GPER1 and colorectal carcinoma: In CRC, GPER differentially regulates the effects of 17β-estradiol on CRC cell proliferation depending on the tumor microenvironment: 17β-estradiol and a GPER agonist suppressed migration and proliferation in a normoxic tumor microenvironment, while they enhanced migration and proliferation under hypoxia, and these effects were lost in GPER-silenced cells (Bustos et al., 2017).