Previous study shows that NR5A2 promotes breast cancer cell resistance to tamoxifen involved in inducing ERα expression.20 Additionally, CREB1 enhances tamoxifen resistance involved in aromatase induction in tamoxifen-resistant breast cancer.21 Therefore, we examined whether NR5A2 and CREB1 induced ER and aromatase expression. The gene discussed is ESR1; the disease is breast carcinoma.