Genetic testing involves looking for “abnormal” genes in an individual, which predict the onset of cancer. We explain who can do it and how.
Near 5% of cancers are due to the presence of a abnormal gene. However, its existence should not be taken lightly: it considerably increases the risk of malignant tumor. Good news though: it is now possible to predict your cancer risk … through the use of genetic test. We explain what it consists of.
Genetic test: what is it for?
According to the ARC Foundation for Cancer Research, the genetic test “identifies the carriers mutation and assess their risk of developing cancer. “Concretely, it aims to detect mutations of a gene in a person with the disease, called “index case”.
If done on time (that is, when the person does not yet have cancer), this test may increase the chances of survival of a patient, thanks to a in charge faster.
Nathalie Gibon, 46, experienced this test. Suffering from breast cancer, she tells on France 3 that it is “this genetic test carried out in 2009 which tells her that she has entered 50% and 70% risk of developing breast cancer “.
Who practices it?
The geneticist – or genetic researcher – is the only expert who can accurately determine the hereditary characteristics of rare diseases / cancers of your family.
Once the test has been carried out, it offers a personalized monitoring to the patient – if the tests are found positives.
And even if no gene mutations were found, if the family of the person tested is strongly affected by cancer, specific follow-up may be recommended.
More what mutations can be screened? In total, “there are tests for 70 predisposing genes,” explains the ARC Foundation.
Genetic testing: how is it done?
The genetic test is carried out via a simple blood test.
The work that follows is then much more complex: the search for mutations suspected is a long process and meticulous, which requires a work of several months (6 months on average).
2 situations are then offered to the person who performed the test :
If she is sick, its own genetic heritage is studied. If she’s not sick, the analysis must be done on another sick member of the family. He must obviously agree, for his part, to be examined.
Genetic testing: discovering the results
When a predisposing mutation to cancer is demonstrated in a patient, there is no doubt: the over-risk of cancer is recognized.
In this situation, the geneticist may decide to look for this mutation in other members of the family.
If they accept, the exam is faster than the first test: it usually only requires a few weeks.
“If no mutation could be detected, the test result is said “undetermined” because we cannot for all that deduce the absence of a hereditary risk. Indeed, the genetic tests available do not detect 100% of mutations “, explains the ARC Foundation for Research on Cancer.
It should also be remembered that certain mutations involved in hereditary predisposition to cancer are not yet known.
If the risk estimated from the family tree is low, the results are said to be “reassuring”.
On the other hand, if the history of cancer is important, the doctor will advise a increased surveillance or will repeat the genetic test in another patient in the family.
The links between cancer and heredity
And one or more members of your family have cancer, you may wonder if you are at risk for it too. And that’s a good question.
Sometimes a genetic mutation that can cause cancer is passed on to you from your parents: these are called hereditary cancers. The genetic alteration can then be inherited of one and / or the other parents: the genetic heritage of a person is indeed the result of a combination of that of his father and mother. In this case, the person presents this anomaly from birth, in all the cells of his body.
Cancer may also appear more often in family members who share similar habits, live in the same place or share others. genetic factors (we are talking about non-hereditary cancers).
According to the Canadian Cancer Society, “Certain types of cancer are also strongly linked to family history, as in the case of breast cancer and colorectal cancer “. an alarming number breast cancer in the same family (paternal or maternal).
Another important point: if a close family member has a cancerous tumor, your risk of developing cancer. can increase.
However, your risk may be even higher if you inherit of a gene which is linked to cancer. This is why it is essential to talk to a specialist about your family (especially family history cancer).
This will help your doctor decide if you need to go genetic tests or not.