Immunohistochemical acid phosphatase level and tumor grade in prostatic carcinoma.

An immunoperoxidase technique to detect prostatic-specific acid phosphatase (PSAP) was used on specimens from 98 cases of prostatic carcinoma that were graded by both the Gleason and the Mostofi systems, to see if tumor grade correlated with amount of PSAP seen in tissue. Most tumors showed strong, diffuse cytoplasmic staining; no significant difference was seen among the various grades. Other than focal, weak staining of renal tubular epithelium, the antibody to PSAP gave uniformly negative results with a variety of normal and neoplastic tissues. In light of the great sensitivity and specificity of this technique, it potential applications include diagnosis of poorly differentiated prostatic malignant neoplasms, whether primary or metastatic.