DDIT4 and hepatocellular carcinoma: mTORC1 activation on its own regulated a gene network, including DNA-damage-inducible transcript 4 (Ddit4), nuclear protein 1 (Nurp1) and fibroblast growth factor 21 (FGF21), and mTORC1–signal transducer and activator of transcription pathway crosstalk that altered specific metabolic pathways contributed to the development of non-inflammatory HCC.