ERBB2 and breast cancer: <h4>Objective</h4>To analyze the risk factors for cardiotoxicity induced by trastuzumab in human epidermal growth factor receptor 2 (HER2) -positive breast cancer patients and provide a basis for early clinical intervention.<h4>Methods</h4>A retrospective analysis was conducted on 298 HER2-positive breast cancer patients treated with trastuzumab.