Among all BC cases, 50% of BC in patients progressed to liver metastases, and there is still no effective therapy to treat liver metastatic estrogen receptor α (ERα)-positive breast cancer, with these patients showing correspondingly poor outcomes (Boudreau et al., 2021; Rashid et al., 2021); however, despite considerable effort, the biological mechanism of metastasis in BC remains unclear. The gene discussed is ESR1; the disease is breast cancer.