Immunohistochemical demonstration of prostate-specific antigen in metastases with the use of monoclonal antibody F5.

With the use of a murine monoclonal antibody (F5), a panel of metastatic tumors was evaluated for the expression of prostate-specific antigen (PA) under immunoperoxidase staining procedures. Specimens studied included 25 of prostatic origin and 73 originating from nonprostatic primary sites. Regardless of the site of dissemination or the malignancy grade, all metastases from the prostate were antibody-reactive. In contrast, nonprostatic metastases were negative in each case, including those originating from other genitourinary neoplasms. Thus, PA expression as detected with monoclonal antibody F5 is a stable characteristic of disseminated prostatic tumors.