This study aimed to evaluate the effect of this SFN enantiomer on phase II enzymes AhR, Nrf2, and ERα expression in breast cancer cell lines differing in ERα status (i.e., ER(+) MCF7, ER(−) MDA-MB-231) and non-tumorigenic immortalized epithelial breast cell line (MCF10A). Here, ESR1 is linked to breast cancer.