ESR1 and breast cancer: Previous studies have shown that 5,7-dihydroxy-8-nitrochrysin, a novel synthetic ChR analog, preferentially suppresses the viability of the MDA-MB-453 human breast cancer cell line (ER-negative, HER-2-overexpressing) and moderately suppresses the viability of the MCF-7 cell line (ER-positive, HER-2-low), but has little effect on the immortalized noncancerous HBL-100 breast cell line (ER-positive, HER-2-low) (15).