Summary of the effects of folic acid supplementation on main primary outcomes of the sentinel mammary tumors.

Weanling female rats were placed on a control diet containing 2 mg kg folic acid/kg diet (basal dietary requirement for rats) until 7 weeks of age when the mammary carcinogen DMBA was administered. The animals continued to receive the control diet until a single mammary tumor between 0.7–0.9 cm (i.e., the sentinel tumor) developed. The animals were then randomized to receive different levels of folic acid (control, 5, 8, and 10 mg folic acid/kg diet) for 12 weeks. The primary objective of this study was to determine the effect of folic acid supplementation on the progression of the sentinel mammary tumors including both histologically confirmed adenocarcinomas and adenomas and on the sentinel tumor burden variables (weight, volume, and area). Diet groups represent the amount of folic acid in mg per kg diet. Results are expressed as mean ± SEM. Within each row, means with different letters significantly differ at p