Clinical Significance

Carcinoembryonic antigen (CEA) is a highly glycosylated molecule with a molecular weight of approximately 180 kDa. CEA, like AFP, belongs to the group of carcinofetal antigens that are produced during the embryonic and fetal period.

CEA has been postulated to play a role in a number of biological processes including cell adhesion, immunity and apoptosis. The formation of CEA is suppressed after birth and shows a low expression in normal adult tissues. Therefore, only very low CEA levels in the blood of healthy adults can be observed. The CEA gene family consists of about 17 active genes in two subgroups. The first group contains CEA and the nonspecific cross-reacting antigens (NCA); the second group contains the pregnancy‑specific glycoproteins (PSG).

High CEA concentrations are frequently found in cases of colorectal adenocarcinoma. Slight to moderate CEA elevations can also occur in non‑malignant diseases of the intestine, the pancreas, the liver, and the lungs (i.e. liver cirrhosis, chronic hepatitis, pancreatitis, ulcerative colitis, Crohn's Disease). Smoking can also lead to elevated CEA values and needs to be taken into account when interpreting CEA levels. CEA determinations are not recommended for cancer‑screening in the general population and CEA concentrations within the normal range do not exclude the possible presence of a malignant disease. The main indication for CEA determinations is the follow‑up and therapy‑management of colorectal carcinoma. 

_{Source: Roche cobas Elecsys CEA method sheet, V 4.0 2023-12}