Ectopic Production of an Alkaline Phosphatase Isoenzyme in Patients with Cancer

Abstract
An alkaline phosphatase isoenzyme (Regan isoenzyme) has been identified in the serum of 27 patients with various malignant tumors. This isoenzyme is biochemically and immunologically indistinguishable from placental alkaline phosphatase. In addition to being present in serum, it has been identified in both tumor tissue and malignant effusion fluids. Measurement of this isoenzyme has been clinically useful in monitoring progression or regression of tumor, identifying a source of serum alkaline phosphatase elevation, and identifying malignant effusions.