Markers in breast cancer.

A large number of markers associated with breast cancer have been tested for potential usefulness in the initial diagnosis, the evaluation of prognosis, the detection of recurrence and the assessment of response to therapy. Useful but limited information has been obtained in some of the cases by measuring the levels of a number of markers such as carcinoembryonic antigen, ferritin and haptoglobin. None of the known markers are specific for breast cancer and no single marker is elevated in all patients with advanced disease. Studies with multiple markers may provide better coverage. A great deal of attention is being focused on the level of immune complexes that are found in 30 to 50% of the patients. It has been claimed that immune complex levels tend to rise in patients with advanced disease, but these claims await further confirmation. The only makers likely to be useful for early diagnosis are tumor-associated antigens (TAA). Several putative TAA have been identified, but clinical trials employing TAA are still a long way off. Identification of breast cancer TAA may be facilitated by current analyses of immune complexes isolated from patients. Preliminary results of such analyses suggest that immune complexes recovered from patients with breast cancer may contain antigens not present in patients with nonmalignant diseases.