The role of GPER1 in BC remains controversial, being reported to exert both tumor-promoting and tumor-suppressing functions, but survival analyses of large datasets including GeneChip RNA microarray data of 4929 BC patients supported GPER1 acting as a tumor suppressor in this cancer entity, with a significantly longer RFS for patients with high GPER1 expression [22]. This evidence concerns the gene GPER1 and breast cancer.