GPX2 and gastric cancer: Of note, among all the GC cell lines examined, GPx2 expression levels were particularly high in NUGC-4 and MKN-45 cells compared with GES-1 normal gastric epithelial cells, MKN-74, AZ-521, MKN-1, etc. Further analysis showed that the NUGC-4 and MKN-45 GC cell lines were derived from patients with gastric signet-ring cell carcinoma, which is a kind of low differentiated adenocarcinoma with strong invasion and metastasis abilities.