On the other hand, DHA concentration in the serum of 10 % FS and 4 % FSO-fed mice was shown to be 244 and 193 μM [7, 14], respectively, while DHA has been shown to reduce breast cancer growth at doses as low as 25 μM in HER2-overexpressing SkBr-3 cells [18]. This evidence concerns the gene ERBB2 and breast cancer.