ESR2 and endometriosis: Furthermore, the estrobolome causes a hyperestrogenic pathologic status via a rise in the abundance of β-glucuronidase-producing bacteria, i.e., an increased Firmicutes/Bacteroidetes ratio, which boosts levels of free circulating estrogens and increases binding to ERα and ERβ, causing diseases such as endometrial cancer, breast cancer, endometriosis, and UFs to force disorders such as endometriosis and cancer (Plottel and Blaser, 2011; Dewi et al., 2012; Baker et al., 2017) (Figures 2A, B).