Immunohistochemical analysis of prostate specific antigen in breast cancer

The presence of immunoreactive prostate-specific antigen (IR-PSA) has been reported in breast cancers and has been suggested to confer a positive prog nosis. However, recent large, well-controlled studies have found no signifi cant prognostic value when IR-PSA positivity is examined as an independent variable, even when ultrasensitive immunofluorometric techniques are utiliz ed. The present study, using indirect immunohistochemistry on 75 formalin-f ixed, paraffin-embedded breast cancers shows PSA immunoreactivity in only s even of 75 cases (9%), suggesting that PSA positivity in breast carcinoma i s not useful as a prognostic or tumor marker with hospital-based methods.