GPER1 and cancer: GPER has been proposed as a novel therapeutic target in different cancer types (Ariazi et al., 2010; Wang et al., 2012; Lv and Wang, 2014; Weißenborn et al., 2014; Chimento et al., 2015; Kurt et al., 2015; Mori et al., 2015; Rudelius et al., 2015).