We focused on assessing the aggressive behaviors of breast cancer in HER2-positive women included in the study by assessing the DFI (disease-free interval), i.e., the onset of remission, without the occurrence of a loco-regional or remote relapse for the non-metastatic stages and the PFS (progression-free survival), respectively, regarding the appearance of new metastatic lesions or the resumption of evolution through the progression of old lesions for the metastatic stages. Here, ERBB2 is linked to breast cancer.