Additionally, targeted therapies, particularly those targeting epidermal growth factor receptor (EGFR), poly (ADP-ribose) polymerase 1 (PARP1), vascular endothelial growth factor (VEGF), cyclin-dependent kinases 4 and 6 (CDK4/6), and phosphatidylinositol-3-kinase (PI3K), have significantly improved the survival rates of patients with breast cancer [12]. This evidence concerns the gene CDK4 and breast cancer.