MTOR and breast cancer: Neoadjuvant endocrine therapy (NET) either alone or in combination with targeted agents, such as cyclin-dependent kinase 4/6 (CDK 4/6), mammalian target of rapamycin (mTOR), and phosphatidylinositol-3 kinase (PI3K) inhibitors, has clinical benefit for patients with luminal BC [3,9,10].