ERBB2 and breast cancer: Such as sacituzumab govitecan, a promising drug targeting Trop-2, due to its outstanding effect for patients with HR + /HER2- advanced BC [18], has been approved by the Food and Drug Administration (FDA) for unresectable locally advanced BC or metastatic HR + /HER2- BC with prior endocrine therapy and ≥2 lines of systemic therapy.