Serum enzymes in disease.V. Isocitric dehydrogenase, malic dehydrogenase, and glycolytic enzymes in patients with carcinoma of the breast

in 1943, ob-vv served increased levels of glycolytic enzymes in the serum of rats bearing tumors.Their studies were stimulated by the earlier report by Warburg26 that neoplastic tissue has a greater glycolytic activity than does normal tissue.Since these early studies, elevated levels of lactic dehydrogenase, aldolase, phosphohexose isomerase, and several other glycolytic enzymes have been found in the serum of patients or animals with neoplastic disease.1,3310, 21, 22 These workers inferred that the elevations reflect increased tumor content of the glycolytic enzymes.