In tumor diseases, the expression of miR-214-3p in the plasma of gastric cancer (GC) patients is significantly higher than that of normal people, and GC patients with high miR-214 expression may have larger tumor lymphatic metastasis and tumor node metastasis (TNM) stage, higher levels of CEA (Carcinoembryonic antigen) and carbohydrate antigen 19-9 (CA19-9), and the survival rate is low. Here, CEACAM5 is linked to neoplasm.