BRCA mutations and DNA sequencing: what connection?

Breast and ovarian cancers are the most frequent malignancies in the female population. In particular, breast cancer is the leading cause of death from oncological disease in women and is diagnosed every year in 1 in 1 Italian women.000. 1 Today we know the main causes that trigger these cancers such as lifestyle, age, environmental factors and genetic predisposition so it is possible to implement a breast cancer prevention plan.

BRCA mutations, hereditarily transmitted mutations

A gene is the functional unit of our genome; it consists of DNA and holds the information responsible for the transmission of traits. In recent years, the concept that, starting from the study of genes and their mutations, one can understand the mechanism of tumor formation and consequently study targeted therapies has been greatly strengthened. Genetic mutations play an important role in the occurrence of breast and ovarian cancer.

In our genome are the BRCA1 and BRCA2 genes, whose mutations can be inherited and cause an increased risk of occurrence of these cancers. In detail, in the case of BRCA gene mutations, risk for breast cancer is about 87%, while for ovarian cancer it is about 40% 3 .

Tests based on DNA sequencing

Thanks to genetic screening tests, it is possible to identify predisposed individuals given the presence of possible mutations. These tests are based on sequencing (i.e., "reading") DNA so as to detect the possible presence of genetic mutations.

Until a few years ago, DNA sequencing was done by Sanger method (named after scientist Fred Sanger), while now it is done by NGS (Next Generation Sequencing): a state-of-the-art technique that reads thousands of genes simultaneously 4 . With the advent of NGS, technique and results have improved and time and costs have been reduced.

All it takes for the test is a blood draw

To perform a genetic test, such as BRCA testing aimed at detecting mutations on these genes, all that is needed is a blood sample from the patient. DNA will be extracted from the sample and this subjected to NGS.

BRCA testing is strongly recommended for women with a family history of breast or breast cancer because there may be a genetic predisposition, but not only that: it is also useful for those who are not familiar with these cancers but want to know their predisposition. In fact, knowing whether one has a genetic predisposition to developing a malignancy is very important in order to outline a personalized prevention strategy.