CEACAM5 and gastric cancer: Serum pepsinogen 11, 12 and its combination with a Helicobacter pylori infection test 13, 14, 15, the serum carcinoembryonic antigen (CEA) level 16, the carbohydrate antigen (CA) 125 level 16, the CA 72‐4 level 16, and a gastrin test 5, 12, 17 are promising tests that have been developed for GC management.