DIETARY DEFICIENCY OR ENRICHMENT OF ESSENTIAL FATTY-ACIDS MODULATES TUMORIGENESIS IN THE WHOLE-BODY OF COBALT-60-IRRADIATED MICE

The effect of dietary polyunsaturated fatty acids (PUFAs) on whole bod y-induced tumorigenesis was assayed in mice fed on essential fatty aci d sufficient (EFAS) or essential fatty acid deficient (EFAD) diets fol lowing cobalt-60 irradiation. Four groups of mice were maintained, one on a control stock diet and three on experimental diets: a) without a dded fat (fat free, FF); b) containing 5% olein (O), rich in n-9; and c) containing 5% corn oil, rich in n-6 EFA (GO). Only mice fed on FF o r O diets showed clinical and biochemical signs of EFAD, Total inciden ce of tumors showed an increase in FF (P < 0.02) and O (P < 0.03) mice . Tumors developed mostly in the liver in each of the EFAD groups (P < 0.001). Slight promoting activity on lung tumorigenesis was recorded in the CO group when this parameter was compared in EFAD and EFA suffi cient mice. It may be concluded that, when a tumor initiator injures t he body as a whole, EFAD, achieved either through a fat-free or an ole ic-supplemented diet, behaves as a general promoting condition for tum origenesis. The borderline tumorigenic effect of n-6 corn oil on the l ungs suggests that this effect, when present, is target specific.