Immunohistochemical evaluation of prostatic carcinoma before and after radiotherapy.

Immunohistochemical procedures were applied to the examination of human tissues for prostatic acid phosphatase. With antisera against purified human prostatic acid phosphatase 173 normal and neoplastic tissues were tested. Samples of 45 non-prostatic carcinomas and their respective normal tissues were negative. Of 4 seminal vesicles studied 2 showed weak reactivity. The epithelial cells of normal prostatic acini were uniformly positive in 25 patients studied. In contrast to normal prostatic tissue the malignant acini in 53 of 55 patients with prostatic carcinoma had variable but positive reactivity. Of 27 patients receiving radiotherapy for adenocarcinoma of the prostate variable staining was observed in the neoplastic cells of 24, 8 to 52 months after treatment. The continued production of prostatic acid phosphatase in the malignant cells after radiotherapy suggests that they also may maintain metabolic activities necessary for growth and metastasis.