Carcinoembryonic Antigen As a Marker for Colorectal Cancer: Is It Clinically Useful?(Minireview) (Clinical Report‪)‬

Carcinoembryonic antigen (CEA) was first described in 1965 by Gold and Freedman (1, 2), when they identified an antigen that was present in both fetal colon and colon adenocarcinoma but that appeared to be absent from healthy adult colon. Because the protein was detected in only cancer and embryonic tissue, it was given the name carcinoembryonic antigen, or CEA. Subsequent work showed that CEA, or at least a CEA-like molecule, was also present in certain healthy tissues, although concentrations in tumors were on average 60-fold higher than in the nonmalignant tissues (3). In one of the first reports on CEA in serum, Thomson et al. (4) found increased concentrations in 35 of 36 patients with colorectal cancer. In contrast, high values were not found in "normal" subjects, pregnant women, patients with nongastrointestinal cancers, or in patients with miscellaneous benign gastrointestinal diseases.