CA19-9

CA19-9

Structure of Sialyl Lewis A, the antigen recognized by CA19-9

CA19-9, also known as carbohydrate antigen 19-9, is a tumor marker primarily used in the management of pancreatic cancer. It is a type of glycoprotein that is expressed on the surface of certain cancer cells and can be detected in the blood of patients.

Structure and Biochemistry

CA19-9 is a sialylated Lewis antigen, specifically known as Sialyl Lewis A. It is a tetrasaccharide that is attached to proteins and lipids on the cell surface. The structure of Sialyl Lewis A is crucial for its role in cell-cell recognition and adhesion processes.

Clinical Use

CA19-9 is primarily used as a biomarker in the diagnosis and management of pancreatic cancer. It is not used for screening due to its lack of specificity and sensitivity. However, it is valuable in monitoring the response to treatment and in detecting recurrence of the disease.

Pancreatic Cancer

In patients with pancreatic adenocarcinoma, elevated levels of CA19-9 can indicate the presence of the disease. However, not all patients with pancreatic cancer will have elevated CA19-9 levels, and some benign conditions can also cause elevated levels.

Other Cancers

CA19-9 can also be elevated in other types of cancer, such as colorectal cancer, gastric cancer, and hepatobiliary cancer. Its role in these cancers is less well-defined compared to pancreatic cancer.

Limitations

CA19-9 is not a perfect marker. It can be elevated in benign conditions such as cholangitis, cirrhosis, and pancreatitis. Additionally, about 5-10% of the population are Lewis antigen-negative and do not produce CA19-9, even if they have cancer.

Related Pages

• Pancreatic cancer
• Tumor marker
• Glycoprotein
• Biomarker