TGM2 and hepatocellular carcinoma: Consequently, in tumour implants devoid of necrosis due to ischaemia and hypoxia, HIF-1a expression was higher in tumour cells following combined injection of HCC cells and hepatic stellate cells, compared with injection of HCC cells alone, and higher HIF-1a expression was evident in tumour cells after implanting HCC-TGM2 OE cells alone, compared with implantation of HCC-Mock cells alone.