[Proteolytic enzymes and their inhibitors in the tumors and blood serum of patients with breast neoplasms].

Content of proteinases and trypsin inhibitor was studied in non-malignant and malignant tumors as well as in blood serum of 120 patients with mammary gland neoplasm. In malignant tumors activity of acid and casein-degrading proteinases was increased as compared with non-impaired tissue of mammary gland. Activity of proteolytic enzymes in non-malignant tumors corresponded to an intermediate value between the activity in malignant tumors and in non-impaired tissue. Content of the trypsin inhibitor was distinctly increased in non-malignant tumors and unaltered -- in malignant tissues. The inhibitor content was increased in blood serum of patients with metastases in lymphoid nodes. These data demonstrate the activation of proteolysis in malignant mammary gland and suggest a possible role of proteolytic enzymes in carcinogenesis.