Serum prostatic acid phosphatase determination in prostatic diseases: a critical comparison of an enzymatic and a radioimmunologic assay

Evaluation of Specific Antigen and Prostatic Acid Phosphatase Specificity. Study of False Values

We assayed prostatic specific antigen (PSA) and prostatic acid phosphatase (PAP) serum levels in 1305 subjects without malignant prostatic pathology by double antibody RIA I125 to evaluate their specifity. When we set a second upper normal limit of 10 ng/ml for PSA and 2.5 ng/ml for PAP there was a significant increase of specificity. There were 2 and 3.7% false positive results in non-prostatic benign pathologies, 1.8 and 7.9% in non-prostatic malignant, 3.5 and 4.7% in non-complicated benign prostatic hypertrophy (BPH) and 3.3% for both in chronic prostatitis. In patients with complicated BPH and acute prostatitis the results were 64.8 and 24% for PSA and 20 and 16% for PAP. In conclusion, PSA is more specific than PAP in patients without acute inflammatory pathology of the prostate; the high rate of false positive values in the latter excludes its usefulness in these patients as diagnostic tumoral markers.

Significance of serum protein and lipid-bound sialic acid as a marker for genitourinary malignancies

A prospective study was done to evaluate the roles of serum N-acetylneuraminic acid (NANA) and the lipid-bound subfraction of sialic acid (LSA) concentrations in the detection and staging of cancer, and the follow-up of treatment in patients with genitourinary malignancies. Multiple determinations were obtained in 177 subjects: 90 normal volunteers, 38 patients with prostate cancer, 20 patients with bladder cancer, 15 patients with renal cell cancer, and 14 patients with benign urologic diseases. The results showed a low incidence of elevated values in patients with early stages of cancer and a high incidence of false-positive values with serum NANA concentrations in patients with benign urologic diseases, especially prostatitis. Serum NANA and LSA concentrations were highly correlated with the stage and grade in patients with advanced urologic cancer, and may be used as markers of tumor activity during follow-up under treatment; currently, however, they are not useful in the screening of patients for urologic cancer. Their usefulness in prostatic cancer is at least comparable to that of acid phosphatase determinations by the enzymatic and radioimmunoassay methods, which were elevated in a smaller percentage of patients with prostate cancer than were the NANA or LSA concentrations.

Immunocytochemical demonstration of prostatic acid phosphatase: different secretion kinetics between normal, hyperplastic and neoplastic prostates

The ultrastructural localization and distribution of prostatic specific acid phosphatase in normal, hyperplastic and neoplastic human prostates was studied by immunocytochemical methods. In normal or hyperplastic prostates, the localization of prostatic specific acid phosphatase was uniformly observed at the apical portion of the glandular epithelium of apical cells under the light microscope. Electron microscopy revealed prostatic specific acid phosphatase localized in the microvilli lining prostatic and vesicular bodies of apical cells. Occasionally the limiting membrane of the blebs and vesicles extruded into the glandular lumen and were stained positively. Light microscopic examination of neoplastic prostates revealed a more intense and uniform staining of tumor cells and the glandular epithelium of well differentiated adenocarcinomas, whereas less intense and more variable staining was seen in neoplastic cells of moderately or poorly differentiated adenocarcinomas. Furthermore, under electron microscopic study, prostatic specific acid phosphatase granules were uniformly and intensely condensed in intracytoplasmic vacuoles in well differentiated adenocarcinomas, whereas in moderately or poorly differentiated adenocarcinomas 2 types of staining were observed. Among neoplastic cells, positive granules with less intensity were found between collagen fibers as well as adjacent to the endothelium of the stromal capillaries in anaplastic tissue.