GPER mediates the participation of forward feedback FGF2/FGFR1 in TME, which connects CAFs with breast cancer cells and promotes tumor progression Specifically, GPER mediates the participation of forward feedback FGF2/FGFR1 in TME, which connects CAFs with breast cancer cells and promotes tumor progression [116]. The gene discussed is FGFR1; the disease is breast carcinoma.