Since 2012, a paradigm shift was observed in the management of HER2‐positive metastatic BC after the results from the CLEOPATRA,21 the EMILIA7 and the TH3RESA trials.11 The first study demonstrated a significant increase in both PFS and OS when adding pertuzumab to trastuzumab plus docetaxel. The gene discussed is ERBB2; the disease is breast cancer.