DDIT3 and hepatocellular carcinoma: Melatonin increases apoptosis through enhancing caspase-3, -8 and -9 activities, Bax/Bcl-2 ratio, PARP cleavage and cytochrome c, p53 and Fas-L proteins concentrations in hepatocellular carcinoma, which this effect is mediated by the elevation of ER stress characterized by up-regulation of ATF6, CHOP and Bip [75].