ABCG2 and breast cancer: The results showed that following treatment of breast cancer cells with 4-cholesten-3-one and SR9238 an LXR inverse agonist together, the mRNA expression of ABCG1 and ABCA1 was suppressed suggesting that the effect of 4-cholesten-3-one on ABC transporters expression is dependent on LXR in MCF-7 and MDA-MB-231 cells [49].