ESR1 and neoplasm: When the ERα antagonist, tamoxifen, was added to the depleting T132E TNBC cells, an additive effect in inhibiting BC proliferation, invasion, and migration was observed using CCK-8 assay, wound healing, Transwell migration, Matrigel invasion experiments in vitro, and tumor xenografts in vivo (Figs. S4D–J; 1G).