ESR1 and adenomyosis: Konopka et al. (1998) also observed increased concentrations of nuclear ER (ERn) in adenomyosis lesions in the SP, as well as the PP and menstrual phases, although statistical significance was not explicitly stated, and the sample size was small. When the menstrual cycle phase was not considered, an increase in ER protein expression was noted in adenomyosis lesions compared to the eutopic endometrium (Zeng et al., 2017).