Basement membrane in human endometrium: possible role of proteolytic enzymes in developing hyperplasia and carcinoma

Basement membranes (BM) are elements of the extracellular matrix that are essential for growth and differentiation of tissues. Several collagenolytic enzymes of tumor cells are involved in degradation of the extracellular matrix; growth and inhibitor factors [e.g. Epidermal Growth Factor (EGF), Transforming Growth Factors alpha and beta (TGF-alpha, beta)] seem to be involved in the extracellular matrix formation and degradation. To establish a possible association between the presence of collagenase (C), urokinase-type plasminogen activator (uPA) and the neoplastic growth of the endometrium, 44 endometrial specimens (14 proliferative, 11 secretive, 7 adenomatous hyperplasia, 12 adenocarcinoma) were studied using immunohistochemistry with antisera for C, uPA, EGF receptors and TGF-alpha. Immunostaining for collagenase revealed a positive reaction in moderately differentiated adeno-carcinoma without staining the normal and hyperplastic endometrium. A progressive increase in uPA immunostaining was observed in proliferative and neoplastic endometrium. TGF-alpha and its receptor (EGFr) were stained in proliferative and more clearly in hyperplastic and carcinomatous endometrium. In conclusion, BM play an important role in proliferation and differentiation of human endometrium; their degradation influences estrogen transportation from blood to the stroma. Endometrial BM degradation is associated with the presence of collagenolytic enzymes and growth factors.