The BRCA gene test is a blood test that uses DNA analysis to identify harmful changes (mutations) in either one of the two breast cancer susceptibility genes — BRCA1 and BRCA2.
A BRCA genetic test looks for changes, known as mutations, in genes called BRCA1 and BRCA2. A mutation in a BRCA1 or BRCA2 gene can cause cell damage that may lead to cancer.
Women with a mutated BRCA gene have a higher risk of getting breast or ovarian cancer. Men with a mutated BRCA gene are at a higher risk for getting breast or prostate cancer. Not everyone who inherits a BRCA1 or BRCA2 mutation will get cancer.
HOW is BRCA genetic MUTATION tested?
BRCA gene mutation is tested by the next generation sequencing technique. A massively parallel sequencing technology that offers ultra-high throughput, scalability, and speed. The technology is used to determine the order of nucleotides in entire genomes or targeted regions of DNA or RNA.
WHY it's done?
Mutations in either breast cancer gene — BRCA1 or BRCA2 — significantly increase the risk of: Breast cancer, Male breast cancer, Ovarian cancer, Prostate cancer, Pancreatic cancer, Melanoma.
Test is useful for:
- Evaluation for patients with a personal or family history suggestive of hereditary breast and ovarian cancer (HBOC) syndrome
- Establishing a diagnosis of HBOC syndrome allowing for targeted cancer surveillance based on associated risks
- Identifying variants within genes known to be associated with increased risk for HBOC syndrome allowing for predictive testing of at-risk family members
- Therapeutic eligibility including poly adenosine diphosphate-ribose polymerase (PARP) inhibitors in select cancer types
So, test is done to have a plan for tomorrow if the patient is at risk, OR test is considered to be done for the aim of precision medicine for these cancers.
WHO should consider BRCA gene testing?
A candidate for genetic testing — is a patient who has:
- A personal history of breast cancer diagnosed before age 45
- A personal history of breast cancer diagnosed before age 50 and a second primary breast cancer, one or more relatives with breast cancer, or an unknown or limited family medical history
- A personal history of triple negative breast cancer diagnosed at age 60 or younger
- A personal history of two or more types of cancer
- A personal history of ovarian cancer
- A personal history of male breast cancer
- A personal history of breast cancer and one or more relatives with breast cancer diagnosed before age 50, two or more relatives diagnosed with breast cancer at any age, one or more relatives with ovarian cancer, one or more relatives with male breast cancer, or two or more relatives with prostate cancer or pancreatic cancer
- A personal history of prostate cancer or pancreatic cancer with two or more relatives with BRCA-associated cancers
- A relative with a known BRCA1 or BRCA2 mutation
What other cancers are linked to harmful variants in BRCA1 and BRCA2?
- Harmful variants in BRCA1 and BRCA2 increase the risk of several additional cancers. In women, these include fallopian tube cancer (6) and primary peritoneal cancer (7), both of which start in the same cells as the most common type of ovarian cancer.
- Men with BRCA2 variants, and to a lesser extent BRCA1 variants, are also at increased risk of breast cancer (8) and prostate cancer (9). Both men and women with harmful BRCA1 or BRCA2 variants are at increased risk of pancreatic cancer, although the risk increase is low (10).
In addition, certain variants in BRCA1 and BRCA2 can cause subtypes of Fanconi anemia, a rare syndrome that is associated with childhood solid tumors and development of acute myeloid leukemia (11). The mutations that cause these Fanconi anemia subtypes have a milder effect on protein function than the mutations that cause breast and ovarian cancer. Children who inherit one of these variants from each parent will develop Fanconi anemia.