As the patient underwent palliative gastrectomy with a high postoperative tumor burden, pre-chemotherapy tumor markers showed elevated levels of carcinoembryonic antigen (CEA, 540.60 ng/mL) (Figure 1A, July 6, 2021) and cancer antigen 125 (CA125, 50.4 U/mL) (Figure 1B, July 6, 2021), while cancer antigen 19-9 (CA19-9, 6.89 U/mL) (Figure 1C, July 6, 2021) remained within the normal range. Here, CEACAM5 is linked to neoplasm.