ESR1 and breast cancer: Among selected compounds tested against breast cancer cell lines, compound 11 again displayed the best antiproliferative activity against both cell lines with IC50 values of 0.26 and 0.08 μM for MDA-MB-468 (TNBC) and MCF-7 (estrogen receptor (ER) positive, p53+) cell lines, respectively, with the more aggressive TNBC cell line was more sensitive than the less aggressive ER+ cell line.