Carcinoembryonic antigen (CEA) describes a set of highly-related glycoproteins involved in cell adhesion.

CEA is normally produced in gastrointestinal tissue during fetal development, but the production stops before birth.

[14] Elevated CEA levels should return to normal after successful surgical removal of the tumor and can be used in follow up, especially of colorectal cancers.

Such antibodies to CEA are commonly used in immunohistochemistry to identify cells expressing the glycoprotein in tissue samples.

In adults, CEA is primarily expressed in cells of tumors (some malignant, some benign) [19] but they are particularly associated with the adenocarcinomas, such as those arising in the colon, lung, breast, stomach, or pancreas.

Because even monoclonal antibodies to CEA tend to have some degree of cross-reactivity, occasionally giving false positive results, it is commonly employed in combination with other immunohistochemistry tests, such as those for BerEp4, WT1, and calretinin.

[25] The following is a list of human genes which encode carcinoembryonic antigen-related cell adhesion proteins:

The results were promising but a number of patients demostrated immune responses and they had to withdraw from participating in the clinical trial.

M5A-DOTA was coupled with 225-Ac , which is an alpa emitter, and an in vivo study was performed where cytokine therapy was combined with a-therapy.