Poly (ADP-ribose) polymerase (PARP), cyclin-dependent kinase (CDK) 4 and 6 (CDK4/6), Ak strain transforming (AKT), and fibroblast growth factor receptor (FGFR) are well-established therapeutic targets that have been the main focus of drug development for the treatment of breast cancer [17–20]. Here, CDK4 is linked to breast cancer.