Prostatic acid phosphatase in serum and bone marrow in patients with prostatic carcinoma.

Sixty-two per cent of 61 patients with prostatic carcinoma showed elevated levels of serum acid phosphatase, analysed by radioimmunoassay (RIA). Enzymatically determined serum acid phosphatase was raised in only 38% of the same patients. Bone marrow acid phosphatase determined by RIA was raised in 41%. In untreated metastatic patients with prostatic carcinoma, radioimmunologically determined serum acid phosphatase was elevated in 12 of 13 patients, whereas bone marrow acid phosphatase (RIA) and enzymatically determined serum prostatic acid phosphatase were increased only in about half of the patients. In a control group the upper reference limit of bone marrow acid phosphatase determined by RIA was significantly raised above that obtained by serum analyses. This indicates that nonprostatic acid phosphatases (possibly from bone marrow cells) cross-react with prostatic acid phosphatase in an unpredictable way, even when using a specific radioimmunoassay. In patients with metastatic carcinoma of the prostate, the results of bone marrow acid phosphatase determinations, analysed by RIA, seem to lack diagnostic and/or prognostic information additional to that obtainable by serum acid phosphatase (RIA) analysis.