[Activity of the proteolytic system in patients with breast cancer]

Proteinase inhibitor activity in patients with stage IIb, III and IV breast cancer was shown to be higher than in healthy donors and cases with stage I-IIa disease. The proteinase activity/inhibitor activity ratio in breast carcinoma tissue appeared higher than in benign tumors and normal tissue. Tumor proteinase activity was in reverse correlation with degree of cell differentiation. Dissemination to regional lymph nodes involved decrease in tumor proteinase activity matched by relevant increase in lymph nodes. Radiation treatment resulted in decreased proteinase activity and increased inhibitory activity both in primary tumor and involved lymph nodes.