Alcohol dehydrogenase (ADH) isoenzymes and aldehyde dehydrogenase (ALDH) activity in the sera of patients with gastric cancer

Background Investigations have shown that alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) are present in some cancer cells and can play role in carcinogenesis. In recent experiments we found elevated alcohol dehydrogenase class IV activity in gastric cancer cells. This suggests these changes may be reflected by enzyme activity in the serum. Aim In this work we measured the activity of alcohol dehydrogenase isoenzymes and aldehyde dehydrogenase in the sera of patients with gastric cancer matched on gender. Methods Serum samples were taken for routine biochemical investigation from 55 patients with gastric cancer, before treatment, and from 55 control subjects. Total ADH activity was measured photometrically and ALDH activity by a fluorimetric method. For measurement of the activity of class I isoenzymes we used a fluorimetric method, with class-specific fluorogenic substrates. The activity of class III and IV alcohol dehydrogenase was measured photometrically. Results The activity of the class IV ADH isoenzyme was significantly higher in the sera of patients with gastric cancer. The median activity of this isoenzyme in the total cancer group was approximately 47% higher (7.45 mU/l) than the control level (5.08 mU/l). For this reason total ADH activity was also significantly increased. The activities of other tested ADH isoenzymes and ALDH were unchanged. Conclusion Changes in the activity of, especially, class IV ADH in the sera of patients with gastric cancer seems to be caused by release of the isoenzyme from cancer cells.