LDH-isoenzyme patterns in the nonmalignant and malignant uterine cervix

The lactate dehydrogenase isoenzyme pattern of the uterine cervical mucosa has been assayed in 64 patients without malignancy and in 54 patients with different clinical stages of cervical malignancy. The ratio of LDHIV to LDHII, which in other malignancies has proved a sensitive parameter, showed no significant increase in malignancy of the uterine cervix. The LDH-isoenzyme ratio (LDHIV/LDHII), however, exhibited significant cyclic variations according to endometrial phase. The highest ratio was found in nonmalignant cervical biopsies obtained in the secretory phase. In the group of patients with suspected or manifest carcinomas of the uterine cervix, no significant cyclic isoenzyme variations were observed. This finding was independent of the presence or absence of tumorous tissue in the biopsies investigated. The finding may be indicative of a dedifferentiation of a tissue normally highly responsive to the inductive capacity of progesterone on LDH synthesis. Whether this may be interpreted as a biochemical sign of early malignant transformation preceding the stage of morphologic malignancy is discussed.