Metastatic breast cancer is an incurable disease, with median Overall Survival (OS) depending on the breast cancer subtype (3), being 43.3 in Hormone Receptor positive (HR+)/Human Epidermal growth factor Receptor 2 negative (HER2-), 50.1 in HER2+; and 14.8 months in triple-negative subtype, as reported in French cohort (3). Here, ERBB2 is linked to breast cancer.