ESR1 and ovarian neoplasm: Considering that the down-regulation of ERα induced by an agonist has been considered an additional hallmark of receptor activation (Santagati et al. 1997), we further investigated whether atrazine could modulate ERα expression in BG-1 cells, which lack ERβ (data not shown), and express a receptor expression pattern similar to that found in primary ovarian tumors (Bardin et al. 2004; Geisinger et al. 1989).