Prostate specific antigen in the female body: its role in breast cancer prognosis.

Prostate-specific antigen, a 33 kDa serine protease, is found at high concentrations in seminal plasma and prostate epithelial cells. It is currently used for the diagnosis and monitoring of prostate carcinoma. However, several investigators have demonstrated nonprostatic sources of prostate specific antigen, including amniotic fluid, breast milk, breast cyst fluid, nipple aspirate fluid, and breast tumor cytosol. Studies have revealed that a high prostate-specific antigen level in tumors of women with breast cancer is associated with good prognosis. This finding is analyzed in this manuscript.