Division of the group of patients with endometriosis according to the concentration of CA-125 into ≤65 U/mL and >65 U/mL subgroups confirmed a statistically insignificant increase in the levels of expression of BMP7 and SMAD4 in the group of patients with a higher concentration of CA-125, while the expression levels of CDH1 and miR-542-3p were higher in the group of patients with CA-125 ≤ 65 U/mL. Here, SMAD4 is linked to endometriosis.