A cancer antigen 125 (CA-125) is a protein found on the surface of many ovarian
cancer cells. It also can be found in other cancers and in small amounts in
normal tissue. A CA-125 test measures the amount of this protein in the blood.
CA-125 is used as a tumor
marker-which means the test can help show if some types of cancer are present.
Most often, the CA-125 test is used to check how well treatment for ovarian
cancer is working or to see if ovarian cancer has returned.
cancer cells. It also can be found in other cancers and in small amounts in
normal tissue. A CA-125 test measures the amount of this protein in the blood.
CA-125 is used as a tumor
marker-which means the test can help show if some types of cancer are present.
Most often, the CA-125 test is used to check how well treatment for ovarian
cancer is working or to see if ovarian cancer has returned.