ESR1 and cancer: In vitro, BPA alters DNA methylation and gene expression through classical estrogen receptor (ER)-binding or through membrane-initiated signaling by GRP30; exemplarily, BPA has been shown to induce SCGB2A1 overexpression—a gene that is associated with proliferation and cancer stem cell survival as well as with response to chemo- and radiotherapy in colorectal cancer cells (Caiazza et al. 2015; Munakata et al. 2014).