CDK4 and breast cancer: While recent therapeutic agents have improved patient prognosis, such as cyclin-dependent kinase 4/6 inhibitors for HR-positive, HER2-negative, advanced breast cancer (Gao et al., 2020) or poly-ADP-ribose polymerase (PARP) and immune check-point inhibitors for TNBC (Vagia et al., 2020), the development of alternative diagnostic and therapeutic options targeting “cancer’s fuel” may provide novel powerful tools to eradicate breast cancer by its metabolic dependencies and vulnerability.