The Role of Genetic Testing in Breast Cancer
There are currently two breast cancer genes recognized:
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.
Keep in mind two simple facts about breast cancer:
- In the United States, one in eight women will be diagnosed with breast
cancer in their lifetime.
- 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.
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.
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.
- 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