Understand the molecular aspects of breast cancer and knowing the biomarkers and genetic mutations associated with this pathology is essential for the therapeutic orientation of patients. It also makes it possible to improve clinical research with the development of more targeted and effective treatments.
Les biomarkers are molecules present in the body (measurable in blood, tissue or biological fluids) indicating normal or pathological functioning. Identifying them makes it possible to influence the diagnosis, the prediction of the prognosis and the selection of treatments. For breast cancer, the biomarkers to be taken into account as a priority are hormone receptors which include estrogen receptors (ER), progesterone receptors (PR) receptors, and human epidermal growth factor type 2 (HER2).
The presence of hormone receptors (ER and/or BY > 10%) in cancer cells indicates hormonal dependence for their growth. These cancers are said hormone dependent. Cancer treatment with hormonal therapy is then indicated to slow or stop the development of cancerous tumors.
The HER2 receptor is overexpressed in 12 to 20% of breast cancers; we then speak of HER2-positive cancer. This type of cancer is more aggressive but treatments for targeted therapies exist to block receptor activity. The HER2 receptor is a protein located on the surface of breast cells, which has the role of promoting growth of these cells. Targeted therapies, such as monoclonal antibodies Trastuzumab (Herceptin®), will block the HER2 receptor and thus stop the development of cancer cells. Another treatment that is regularly used to treat HER2-positive cancers is Lapatinib (Tyverb®) which will also block the receiver.
Patients with a HER2-low cancer present a low expression of the HER2 protein gene, unlike HER2-positive cancers. Cancer cells have few HER2 receptors on their surface. On medical examination reports, a patient has HER2-low cancer if his score is 1+ or 2+ in immunohistochemistry (IHC) and negative in situ hybridization in situ hybridization (FISH). New treatments are now being used for this type of cancer, such as Trastuzumab Deruxtecan (Enhertu®).
NB: If breast cancer does not have hormone receptors or overexpression of the HER2 gene, we then speak of triple negative breast cancer.
At the same time, others genetic mutations are also important factors in breast cancer, especially if they are hereditary. A gene mutation BRCA1 (Breast Cancer 1) and BRCA2 involves a greater risk of developing breast cancer more precocious among women. Several treatments are used for patients with a BRCA gene mutation. Olaparib (Lynparza®), Talazoparib (Talzenna®) etc...
Other genes whose mutations are predisposing to breast cancers include the PIK3CA gene and the PALB2 gene. A gene mutation PIK3CA causes an excess of proliferation of cancer cells and is present in 40% of patients with advanced breast cancer. About the gene PALB2, its mutation is rarer but is also associated with a higher risk of developing breast cancer.
Biomarkers and genetic mutations that are specific to your breast cancer are usually listed on the molecular biology report (NGS) or consultation reports.
Of clinical trials are available specifically for some of these biomarkers and genetic mutations. Do not hesitate to do a search by going to Klineo.
Sources: National Cancer Institute, Roche, Canadian Cancer Society, Univadis
Taking action for women with triple negative breast cancer
Discover this association ->
Develop communities for patients and their loved ones.
Discover this association ->
