ESR1 and breast neoplasm: Mechanistically, it is negotiable how exactly TVB‐3166 exerts its antitumor effect as another study showed that TVB‐3166 treatment alters ERα subcellular localization and reduces ERα levels by inducing endoplasmic reticulum stress, and exhibits antitumor activity in tamoxifen‐resistant breast tumor cells [141] (Table 1).