Breast cancer risk in rats fed a diet high in n-6 polyunsaturated fatty acids during pregnancy. J Natl Cancer Inst

Background: Women who took the synthetic estrogen di-ethylstilbestrol during pregnancy exhibit an elevated risk of breast cancer, whereas those who suffered from preeclampsia, which is associated with low circulating preg-nancy estrogens, exhibit a reduced risk. Since a high-fat diet may increase circulating estrogen levels and possibly breast cancer risk, dietary factors during pregnancy could in-fluence the risk of developing this disease. Purpose: We tested the hypothesis that consumption of a high-fat diet during pregnancy increases carcinogen-induced mammary tumor incidence in rats. Methods: Pregnant or virgin female Sprague-Dawley rats that had been previously treated with 10 mg 7,12-dimethylbenz[a]anthracene (DMBA) by oral gavage when 55 days old were assigned to one of two isocaloric diets containing either 16 % calories from fat (low