Hepatocellular carcinoma and a variant alkaline phosphatase.

Four patients with hepatocellular carcinoma had a variant alkaline phosphatase that resembles the placental D-variant but is different from it in electrophoretic mobility, pH optimum, heat stability, and inhibition by phosphate. The appearance of this enzyme has been specific to hepatocellular carcinoma. Its prevalence was about 30%, while that of another marker protein, alpha-fetoprotein was 77%. The occurrence of this enzyme in serum of patients with hepatoma was, accordingly, independent of the serum alpha-fetoprotein concentration, and also independent of the appearance of the Regan or the Nagao isoenzymes and of the serum alkaline phosphatase activity. Patients with the enzyme had a massive type of hepatocellular carcinoma with grade III differentiation by Edmondson's classification. The detection of this enzyme in serum may be of help in confirming the diagnosis of hepatoma.