abbreviation for cancer antigen 19-9 antigen, a blood tumor marker for pancreatic, hepatobiliary and colorectal cancer. This tumor marker is used in diagnosis, evaluation of a patient's response to treatment, and surveillance of the disease.
CA 19-9A tumour-associated carbohydrate antigen located on the sialylated Lewis A blood group antigen (individuals who are genotypically Lewis a-b-[Lea-b-] comprise 5% of the population and cannot synthesize the antigen).
> 37 U/mL occur in 72–100% of patients with pancreatic cancer; 97% of those with levels > 1000 U/m; 65% of those with hepatocellular carcinoma; 20+% of those with gastric cancer; 20% of those with colorectal cancer. Because CA19-9 is also elevated in benign conditions (e.g., obstructive jaundice, liver disease, acute and chronic pancreatitis, diabetes, interstitial lung disease, collagen vascular disease, cholecystitis and cirrhosis of the liver), it is not widely used as a cancer marker. At one time it was regarded as useful in differentiating mesothelioma (in which it is negative) from various adenocarcinomas (in which it is positive).
CA 19-9 (Cancer antigen 19-9)
A tumor marker associated with pancreatic cancer.
Mentioned in: Tumor Markers