MTOR and neoplasm: By its activation of the PI3K/AKT/mTOR pathway, Ras is predicted to inhibit autophagy.66 However, there is increasing evidence that Ras positively regulates autophagy, and higher levels of autophagy are observed in Ras-expressing tumour cells.24, 58, 67, 68 Furthermore, the proto-oncogene Myc, a downstream activator of Ras signalling, also induces autophagy and tissue growth in the Drosophila wing disc.56 We show here that positive regulation of autophagy by Ras is conserved in Drosophila. Conversely, autophagy regulates the Ras signalling pathway.