To our knowledge, this is the first report that shows USF2 variants protein expression patterns in human normal and pathologic endometria during the menstrual cycle and its E2 stimulation mediated by ERα and GPER1 visualized by the response of cells obtained from control endometria, being unaffected the endogenously stimulated cells from endometriosis origin. The gene discussed is ESR1; the disease is endometriosis.