[Creatine kinase and its isoenzymes in breast tumor tissue].

The activity and isoenzyme spectrum of creatine kinase (CK) were studied in cytosole fraction 60 of the mammary gland carcinoma (MGC) and in the corresponding unchanged tissues. The values of the CK activity in MGC were found to be highly different (0.05-14.6 unit/g of tissue). The correlation of CK activity in MGC with the menstrual function was revealed. Enhancement in the CK activity is due to an increase in the BB-isoenzyme activity and an appearance of atypical supplementary MM1-isoenzyme is, possibly, of mitochondrial origin. These isoenzymes may be nonspecific markers of malignancy and may be used for diagnosis of mammary gland carcinoma.