CDK4 and breast cancer: These guidelines also suggest that sacituzumab govitecan may represent a new treatment option for patients with advanced hormone receptor-positive HER2-negative BC that has progressed despite prior treatments (including endocrine therapy, cyclin-dependent kinase 4/6 inhibitors, and ≥ 2 lines of chemotherapy) [11], on the basis of the TROPiCS-02 study [21].