Carcinoplacental isoenzyme (Regan) in carcinoma of the prostate. National Prostatic Cancer Project.

Serum samples were examined for the placental-like "Regan" isoenzyme of alkaline phosphatase in two groups of patients with advanced cancer of the prostate from clinical trials of the National Prostatic Cancer Project. In the first group, 98 samples from 76 patients over three consecutive months revealed elevated isoenzyme activity in 14 (18%) of the patients, a frequency similar to those reported for some other tumor types. Four of these patients whose serum demonstrated the "Regan" isoenzyme had samples taken more than once, and their sera had negative readings when taken a month or more before or after the sample that was positive for the isoenzyme. Comparisons of general disease and patient characteristics for patients whose sera were positive or negative for Regan isoenzyme revealed no demonstrable relationships. The second group consists of 72 samples received from 52 study patients with metastatic lesions under treatment from August 1, 1979 to November 16, 1979. Fifteen patients had sufficient serial values. In this study to date, the relationship with clinical response to treatment is inconclusive, although elevated levels of the isoenzyme appear to occur in patients with metastatic disease with bony lesions that are clinically in progression, as well as in those apparently responding to chemotherapy.