MTOR and cancer: In cancer cells, it has recently been demonstrated that SP, through the NK-1R, induces the mammalian target of rapamycin (mTOR) signaling axis and increases cancer cell growth/metastasis by the activation of the eukaryotic initiation factor 4E-binding protein 1 and p70 S6 kinase (Figure 1) [20], whereas aprepitant (a NK-1R antagonist) attenuates the mTOR activation by decreasing the phosphorylation of p70 S6 kinase [46].