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.
Tumor markers include:
- Cancer antigen 15-3 (CA 153). This is a marker for breast
cancer.
- Cancer antigen 125 (CA 125). This is a marker for ovarian
cancer.
- Carcinoembryonic antigen (CEA). This is a marker for
gastrointestinal tract cancer, among others.
- Prostate-specific
antigen (PSA). This is a marker for prostate cancer.