ERBB2 and breast cancer: Breast cancer is among the most prevalent malignancies affecting women worldwide, while the HER2‐positive subtype accounts for approximately 25% of all breast cancer cases.[1] Currently, anti‐HER2 treatments are widely employed in the management of HER2‐positive breast cancer.[2, 3] These treatments encompass not only traditional trastuzumab, which directly inhibits HER2 dimerization and downstream signal cascades, but also trastuzumab‐derived antibody‐drug conjugates (ADCs) to induce additional anti‐tumor cytotoxic effects.[4]