Immunocytochemical study of epidermal growth factor receptor, transforming growth factor alpha, and "squamous differentiation" in human endometrial carcinoma.

The expression of epidermal growth factor receptor (EGFr) and transforming growth factor alpha (TGF-alpha) was compared with the presence of "squamous differentiation" (SD) visualized in various histotypes of endometrial carcinoma by using a panel of monoclonal antibodies. The results of the current study demonstrate that EGFr and TGF-alpha are present in routinely processed endometrial carcinoma. The highest positive EGFr and TGF-alpha expression was seen in the group of adenocarcinomas with SD. The more intense EGFr and TGF-alpha immunoreactivity was observed in "squamous" foci both in adenoacanthomas (AA) and in adenosquamous carcinomas (AS). These EGFr- and TGF-alpha-positive squamous areas prevalently displayed a "stratification-related" cytokeratin (CK) immunoprofile characterized by the expression of CKs 1, 4, 5, 10, 13, 14, and 16. No correlation was found between EGFr- and TGF-alpha-positive status and depth of myometrial invasion or surgical stage. These results clearly demonstrate that EGFr and TGF-alpha expression is related remarkably to endometrial carcinoma with "squamous" areas both morphologically and immunophenotypically. This specific association leads us to suggest that EGFr and TGF-alpha expression in endometrial carcinoma may be prevalently involved in the equilibrium of cell differentiation of the "squamous" foci commonly observed in this group of neoplasias.