MUC16 and digestive system neoplasm: Serum tumor markers (TMs) are commonly used for aid in evaluating diagnosis, prognosis, and treatment response in different types of malignant neoplasms.10,11 Three TMs have been well established in gastrointestinal cancers: carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA19-9), and cancer antigen 125 (CA125).12,13,14 These TMs have been associated with metastatic dissemination of tumor cells.15,16,17 While serum markers have been useful in detecting gastrointestinal tumors, there is a lack of information regarding their efficacy in patients with AA.