DIFFERENTIAL MODULATION BY DIETARY N-6 OR N-9 UNSATURATED FATTY-ACIDSON THE DEVELOPMENT OF 2 MURINE MAMMARY-GLAND TUMORS HAVING DIFFERENT METASTATIC CAPABILITIES

It is widely known that dietary lipids can modify the ability of diffe rent cancers to grow up and metastasize, especially mammary gland tumo rs. However, it is still unclear whether n-6 fatty acids behave as tum or promoters in this gland cell population. The effect of different nu tritional polyunsaturated fatty acids (PUFAs) on tumor growth paramete rs of two transplantable murine mammary gland adenocarcinomas of low a nd high metastatic ability was tested on hosts fed diets with corn oil (CO) rich in 18:2n-6, evening primrose oil (EPO) containing 18:3n-6 ( GLA) and a third formula supplemented with olein (O) 18:1n-9, which in duces an essential fatty acid deficiency (EFAD). Tumor growth paramete rs were not adversely affected in the corn oil group with respect to s tock-fed controls. Furthermore, metastatic spreading diminished in thi s group. EPO showed a moderate antitumor activity whereas the n-9-enri ched diet showed no clear-cut effects. In both mammary gland tumors, n -6 fatty acid-rich lipids formulae, containing GLA and linoleic acid, were not tumor promoters. On the contrary, both exhibited anticancer a ctivity. (C) 1998 Elsevier Science Ireland Ltd.