CEACAM5 and Familial adenomatous polyposis: We investigated a total of 300 patients who underwent preoperative CEA and CA19-9 measurement and met our inclusion criteria: i) BMI>16 kg/m2, ii) no history of malignant disease, inflammatory bowel disease, renal insufficiency requiring hemodialysis, advanced stage of liver cirrhosis, cancer of mucinous or squamous histology, familial adenomatous polyposis, or synchronous colon cancer, and iii) complete clinical data.