DIPEPTIDYL PEPTIDASE-III IN MALIGNANT AND NONMALIGNANT GYNECOLOGICAL TISSUE

Exopeptidases, in contrast to endopeptidases (proteinases) have been m uch less studied in relation to cancer. The aim of this study was to i nvestigate one such enzyme, dipeptidyl peptidase III (DPP III), in gyn aecological tissues, by measuring both the enzyme activity and enzyme content. DPP III activity was assessed in normal (n = 65), benign (n = 9) and malignant (n = 51) gynaecological tissues. A statistically sig nificant higher DPP III activity was observed in endometrial (n = 40, P = 4.6 x 10(-7)) and ovarian (n = 11, P = 8.1 x 10(-4)) malignant tum ours, whereas no significant difference was detected for leiomyomas (n = 8), if compared to the activity in normal tissue. A matched pair an alysis of normal and cancerous endometrial tissue confirmed the signif icance of the DPP III activity increase in the transformed tissue (n = 7, P = 0.022). Western blot analysis revealed a significantly (P = 0. 014) increased level of DPP III in endometrial cancer. Further, regres sion analysis showed a positive correlation between the activity and t he content of DPP III in normal tissue (r = 0.637, P = 0.047) and in e ndometrial cancer (r = 0.574, P < 0.007). The increase of the DPP III activity was observed in the endometrial carcinomas of various histolo gical types, grade or the depth of myometrial invasion. The easy-to-pe rform determination of this exopeptidase activity may serve as a poten tial indicator of endometrial and ovarian malignancies. (C) 1998 Elsev ier Science Ltd. All rights reserved.