ERBB2 and breast cancer: This subtype is known for its aggressive nature, poor prognosis, short survival time, and high recurrence rate.[2] However, the clinical use of monoclonal antibody drugs targeting HER2, such as trastuzumab, has remarkably improved the diagnosis, treatment, and prognosis of HER2+ BC.[3,4] Accurate assessment of HER2 positivity is crucial in selecting individuals who can benefit from HER2-targeted therapy and improving outcomes for patients with HER2+ BC.