CA 19-9

Cancer antigen (CA) 19-9 is a protein on the surface of certain cells. CA 19-9 does not cause cancer; but it is produced by the tumour cells, making it useful as a tumour marker to follow the course of the cancer. CA 19-9 is elevated in most patients with advanced pancreatic cancer, but it may also be raised in other cancers and diseases such as bowel cancer, lung cancer and gall bladder cancer, as well as in benign diseases such as gall stones, pancreatitis, cystic fibrosis, and liver disease. Therefore elevated levels of CA 19-9 do not necessary mean the presence of pancreatic cancer. Very small amounts of CA19-9 may also be found in healthy patients.