Likewise, carcinoembryonic antigen (CEA) serum levels of patients studied were significantly likely to be lower after neoadjuvant treatment of the disease (10 patients [41%] pre-treatment vs. 5 patients [13%] after tumor surgery with CEA serum levels ≥5 ng/mL; p = 0.005). Here, CEACAM5 is linked to neoplasm.