In mouse models with gastric, colorectal, and hepatocellular carcinoma, administration of immune checkpoint inhibitors (α-PD-1 (programmed death 1) and αTIGHT (T cell immunoreceptor with immunoglobulin and ITIM domain) antibodies) displayed greater tumor reduction in APOE −/− than APOE +/+ mice. Moreover, in APOE +/+ mice, the addition of a ApoE competitive inhibitor (COG133TFA) to the combination enhanced the antitumor effect [144]. The gene discussed is APOE; the disease is hepatocellular carcinoma.