MTOR and cancer: Our model (Figure 8) can also explain why this mitophagy-dependent phenotype is not observed in PTENMut melanoma cells: It has long been known that PTEN can increase autophagy by inhibiting AKT activity97 (and independently of AKT-mTOR activity98), and that loss of AKT in PTEN-null cancer cells induces autophagy,99 suggesting that tumor cells with reduced PTEN expression will have reduced autophagy in general.