CDK4 and neoplasm: As precision therapy continues to progress, targeted agents, including cyclin-dependent kinase 4 and 6 inhibitors (CDK4/6is), PI3K/AKT/mTOR(PAM) inhibitors, HER2 inhibitors, vascular endothelial growth factor (VEGF) inhibitors, and histone deacetylase inhibitors (HDACis), are being combined with endocrine drug therapy to improve tumor prognosis.