Changes in tissue fatty acid composition in murine malignancy and following anticancer therapy.

We measured 17 fatty acids (FAs), the combined amounts of n-3, n-6, saturated, unsaturated, and total FAs, and of various FA ratios in mouse NC adenocarcinoma, mammary tissue, spleen, liver and plasma. Compared with mammary tissue from normal mice, tumors of vehicle-treated controls had less of 7 FAs and more of 2 FAs. Mice bearing the NC tumor often had changed (usually decreased) amounts of FAs in the ‘normal’ spleen, liver and plasma, but not in mammary tissue. Methotrexate (MTX) 2 or 4 mg/kg in general partly restored (increased) the amounts of tumor FAs, and reduced the saturated/unsaturated FA ratio. Similarly in the ‘normal’ spleen and plasma, but not in the liver, MTX 2 mg generally in part restored the FA composition. However, with MTX 4 mg, some of the plasma and liver FAs decreased, in contrast to the increase in the tumor.