The immunochemical complexity of CEA: a golden dream or molecular nightmare?

Carcinoembryonic antigen is only a tumor assoicated antigen and is less clinically useful than the original report suggested. However, the CEA assays in clinical use utilize reagents operationally defined by old criteria. There is now abundant evidence that "CEA" consists of a heterogenous family of related glycoproteins with shared, as well as distinctive, antigenic determinants. Antigenic differences can be demonstrated between some cancer sera "CEA" and various operationally defined tissue "CEA" preparations. Further definition of the biochemical and antigenic characteristics of serum and tumor tissue "CEA" is required in order to determine whether a more tumor specific antigenic determinant can be identified.