CA 19-9 is a tumor associated antigenic determinant (1116NS19-9), without a specific organ.
CA 19-9 is an oligosaccharide epitope present in tissues as a monosialogangliozid (glycolipid) in serum as a carbohydrate-rich mucin with a molecular weight of over 1000kDa.
CA 19-9 was first isolated in 1979 from colorectal carcinoma (Kaprowski).
CA 19-9 is a derivative of the Lewis blood group system. People with Le a-/b- group (7-10% of the population) are genetically unable to synthesize CA 19-9, with sialil-transferase deficiency, important for the expression of an epitope of CA 19-9 and fucozilat precursor.
CA 19-9 is normally found in fetal epithelial cells in the stomach, intestine, liver, pancreas. The adult is found in small amounts in the pancreas, liver, gallbladder, lung, and as an important component of many mucous cells and their secretory products, in healthy individuals, values exceed 100,000 CA 19-9 U / ml in milk sputum, saliva, bronchial secretions, semen, cervical mucus, gastric secretions, amniotic fluid, urine, fluid from ovarian cysts. For this reason, great attention should be paid to avoid contamination of samples.
The reference levels for CA 19-9 is 37 U / ml.
CA 19-9 is a primary marker in pancreatic carcinoma (80% of cases), in which there is a good correlation between serum levels and tumor size. Combination of CA 19-9 with CEA cause an increase in sensitivity with only 5-7%.
CA 19-9 can be used as a secondary marker (after carcino embryonic antigen (CEA)) in biliary carcinomas (40%), colorectal (45%), liver metastases, gastric carcinoma (50-70%) - although recent recommendations are CEA and CA 72-4 assessment. Increases were also reported CA 19-9 in lung cancer, breast, ovarian (mucinous type), cancer.
If untreated cancer, CA 19-9 level increased exponentially to> 1000 U / ml to> 10,000 U / ml. After complete resection of the tumor, the levels normalized in 2-4 weeks. In case of Racadau or metastases, CA 19-9 can determine the diagnosis early. Levels of over 10,000 U / ml indicates the presence of marrow metastases.
Slightly elevated levels (100-500 U / ml) and appear in different transient benign: gastro-intestinal inflammation, bile duct stones, cholecystitis, obstructive jaundice, chronic hepatitis, cirrhosis, acute or chronic pancreatitis, cystic fibrosis, rheumatoid.