In this work, CDX2 and mucin (CD10, MUC2, MUC5AC, and MUC6) protein expressions were studied in a prospective evaluation cohort of patients with stage II/III gastric adenocarcinoma, and compared with survival, clinicopathologic variables, and benefits from fluorouracil‐based adjuvant chemotherapy in these patients. This evidence concerns the gene MUC5AC and gastric adenocarcinoma.