ESR1 and adenomyosis: Polymorphisms of the ERα gene are associated with an increased risk of adenomyosis through increased receptor activity (Kitawaki et al., 2001; Oehler et al., 2004), and the expression levels of ERα and ERβ in the eutopic endometrium of women with adenomyosis have been found to be significantly higher compared to women without the condition (Sztachelska et al., 2022).