At the same time, we detected the expression of GPX4 protein in normal gastric mucosa epithelial cells GES-1 and gastric cancer cell lines AGS etc., the results showed that the level of GPX4 protein in gastric cancer cells increased (Fig. S8B), which was a good correlation with the expression of CST1 protein in Fig. 2B. This evidence concerns the gene CST1 and gastric cancer.