To date, three HER2-targeted TKIs have been approved by the FDA for the treatment of HER2-positive breast cancer: a dual EGFR/HER2 inhibitor lapatinib, pan-HER inhibitor neratinib, and selective HER2 inhibitor tucatinib14,15, which are not used in GC. The gene discussed is EGFR; the disease is breast carcinoma.