Immunological detection of metastases from prostatic adenocarcinoma

In six patients with known prostatic adenocarcinoma, extraprostatic (metastatic) tumor was suspected on radiographic or radionucleotide studies. When cytological examination of tissue obtained by needle aspiration or biopsy was nondiagnostic, radial gel immunodiffusion was used to identify the presence of prostatic acid phosphatase in the tissue. Four specimens demonstrated prostate-specific acid phosphatase activity, permitting the diagnosis of metastatic prostatic adenocarcinoma. The technique is simple and highly specific.