Cancer Genetic Testing

Genetic Testing

The Role of Genetic Testing in Cancer

There are currently two breast cancer genes recognized:

  • BRCA 1
  • BRCA 2

These genes are involved in DNA repair, and when certain mutations in these genes are present, the ability of a breast cell to repair its DNA is hampered, and the cell becomes prone to becoming cancerous. To date, nearly a thousand mutations in the BRCA 1 and BRCA 2 genes have been identified, and many of these have been found to be associated with a significantly increased risk of breast cancer and ovarian cancer.

Important Breast Cancer Facts

  1. In the United States, one in eight women will be diagnosed with breast cancer in their lifetime.
  2. The majority of breast cancers are not hereditary. Therefore, the absence of a family history of breast cancer does not preclude a woman from being diagnosed with breast cancer herself. Conversely, the presence of a family history of breast cancer does not necessarily mean that your cancer is hereditary. In order to determine whether or not there is a significant family history that may be suggestive of a hereditary predisposition, your doctor will ask a for a detailed cancer history of your family tree.

Certain patterns of cancer in a family may indicate the presence of a BRCA gene mutation. BRCA gene testing is a DNA test which can be performed on either a blood sample or saliva sample. Most insurance plans will cover all/part of the test expense if you meet the appropriate criteria. If you meet any of these criteria, your doctor will discuss genetic testing with you, or refer you to a genetic counselor, medical geneticist, oncologist, or other health professional with expertise and experience in cancer genetics.

Should I Do Genetic Testing?

Identification of a deleterious BRCA mutation may have significant implications on your future risk of a new breast cancer or ovarian cancer, and may be helpful in helping you and your doctors determine the best treatment option and follow-up/surveillance plan for you.

The NCCN (National Comprehensive Cancer Network) has published a set of guidelines to help doctors determine when genetic testing may be appropriate in a breast cancer patient.

These include:

  • Early age onset breast cancer ≤ 50 years old
  • Triple negative [ER(-) PR (-) HER2/neu (-)] breast cancer ≤ 60 years old
  • Two breast cancer primaries in a single individual (at the same time, or at different times)
  • Breast cancer at any age with: ≥ 1 close blood relative (1st, 2nd, 3rd degree) with breast cancer ≤ 50 years old, or ≥ 1 close blood relative (1st, 2nd, 3rd degree) with ovarian/fallopian tube cancer at any age, or ≥ 2 close blood relatives with breast cancer and/or pancreatic cancer at any age
  • Ovarian/fallopian tube cancer
  • Male breast cancer
  • Ashkenazi Jewish descent