carcinoembryonic antigen
Meaning of carcinoembryonic antigen: Carcinoembryonic antigen is a blood protein used as a tumor marker, most established for monitoring colorectal cancer after treatment.
Definition of carcinoembryonic antigen
Carcinoembryonic antigen is a protein that can be measured in the blood and is used mainly as a tumor marker for colorectal cancer. Blood levels are often measured before treatment to establish a baseline and afterward to help monitor for cancer recurrence, since a rising level over time can suggest that cancer has returned or progressed.
Carcinoembryonic antigen levels can also be elevated in several other cancers and in certain noncancerous conditions, including some liver and digestive disorders, and levels tend to run higher in people who smoke. Because of this, an elevated result on its own does not confirm cancer, and a normal result does not rule it out.
Carcinoembryonic antigen is therefore generally used alongside other testing and imaging rather than as a stand-alone screening test, and its greatest usefulness lies in tracking changes in level over time in someone already diagnosed with a cancer known to produce it.
Also known as
Used in a sentence
Carcinoembryonic antigen levels were monitored periodically after treatment to help detect a possible recurrence.
Good to know
An elevated carcinoembryonic antigen level does not confirm cancer by itself, since smoking and several noncancerous conditions can also raise it, so the test is generally used to track change over time rather than as a stand-alone diagnostic result.
Word origin
Where “carcinoembryonic antigen” comes from
Formed from Greek karkinos, meaning crab, the root of carcinoma, and embryonic, from Greek embryon, meaning embryo, combined with antigen, from Greek anti-, meaning against, and -gen, meaning producing.