Background: The Prostate Specific Antigen (PSA) has been characterized as a specific prostate marker. Recent studies have indicated the existence of a PSA of nonprostatic origin detected in lactating women and breast tumors.
Methods: We have evaluated the presence of PSA by an ultrasensitive assay (COBAS CORE) in 252 serum and non serum samples from women.
Results: The results demonstrate the presence of PSA in 100% of the breast secretions, 81% of the breast cysts, 80% of the bronchoalveolar lavage fluids and 71% of the cytosols of breast cancer. Likewise, PSA was detected in 14% of the sera evaluated, although the concentrations were always lower than 0.5 ng/ml.
Conclusions: We conclude that PSA should not continue being considered as the specific prostate tissue marker although, given that the serum concentrations detected are very low, they do appear to interfere to a minimum extent in the usefulness of PSA as a tumor marker.