CD28 and hepatocellular carcinoma: Another study of the glypican 3 (GPC3)-CD3ζ and asialoglycoprotein receptor 1 (ASGR1)-CD28-41BB- against hepatocellular carcinoma (HCC) CAR-T cells study also demonstrated that CAR-T cells separating CD28 and CD3ζ signals had potent antitumor activity and safety against tumor cells carrying both antigens.