GPER1 and cancer: In fact, an orphan GPCR was identified as an estrogen-binding membrane GPCR from vascular and cancer cells and is now included in the official GPCR nomenclature and was designated GPER or GPR30 by the International Union of Pharmacology (Revankar et al., 2005; Thomas et al., 2005; Prossnitz et al., 2008a; Alexander et al., 2011).