HIF1A and cancer: ROS can trigger metabolic reprogramming of cancer cells to increase tumor aggressiveness and chemoresistance.4, 5 ROS released from cancer cells into the microenvironment can induce stromal oxidative stress and activate nuclear factor erythroid-2-related factor, hypoxia-inducible factor 1-alpha, vascular endothelial growth factor and nuclear factor kappa-light-chain-enhancer of activated B cells, which promote tumor immunity, inflammation and angiogenesis.6, 7, 8