ESR1 and melanoma: C3G exerted a significant anti-proliferative effect on both melanoma cell lines at a concentration of 5 × 10−5 M. In a time course study, we observed the anti-proliferative activities of DPN, E2 (10−8 M), and C3G were completely counteracted by co-treatment of the cells with the ER antagonist ICI 182,780 (10−6 M) at 24 h (Figures 3B,C), and statistically significant results were obtained at 72 h (Figures 3B,C).