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BRCA-1 and BRCA-2 Genetic Test

Last updated May 7, 2018

NIH

BRCA-1 and BRCA-2 test is a genetic blood test to detect mutation (harmful changes) in either of the two genes called BRCA-1 and BRCA-2 that belong to a class of genes known as tumor suppressors. The test includes DNA analysis and protein analysis to detect any harmful changes. This image shows that BRCA mutations are inherited in a genetically dominant fashion, from either parent.


What are the other Names for this Test? (Equivalent Terms)

  • BRCA Analysis Testing
  • BRCA Panel Test
  • Breast Cancer Gene 1 and 2 Test

What is BRCA-1 and BRCA-2 Genetic Test? (Background Information)

  • BRCA-1 and BRCA-2 test is a genetic blood test to detect mutation (harmful changes) in either of the two genes called BRCA-1 and BRCA-2 that belong to a class of genes known as tumor suppressors. The test includes DNA analysis and protein analysis to detect any harmful changes
  • BRCA-1 is Breast Cancer susceptibility gene-1 and BRCA-2 is Breast Cancer susceptibility gene-2, respectively
  • BRCA-1 and BRCA-2 are called tumor suppressor genes, because as normal cells these genes help prevent cancer by preventing any abnormal and uncontrolled cell growth
  • These genes help maintain the stability of the cell’s genetic material (DNA). Harmful mutation of these genes affects their normal functioning and greatly increases the chances of development of hereditary breast and ovarian cancer in women. In men these harmful mutations increases the risk of breast cancer
  • 5-10% of breast cancer and 10-15% of ovarian cancer (in US, amongst white women) have been linked to BRCA-1 and BRCA-2 mutations
  • It is important to understand that not every woman with BRCA-1 and BRCA-2 mutation will develop breast and/or ovarian cancer. Likewise, not every case of breast and/or ovarian cancer is linked to BRCA-1 and BRCA-2 gene mutation
  • The presence of BRCA-1 and BRCA-2 gene mutations increases the risk of developing breast cancer by up to five times. It also greatly increases the risk of developing ovarian cancer. However, since most of the data collected is through research on large families having individuals affected with cancers, this data may or may not apply to the general population

What are the Clinical Indications for performing the BRCA-1 and BRCA-2 Genetic Test?

Currently BRCA-1 and BRCA-2 mutation testing in not recommended for the general population. Also, there is no standard criterion for referring or recommending this test to any particular individual.

BRCA-1 or BRCA-2 tests may be ordered for individuals in the following category:

  • Those having a history of breast cancer, at age 50 or less
  • Those having a history of ovarian cancer, at any age
  • Those having a personal history or a family history of cancer, in both breasts
  • Those having a personal history or a family history of male breast cancer
  • Individuals with 1 or more close relative diagnosed with breast cancer, before age 50
  • Individuals with 3 or more close relatives diagnosed with breast cancer, at any age
  • Individuals with 1 or more close relative diagnosed with ovarian cancer, at any age
  • Individuals with a family history of both breast and ovarian cancers, either on mother’s side or on father’s side of the family
  • Those having a personal history of breast cancer labeled as ‘triple negative’ (negative for estrogen receptor, progesterone receptor, and HER2/neu receptor)
  • Ashkenazi Jewish descent individuals with 1 close relative diagnosed with breast and/or ovarian cancer

It is strongly recommended that individuals undergoing this test seek genetic counseling, prior to testing and after testing.

How is the Specimen Collected for BRCA-1 and BRCA-2 Genetic Test?

Sample required: Blood

Process: Insertion of needle into a vein (arm)

Preparation required: None; however, genetic counseling is strongly recommended before and after the test

What is the Significance of the BRCA-1 and BRCA-2 Genetic Test Result?

The test result may be negative, positive, or ambiguous/uncertain. These are described below:

 Negative test result:

  • A negative (or ‘true negative’) test result indicates that it is unlikely that an individual has an inherited susceptibility to cancer, associated with the gene BRCA-1 or BRCA-2. Sometimes, harmful mutations in BRCA-1 and BRCA-2 gene may not be detected by the test (termed as ‘false negative’)
  • A negative test result does not mean that an individual will never get either breast or ovarian cancer. It indicates that the individual’s chances of getting breast/ovarian cancer are lower than somebody with a positive test result
  • In other words, a true negative test result does not mean that an individual will not develop cancer; instead, the results are an indicator that the individual’s risk of cancer is probably similar to that of people in the general population.

 Positive test result:

  • A positive test result is an indicator that the individual has inherited the harmful mutation in BRCA-1 or BRCA-2 gene and therefore, has an increased risk of developing certain cancers, including breast and ovarian cancer
  • A positive test result enables the individual make an informed decision about their future and in managing their cancer risk through steps such as: Undergoing frequent screening for early detection of cancer, prophylactic surgery, avoidance of certain behaviors associated with an increased risk of cancer, and the use of certain medications to prevent cancer
  • The detection of such a harmful mutation can only inform the healthcare providers and the individual, that there is a risk of developing certain cancers; not if and when the cancers would develop

 Ambiguous/uncertain test results:

  • Tests results are sometimes classified as ambiguous/uncertain. If genetic testing indicates a change in BRCA-1 or BRCA-2 gene, which has not been previously tied to cancer in other people, it is labeled as ambiguous or uncertain
  • It is sometimes difficult to conclude, if a specific DNA change affects a person’s risk of developing cancer. This is because each individual has certain genetic differences that are not associated with an increased risk for the disease

The laboratory test results are NOT to be interpreted as results of a "stand-alone" test. The test results have to be interpreted after correlating with suitable clinical findings and additional supplemental tests/information. Your healthcare providers will explain the meaning of your tests results, based on the overall clinical scenario.

Additional and Relevant Useful Information:

  • Detection of harmful BRCA-1 and BRCA-2 mutations in women, also may increase their risk to a host of other cancers such as cervical, uterine, pancreatic, colon, stomach, gallbladder, bile duct cancer, and melanoma (a type of skin cancer)
  • Detection of harmful BRCA-1 and BRCA-2 mutations in men, also may increase their risk to testicular, pancreatic, and early-onset prostate cancer

Certain medications that you may be currently taking may influence the outcome of the test. Hence, it is important to inform your healthcare provider, the complete list of medications (including any herbal supplements) you are currently taking. This will help the healthcare provider interpret your test results more accurately and avoid unnecessary chances of a misdiagnosis.

References and Information Sources used for the Article:


Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: May 20, 2013
Last updated: May 7, 2018

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