MTOR and cancer: Numerous structurally diverse small-molecule compounds, such as MEK inhibitors (e.g., PD0325901 and Selumetinib) and PI3K inhibitors (e.g., Buparlisib and Idelalisib), have been discovered by targeting the RAF/MEK/ERK or PI3K/Akt/mTOR signaling pathways in the search for potential drugs for human cancers (Houédé & Pourquier, 2015; Yu et al., 2015).