Phosphatases XII. Isoenzymes of alkaline phosphatase and radionuclear investigation (85Sr) of patients with neoplastic affection of the skeleton.

In a group of 30 patients with neoplastic processes, 13 were found to have a significantly increased serum alkaline phosphatase activity. This finding correlated with the results of investigation with 85Sr in 7 patients, but owing to a concomitant hepatal symptomatology, it proved of differential diagnostic value in only one of them. On the other hand, the activity of bone isoenzyme of alkaline phosphatase was significantly altered in 15 patients. In 14 of them the increase in bone isoenzyme activity corresponded to an X-ray and a radionuclear finding of a tumor process in the bones. This activity was within the normal range of values in only one patient with a positive result of the 85Sr investigation. An agreement between the results of determination of bone isoenzyme activity of alkaline phosphatase and those of radionuclear investigations was found in 27 patients. In addition, a correlation was established between the increased activity of bone isoenzyme and that of intestinal isoenzyme of alkaline phosphatase. Enzyme investigation can be suitably utilized, alongside radionuclear examination, for early detection of a bone process.