Practical Aspects of Genetic Counseling: Genetic Tests to Identify Risks

Germline mutations in hereditary predisposition genes to cancer account for about 5–10% of all diagnosed cases of breast cancer. The loss of function of about 30 different genes presents a clear correlation with patterns of heredity, i.e., individuals with germ mutation in one of these genes are more likely to develop breast cancer, as well as other types of cancer throughout their lives, in comparison with the general population. These mutation-bearing patients have what is called hereditary breast cancer. Currently, the identification of individuals with these genetic alterations is fundamental, as it can not only be extremely useful for guiding the clinical-surgical treatment of patients affected by neoplasias, but it can also guide personalized prevention and risk-reduction strategies for asymptomatic patients who are part of the same family. It is important to note that, once a proband mutation is identified in the test, there is a 50% chance that first-degree relatives (children, siblings, and parents) have this mutation and are at increased risk of developing cancer. Further, distant relatives may also have this genetic variant and therefore, this risk should be evaluated individually.