The rapid growth in the number of molecular biomarkers and the development of drugs for targeted therapy in the treatment of breast cancer began after the discovery of tyrosine kinase receptors, which allowed the emergence of the first target therapy using the humanized anti-HER2 IgG1 monoclonal antibody, trastuzumab, approved by the Food and Drug Administration (FDA) in 1998 [12,13,14]. Here, ERBB2 is linked to breast cancer.