CARD9 and neoplasm: Conversely, when activated on DCs, NK cells, or B cells by structured β-glucans, Dectin-1 initiates SYK–CARD9–NF-κB signaling cascades that promote M1 macrophage polarization, IL-33/Th9 and IL-9 axis activation, NK cell–mediated cytotoxicity, and B cell differentiation, thereby amplifying anti-tumor immunity.