PRF1 and neoplasm: Once activated, CAR-T cells efficiently kill tumor cells via multiple mechanisms (Table 1): release perforin and granzyme B to induce tumor cell apoptosis (19); express Fas ligand (FasL) to engage death receptors on tumor cells, triggering apoptotic signaling pathways (19); and secrete proinflammatory cytokines such as IFN-γ and TNF-α to directly suppress tumor growth or induce cell death while simultaneously recruiting and activating other immune cells to remodel the immunosuppressive tumor microenvironment (TME) (20), thereby enhancing systemic antitumor immunity.