Plasminogen activators and their inhibitors in normal, hyperplastic and carcinomatous human endometrium.

Plasminogen activators (PA) and inhibitors of urokinase were determined by a solid phase 125I-fibrin assay in endometrial tissue homogenates from 87 patients. PA was also determined by a histochemical method. Patients were divided according to histopathological diagnosis into three groups; normal, hyperplastic and cancerous. The mean values and S.D. of PA in control endometria, in hyperplastic endometria and in endometrial cancer were 0.68 +/- 0.55 units per mg protein, 1.9 +/- 1.6 units per mg protein and 3.21 +/- 1.03 units per mg protein, respectively. The results of the histochemical assay of PA correlated with the results of 125I-fibrin assay (R = 0.818, p less than or equal to 0.001). The relative PA activity of urokinase-type was the lowest in normal endometrium; it increased in hyperplastic and it was the highest in carcinomatous endometrium. The urokinase inhibitor activity was similar in control and carcinomatous groups; it was slightly but significantly higher in hyperplasia. The results support the contention that PA reflects malignant transformation of endometrial cells. We suggest that determination of PA may facilitate diagnosis and proper treatment of precancerous and cancerous states of endometrium.