The carcinoembryonic antigen (CEA) is produced by tumours arising from specific types of tissue (endodermal tissue). Its presence in blood can be measured and the normal value is less than 2.5 µg/L.
Higher levels occur in patients who may have colorectal cancer, stomach cancer, thyroid gland cancer, breast cancer, lung cancer, cervix cancer, testicular cancer (a seminoma), cancer of the pancreas, liver cancer (hepatoma), cirrhosis of the liver or are heavy smokers. False positive results are common. It is a useful to follow the progress of cancer therapy, but the test is not for diagnosis or screening of cancer.