Recently, some clinicians have employed a combination of CEA, CA19-9, cytokeratin-1 (CK-1), CA72-4 and mucin-1 (MUC-1) to predict unfavorable outcomes in gastrointestinal tumors, which has improved the sensitivity and specificity of tumor surveillance while also evaluating tumor stage and metastasis (Pua et al., 2020). Here, CEACAM5 is linked to digestive system neoplasm.