Carcinoembryonic antigen (CEA) describes a set of highly-related
glycoproteins involved in
cell adhesion. CEA is normally produced in gastrointestinal tissue during fetal development, but the production stops before birth. Consequently, CEA is usually present at very low levels in the blood of healthy adults (about 2–4 ng/mL).[2] However, the serum levels are raised in some types of cancer, which means that it can be used as a
tumor marker in
clinical tests. Serum levels can also be elevated in heavy
smokers.[3]
CEA was first identified in 1965 by
Phil Gold,a
Canadian physician, scientist and professor and
Samuel O. Freedman who is also a Canadian professor of immunology in human
colon cancer tissue extracts.[7]
Diagnostic significance
The CEA blood test is not reliable for diagnosing cancer or as a screening test for early detection of cancer.[8] Most types of cancer do not result in a high CEA level.[9]
CEA elevation is known to be affected by multiple factors. It varies inversely with tumor grade; well-differentiated tumors secrete more CEA. CEA is elevated more in tumors with lymph node and distant metastasis than in organ-confined tumors and, thus, varies directly with tumor stage. Left-sided tumors generally tend to have higher CEA levels than right-sided tumors.[16] Tumors causing bowel obstruction produce higher CEA levels.[16] Aneuploid tumors produce more CEA than diploid tumors.[17] Liver dysfunction increases CEA levels as the liver is the primary site of CEA metabolism.[3]
Antibodies
An anti-CEA antibody is an
antibody against CEA. Such antibodies to CEA are commonly used in
immunohistochemistry to identify cells expressing the glycoprotein in tissue samples. In adults, CEA is primarily expressed in cells of tumors (some malignant, some benign) [19] but they are particularly associated with the
adenocarcinomas, such as those arising in the colon, lung, breast, stomach, or pancreas. It can therefore be used to distinguish between these and other similar cancers. For example, it can help to distinguish between adenocarcinoma of the lung and
mesothelioma, a different type of lung cancer which is not normally CEA positive. Because even
monoclonal antibodies to CEA tend to have some degree of cross-reactivity, occasionally giving
false positive results, it is commonly employed in combination with other immunohistochemistry tests, such as those for
BerEp4,
WT1, and
calretinin.[20] For cancers that highly express CEA, targeting CEA through radioimmunotherapy is one of the therapy approaches.[21] Engineered antibodies such as single-chain Fv antibodies (sFvs) or bispecific antibodies have been used for targeting and therapy of CEA expressing tumors both in vitro and in vivo with promising results [22][23]
Regions of high CEA levels in the body can be detected with the
monoclonal antibodyarcitumomab.[24]
Genetics
CEA and related
genes make up the CEA family belonging to the
immunoglobulin superfamily.
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^Duffy MJ, van Dalen A, Haglund C, Hansson L, Klapdor R, Lamerz R, Nilsson O, Sturgeon C, Topolcan O (April 2003). "Clinical utility of biochemical markers in colorectal cancer: European Group on Tumour Markers (EGTM) guidelines". European Journal of Cancer. 39 (6): 718–27.
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^Ballesta AM, Molina R, Filella X, Jo J, Giménez N (1995). "Carcinoembryonic antigen in staging and follow-up of patients with solid tumors". Tumour Biology. 16 (1): 32–41.
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^Maestranzi S, Przemioslo R, Mitchell H, Sherwood RA (January 1998). "The effect of benign and malignant liver disease on the tumour markers CA19-9 and CEA". Annals of Clinical Biochemistry. 35 ( Pt 1) (1): 99–103.
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^Sajid KM, Parveen R, Durr-e-Sabih, Chaouachi K, Naeem A, Mahmood R, Shamim R (December 2007). "Carcinoembryonic antigen (CEA) levels in hookah smokers, cigarette smokers and non-smokers". The Journal of the Pakistan Medical Association. 57 (12): 595–9.
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^Goldstein MJ, Mitchell EP (2005). "Carcinoembryonic antigen in the staging and follow-up of patients with colorectal cancer". Cancer Investigation. 23 (4): 338–51.
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^Rodriguez-Bigas, Miguel A.; Lin, Edward H.; Crane, Christopher H. (2003),
"Tumor Markers", Holland-Frei Cancer Medicine. 6th edition, BC Decker, retrieved 2023-10-13
^Kankanala, Vijaya L.; Mukkamalla, Shiva Kumar R. (2023),
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^Leong AS, Cooper K, Leong FJ (2003). Manual of Diagnostic Cytology (2ND ed.). Greenwich Medical Media, Ltd. pp. 51–52.
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^Wong, JY; Chu, DZ; Williams, LE; Liu, A; Zhan, J; Yamauchi, DM; Wilczynski, S; Wu, AM; Yazaki, PJ; Shively, JE; Leong, L; Raubitschek, AA (April 2006). "A phase I trial of (90)Y-DOTA-anti-CEA chimeric T84.66 (cT84.66) radioimmunotherapy in patients with metastatic CEA-producing malignancies". Cancer Biotherapy & Radiopharmaceuticals. 21 (2): 88–100.
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^Chester, Kerry A.; Mayer, Astrid; Bhatia, Jeetendra; Robson, Lynda; Spencer, Daniel I. R.; Cooke, Stephen P.; Flynn, Aiden A.; Sharma, Surinder K.; Boxer, Geoffery; Pedley, R. Barbara; Begent, Richard H. J. (19 July 2000). "Recombinant anti-carcinoembryonic antigen antibodies for targeting cancer". Cancer Chemotherapy and Pharmacology. 46 (S1): S8–S12.
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^Cheng KT (2013).
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^Hammarström S (April 1999). "The carcinoembryonic antigen (CEA) family: structures, suggested functions and expression in normal and malignant tissues". Seminars in Cancer Biology. 9 (2): 67–81.
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