HIF1A and hepatocellular carcinoma: Mechanistically, activated hepatic stellate cells promote TGM2 upregulation in HCC cells through inflammatory signalling; and TGM2-induced depletion of von Hippel-Lindau (VHL) protein, a key molecule in the degradation of hypoxia inducible factor-1a (HIF-1a) under normoxia, then causes HIF-1a to accumulate, thereby producing a pseudohypoxic state that promotes EMT in HCC cells.