CEACAM5 and rectal cancer: The prognosis of rectal cancer is associated with many factors, such as TNM staging, histological differentiation, extramural vascular invasion (EMVI), circumferential margin (CRM) involvement, range of tumor involvement in the circumference lumen (TIL) and tumor markers including carcinoembryonic antigen (CEA) and cancer antigen 19-9 (CA19-9) (3–7).