CEACAM5 and gastric cancer: Because of the differences in biological and clinical characteristics, carcinoembryonic antigen and carbohydrate antigen 19-9 have been found to be the most common GC markers measured before and after surgery (Lin et al., 2020), although which preoperative or postoperative combined tumor markers have a more prognostic value has not been clear yet, as well as whether change of the preoperative and postoperative systemic inflammatory response (SIR) levels affects the prognosis of GC.