Effect of Medroxyprogesterone and an Aorta-Derived Cell Growth Inhibitor on B16 Melanoma in Mice

: An aorta-derived inhibitor of endothelial cell and tumor cell growth and medroxyprogesterone, which depresses collagenase expression in vivo, were tested alone and in combination against B16-F10 melanoma in C57BL/6 mice in such doses that either agent alone had little effect. Together, these agents retarded growth of subcutaneously transplanted tumor cells and reduced the number and size of pulmonary tumors after iv tumor cell injection. Of the treatments used, only the aortic factor administered alone prolonged life in mice with pulmonary tumors.