Enzyme activities in human breast tumours.

The activities of six enzymes associated with carbohydrate metabolism were measured both in carcinomas and in normal breast tissues. The following differences were observed. 1. The carcinoma showed higher enzyme activities than the normal mammary tissue. 2. The ratios of glutamate dehydrogenase, hydroxybutyrate dehydrogenase, glutathione reductase and catalase to lactate dehydrogenase were lower in carcinomas than in normal tissues. Similarly, the ratios of glutamate dehydrogenase, hydroxybutyrate dehydrogenase, glutathione reductase and catalase to glucose-6-phosphate dehydrogenase were also significantly lower in carcinomas. 3. There were no significant differences in enzyme activities between I and II stage of the disease and the metastatic tissues, however, there were significant differences between I and III stage. The significance of these findings is discussed in terms of the alterations in the balance between the metabolic pathways.