AN “ ACID ” PHOSPHATASE OCCURRING IN THE SERUM OF PATIENTS WITH METASTASIZING CARCINOMA OF THE PROSTATE GLAND

Abstract

In 1935, Kutscher and Wolbergs (1) found that normal prostate tissue is extraordinarily rich in a phosphatase with optimum activity at about pH 5.0. This observation was confirmed for nor-mal and carcinomatous prostate tissue by Gutman, Sproul, and Gutman (2), who further noted the presence of "acid" phosphatase at the site of skeletal metastases secondary to carcinoma of the prostate gland. The present investigation was directed toward the possibility that invasion of lymph or blood channels by prostate carcinoma might result in the escape into the circulating fluids of prostate phosphatase sufficient to cause a measurable in-crease in the " acid " phosphatase activity of blood serum. Significant amounts of such an "acid" phosphatase were found in the serum of 11 of 15 patients with disseminated carcinoma of the pros-tate gland. The " acid " phosphatase noted in the serum of these patients corresponds closely in its characteristics with prostate tissue phosphatase, as described by Kutscher and Worner (3). Its properties differ in significant respects from those of recognized phosphatases of the blood. With the exception of one case, no appreciable rise in "acid" serum phosphatase activity was noted in a variety of diseases other than car-cinoma of the prostate gland, including conditions presenting marked increases in " alkaline " serum phosphatase activity. The determination proved to be helpful in the diagnosis of disseminated car-cinoma of the prostate gland. METHODS The method of King and Armstrong (4) has been shown to be readily adaptable to the estima-tion of phosphatase activity on the acid side of neutrality (2). Preliminary experiments indi-cated that pH 4.9 was within the optimum range of activity of the serum phosphatase with which we are here concerned, and beyond the range of significant activity of " alkaline" serum phospha-tase. The buffer-substrate employed was M/200