Our results showed that ERβ expression was significantly increased in endometriotic cells as well as ERβ target genes, including SOD2, NRF1, COX2, and MMP1, subsequently contributing to endometriosis (EMS) development (4, 5), while ERα expression was significantly decreased, and the ERβ:ERα ratio in endometriotic 12Z cells is increased to 38:1 compared to endometrial HEEC cells as calculated from data in Figure 1A, which is consistent with previous report (4, 5). The gene discussed is PTGS2; the disease is endometriosis.