CEACAM5 and neoplasm: In recent years, tumor markers have become commonly used in cancer for early screening and diagnosis, guidance of treatment, evaluation of curative effect, monitoring of recurrence and metastasis, and judgment of prognosis and survival.[10] Especially, carcinoembryonic antigen (CEA) has shown great value for differential diagnosis, disease monitoring, and evaluation of efficacy of treatment of malignant tumors.