Glutathione S‐Transferase in Human Hepatocellular Carcinoma

Qualitative and quantitative changes in glutathione S‐transferase (GSH‐T) were studied in human hepatocellular carcinoma. GSH‐T specific activity (/imoles per min per mg protein) was variably reduced in hepatocellular carcinoma. Similar changes were seen in “cationic” GSH‐T (ligandin) concentration determined by radioimmunoassay. Immunohistochemical studies with antihuman liver ligandin suggest that positive staining was more frequently found in well‐differentiated tumors. The relative activities of “cationic,” “neutral,” and “anionic” transferases were estimated after separation by isoelectric focusing. Tumor “cationic” transferase (pI ± 7.5) activity ranged from virtually absent to near normal values. “Neutral” (pI 6 to 6.5) and “anionic” (pI < 5.4) species were present more often in tumors than in normal liver. In two cases, normal liver tissue and tumor were obtained from the same patient. In one, only quantitative differences were present, while in the other “cationic” and “neutral” GSH‐Ts were present in the normal liver tissue while both “cationic” and “anionic” species were found in the tumor. Our studies indicate that qualitative as well as quantitative changes of GSH‐T occur in human hepatocellular carcinoma.