We investigated the effect of BP7033Br and its esterified analogue BP7033Br ALK on the proliferation of several breast cancer cell lines with different estrogen-receptor statuses as T47D (Fig. 2A), MCF-7 (B), SKBR3 (C), MDA-MB-231(D) and its D3H2LN metastatic subclone (E). This evidence concerns the gene ESR1 and breast cancer.