,236 Fulvestrant induces the coordination of GPER-mediated fibronectin matrix assembly and growth factor release through a Shc-dependent signaling237,238 and activates the GPER-mediated ERK/calpain/cell adhesion pathway to enhance metastasis and reduce the efficacy of antiestrogens in the treatment of HR+ BC.239. This evidence concerns the gene GPER1 and breast cancer.