Among them, lapatinib is a reversible TKI and is mainly used in combination with capecitabine for the treatment of advanced or metastatic breast cancers that show HER2 overexpression and have previously received treatment by anthracycline, paclitaxel, or Herceptin.85 Neratinib is an irreversible inhibitor mainly used in breast cancer patients who have completed standard Herceptin-assisted treatment and are currently without but at high risk of progression.86 Besides, tucatinib (irbinitinib) is a potent and selective HER2 inhibitor with an IC50 of 8 nM. This evidence concerns the gene ERBB2 and breast cancer.