In a parallel study (unpublished data) conducted by our research group, we observed that Fz25 (IC50 of 8.13 ± 0.15) and Fz57 (IC50 of 11.94 ± 0.19) were cytotoxic against MCF-7 (ER + and EGFR -) breast cancer cells comparable to sorafenib, positive control (IC50 of 12.21 ± 0.96). Here, ESR1 is linked to breast cancer.