Among newly synthesized gold (I) compounds, 3F1, 3F3, and the ligand 3FL, the compound 3F1 (triphenylphosphanegold(I) O-methyl-N-3-fluorophenyl thiocarbamate) demonstrated significant inhibition of the in vitro growth of triple-negative breast cancer cells (MDA-MB-231), estrogen receptor-positive breast cancer cells (MCF-7), BCA, BCSC-P and BCSC. Here, ESR1 is linked to triple-negative breast carcinoma.