The Activity of Class I, II, III, and IV Alcohol Dehydrogenase (ADH) Isoenzymes and Aldehyde Dehydrogenase (ALDH) in Liver Cancer

Background Alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH), which are most abundant in the liver, are the main enzymes involved in ethanol and acetaldehyde metabolism. Aims The purpose of this study was to compare the activity of ADH isoenzymes and ALDH between liver carcinoma cells and healthy hepatocytes. Patients Samples were taken from 44 liver cancer patients (19 drinkers, 25 nondrinkers). Seventeen patients had primary liver tumors and 27 had metastatic liver tumors. Methods Fluorimetric methods were used for measurement of the activity of class I and II ADH isoenzymes and ALDH activity. Total ADH activity and activity of class III and IV isoenzymes were measured by a photometric method. Results The activities of total ADH, ALDH, and class I ADH were significantly higher in cancer cells than in healthy tissues. The other tested classes of ADH showed a tendency toward higher activity in cancer than in normal cells. The differences between enzymes of drinkers and nondrinkers in both cancer and healthy tissue, were not significant. Conclusion Differences in the activities of total ADH, ALDH and class I ADH isoenzyme between cancer liver tissues and healthy hepatocytes might be a factor in ethanol metabolism disorders, which can intensify carcinogenesis.