A previous study reported that 8.6% of HER2-positive breast cancer patients undergoing dual anti-HER2 therapy experienced cardiotoxicity (Huang et al., 2022), and another study reported that the rate of cardiotoxicity was 2.0%–6.5% under dual anti-HER2 therapy (Swain et al., 2018). The gene discussed is ERBB2; the disease is breast carcinoma.