GPX4 and gastric cancer: Further, we investigated whether GPX4-K11 ubiquitination site mutation affects the migration and invasion ability of gastric cancer cells, and found that in HGC-27-Vector cells with low CST1 protein, after GPX4-K11 site mutation, the migration and invasion abilities of HGC-27 cells were enhanced; in HGC-27-CST1 cells with up-regulated CST1, after GPX4-K11 site mutation, more HGC-27 cells migrated and invaded, and the difference was statistically significant (Fig. S7C, D).