Several people in my family have had cancer... so will I get it too? This fear, this question is something that is on the minds of many of us. We have heard that some types of cancer are passed down from generation to generation, that is, they come from genes, right? Well, today we are going to talk about a special method that can help you find out if you have a hereditary cancer risk.
What is this genetic testing?
Simply put, this is a test that looks at the DNA in our body. Think of our body as a big instruction book. This book tells every cell in our body how to function, how they should divide, and when they should die. These instructions are what we call genes .
Sometimes, there may be typos or other errors in this guide. In medical terms, we call these genetic mutations . Cancer occurs when normal cells start dividing uncontrollably due to this type of genetic mutation.
Most of the time, these genetic mutations that cause cancer are not inherited. However, between 5% and 10% of all cancers are caused by genetic mutations that we inherit from our parents. A genetic test involves taking a sample of your blood or saliva and looking for a genetic mutation in your body.
But keep this in mind. Even if this test finds that you have a genetic mutation that increases your risk of cancer, it doesn't mean that you will definitely get cancer. It just means that your 'risk' of developing cancer is slightly higher than other people.
A genetic counselor can explain to you exactly how these results may affect your health.
What types of cancer can be inherited?
There are several types of cancer that can be caused by inherited genetic mutations. The main ones are:
- Breast cancer
- Colon cancer
- Kidney cancer
- Ovarian cancer
- Pancreatic cancer
- Prostate cancer
- Stomach cancer
- Thyroid cancer
- Uterine cancer
These genetic tests do not test for cancer. Instead, they test for specific genetic mutations that can cause cancer. Scientists have so far identified more than 400 genes linked to hereditary cancer. These can be divided into three main groups.
| Genotype | Simply put, what you do | What happens when it gets distorted? |
|---|---|---|
| Tumor suppressor genes Ex: BRCA, P53 genes | These are like the 'brakes' of a car. Their job is to stop the growth of cancer cells. | Just as a car cannot stop when the brakes stop working, when these genes are mutated, cancer cells grow uncontrollably. |
| Proto-oncogenes | These are like the 'accelerator' in a car. They help cells grow at a normal rate, as needed. | Just as when the accelerator is jammed, the speed of the car cannot be controlled, when these are distorted, the growth of cancer cells accelerates. |
| DNA repair genes | These are like the 'garage' where cars are built. They repair mistakes and damage that occur in our DNA. | Just as a car cannot be repaired when the garage is closed, when these genes are mutated, DNA errors cannot be repaired, paving the way for cancer to occur. |
Who wants to do this kind of test?
If your doctor thinks you may have a hereditary risk of cancer based on your personal medical history or family medical history, he or she may recommend this test.
According to your personal medical history:
- If you have had several different types of cancer .
- If you had cancer at a very young age .
- If someone your age or gender has been diagnosed with a type of cancer that is not common .
- In both paired organs , like two kidneys and two breastsIf you have cancer.
- If you have other symptoms associated with certain hereditary cancer syndromes (for example, someone with Neurofibromatosis Type 1 may also develop non-cancerous lumps).
According to your family medical history:
- If several people in your family have had the same type of cancer .
- If several family members have developed cancer at a young age .
- If several relatives on the same side of the family have developed the same type of cancer (e.g., on the mother's side).
- If someone in your family has already been diagnosed with a genetic mutation that increases your risk of cancer.
"A close relative" can be a bit confusing, isn't it? Doctors usually consider your first-degree relatives the most. That means your mother, father, siblings, and your children . But in some cases, the medical history of more distant relatives can also be important.
If you're not sure whether you need this test or not, it's best to talk to your doctor or a genetic counselor about it .
How is this test done?
The first and most important step before undergoing this test is genetic counseling . A specially trained counselor will explain everything to you.
- Is this test really right for you?
- What is the most suitable test for you to do?
- What are the advantages and disadvantages of this test?
- The results can affect your health and life.
- How do these results affect your family?
After discussing all of this, the test is done based on your wishes. Usually, a blood sample or saliva sample is taken from you and sent to a laboratory. There, technicians check your genes for changes. Once the results are in, the report is sent to your doctor.
You may have seen home test kits. But the results they provide are not always complete or accurate. Also, when done through a doctor , the confidentiality of your medical information is protected by law . Therefore , it is always safest and best to do this in consultation with a doctor or genetic counselor .
It usually takes about two or three weeks to get results.
How to understand the answers in the test report?
The results can be divided into three main categories.
| Result | What does this mean? |
|---|---|
| Positive | You have been diagnosed with a genetic mutation that increases your risk of cancer. That doesn't mean you will definitely develop cancer, but the risk is higher . |
| Negative | The genes tested did not find a mutation that increases the risk of cancer. If you know that someone in your family has this mutation, but you do not have it, it is called a "true negative." |
| Variant of Uncertain Significance (VUS) | A change (mutation) has been found in your genes, but scientists are not yet sure whether it increases your risk of cancer. It could be a normal, harmless change, or it could be one that could be found to be linked to cancer in the future. |
What do you do after receiving the results?
Whatever your result, the genetic counselor will talk to you about it in detail. If the result is positive , you will talk about:
- Changes to your health plan: Discusses special screenings for early detection of cancer, such as regular mammograms or colonoscopies, and things you can do to reduce your risk of cancer.
- Family planning: This genetic mutation is discussed in terms of the chances of passing it on to your child.
- Notifying family: This will talk about how the result will affect your blood relatives (parents, siblings, children) and the steps they should take.
Even if the result is negative or VUS , you may need to see your doctor more often or have other tests. If new scientific information becomes available regarding a VUS result, your doctor will let you know.
What are the advantages and challenges of this test?
Like any medical test, this one has its benefits as well as some challenges.
| Benefits | Disadvantages / Challenges |
|---|---|
| The fear and uncertainty in my heart disappear and I feel some relief. | Unnecessary fear, anxiety, and stress about the results may arise. |
| You can take steps to reduce the risk of cancer and detect it early. | Telling family about this may affect relationships. |
| Your doctor will help you create a health plan that is specific to you. | Guilt can arise from something that is inherited. |
| Your family also gets the opportunity to be aware of their health risks. | The test costs some money. |
A genetic counselor can help you deal with these emotional feelings and guide you on how to talk to your family about this, which is why it's so important to have their support throughout this process.
Take-Home Message
- A genetic test for cancer does not tell you that you have cancer, only about your hereditary risk of developing cancer.
- It is very important to speak with a genetic counselor before and after receiving the results of this test.
- Even if the result is positive, don't panic and take the necessary steps to reduce your risk and detect cancer early, as your doctor recommends.
- Talking openly and honestly with your doctor about your family's cancer history is one of the best steps you can take to protect your health.
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