Enzyme histochemical study on hepatoma--the relation between enzyme activity and histological type.

The activities of gamma-glutamyl transpeptidase (gamma-GTP), alkaline phosphatase (A-p), and leucine aminopeptidase (LAP) were examined in 18 cases of hepatomas. The activity of gamma-GTP was most remarkable in the hepatoma consisting of small to medium-sized tumor cells showing the least atypism. The enzyme activity found in the type composed of large tumor cells resembled that of normal liver and was considered to be the most mature form of the neoplasm. This enzyme was not found in the immature type composed of small typical tumor cells. A-P activity was seen in only a few cases of hepatoma; conspicuous in one case showing immature features and sporadically in one case with florid histological pattern. The activity of this enzyme could not be confirmed in the type demonstrating marked gamma-GTP activity. LAP activity was noted in the majority of cases, especially marked in the medium-sized tumor cells, but there was hardly any connection between this enzyme and histological type. In general, the cases demonstrating positive gamma-GTP activity tended to show LAP activity. Although the activity of gamma-GTP and that of A-p usually showed an inverse relation, all three enzymes demonstrated almost equal activity in the type showing a florid histological pattern.