TLR4 and breast cancer: Based on our previous findings, we investigated the role of estrogen receptors in modulating the effect of TLR4/7-induced inflammation in breast cancer epithelial cell lines, MCF7, bearing the classical ERα (or ERα66) [11], together with the ERα36 isoform and the GPCR estrogen receptor GPER1 and SKBR6 cells, negative for ERα66 [6,15], but positive for the other two receptors.