Total tissue lactate dehydrogenase activity in endometrial carcinoma.

Lactate dehydrogenase (LDH) is essential for continuous glycolysis necessary for accelerated tumor growth. The aim of this study was to reconsider if assay of total tissue activity of this enzyme could be useful as marker for endometrial carcinoma (EC). Activity of LDH was measured spectrophotometrically in homogenate supernatants of uterine tissue samples of 40 patients (10 normal endometria, 27 normal myometria, and 33 EC), including 30 matched pairs. Data obtained were analyzed in relation to clinical and histopathologic findings and compared with our previously published results on the tissue levels of the same enzyme in ovarian cancer and on the proteolytic activity of dipeptidyl peptidase III (DPP III) in EC (suggested biochemical indicator of this malignancy). Significantly increased (1.8-3.0 times; P < 1 x 10(-4)) LDH activity was observed in EC samples if compared with normal uterine tissues. This rise was not related to the clinicopathologic findings, however. In contrast to previous results on LDH in ovarian carcinomas, a significant rise in LDH activity was found already in grade 1 EC. Using the cutoff value of 1.06 U/mg, diagnostic sensitivity of 82%, specificity of 100%, and accuracy of 91% for total tissue LDH assay have been calculated. A correlation of tissue's LDH and DPP III activities was found, and their combined assay for EC showed increased diagnostic sensitivity (94%) and accuracy (96%).