Acetylation phenotype in colorectal carcinoma.

Sulfamethazine acetylation phenotype was determined in 49 patients with cancer of the colon or rectum, 41 old, and 45 young control subjects. Metabolic clearance of sulfamethazine, plasma ratio of N-acetylsulfamethazine:N-acetylsulfamethazine plus sulfamethazine and urinary ratio of N-acetylsulfamethazine:N-acetylsulfamethazine plus sulfamethazine were used to classify subjects into slow and fast acetylation phenotypes. All three measures gave similar results. The proportions of slow and fast acetylators were similar in both control groups and there were significantly more fast acetylators in the cancer group than in the control groups (chi 2 = 5.0-8.5; P less than 0.05). The data suggest that there may be an association between acetylation phenotype and colorectal carcinoma.