Plasma activity of proteolytic enzymes and their inhibitors in mice with neoplasms

In BALB/c mice with syngeneic mastocytoma P-815, plasma activity of trypsin-like proteinases and the ratio of α1-proteinase inhibitor activity to β2-macroglobulin plasma level increased in comparison with the same parameters in noninbred mice with allogenic Ehrlich carcinoma. It is suggested that activation of the proteinase-inhibitor system is essential forin vivo tumor growth.