Immunohistochemical demonstration of tumor-associated antigens in prostatic carcinomas of various histological differentiations

Prostate acid phosphatase (PAP), prostate-specific antigen (PSA), carcinoembryonic antigen (CEA) and keratin were determined immunohistochemically in paraffin sections from 64 prostatic carcinomas fixed in formalin according to the conventional method. The results obtained with PSA led to the correct diagnosis of prostatic carcinoma in 90.7% of the cases. 80.3% of the diagnoses obtained with PAP were correct. The intensity of the staining of the marker decreased with increasing differentiation. 3 utricular carcinomas were positive for PAP and PSA. CEA and keratin may be considered unspecific tumor markers only. However, metaplastic squamous epithelium from poorly differentiated carcinomas was always positive for keratin. PAP and PSA are also suitable for differentiating between tumors of prostatic and nonprostatic origin and could thus be successfully used to determine immunohistochemically the histogenesis of 15 invasive, poorly differentiated carcinomas of the prostate and bladder. PSA again proved to be a more specific epithelial marker than PAP.