ERBB2 and breast cancer: <h4>Objectives</h4>This study investigated vascular differences between human epidermal growth factor receptor 2 (HER2)-positive and HER2-negative breast cancers using multimodal ultrasound and evaluated their diagnostic utility.<h4>Methods</h4>Breast masses were examined with conventional ultrasound (CUS), color Doppler flow imaging (CDFI), contrast-enhanced ultrasound (CEUS), and super-resolution ultrasound (SRUS).