Inhibition of Growth of Mouse Mammary Carcinoma by Streptovaricin 1 2

Summary

The growth of preexisting mammary tumors and the formation of additional tumors in MTV-positive RIII mice were significantly inhibited by streptovaricin complex. Mice bearing small tumors were given streptovaricin orally in two experiments and the rate of growth of their tumors was compared with that of matched controls. In the 1st experiment treatment was discontinued after 5 weeks while in the 2nd the animals were treated until they died. The growth rates in the two treated groups were 49% and 13% of the rates in the respective control groups. Measurements were made for 5 weeks in the 1st experiment and for 8 weeks in the second. Fewer new tumors arose in the experimental mice than in the controls. More tumors regressed in the treated mice than in the controls. Short term prophylactic treatment of MTV-negative C57BL mice with streptovaricin complex failed to protect the mice significantly from infection with MTV.