Other studies have provided evidence that 8-OHdG levels in the ER-positive MCF-7 breast cancer cell line are over 9-fold higher than in triple-negative MDA-MB-231 cells [9] and inhibition of estrogen receptor alpha expression significantly reduces estrogen-induced 8-OHdG formation in MCF-7 cells [21]. The gene discussed is ESR1; the disease is breast carcinoma.