PTEN and neoplasm: As a tumor suppressor gene, PTEN negatively regulates the PI3K/AKT/mTOR pathway (Hollander et al., 2011), and deletion of PTEN can specifically increase the protein level of HIF-1α through PI3K signaling (Jiang et al., 2001), mTOR is closely related to cell growth and mTOR expression is regulated by a variety of factors, including the energy regulator AMPK.