Objective: Proteolytic enzymes have been implicated in the progression of various human malignancies, including ovarian cancer. The enhanced expression of dipeptidyl peptidase III (DPP III) was found in endometrial carcinomas of various histological types and grade. The aim of this study was to assess activity of DPP III in ovarian tissue specimens and to correlate it with clinico-pathological data.
Methods: DPP III hydrolytic activity toward Arg-Arg-2-naphthylamide was determined in 108 ovarian tissue cytosol specimens of 79 patients. The data obtained for 41 ovarian primary carcinoma specimens were stratified according to clinical stage, histological grade and type, and age of the patients.
Results: Median DPP III activity expressed as milliunits per milligram protein was 6 in normal ovarian tissues (n = 29), 6.5 in benign ovarian tumors (n = 19), 19.5 in primary ovarian carcinomas (n = 41), 12.5 in nonepithelial primary ovarian tumors (n = 7), and 22.1 in metastatic ovarian malignancies (n = 12). A significant rise in median DPP III specific activity was observed in malignant ovarian tumors (of epithelial, nonepithelial, and metastatic origin), but not in benign ovarian tumors, compared to the activity in normal tissue. A significant difference of DPP III expression was found between the group of normal tissues and tumors of clinical stage I and II, of grade 2 and 3, of serous and mucinous histologic type.
Conclusions: DPP III activity of benign ovarian tumors equaled that in normal ovarian tissue. In malignant neoplasms of the ovary it increased with growing histologic grade.