ESR1 and cervical intraepithelial neoplasia: Since the cervical epithelium slowly loses its ERα expression in the course of carcinogenesis via the various stages of cervical intraepithelial neoplasia (CIN1–3) to invasive CxCa, estradiol (E2) likely initially acts via the classical genomic pathway, with decreasing ERα-Expression levels within the transformed cells possibly via the non-classical, non-genomic pathways.