ESR1 and lung cancer: Evidence for ER mediated non-genomic signaling in lung cancer has been reported in several in vitro studies which demonstrate that that membrane ERs are co-localized with EGFR and 17β-estradiol administration results in rapid phosphorylation of the MAPK pathway in lung cancer cell lines, thus indicating membrane signaling in NSCLC by ER [9,54,55,56].