Tumor markers are substances made in excess in the body when
cancer or a benign (harmless) condition is present. Tests done on blood or
other body fluids can find tumor markers.
Some tumor markers can
help the doctor diagnose certain cancers. And tumor markers often help the
doctor track a person's response to treatment. For example, a woman with
ovarian cancer may have a high CA 125 level when she is first diagnosed. After
treatment, her levels of CA 125 should fall. Then if her tumor marker level
goes up in the future, it could mean that the cancer has come back.
Some tumor markers help doctors choose the most effective treatment. For example, a person who has non-small cell lung cancer may have a tumor sample checked for the KRAS gene mutation to see if a certain kind of targeted therapy will work.
Tumor markers include:
ALK gene rearrangements. This is a marker for non-small cell lung cancer and anaplastic large cell lymphoma.
Cancer antigen 125 (CA 125). This is a marker for ovarian
Cancer antigen 15-3 (CA 153). This is a marker for breast
Carcinoembryonic antigen (CEA). This is a marker for
breast cancer and colorectal cancer.
Epidermal growth factor receptor (EGFR) mutation. This is a marker for non-small cell lung cancer.
KRAS mutation. This is a marker for colorectal cancer and non-small cell lung cancer.
antigen (PSA). This is a marker for prostate cancer.