APOE-/- mice exhibited more resistance against tumor progression compared with wild-type mice and experienced better responses to αPD-1 (anti-PD-1) immunotherapy, and inhibition of APOE (using inhibitors such as COG 133TFA, αAPOE) could curb carcinoma development and foster regression when combined with αPD-1 therapy (76). This evidence concerns the gene PDCD1 and carcinoma.