A prominentexample is bisphenol A (BPA) activating G protein-coupled estrogenreceptor 1 (GPER), leading to various cancer-promoting mechanisms,such as increased reactive oxygen species,4 cellular proliferation,5 apoptosis,6 and cell migration.7 Beyond GPER and bisphenols, scattered evidence suggests that otherchemicals can also interfere with GPCR signaling. Here, GPER1 is linked to cancer.