Carcinoembryonic Antigen (CEA)

CEA is a protein normally produced during fetal development that can reappear in the blood of adults with certain cancers. Doctors measure it as a tumor marker to help evaluate, monitor, or follow treatment response in cancers of the colon, lung, breast, pancreas, and stomach. It is not a screening test and cannot diagnose cancer on its own.

Origin

CEA was discovered in 1965 by Phil Gold and Samuel O. Freedman at McGill University, who identified it in colon cancer tissue and fetal gut. They named it "carcinoembryonic" because it appears in both carcinoma (cancer) and embryonic tissue.

Significance in Asbestos Context

CEA has a specific and often overlooked role in the workup of asbestos-related disease: it helps distinguish mesothelioma from metastatic adenocarcinoma in the chest. Mesothelioma cells typically do NOT produce CEA (blood and tissue stains are usually negative), while lung, colon, and other adenocarcinomas that have spread to the pleura usually do. A low or negative CEA, combined with positive mesothelial markers, supports a mesothelioma diagnosis, which directly affects prognosis, treatment, and the legal value of an asbestos claim. CEA may also be tracked during treatment of an asbestos-related lung cancer to gauge response.

Example Sentence

"The pathologist noted that the pleural biopsy was CEA-negative and calretinin-positive, supporting a diagnosis of epithelioid mesothelioma rather than metastatic lung adenocarcinoma."

Related Terms

Tumor Marker, Immunohistochemistry, Calretinin, Mesothelioma, Adenocarcinoma, Differential Diagnosis

Notes

• Ask your pathologist whether CEA staining was part of the immunohistochemistry panel used to confirm or rule out mesothelioma. This is standard practice and the result should appear in your pathology report.
• Request a complete copy of your pathology and immunohistochemistry reports; the specific markers tested (CEA, calretinin, WT-1, TTF-1, BerEP4, others) can be central evidence in an asbestos claim.
• CEA can be elevated in smokers and in non-cancer conditions (inflammatory bowel disease, liver disease, pancreatitis), so a single number is rarely meaningful on its own. Trends over time matter more.
• If CEA is being used to monitor treatment, ask your oncologist what baseline value they are tracking from and what change would prompt new imaging.