E-CADHERIN EXPRESSION IN HUMAN EPITHELIAL OVARIAN-CANCER AND NORMAL OVARY

The ovarian surface epithelium (OSE) is the origin of the majority of human ovarian cancers. These adenocarcinomas are characterized by init ial local growth followed by spreading into the peritoneal cavity at l ater stages of tumor progression, The cell-adhesion molecule E-cadheri n (E-cad) plays an important role in maintaining tissue integrity, Dis appearance or impaired function of E-cad have often been associated wi th tumor formation and invasion in vivo and in vitro, The cell-specifi c expression of E-cad was investigated in normal human ovaries (n = 12 ), in benign (n = 5) and borderline (n = 4) ovarian epithelial tumors and in adenocarcinomas of different stages and histological grades (n = 18), by immunohistochemistry and immunoblotting, An ovarian cancer c ell line (NIH-OVCAR3) was used as a reference. The epithelial origin o f the cells was confirmed with cytokeratin (AE1/AE3) staining, In norm al ovaries, the expression of E-cad was limited to inclusion cysts or deep clefts lined with OSE, whereas no staining of the OSE could be de monstrated at the surface of the ovary, In contrast, benign and border line tumors uniformly expressed E-cad. This was observed in malignant tumors of all stages despite their degree of differentiation, E-cad wa s also present in metastasis from such tumors. The cell-specific expre ssion of E-cad in inclusion cysts of normal ovaries and in epithelial layers of borderline tumors indicates a role for E-cad in the early ev ents of the progression to a malignant phenotype. E-cad was not downre gulated in later stages of ovarian cancer progression. (C) 1997 Wiley- Liss, Inc.