STAT3 and hepatocellular carcinoma: Nuclear PKM2 can phosphorylate transcription factor STAT3 at Y105 site, reshaping the HCC tumor microenvironment and promoting HCC migration.[21,22] Hou PP et al[21] found that ubiquitin-like modification of PKM2 in liver cancer cells led to PKM2 interaction with arrestin domain-containing protein 1, which promoted the release of extracellular granules containing PKM2.