Effect of Dietary Fats on Growth and Composition of Tumors

Abstract

While many studies of the effect of diet on tumor growth have been made, few deal with the quality of the dietary fat and its effect on the lipid content of the tumor. Sugiura and Benedict 1 , 2 found that oral administration of 10% cod liver, olive, linseed and chaulmoogra oils had no influence upon susceptibility to and growth of Flexner-Jobling rat carcinoma. Feeding 40% butter fat gave a decreased take and growth rate of Flexner-Jobling rat carcinoma, and increased regressions. The same diet had no influence upon the growth of a rat sarcoma. Freund, Lustig and Kellner 3 found that diet free from palmitin but rich in olein rendered half of a series of mice refractory to carcinoma inoculation, and caused a decreased carcinoma growth rate in the animals. Caspari 4 reported retarded growth of tumors in mice fed large amounts of butter fat or palmitin.

This report deals with the effect of a synthetic diet, varying only in the nature of the fat, on the growth of rat Carcino-Sarcoma No. 256 obtained from Dr. Frances Wood of Columbia University. The rats were inoculated subcutaneously in the groin by the trocar method. On the day of inoculation, they were placed on Diet 262, Sinclair. 5

From 4 to 7 weeks after inoculation, the rat was decapitated, the tumor removed, weighed, and portions of the outside taken for analysis. Cholesterol, fatty acids, and phospholipids were determined by Bloor's method 6 , 7 and the micro iodine numbers by Yasuda's modification 9 of the Rosenmund-Kuhnhenn 8 method.

The growth of the tumor is expressed by a formula of Bierich and Lang 10 involving the weight of the tumor in grams and its age in days from the time of inoculation, or Wt = a·t 2 ; a (growth tendency of tumor) = × 10,000.