ERBB2 and skin disorder: Subgroup analysis of dual anti-HER2 regimens and chemotherapy regimens was performed for each toxicity, the results showed that diarrhea was mainly associated with the trastuzumab plus neratinib group and trastuzumab plus lapatinib group, and hepatic toxicity and skin disorders were mainly associated with the trastuzumab plus lapatinib group, while nausea and vomiting were associated with the trastuzumab plus neratinib group.