Further study of specific downstream molecular targets facilitating crosstalk between ER and TGFβRII in mediating osteolysis in bone-tropic ER+ cells, particularly in light of the high prevalence of activating ERα mutations in metastatic breast cancer [80,81] may, therefore, provide fertile ground for new therapeutic discoveries to benefit the majority of patients with breast cancer BMETs. Here, ESR1 is linked to breast carcinoma.