The first study suggesting GPER-1 to have tumor-promoting properties reported that knockdown of this receptor in GPER-1 expressing TNBC cells inhibited E2-induced proliferation, c-Fos expression, Src kinase activation, and EGFR transactivation, suggesting that GPER-1 is able to mediate growth-promoting E2 effects in TNBC cells [63]. The gene discussed is GPER1; the disease is neoplasm.