STAT3 and glioblastoma: We also observed that concurrent with reduced cell viability, 2.5 and 5 μM garcinol or stattic induced significant downregulation of p-STAT3 (garcinol: 40% and 85%, p < 0.01; stattic: 56% and 89%, p < 0.01) and p-STAT5A (garcinol: 35% and 83%, p < 0.01; stattic: 48% and 74%, p < 0.01) in the primary GBM culture cells (Figure 6B).