DIFFERENTIAL PROCESSING OF TYPE-I AND TYPE-III PROCOLLAGENS IN THE TUMOR CYSTS AND PERITONEAL ASCITIC FLUID OF PATIENTS WITH BENIGN AND MALIGNANT OVARIAN-TUMORS

Progressive ovarian carcinoma induces the synthesis of type I and type III procollagens both in the tumour tissue and in the peritoneal cavi ty. We studied the processing of these proteins by determining the dif ferent antigen forms related to their propeptide parts by gel filtrati on and subsequent immunological assays. Samples of ovarian cyst fluid and peritoneal ascitic fluid were obtained from patients with benign a nd malignant ovarian tumours. In both benign and malignant ovarian cys ts, the predominant procollagen antigens were the free propeptides, wi th few or no larger components, indicating efficient processing of typ es I and III procollagens in the tumour tissue. In ascitic fluid the p rocessing was more variable. The aminoterminus of type III procollagen was partially unprocessed in all samples studied, whereas that of typ e I procollagen was nearly always completely processed. There was a cl ear difference between malignant and benign tumours in the processing of the carboxyterminus of type I procollagen: a significant part of th e carboxyterminal propeptide antigen was invariably associated with a collagenous domain in malignant tumours, whereas in benign tumours the free propeptide predominated. The results indicate that interstitial procollagens are effectively processed in the tumour tissue during the fibroproliferative reaction typical of malignant ovarian tumours, whe reas the processing of the procollagens released into peritoneal ascit ic fluid is incomplete.