However, there are clinical limits for accurate tumor detection and diagnoses using preoperative examinations such as endoscopy, endoscopic ultrasonography (EUS), computed tomography (CT), and positron emission tomography‐computed tomography.2, 3, 4 Carcinoembryonic antigen (CEA) and carbohydrate antigen 19‐9 (CA19‐9) are now commonly used as established serum markers in the clinical management of patients with gastric cancer. This evidence concerns the gene CEACAM5 and gastric cancer.