Of all the ligand-responsive genes, 83 (23 upregulated and 60 downregulated) were responsive in all four breast cancer cell lines, including known LXR target genes such as ABCA1 and ABCG1 [30,31], and they represent candidate mechanisms for the anti-proliferative effects of LXR ligands in these cell lines. This evidence concerns the gene ABCG1 and breast carcinoma.