Inherited BRCA gene mutations & Risk of breast and ovarian cancer

The article is professionally consulted by doctors of Internal Oncology - Radiation Oncology Center, Vinmec Times City International Hospital.

Genetic testing can show whether you have inherited an abnormal gene that increases your risk of breast and ovarian cancer.
This article will help you understand better about checking for mutations in two main genes, BRCA1 and BRCA2, which are known to increase a person's risk of developing breast or ovarian cancer.

Genetic testing looks for abnormalities (also known as mutations or variations) in certain genes. These genes hold information about how your body looks and works; they are passed from parent to child. Genetic test results can help you understand your risk of developing certain diseases, such as breast and ovarian cancer.

There are two types of gene mutations:
2.1. Primary mutations are inherited, passed from parent to child About 5 to 10% of people with breast cancer are due to geneline mutations. Mutations in two key genes, called BRCA1 and BRCA2, are a common cause of hereditary breast and ovarian cancer. These mutations increase the risk of breast and ovarian cancer, as well as other cancers. Genetic testing is done on a sample of saliva or blood. In addition to 2 genes BRCA 1 and BRCA2, there will also be a number of other genes related to hereditary cancer. The specialist will provide analysis and advice before deciding to have this test.

2.2. Acquired Mutations Non-Inherited or Acquired Mutations Acquired mutations can be caused by exposure to environmental agents such as radiation, chemicals (including those found in tobacco smoke) or viruses; Sometimes mutations appear without a cause. Most cancers, including breast cancer, are caused by acquired mutations. This mutation is found only in the tumor itself, while the former is present in cells throughout a person's entire body.

Testing is recommended if you have (or have had):
Ever had breast cancer Diagnosed with breast cancer aged 50 years or younger, or under 60 but in a "triple negative" breast cancer category (ER-PR negative endocrine receptor, Her-2 epidermal growth factor negative) Cancer in both breasts (at the same time or at separate times) Male breast cancer Diagnosed at any age , but have one or more relatives with cancer cancer (including breast, colon and pancreatic cancer) No personal history, but first or second relative with breast cancer diagnosed ≤45 years old, ovarian cancer, cancer male breast , pancreatic cancer or metastatic prostate cancer . If you have not had cancer and are concerned that the mutation may run in your family (for example, a family history of breast or ovarian cancer), it is generally recommended that First experience someone in the family has had cancer. If the person is found to be mutation-free, it is usually not necessary to test other members.

Pre-consultation - Before you have genetic testing, it's a good idea to talk to a geneticist or doctor who specializes in this area to better understand your cancer risk. A detailed personal and family history should be discussed to better understand future cancer risk. The specialist will talk to you about:
● Your choices when deciding on genetic testing.
Risks, benefits and limitations of testing.
● Results of studies related to genetic mutations.
● Impact, affect (both good and bad) your test results on other family members.

It is not always easy to interpret the results of genetic tests. The results can be:
Positive (mutation) of the BRCA1 gene or the BRCA2 gene or both : This means that the identified mutation is associated with an increased risk of cancer. However, it does not mean that you have cancer or will definitely get cancer.
● Negative, it means that you do not carry a mutated BRCA gene : This result does not rule out the possibility that you may be at risk. hereditary cancer because not every mutation can be detected by genetic testing. In addition, there are many unknown or undetected genetic mutations.
A "true" negative result : This means that there was a mutation present in one or more of your family members (for example, your mother, sibling or aunt), but you no mutations. This result usually means that your cancer risk will be about the same as that of other women in the general population. However, your doctor or genetic counselor will evaluate your other cancer risk factors.
You have a genetic mutation that is "clinically unknown" : This means you have an inherited mutation, but it is not clear whether it increases your risk of breast or ovarian cancer Or it could just be a normal change in the gene.
It is important to remember that a negative result does not mean you will not get cancer and a positive result does not mean that you will definitely develop cancer.

If a woman tests positive for a BRCA mutation: ● The lifetime risk (up to age 70) of breast cancer is 55% to 70% for BRCA1 and 45% to 70% for BRCA2. This means that in a group of 100 women with a BRCA1 mutation, between 55 and 70 women will develop breast cancer in their lifetime.
● The risk of ovarian cancer is about 40% to 45% for BRCA1 and 15% to 20% for BRCA2.
Interpretation of results can be complicated. Sometimes "negative" results are more difficult to interpret than "positive" results. This is why it's so important to discuss test results with your genetic counselor and doctor.

Some ways to screen for cancer and reduce your risk of developing it:
● Preventive surgery (removal of the breasts and ovaries to reduce the risk)
Take medicine to reduce your risk
● Especially often Screening for breast and ovarian cancer more
If in the past, many families often chose to be screened in countries such as Japan, the US, Singapore, Thailand... now, cancer screening technology gen has been present in Vietnam with the best quality and service, comparable to major countries in the world.
Currently, Vinmec International General Hospital is the first medical facility in Vietnam capable of implementing cancer screening by combining 4 technologies: genetic testing, endoscopy, ultrasound and laboratory testing. immunity. In particular, cancer screening with genetic technology is a method that is considered a breakthrough in medicine.
Early screening is considered the "golden key" to detect and provide prevention methods, reduce the risk of death and costs for patients. Due to late detection (70% of patients are treated when they are at the end stage), the death rate from cancer in Vietnam is very high.

Source: update 2018