Transforming growth factor-beta1 and insulin growth factor-1 expression in ovarian endometriotic cysts: a preliminary study

Increased concentrations of TGF-beta1 in endometriotic tissue are considered important in the pathophysiology of endometrial diseases since TGF-beta1 may inhibit natural killer activity and induce angiogenesis and proliferation of endometrial stromal cells. In the present study we report on TGF-beta1, IGF-I and their receptor localization, as detected by Northern hybridization and immunohistochemistry, in ovarian endometriotic tissues removed during surgical procedures. We detected comparable expression of IGF-1 and IGF-1 receptor in the stromal and epithelial compartments, thus confirming disregulated expression of the IGF system in ovarian endometriosis. On the contrary, strongly increased TGF-beta1 steady state level mRNA expression was detected in all endometriotic samples. In addition, we demonstrated weak TGF-beta1 immunohistochemical expression in the epithelial lining and intense expression in the cellular stroma of ovarian endometriomas, thus suggesting that TGF-beta1 could have an important role in the maintenance and propagation of the disease. On the basis of these preliminary results we can assume that TGF-beta1, IGF-1 and their receptors may play an important role in the pathogenesis of endometriosis.