Gosset Molecular Classification
Carbohydrate antigen, Glycan, Tumor marker
Other Names
cancer antigen 19-9, sialyl-Lewis A
Disease Roles
Carbohydrate Antigen 19-9 Overview
Carbohydrate antigen 19-9 (CA 19-9) is a tetrasaccharide carbohydrate antigen, specifically the sialylated form of the Lewis A blood group antigen (sialyl-Lewis A). It is produced by ductal cells of the pancreas and biliary system, and also expressed by epithelial cells in the stomach, colon, uterus, salivary glands, liver, and gallbladder. CA 19-9 functions as a ligand for endothelial E-selectin, facilitating hematogenous metastasis in cancer. Clinically, CA 19-9 is used as a tumor marker, primarily for pancreatic ductal adenocarcinoma (PDAC), to monitor treatment response and detect recurrence. However, it is not suitable as a screening tool due to false positives/negatives and genetic variations affecting production.
Mechanism of Action
Biological Functions
Cell adhesion
Cell-to-cell recognition
Ligand for E-selectin
Hematogenous metastasis
Disease Associations
Cancer
Pancreatic cancer
Biliary tract cancers
Gastrointestinal cancers
Liver disease
Inflammation
Pancreatitis
Safety Considerations
- False positives in benign conditions
- False negatives in Le(a-b-) individuals
- Not diagnostic alone
Associated Biomarkers
| Biomarker |
|---|
| Pancreatic cancer |
| Biliary tract cancers |
| Gastrointestinal cancers |
| Treatment response monitoring |
| Recurrence detection |
| Prognosis |