NPC1 and neoplasm: Sertraline caused lysosomal cholesterol accumulation in cancer cells by blocking cholesterol binding to NPC1/2 transporters and upregulating PLA2G15It triggered lysosomal membrane permeabilization, disrupting autophagy and inducing cell deathIn in vivo models, sertraline‐treated cancer cells served as prophylactic vaccines, inducing tumor‐specific immune memory and protecting mice against rechallengeA single sertraline injection in mice significantly delayed tumor growth via a T‐cell‐dependent immune response