GPX4 and cancer: Ferritin 1 (a kind of small‐molecule antioxidant) can prevent murine cancer cell ferroptosis induced by erastin or GPX4 inactivation from an L‐ROS (lipid ROS) stockpile, increasing PUFA exhaustion and, eventually, ferroptotic cell death; this finding indicates that lipid ROS‐ mediated damage is necessary for ferroptosis17, 18, 33 (Figure 1).