A study of serum glycosidases in cancer.

N-Acetyl-beta-glucosaminidase (NAG) and beta-glucuronidase were measured in the serum of 70 patients with breast and digestive-tract neoplasms and in 70 healthy subjects. The mean value of the NAG activity was significantly (P < 0.001) elevated in patients with gastric, liver and pancreas cancer as compared with the reference population. In patients with liver and pancreas cancer the very high sensitivity contrasted with a low specificity. NAG elevations above normal were observed in 14 (78%) patients with breast cancer, in 11 (100%) with gastric cancer, in 17 (70%) with colorectal cancer, in 8 (100%) with liver cancer and in 9 (100%) with pancreas cancer. In patients with breast and gastric cancer the enzyme shows a good specificity and sufficient sensitivity as a tumor marker. beta-Glucuronidase appeared less sensitive and was significantly elevated (100%) only in patients with pancreas cancer.