TGM2 and hepatocellular carcinoma: The loss-of-function of TG2 selectively induced cell death in the liver CSC subpopulation in HCC cells, accompanying by suppressing the gene and/or protein expression of enzymes involved in cell recognition and membrane protein regulation such as exostosin glycosyltransferase 1 (EXT1) and cellular lipid composition and heparan sulfate (HS) biosynthesis.