Stains & CD markers
CA 19-9
Copyright: 2018-2024, PathologyOutlines.com, Inc.
PubMed Search: CA 19-9 stain
CA 19-9
Author: Nat Pernick, M.D.
Last author update: 1 August 2018
Last staff update: 23 June 2021
Copyright: 2018-2024, PathologyOutlines.com, Inc.
PubMed Search: CA 19-9 stain
Table of Contents
Definition / general | Terminology | Pathophysiology | Prognostic factors | Clinical features | Microscopic (histologic) images | Positive staining - normalCite this page: Pernick N. CA 19-9. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/stainsca19-9.html. Accessed December 22nd, 2024.
Definition / general
- Modified Lewis(a) blood group antigen secreted by or expressed on the surface of cancer cells
- Used primarily as a serum tumor marker to screen for pancreatic cancer and to monitor effectiveness of therapy
- However, only 50 - 75% sensitive for initial screening of pancreatic cancer and relatively nonspecific
Terminology
- Carbohydrate Antigen 19-9
Pathophysiology
- Synthesis strongly depends on tissue specific and epigenetically regulated expression of B3GALT5 and ST3GAL (Biochim Biophys Acta 2017;1861:3210)
- Acquires tumor marker properties in pancreas due to its reabsorption into vessels and elevation in serum
- May play an active role in metastatic spread of cancer by facilitating the adhesion of cancer cells to platelets, endothelium and leukocytes (Pathol Res Pract 2000;196:259, Acta Biochim Pol 2002;49:303, J Biol Chem 2008;283:15647)
Prognostic factors
- Negative staining may be favorable in medullary thyroid cancer (Endocr Pract 2015;21:590)
- High preoperative serum levels are a poor prognostic factor for pancreatic cancer (Hepatogastroenterology 1998;45:253)
Clinical features
- Used primarily as a serum biomarker
- As a serum screening test for pancreatic cancer, is more sensitive than CEA but less sensitive than CXCL8 (Pol Arch Intern Med 2018 Jul 27 [Epub ahead of print])
- Used to screen for pancreatic cancer but has limited sensitivity and specificity
- May also be elevated in patients with cholangiocarcinoma or colon cancer
- Serum levels also elevated in cirrhosis, cholestasis and pancreatitis but values are usually below 1,000 U/mL.
- Note: individuals that are Lewis negative (5 - 7% of population) do not express CA 19-9 due to the lack of the enzyme fucosyltransferase needed for CA 19-9 production; as a result, a low or undetectable serum CA 19-9 concentration is not informative regarding cancer recurrence (Mayo Clinic: CA19 [Accessed 10 September 2018])
- Medullary thyroid carcinoma:
- Serum testing is routinely used in diagnosis and followup (J Clin Endocrinol Metab 2005;90:6077, Eur J Endocrinol 2008;158:239)
- Detected in 6% of pathologic specimens (Endocr Pract 2015;21:590)
- Lung adenocarcinoma associated malignant pleural effusions:
- Highly specific (98%) to differentiate from benign effusions but only 55% sensitive (Pathology 2015;47:123)
Microscopic (histologic) images
Images hosted on other servers:
Medullary thyroid cancer
Positive staining - normal
- Placenta (Eur J Gynaecol Oncol 2012;33:281)
