Measurement of enzyme activity in colonic biopsies: a test for premalignancy in ulcerative colitis?

Enzyme activity was studied in relationship to histological changes in biopsy specimens removed after resection from patients with inflammatory bowel disease. Glucose-6-phosphate dehydrogenase (G6-PDH) and lactate dehydrogenase activities were measured in homogenates from 276 large-intestinal biopsy specimens, classified histologically in accordance with grade of inflammation and dysplasia. The mean activity of both enzymes was highest in the presence of dysplasia; however, only G6-PDH activity seemed independent of inflammatory changes. In the seven patients with dysplasia both enzyme activities were significantly raised in segments with dysplasia, compared with those without. The results support the use of dysplasia as a marker of premalignancy and may suggest a role for measurements of enzyme activity in the evaluation of patients with ulcerative colitis.