Lactate dehydrogenase in breast carcinoma: correlation with estrogen and progesterone receptors.

Analysis of estrogen receptor (ER), progesterone receptor (PR), and total activity of lactate dehydrogenase (LDH) as well as electrophoretic separation of the LDH isoenzymes was performed in samples of primary infiltrating ductal carcinomas and normal breast. Estrogen receptor and progesterone receptor were determined by a dextran charcoal procedure. Total LDH activity was assayed in the cytosol by measuring the decrease in NADH absorbance with pyruvate as substrate. The LDH activity was expressed as mumoles cofactor altered per minute per mg DNA. Incidence of ER + PR + tumors was higher in postmenopausal than in premenopausal women but PR + was found in about 70% of ER + cases in both groups. In postmenopausal women the mean level of ER or PR decreased in tumors that had either ER or PR. In premenopausal women differences were not significant, but frequency of PR + depended on the phase of the menstrual cycle. The mean value of LDH in ER + PR + tumors was lower than in the ER- PR- subset regardless of menopausal status. The mean enzyme level is twofold greater than in normal breast tissue. A large increase in LDH-5 and a small but significant increase in LDH-4 was demonstrated by cellulose acetate electrophoresis.