What are breast cancer tumor markers?
Tumor markers are proteins or other substances in the body that help reveal the presence of certain forms of cancer. Markers for breast cancer may help in diagnosis of the disease, as well as determining its outlook and the course of treatment.The FactsAccording to the National Cancer Institute, tumor markers are found in tumors or other tissues, as well as in blood or urine. Typically, doctors uncover these markers by exposing them to man-made antibodies that react to their presence.HER2The protein HER2 appears in elevated levels in roughly one-fifth of all breast cancer patients. It triggers growth in breast cancer cells, and breast cancers that are susceptible to its influence (HER2-positive cancers) have higher rates of growth and spread than non-susceptible cancers.Estrogen and Progesterone ReceptorsBreast tumors may also contain markers called estrogen (ER-positive) receptors and progesterone (PR-positive) receptors. Cancers with these receptors frequently grow slowly and provide