MTOR and metastatic neoplasm: Therapies that target the phosphatidylinositol 3-kinase (PI4K)-mammalian target of rapamycin (mTOR) such as everolimus (an mTOR inhibitor) and PIK3Cα inhibitors have also shown to be effective in combination with endocrine therapy in metastatic disease [20,21,22,23] (Table 1).