GPER1 and breast cancer: The G protein‐coupled estrogen receptor (GPER, nomenclature as agreed by the NC‐IUPHAR Subcommittee on the G protein‐coupled estrogen receptor [http://www.ncbi.nlm.nih.gov/pubmed/26023144?dopt=AbstractPlus]) was identified following observations of estrogen‐evoked http://www.guidetopharmacology.org/GRAC/LigandDisplayForward?ligandId=2352 signalling in breast cancer cells [http://www.ncbi.nlm.nih.gov/pubmed/8078914?dopt=AbstractPlus], which mirrored the differential expression of an orphan 7‐transmembrane receptor GPR30 [http://www.ncbi.nlm.nih.gov/pubmed/9367686?dopt=AbstractPlus].