However, when ERRα action was inhibited using cpd29, the cholesterol-induced effect was compromised in these breast cancer cells, demonstrating that ERRα mediates the cholesterol effect on those OXPHOS target genes, except for the expression of COX5B in MCF-7 cells, where it was significantly higher in the presence of cholesterol while ERRα was inhibited. This evidence concerns the gene COX5B and breast cancer.