An inhibitor of the mammalian target of rapamycin (mTOR) with potential antineoplastic activity. mTOR kinase inhibitor AZD8055 inhibits the serine/threonine kinase activity of mTOR, resulting in decreased expression of mRNAs necessary for cell cycle progression, which may induce cell cycle arrest and tumor cell apoptosis. mTOR phosphorylates transcription factors, such as S6K1 and 4E-BP1, which stimulate protein synthesis and regulate cell growth, proliferation, motility, and survival.