ESR1 and breast cancer: As decreased cellular demand for estrogen is closely related to endocrine resistance in ER+ breast cancer patients,[2, 27] we investigated whether MIR497HG depletion contributes to tamoxifen resistance using MCF7/TamR (an acquired tamoxifen‐resistant MCF7 cell line) as previously described.[28] Compared to the parental control cells, MIR497HG expression was remarkably lower in MCF7/TamR cells (Figure 4E).