This test measures the amount of the protein CA 125 (cancer antigen 125) in the blood. The test may be used to look for early signs of ovarian cancer.
Cancer Antigen 15.3 is a protein that is elevated in the blood in some people with breast cancer.
Cancer antigen 19.9 is a protein that exists on the surface of certain cancer cells. High levels of CA 19.9 are often a sign of pancreatic cancer.