DETECTION OF PROSTATE-SPECIFIC ANTIGEN MESSENGER-RNA AND PROTEIN IN BREAST-TUMORS

We have developed reverse transcription-polymerase chain reaction (RT- PCR) methods for detecting prostate-specific antigen (PSA) mRNA. Using these methods, and a highly sensitive immunofluorometric assay for me asuring PSA protein, we have assessed the concentrations of PSA mRNA. and PSA protein in 30 primary breast tumors and a few other control ti ssues. We found good agreement between presence of PSA protein and PSA mRNA in breast tumors. We thus propose that, in women, detection of P SA protein or PSA mRNA in tissues and tumors offers equivalent informa tion. Because PSA protein is present in male blood and thus could cont aminate extracts from tumors and tissues from men, we propose that the RT-PCR methods we describe be used to assess nonprostatic expression of the PSA gene in men.