The activation of GPER, however, can also be viewed as potentially adverse in itself because such activation may trigger a range of downstream cellular events through intracellular kinases (Figure 15; ERK1/2, P13K and AKT (Madeo and Maggiolini, 2010; Qui et al., 2021)] that can lead to cell proliferation, enhanced survival of cancer cells, cell migration and metastasis (Figure 15; [Vivacqua et al., 2006a; b, Pandey et al., 2009; Prossnitz and Barton, 2011; Madeo and Maggiolini, 2010; Filardo, 2018; Qui et al., 2021]). This evidence concerns the gene GPER1 and cancer.