GPX4 and gastric cancer: Glutathione peroxidase 4, NRF2, and SLC7A11 expression in 6 GC cell lines (AGS, BGC-823, HGC-27, MKN-45, MNK-28, and SGC-7901) and normal gastric epithelial cell GES-1 were detected by western blot and RT-qPCR after stable culture.