CEA is used as a general cancer/tumor marker for several forms of cancer, including colon, cancers of the rectum, lung, breast, liver, pancreas, stomach, and ovary. Not all cancers produce CEA, and a positive CEA test is not always due to cancer. Smokers will have an elevated CEA. A positive CEA is a warning to have additional tests to rule out cancer. Helpful when considering hormone/anabolic therapy for anti-aging patients.