Although moststudies indicate that PPARδ activation results in stimulation of cellgrowth, mostly in human and mouse colon cancer cells [7, 36], there have beenprevious findings showing that PPARδ agonists, including GW501516, can hinder orhave no effect on cell growth in certain human breast cancer cells andmelanomas [37, 38]. This evidence concerns the gene PPARD and breast cancer.