GPX4 and selenium deficiency: Either selenium deficiency or GSH deficiency is responsible for ferroptosis.[34,39] Besides, SLC7A11-mediated cystine uptake was found to promote GPX4 protein synthesis via activating rapamycin complex 1 (mTORC1) in a GSH-independent way.[40] Thus, the xCT/GSH/GPX4 axis is critical for defending against ferroptosis.