Resistance to Spontaneous Mouse Cancer In- Duced by Injections of Oleic

We have previously shown that resistance to transplanted cancer in mice can be greatly increased by a previous injection of a small quantity of olive oil,' or such unsaturated fatty acids as oleic, linolic, and linolenic acids.2 It is of interest to extend these observations by the study of the action of the fatty acids on the resistance of animals to their own spontaneously developed neoplasms. In a preliminary experiment, mice with spontaneous cancers were treated with oleic acid without operative intervention. The result, though inconclusive, was sufficiently suggestive of influence upon the growths to lead to more elaborate experiments. In the studies to be presented in this communication, an attempt has been made to determine, first, the effect of oleic acid injections on the frequency of recurrence after operative removal of spontaneous mouse cancer, and second, the effect on the incidence of takes of autoplastic cancer grafts. Oleic acid was used in these experiments for the reason that the range of doses effective against transplanted cancer is wider than in the other unsaturated fatty acids which have been tested.