CEACAM5 and gastric cancer: Consistent with previous publication, levels of CEA, CA72-4 and CA19-9 remained slightly altered in phase I/II GC patients compared with those in healthy controls (Fig. 2D–F and Table 2); however, plasma TrxR activity in phase I/II GC patients were significantly higher than that in healthy controls (P < 0.0001), suggesting its high sensitivity and diagnostic efficiency (AUC > 0.900) in early-stage GC diagnosis (Fig. 2C).