The genetic test for breast cancer has as its main objective to verify the risk of developing breast cancer, in addition to allowing the doctor to know the mutation associated with the cancerous change.
This type of test is usually indicated for people who have close relatives who were diagnosed with breast cancer before age 50, ovarian cancer or male breast cancer. The test consists of a blood test that, through molecular diagnostic techniques, identifies one or more mutations associated with breast cancer susceptibility, the main markers being requested in the BRCA1 and BRCA2 tests.
It is also important to have regular tests and be aware of the first symptoms of the disease so that the diagnosis is made at the beginning and thus the treatment is initiated. Learn how to identify the early symptoms of breast cancer.
Price of genetic test
Genetic testing is expensive because it is done with the aid of state-of-the-art equipment of high sensitivity and specificity. Thus, depending on the laboratory in which it is performed, the genetic test can cost between R $ 1500 and R $ 7, 000, 000 and is not included in the health plans, however, it is possible to obtain authorization for the examination by the SUS through authorization Special.
When to do
The genetic examination for breast cancer is an examination by the oncologist, mastologist or geneticist, done from the analysis of a blood sample and recommended for people who have family members diagnosed with breast cancer, female or male, before the age of 50 or ovarian cancer at any age. By means of this test, it is possible to know if there are mutations present in BRCA1 or BRCA2 and, thus, it is possible to verify the chance of developing breast cancer.
Usually when mutations are indicated in these genes, the person is likely to develop breast cancer throughout life. It is up to the physician to identify the risk of manifestation of the disease so that preventive measures are adopted according to the risk of developing the disease.
How is done
The genetic test for breast cancer is done from the analysis of a small blood sample, which is sent to the laboratory for analysis. To do the test does not need special preparation and fasting and does not cause pain, the most that can happen is a slight discomfort at the time of collection.
This test has as main objective to evaluate the BRCA1 and BRCA2 genes, which are tumor suppressor genes, that is, they prevent the cancer cells from proliferating. However, when there is a mutation in some of these genes, the function of stopping or delaying the development of the tumor is impaired, with the proliferation of tumor cells and, consequently, the development of cancer.
The type of methodology and mutation to be investigated is defined by the physician, and the following may be indicated:
- Complete sequencing, in which the whole genome of the person is seen, being possible to identify all the mutations that it has;
- Genome sequencing, in which only specific regions of the DNA are sequenced, identifying mutations present in those regions;
- A specific mutation search, in which the doctor indicates which mutation he or she wishes to know, and specific tests are performed to identify the desired mutation. This method is most suitable for people who have relatives with some genetic alteration already identified for breast cancer;
- Isolated insertion and deletion research, in which changes in specific genes are verified, being this methodology more suitable for those who have already done the sequencing but need complementation.
The result of the genetic test is sent to the physician and the report includes the method of detection as well as the presence of the genes and the mutation identified, if present. In addition, depending on the methodology used, it can be informed in the report how much the mutation or gene is expressed, which may help the doctor to verify the risk of developing breast cancer. Learn more about molecular diagnostics.
Possible results
The results of the examination are sent to the physician in the form of a report, which may be positive or negative. The genetic test is said to be positive when the presence of a mutation is verified in at least one of the genes, but does not necessarily indicate whether or not the person will have cancer, nor the age at which it may occur, requiring quantitative testing.
However, when a mutation in the BRCA1 gene is detected, for example, there is a chance of up to 81% of breast cancer development, and it is recommended that the person perform MRI annually, in addition to being able to perform mastectomy as a form of prevention.
The negative genetic test is one in which no mutation was found in the analyzed genes, but there is still a chance of developing cancer, although it is very low, and medical examination is necessary through regular tests. Get to know other tests that confirm breast cancer.
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