Abstract
Thirty-seven specimens of benign and malignant prostatic tumors were studied for the localization of tissue polypeptide antigen (TPA) by an avidin-biotin-peroxidase complex technique. In addition, 23 metastases of prostatic carcinoma in other organs and 12 nonepithelial tumors of prostate also were studied. All benign and malignant tumors of epithelial origin, including their metastasis, stained positively. Nonepithelial tumors were uniformly negative. In the metastatic lesions, small foci of tumor cells and even single tumor cells could be identified by TPA staining. Immunohistochemical localization of TPA appeared to be a useful tool for assessing the micrometastases of prostatic carcinoma in other organs, especially lymph nodes, or elucidating the epithelial origin of an otherwise undifferentiated prostatic cancer.