It is called Pink October: this month is, in many countries, dedicated to raising awareness of breast cancer, the most common cancer in the world. In France, there are nearly 60,000 new cases per year. Smoking, alcohol, a sedentary lifestyle and being overweight are among the risk factors. But between 5 and 10% of cases are of hereditary origin. Some women therefore have a genetic predisposition which increases their risk of having breast cancer. Report by Valérie Cohen.
We are at the genetics laboratory of the Institut Curie, in Paris. Here, we carry out very detailed analyzes on blood samples from women in whom we suspect a genetic predisposition to breast cancer, because, for example, there have been several cases in their family. In an imposing machine, an articulated arm manipulates pipettes above test tubes.
“ We have an arm that can move. On this side, we will load our blood samples, we will load the reagents, and at the output, we will recover our DNA with a translucent liquid in small tubes », explains Henrique Tenreiro, laboratory technician.
Women, carriers of these genes, to be monitored closely and very early
Once the DNA is extracted, geneticists determine, through sequencing, whether there are alterations in certain genes, particularly those called BRCA1 and BRCA2, which increase the risk of breast cancer. They can be transmitted by the father or the mother. One in 250 people carry it in the Western population.
“ For BRCA1 and BRCA2, this is a risk that is increased by a factor of six to seven compared to the general population. The average age at diagnosis in a BRCA1 or 2 context is more like 45 years, when it is more like 65 years in the general population. And this explains why we have to monitor these high-risk women very early on. », Develops Professor Dominique Stoppa-Lyonnet, head of the genetics department.
These women thus benefit from close monitoring, by imaging, from the age of 30 in France.
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