Serum N-acetyl-beta-glucosaminidase activity in breast cancer.

N-acetyl-beta-glucosaminidase (NAG) and its isoenzymes were measured in 60 patients with breast cancer and in 30 patients suffering from benign breast tumors. NAG activity was significantly increased (P < 0.001) in cancer patients. The concentration of isoenzyme A always exceeded that of isoenzyme B, but isoenzyme B concentration was significantly (p < 0.001) higher in patients than in controls. An intermediate form, I, was more evident but not significant in patients. Evaluation of the predictive value of the NAG isoenzyme B, revealed a good sensitivity, efficiency and specificity. It seems from this study that the determination of the isoenzyme NAG B activity may be useful for better diagnosis of breast cancer.