SMAD4 and endometriosis: In the ectopic endometrium (ECE) samples collected from patients with endometriosis in the proliferative phase of the menstrual cycle, insignificant upward trends in the expression levels of SMAD4 and miR-542-3p and insignificant downward trends in the expression levels of BMP7 and CDH1 were observed compared to tissue samples from patients in the secretory phase.