ERRα has been reported to regulate the proliferation, migration and epithelial to mesenchymal transition of cancer cells.32, 33 Recently, studies also suggested that ERRα mediates metabolic adaptations driving drug resistance in breast cancer.23, 34 Our study revealed that the expression of ERRα was up‐regulated in OS resistant cells as compared to their parental cells. The gene discussed is ESRRA; the disease is cancer.