Overview
BRCA genes, BRCA1 and BRCA2, are two important genes that help fight cancer. They are, therefore, referred to as tumor suppressor genes.
These genes normally prevent breast, ovarian, and some other cells from growing and dividing too rapidly in an uncontrolled fashion and turning into cancer cells
Sometimes, the BRCA genes undergo a change or mutation that prevents them from performing their function. This raises a person’s risk of developing breast, ovarian, and some other cancers.
BRCA gene testing is about identifying a cancer gene in a person through a blood test. It is particularly used mostly in breast cancer and ovarian cancer
The BRCA1 and BRCA2 genes give stability to the DNA in the cell and prevent mutation and uncontrolled growth of the cells. They prevent the normal cells from becoming cancerous.
The BRCA stands for breast cancer and genetic testing for breast cancer is about testing to see if the person is carrying these mutated or cancer genes.
Risk of breast cancer in positive BRCA test cases
Women who inherit these mutated BRCA1 and BRCA2 genes face a higher risk of developing breast cancer, which is five times the normal risk, and an ovarian cancer risk which is 10 to 30 times the normal risk
It is important to know that having a mutated BRCA gene does not guarantee that you will develop cancer or even if you do have cancer, it does not imply that it is due to mutated genes that you inherited.
In women, besides the risk of breast and ovarian cancer at an early age, mutation of these genes increases the risk of uterine, cervical, colon, and pancreatic cancer.
In men, mutation of BRCA1 and BRCA2 genes increases the risk of breast cancer, testicular, prostate, and pancreatic cancer.
- Harmful BRCA1 mutation in women increases the risk of developing breast, ovarian, uterine, cervical, colon, and pancreatic cancer.
- Harmful BRCA1 mutation in men increases the risk of developing breast cancer and probably cancer of the pancreas, testicles, and prostate.
- Harmful mutation of the BRCA2 gene in women, besides increasing the risk of breast and ovarian cancer, increases the risk of cancer of the stomach, pancreas, gall bladder, and skin.
- BRCA2 mutation in men increases the risk of breast cancer and cancer of the pancreas and prostate.
When is BRCA testing done?
Having BRCA mutations is uncommon. Only about 5% of breast cancer cases and 15% of ovarian cancer cases are due to inherited mutated BRCA genes.
The BRCA test is done only on those women who have a strong family history of breast and ovarian cancer. The following are the indications for BRCA screening, which strongly suggest that you have mutated BRCA genes.
Among Ashkenazi Jewish women
- Ashkenazi Jewish women who have at least one family history of breast or ovarian cancer among immediate relatives (parents, brothers, sisters, and children)
- Ashkenazi Jewish women with two-second degree relatives who have developed breast or ovarian cancer – by second-degree we mean, grandparents, uncles, aunties, nephews, and nieces.
Among the general population
BRCA gene testing is indicated in women with the following conditions:
- A personal history of breast cancer during the premenopausal age, bilateral breast cancer, or development of both breast and ovarian cancer
- Two immediate relatives who have breast cancer of which at least one developed it during the premenopausal age
- Any three or more relatives with breast cancer, which developed at any age
- A family history of both breast and ovarian cancer
- Bilateral breast cancer in any immediate relative
- Development of both breast and ovarian cancer in the family
- Two relatives or more with ovarian cancer
- A male relative with breast cancer
In a family, which is suspected to carry the mutated gene, the youngest family member who has developed breast cancer is tested first for the gene test. If it is found that the youngest family member does not carry the mutated gene, then the other members need not undergo the test.
Cost of BRCA test
The BRCA test is expensive. It could cost anywhere between $500 to $3000 depending on whether you undergo the limited test or the full test. You may or may not be covered by insurance.
Disadvantages of BRCA testing
A genetic counselor takes your family history and decides whether you need to undergo the gene test or not. Once decided, having to undergo BRCA testing does carry some disadvantages besides the financial burden.
- The test is expensive.
- After you undergo the test and test positive, you and your family spend the rest of your life under stress and anxiety, and in fear of developing breast or ovarian cancer.
- If you test negative, you still are not sure that you will not develop breast cancer.
Interpretation of BRCA gene test results
What do the positive and negative results of the BRCA gene test mean?
Positive BRCA test result
A positive test indicates that you have the BRCA mutation. If you test positive for this test, there are certain instructions, which you have to follow.
A positive BRCA gene test does indicate that you are at higher risk of developing cancer but it does not mean that you will get cancer. However, to reduce the risks of cancer in case you test positive, following the guidelines below will help you.
- Increase screening frequency. Screening for breast cancer should be started at the age of 25 years. Besides doing a self-breast exam every month, you need to clinically examine your breast by a doctor every six months and undergo a mammogram (preferably a digital mammogram) and a breast MRI every year.
- Using oral contraceptives. The use of oral contraceptives has been found to decrease the risk of breast cancer in people who carry the mutated BRCA gene. The risk, however, increases after the use is continued for more than 5 years.
- Tamoxifen. Taking estrogen significantly reduces breast cancer risk by 50% in carriers of mutated BRCA genes.
- Prophylactic mastectomy. Undergoing a preventive bilateral mastectomy reduces the risk of breast cancer by 90% in both pre and postmenopausal women. An example is Angelina Jolie who had an 85% risk of developing breast cancer. After the bilateral mastectomy, her risk dropped to under 5%.
- Prophylactic salpingo-oophorectomy. This involves the removal of the healthy fallopian tubes and ovaries on both sides. This reduces the breast cancer risk by 50% in premenopausal women and ovarian cancer risk by 90% in women of all ages.
Negative BRCA Test Result
A negative BRCA test report indicates that no gene mutation was detected. It is necessary that the specific mutated BRCA gene that was detected in your breast cancer relative not be found in the test. This will be a true negative test.
A negative test indicates that you are not at a higher risk of getting breast cancer. But, you do carry the risk as to the general population.
It is possible that researchers have yet to identify all BRCA gene mutations and develop BRCA tests for the same. There are limitations, which you have to prepare your mind for, as the possibility of that high risk may still exist.