MTOR and cancer: The mammalian target of rapamycin (mTOR) is a serine/threonine protein kinase that operates as the catalytic subunit of two protein complexes, mTORC1 and mTORC2, that act as sensors to integrate multiple extracellular and intracellular signals from the to coordinate the cell cycle.84,85 While increased mTOR expression and/or activation is observed in several cancers,85,86 the kinase itself is rarely directly mutated, with overactivation being triggered by mutations in upstream regulators, such as EGFR, PI3Ks, AKT, PTEN, RAS and RAF.