As SOX2 affected migration/invasion by downregulating matrix metalloproteinase-2 in colorectal cancer[15], we believe that its overexpression in ovarian endometriosis may be a potential mechanism that leads to the intrinsic differentiation of eutopic endometrial cells from that in normal endometria, and play an important role in the disease pathogenesis. The gene discussed is MMP2; the disease is ovarian endometriosis.