Placenta-like isoenzyme of alkaline phosphatase in prostatic cancer.

Assays for serum placenta-like (Regan) isoenzyme of alkaline phosphatase were done on 157 samples from 96 patients with prostatic cancer entered into various National Prostatic Cancer Project protocols. Elevated placenta-like isoenzyme levels were found in 19 patients (20 per cent). Increased isoenzyme activity was seen in some patients with early clinical stages of the disease (B1 and B2), as well as in those with advanced disease. As in other reports results were not consistent in any individual patient. No correlations could be made between elevated isoenzyme activity and either stage of the disease or response to therapy. The placenta-like isoenzyme of alkaline phosphatase appears to be a nonspecific oncodevelopmental marker that is not helpful alone as a diagnostic indicator but that may be promising as part of a profile of markers for a patient with prostatic cancer.