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.