Biochemical markers in breast cancer: which ones are clinically useful?

Breast cancer is the most common neoplasm affecting women in the Western world with approximately 1 in 11 developing the malignancy and 1 in 30 dying from the disease. For optimum management of these patients, assay of certain biochemical markers is necessary. Clinically, the most useful markers in breast cancer are the estrogen and progesterone receptors that are used to predict response to hormone therapy. Both American and European Expert Panels have recommended routine determination of these steroid hormone receptors in all patients with breast cancer. For surveillance of patients with diagnosed breast cancer, both CA 15-3 and BR 27.29 can be used. Serial determinations of these markers have the potential to preclinically detect recurrent disease and monitor the treatment of advanced disease. However, the benefit of this monitoring on patient outcome or quality of life is not clear. New or potentially new markers for breast cancer include BRCA1 and BRCA2 for selecting patients at high risk of developing breast cancer, urokinase plasminogen activator and PA1-1 for assessing prognosis and HER-2 for predicting response to the therapeutic antibody, Herceptin.