CEACAM5 and gastric cancer: Although many studies have reported that preoperative carcinoembryonic antigen (CEA), carbohydrate antigen 19 − 9 (CA19-9) and carbohydrate antigen 72 − 4 (CA72-4) can be used as prognostic factors [12, 13], their association with the prognosis and recurrence in different GC stages remains unclear.