Although tumor markers, carcinoembryonic antigen (CEA), and carbohydrate antigen 19-9 (CA19-9) are useful biomarkers widely utilized for the prediction of tumor recurrence after the curative resection of gastric cancer [3], they are not recommended for the screening of gastric cancer in the National Comprehensive Cancer Network guidelines due to their low sensitivity and specificity [4]. Here, CEACAM5 is linked to gastric cancer.