GPX4 and esophageal cancer: Figure 9 revealed that the inhibitory effects of sh-circBCAR3 on ferroptosis of esophageal cancer cells were rescued by TNPO1 overexpression, as evidenced by the pcDNA-TNPO1-induced increase of intracellular Fe2+, MDA, lipid ROS, and decrease of GSH and GPX4 levels.