down to two particular genes: Breast Cancer Gene 1 (BRCA1) and 2 (BRCA2).

Through genetic testing, specialized medical practitioners are able to assess your risk for breast cancer based on the inherited alterations to BRCA1 and BRCA2 genes. While the absence or existence of alterations to these genes doesn’t mean you’ll eventually develop breast cancer, the test results can help inform your decisions and provide answers to help prepare you and your family for the future.


The BRCA genes function to keep breast cells growing normally and to prevent cancer-cell growth. Scientists have identified mutations of the BRCA1 and BRCA2 gene that can make someone susceptible to developing breast and/or ovarian cancer at some point in their life. When these genes contain the mutations, they don’t function normally, and cancer risk increases. Mutations in these genes can be passed from either parent to their children.

The lifetime risk of developing breast cancer is as high as 84% for women who have inherited a BRCA1 or BRCA2 mutation.

The lifetime risk of developing ovarian cancer is as high as 60% for women who carry a BRCA1 or BRCA2 genetic mutation.

A blood test, or a cheek swab test called BRCAnalysis®, can determine if you carry a BRCA1 or BRCA2 gene mutation and empower you to make informed choices about risk reduction surgery such as preventative mastectomy.

If you have a strong family history of breast cancer but don’t carry the BRCA1 or BRCA2 gene mutations, you should keep in mind that a significant proportion of all hereditary breast cancer may be caused by mutations in genes other than BRCA1 and BRCA2. In other words, if you’re BRCA negative, but have strong family history of breast cancer, you may have inherited a different gene (for which a test to identify it does not exist) that puts you at higher than average risk for developing breast cancer.