CA 19-9 (carbohydrate antigen 19-9) is a tumor marker used mainly in the diagnosis of pancreatic cancer . It is a glycoprotein with a molecular weight of about 1000 kDa. Normally, it is produced by epithelial cells of the digestive tract of the fetus, in adults it can be excreted in small quantities. [one]
Content
History
CA 19-9 was first detected in the blood of patients with cancer of the colon and pancreas in 1981. [2]
Diagnostic Importance
CA 19-9 does not have sufficient specificity and sensitivity, which is why it is not recommended for screening pancreatic cancer in healthy people. [3] Both false positive and false negative test results are frequent. Nevertheless, the marker is well suited for tracking the dynamics of tumor development and differential diagnosis of pancreatic volumetric formations (for example, detected by ultrasound). [one]
Elevated levels of CA 19-9 in patients with colon cancer have poor prognostic value. Although the increase level is not directly related to the mass of the tumor, values of more than 10,000 U / ml indicate the presence of metastases.
The excretion of CA 19-9 from the body occurs through the biliary tract, so any difficulty in the outflow of bile is accompanied by an increase in its level. In these cases, to clarify the diagnosis, indicators of gammaglutamine transferase and alkaline phosphatase are used.
Marker CA 19-9 allows you to evaluate the possibility of tumor resection and the likelihood of relapse. At a concentration of more than 1000 U / ml, the tumor is operable in 5% of patients. At a concentration of less than 1000 U / ml, the tumor can be removed in 50% of patients. If within 1-7 months after surgery, the level of CA 19-9 increases, this indicates the likelihood of a tumor recurrence. Almost all patients with very high levels of CA 19-9 (more than 10,000 units / ml) have distant metastases.
Limitations
Marker CA 19-9 can increase not only with cancer of the pancreas, but also with cancer of the colon, esophagus, hepatocellular carcinoma. [1] In the absence of cancer, elevated levels of CA 19-9 can be observed with pancreatitis, cirrhosis, bile duct disease, and bile duct obstruction. [four]
In people with a lack of Lewis antigen (protein on the surface of red blood cells), which include about 10% of white-skinned people, CA 19-9 is not expressed even with large tumors [4] [3] . This is due to a deficiency of the fucosyltransferase enzyme necessary for the synthesis of CA 19-9 protein and Lewis antigen.
Literature
- Kamyshnikov V.S. Oncomarkers: determination methods, reference values, interpretation of tests. - M .: MEDpress-inform, 2011.
Links
- Oncomarkers review article . (Russian)
- Pancreatic cancer . (Russian)
Notes
- ↑ 1 2 3 Perkins, G .; Slater, E .; Sanders, G .; Prichard, J. Serum tumor markers. Am Fam Physician. 2003 Sep 15; 68 (6): 1075-82.
- ↑ Koprowski H., Herlyn M., Steplewski Z., Sears HF Specific antigen in serum of patients with colon carcinoma (Eng.) // Science: journal. - 1981. - Vol. 212 , no. 4490 . - P. 53-5 . - DOI : 10.1126 / science.6163212 . - PMID 6163212 .
- ↑ 1 2 Locker G., Hamilton S., Harris J., Jessup J., Kemeny N., Macdonald J., Somerfield M., Hayes D., Bast R. ASCO 2006 update of recommendations for the use of tumor markers in gastrointestinal cancer (English) // J. Clin. Oncol. : journal. - 2006. - Vol. 24 , no. 33 . - P. 5313-5327 . - DOI : 10.1200 / JCO.2006.08.2644 . - PMID 17060676 .
- ↑ 1 2 Goonetilleke KS, Siriwardena AK Systematic review of carbohydrate antigen (CA 19-9) as a biochemical marker in the diagnosis of pancreatic cancer (English) // Eur J Surg Oncol: journal. - 2007 .-- April ( vol. 33 , no. 3 ). - P. 266-270 . - DOI : 10.1016 / j.ejso.2006.10.004 . - PMID 17097848 .