The diagnostic and prognostic utility of prostate-specific antigen for diseases of the breast

Although prostate-specific antigen (PSA) is the most valuable tumor marker for the diagnosis and management of prostate carcinoma, it is widely accept ed that PSA is not prostate specific. Numerous studies have shown that PSA is present in some female hormonally regulated tissues, principally the bre ast and its secretions. In this review, we summarize the findings of PSA in the breast, and focus on its potential for clinical applications in breast disease. PSA is produced by the majority of breast tumors and is a favorab le indicator of prognosis in breast cancer. Low levels of PSA are released into the female circulation, and while the level of serum PSA is elevated i n both benign and malignant breast disease, the molecular form of circulati ng PSA differs between women with and without breast cancer. These findings indicate that PSA may have potential diagnostic utility in breast cancer. PSA may also have a clinical application in benign breast disease, as both the level and molecular form of PSA differ between Type I and II breast cys ts. High levels of PSA have been reported in nipple aspirate fluid (NAF) an d recent studies have shown that the concentration of PSA in NAF is inverse ly related to breast cancer risk, indicating that NAF PSA may represent a c linical tool for breast cancer risk assessment. Thus, PSA represents a mark er with numerous potential clinical applications as a diagnostic and/or pro gnostic tool in breast disease.