There is a huge misconception among general population about breast cancer and genetic predisposition. First of all, most cancers are not inherited. Only about 10% of all the cancers are due to a specific genetic change that had been inherited from one of the parents. The other 90% are sporadic cancers, which affect usually older patients, without any particular family history and they result from a lifetime exposure to estrogen (female hormone).
Genetic testing is the only way to accurately identify mutation carriers. The best person to be tested first is always an affected individual, because the results are the most informative. If the mutation is found, all first degree relatives have a 50% risk of having the same mutation (parents, children, sisters and brothers). The person who tests negative has a risk of hereditary cancer reduced to a general population risk.
The test can be performed either in a doctor’s office, who has an account with the lab that performs the test or any genetic center, which employs a cancer genetic counselor. Most health insurances will cover the cost of the test. It is very important that the person who orders the test has enough genetic background to discuss the results with the patients. The genetic counselors are highly trained health professionals with Masters in Human Genetics, who specialize in helping patients to reduce stress and anxiety associated with genetic testing, estimating personalized risk assessment and explaining genetic test results in lay terms.