DOWN-REGULATED EXPRESSION OF TRANSFORMING-GROWTH-FACTOR-BETA-1 MESSENGER-RNA IN ENDOMETRIAL CARCINOMA

Transforming growth factor beta 1 (TGF-beta 1) is a potent modulator o f cell proliferation in vitro, and recent studies have demonstrated it s overexpression in several different tumours; nevertheless, the molec ular mechanisms of TGF-beta 1 action on cell growth and differentiatio n have not been fully elucidated. To clarify the role of TGF-beta and its receptor in human endometrial proliferation and differentiation, T GF-beta 1 expression at both the mRNA and protein levels has been eval uated by using Northern blotting and immunohistochemistry, in both nor mal (atrophic, proliferative and secretory) and neoplastic (adenocarci noma) endometrial samples. This study demonstrates that TGF-beta 1 mRN A expression is dramatically reduced in endometrial carcinomas with re spect to non-neoplastic tissues, whereas the immunohistochemical expre ssion of TGF-beta 1 is enhanced in the epithelial component of endomet rial carcinomas compared with non-neoplastic tissues. These data sugge st that TGF-beta 1 acts as a paracrine regulator of endometrial cell p roliferation and that it may contribute to the carcinogenic mechanisms of endometrial carcinoma.