DECREASED ACTIVITY OF SCAVENGER ENZYMES IN HUMAN HEPATOCELLULAR-CARCINOMA, BUT NOT IN LIVER METASTASES

To investigate the role of oxygen free radicals in hepatocellular carc inoma we assayed tissue scavenger enzymes (superoxide dismutase and se lenium-dependent glutathione peroxidase) in liver homogenate, plasma c oncentrations of vitamins A and E and the serum selenium level from 19 control patients, 23 cases of hepatocellular carcinoma and 18 cases o f metastases to liver from different carcinomas. In hepatocellular car cinoma tissue the enzyme activities were all significantly lower than in control liver and in metastases-bearing liver; the enzyme activitie s of the latter tissues were not different from control liver. In cont rast, normal liver adjacent to the hepatocellular carcinoma had decrea sed activity of superoxide dismutase. Serum selenium concentrations we re significantly decreased in patients with hepatocellular carcinoma a nd those with liver metastases, while vitamin A was significantly decr eased only in the former. These findings suggest that hepatocellular c arcinoma develops in liver with severe impairment of cellular antioxid ant systems, since, in patients with liver metastases from different c ancers, despite low selenium concentrations, cellular scavenger enzyme s have normal activities.