MTOR and cancer: Accordingly, small-molecule inhibitors of PI3K/mTOR were shown to chemosensitize various cancers to a large variety of anticancer drugs, e.g., topoisomerase-1 or -2 inhibitors, platinum compounds, or microtubule interfering agents (Wallin et al., 2010; Bender et al., 2011; Kim et al., 2011; Mueller et al., 2012).