CEACAM5 and neoplasm: A well-known method to monitor cancer is the screening of serum tumor markers.24–26 Nowadays, there are various tumor markers (e.g., AFP, PSA, CA-125, HCG, CA-15-3, and CA19-9) available in routine clinical use for diagnosis.27 Among all the tumor markers, CEA is approved by the US Food and Drug Administration (FDA) and is an established tumor-associated antigen (TAA).13,28 According to Zhu and Basu et al., CEA a glycoprotein with a molecular weight of about 180–200 kDa, comes from the CEA-related cell-adhesion (CEACAM) superfamily.